Search This Blog

Wednesday, November 2, 2022

Societal and cultural aspects of autism

Societal and cultural aspects of autism or sociology of autism come into play with recognition of autism, approaches to its support services and therapies, and how autism affects the definition of personhood. The autistic community is divided primarily into two camps; the neurodiversity movement and the Pathology paradigm. The pathology paradigm advocates for supporting research into therapies, treatments, and/or a cure to help minimize or remove autistic traits, seeing treatment as vital to help individuals with autism, while the neurodiversity movement believes autism should be seen as a different way of being and advocates against treatments, therapies or a cure, seeing it as trying to exterminate autistic people and their individuality. Both are controversial in autism communities and advocacy which has led to significant infighting between these two camps. While the dominant paradigm is the pathology paradigm and is followed largely by autism research and scientific communities, the neurodiversity movement is highly popular within autism advocacy and autism rights organizations.

There are many autism-related events and celebrations; including World Autism Awareness Day, Autism Sunday and Autistic Pride Day, and notable people have spoken about being autistic or are thought to be or have been autistic. Autism is diagnosed more frequently in males than in females.

Terminology

Although some prefer to use the person-first terminology person with autism, other members of the autistic community prefer identity-first terminology, such as autistic person or autistic in formal English, to stress that autism is a part of their identity rather than a disease they have. In addition, phrases like suffers from autism are objectionable to many people.

The autistic community has developed abbreviations for commonly used terms, such as:

  • Aspie – a person with Asperger syndrome.
  • Autie – an autistic person. It can be contrasted with aspie to refer to those specifically diagnosed with classic autism or another autism spectrum disorder.
  • Autistics and Cousins (AC) – a cover term including aspies, auties, and their "cousins", i.e. people with some autistic traits but no formal diagnosis.
  • Curebie – a person with the desire to cure autism. This term is highly derogatory.
  • Neurodiversity – tolerance of people regardless of neurological makeup.
  • Neurotypical (NT) – a person who does not have any developmental or neurological disorders. Often used to describe an individual who is not on the autism spectrum.
  • Allistic – a person who is not autistic but may or may not be neurodivergent in other ways, for example, a dyslexic person, or someone with ADHD. Originally and commonly, however, it is used satirically to describe those without autism.

Autism spectrum disorders; DSM-V; Diagnostic criteria-Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is the 2013 update to the American Psychiatric Association's (APA) classification and diagnostic tool. In the United States, the DSM serves as a universal authority for psychiatric diagnosis.

Overview

Autistic adults

Communication and social problems often cause difficulties in many areas of an autistic adult's life. A 2008 study found that adults with ASD commonly experience difficulty starting social interactions, a longing for greater intimacy, a profound sense of isolation, and effort to develop greater social or self-awareness.

A much smaller proportion of adult autistics marry than the general population. It has been hypothesized that autistic people are subject to assortative mating; they tend to pair with each other and raise autistic offspring. This hypothesis has been publicized in the popular press, but has not been empirically tested.

British psychologist Simon Baron-Cohen said that an increasingly technological society has opened up niches for people with Asperger syndrome, who may choose fields that are "highly systematised and predictable." People with AS could do well in workplace roles that are "system-centered, and connect with the nitty-gritty detail of the product or the system."

Autistic savants

An autistic savant is an autistic person with extreme talent in one or more areas of study. Although there is a common association between savant syndrome and autism (an association made popular by the 1988 film Rain Man), most autistic people are not savants and savantism is not unique to autistic people, though there does seem to be some relation. One in ten autistic people may have notable abilities, but prodigious savants like Stephen Wiltshire are very rare; only about 100 such people have been described/identified in the century since savants were first identified, and there are only about 25 living identified prodigious savants worldwide.

Gender aspects

Autistic women

Autism is thought of as a condition mostly affecting males, with males up to four times more likely than females to be diagnosed as autistic and among those with Asperger syndrome or "high-functioning autism", males are up to ten times more likely to be diagnosed. This may be due to the fact that many of the diagnostic tools used to diagnose autism have been crafted through the observation of males on the autism spectrum and are therefore more likely to identify men and boys with autism than their female counterparts. To date, the research and support surrounding autistic people has been male-centric, women and non-binary people are seriously underrepresented.

For many autistic females the lack of diagnosis or a late diagnosis results in them missing out on supports and interventions that are most valuable when implemented at a younger age. For those females who do receive a diagnosis and are provided with those supports, often have to face the many of them have been created with males in mind and may not acknowledge the physical, psychological and societal differences that females face.

Some autistic women find themselves misdiagnosed with personality disorders, such as borderline personality disorder, avoidant personality disorder and schizoid personality disorder. Autistic females are "research orphans" according to Yale's Ami Klin; some drugs used to treat anxiety or hyperactivity that may accompany autism are rarely tested on autistic females. Autism may express differently in the sexes, with many females on the spectrum presenting more subtly than males and may be more adept at developing more sophisticated social masking behaviours, as such females with more prominent difficulties are more likely to be diagnosed than those who present differently. Autistic females are more likely to develop a more sophisticated social camouflage for a variety of reasons. One theory as to why is that women as a whole face more complex social expectations than men, creating a greater need to "prepare more thoroughly for social situations, or risk ostracism".

Another theory suggests that women on the spectrum have a more inborn need for social interaction than their male counterparts, leading many women and girls to be more invested in creating social camouflage strategies. These strategies are developed in a variety of ways such as, observing and copying the social interactions of those around them as well as creating strategies to attempt to "go undetected". These coping mechanisms can take an immense amount of time and energy to learn and practice and can as Dr. Shana Nicols states "more often than not lead to exhaustion, withdrawal, anxiety, selective mutism and depression". Females may be more concerned with how they are viewed by peers and the failure to connect with people outside of their immediate family could lead to severe anxiety or clinical depression. Autistic girls who have "normal" intelligence may be more socially disadvantaged than males because of the "rising level of social interaction that comes in middle school," when girls' "friendships often hinge on attention to feelings and lots of rapid and nuanced communication."

Autistic girls may suffer additionally by being placed in specialized educational programs, where they will be surrounded by males and further isolated from female social contacts. Females on the autism spectrum often "internalize feelings of frustration and failure" and are believed to have higher rates of certain comorbidities such as anxiety and depression (36 and 34 percent respectively), due in large part to the desire for along with the difficulties in finding social inclusion along with other social and sensory challenges. Lack of diagnosis can also lead autistic females to have higher rates of depression, anxiety and self-esteem issues as they are left without a clear understanding as to why they do not "fit in" with their peers. Females on the spectrum also seem to have higher rates of eating disorders, such as anorexia, than other females. This may be related to social isolation and elevated levels of anxiety along with a need to control their environment more fully, although a complicating factor which is just being explored in the scientific literature is that functional disorders of eating and digestion such as IBS, GERD, food allergies, gastroparesis et al, as well as sensory issues common in autistic people generally, may contribute heavily to "disordered eating" behavior which is physical, sensory, allergic, or pain-related rather than psychological.

Although both males and females on the spectrum have a higher risk of experiencing bullying, these experiences often present differently based on gender. Although sample sizes are too small to draw firm conclusions, one study suggests that autistic women are less likely than males over the long term to marry, have families, go to college, have careers and live independently. An intense interest in specific topics plays a significant factor in the lives of those on the autism spectrum of both genders. Females on the spectrum may focus on different topics than their male counterparts; autistic females rarely have interests in numbers or have stores of specialized knowledge, the intense interests of autistic females can be overlooked as they are often seen to be more applicable to a broader section of society.

Both males and females with autism deal with the same core symptom, but when those symptoms are mixed with ideas of gender, they can offer very different lived experiences for females than their male counterparts. The profile of autism may change as more is understood about females, whose autism may go undiagnosed.

Gender identity and sexual orientation

In recent years, some people have suggested overlap between people with autism and a non-heterosexual identity (with autistic people more likely to be identified as gay, bisexual or asexual) as well as an overlap with a transgender identity. This issue has not been without controversy, as the issue is open to confusion; it is currently unclear whether this correlation exists due to any innate characteristic of autism that may also cause unusual discrepancies in sex or gender, or whether it is the result of exposing a group of people who experience difficulty in abiding by social norms, including those related to gender, to sexism and gender stereotypes.

Relationships with animals

Temple Grandin

Temple Grandin, autistic designer of cattle handling systems, said that one reason she can easily figure out how a cow would react is because autistic people can easily "think the way that animals think." According to Grandin, animals do not have "complex emotions such as shame or guilt" and they do not think in language. She says that, although not everything about animals is like an autistic person, the similarity is that they think visually and without language. She says people do not make this connection because the study of autism and the study of animal behavior are parallel disciplines involving different individuals. Despite these similarities, the degree to which autistic individuals can be said to think like animals remains undetermined; non-human animals, as well as humans, have evolved cognitive specializations that may or may not share characteristics with other species.

Dawn Prince-Hughes, diagnosed with Asperger's, describes her observations of gorillas in Songs of the Gorilla Nation.

Asperger syndrome and interpersonal relationships

Individuals with Asperger syndrome (AS) may develop problems in their abilities to engage successfully in interpersonal relationships.

Social impact

Asperger syndrome may lead to problems in social interaction with peers. These problems can be severe or mild depending on the individual. People with AS are often the target of bullying behavior. Children with AS are often the target of bullying at school due to their idiosyncratic behavior, precise language, unusual interests, and impaired ability to perceive and respond in socially expected ways to nonverbal cues, particularly in interpersonal conflict, which results in them being sought out by classmates and rejected. People with AS may be overly literal and may have difficulty interpreting and responding to sarcasm, banter, or metaphorical speech. Difficulties with social interaction may also manifest in a lack of play with other children.

The above problems can even arise in the family; given an unfavorable family environment, the child may be subject to emotional abuse. A child, teen, or adult with AS is often puzzled by this mistreatment, unaware of what has been done incorrectly. Unlike with other pervasive development disorders, most persons with AS want to be social, but fail to socialize successfully, which can lead to later withdrawal and asocial behavior, especially in adolescence. At this stage of life especially, they risk being drawn into unsuitable and inappropriate friendships and social groups. People with AS often interact better with those considerably older or younger than themselves, rather than those within their own age group.

Children with AS often display advanced abilities for their age in language, reading, mathematics, spatial skills, or music—sometimes into the "gifted" range—but this may be counterbalanced by considerable delays in other developmental areas, like verbal and nonverbal communication or some lack of motor coordination. This combination of traits can lead to problems with teachers and other authority figures. A child with AS might be regarded by teachers as a "problem child" or a "poor performer". The child's extremely low tolerance for what they perceive to be ordinary and mundane tasks, such as typical homework assignments, can easily become frustrating; a teacher may well consider the child arrogant, spiteful, and insubordinate. Lack of support and understanding, in combination with the child's anxieties, can result in problematic behavior (such as severe tantrums, violent and angry outbursts, and withdrawal).

Employment for those with AS may be difficult. The impaired social skills can be likely to interfere with the interview process—and people with often superior skills can be passed over due to these conflicts with interviewers. Once hired, people with AS may continue to have difficulty with interpersonal communications. Homelessness is very common among people with AS.

While some researchers have suggested that autistic individuals are less likely to self-enhance their reputation compared to those without autism, others argue that autistic individuals do not have less of a desire for self-enhancement than non-autistic individuals.

Difficulties in relationships

Two traits sometimes found in AS individuals are mind-blindness (the inability to predict the beliefs and intentions of others) and alexithymia (the inability to identify and interpret emotional signals in oneself or others), which reduce the ability to be empathetically attuned to others. Alexithymia in AS functions as an independent variable relying on different neural networks than those implicated in theory of mind (ToM). In fact, a lack of ToM in AS may be a result of a lack of information available to the mind due to the operation of the alexithymic deficit.

A second issue related to alexithymia involves the inability to identify and modulate strong emotions such as sadness or anger, which leaves the individual prone to "sudden affective outbursts such as crying or rage". According to Tony Attwood, the inability to express feelings using words may also predispose the individual to use physical acts to articulate the mood and release the emotional energy.

People with AS report a feeling of being detached against their will from the world around them ("on the outside looking in"). They may have difficulty finding a life partner or getting married due to poor social skills. The complexity and inconsistency of the social world can pose an extreme challenge for individuals with AS. In the UK Asperger's is covered by the Disability Discrimination Act; those with AS who get treated badly because of it may have some redress. The first case was Hewett v Motorola 2004 (sometimes referred to as Hewitt) and the second was Isles v Ealing Council. The same applies in the United States with the Americans with Disabilities Act, amended in 2008 to include autism spectrum disorders.

The intense focus and tendency to work things out logically often grants people with AS a high level of ability in their field of interest. When these special interests coincide with a materially or socially useful task, the person with AS can lead a profitable career and a fulfilled life. The child obsessed with a specific area may succeed in employment related to that area.

According to Elizabeth Fein, the dynamic of role-playing games is especially positive and attractive to people on the autism spectrum. The social information exchanged in these games are explicit, top-down and systematic and they follow a set of shared abstract rules. Baez and Rattazzi showed that interpreting the implicit social information of daily life is difficult for autistics.

Despite the fact that AS individuals are commonly known to lack ToM, recent research has suggested that ToM may be not only present in AS individuals but also act differently compared to neurotypicals as suggested in the double empathy problem. Autistic ToM is simply based on the use of rules and logic. It is also suggested that people on the autism spectrum can understand and predict the thoughts and motivations of each other better than neurotypicals can, and autistic interactions may display even greater social signals of shared enjoyment, ease, and rapport when interacting. This means AS individuals present mind-blindness and alexithymia towards neurotypicals and vice versa due to bidirectional differences in communication style as well as a reciprocal lack of understanding since the two neurotypes clash.

Autism rights movement

Autism rainbow infinity
The rainbow-colored infinity symbol represents the diversity of the autism spectrum as well as the greater neurodiversity movement. Opinions are divided on replacing jigsaw puzzle-piece based symbols to represent autism.
 

The autism rights movement is a social movement within the context of disability rights that emphasizes the concept of neurodiversity, viewing the autism spectrum as a result of natural variations in the human brain rather than a disorder to be cured. The ARM advocates a variety of goals, including greater acceptance of autistic behaviors; therapies that focus on coping skills rather than imitating the behaviors of neurotypical peers; the creation of social networks and events that allow autistic people to socialize on their own terms; and the recognition of the autistic community as a minority group.

Autism rights or neurodiversity advocates believe that the autism spectrum is genetic and should be accepted as a natural expression of the human genome. This perspective is distinct from two other likewise distinct views: the medical perspective, that autism is caused by a genetic defect and should be addressed by targeting the autism gene(s), and the fringe theory that autism is caused by environmental factors like vaccines and pollution and could be cured by addressing environmental causes.

The movement is controversial. There are a wide variety of both supportive and critical opinions about the movement among people who are autistic or associated with autistic people. A common criticism leveled against autistic activists is that the majority of them are "high-functioning" or have Asperger syndrome and do not represent the views of "low-functioning" autistic people.

Autistic pride

Autistic pride refers to pride in autism and shifting views of autism from "disease" to "difference." Autistic pride emphasizes the innate potential in all human phenotypic expressions and celebrates the diversity various neurological types express.

Autistic pride asserts that autistic people are not impaired or damaged; rather, they have a unique set of characteristics that provide them many rewards and challenges, not unlike their non-autistic peers.

Curing autism is a controversial and politicized issue. The "autistic community" can be divided into several groups. Some seek a cure for autism—sometimes dubbed as pro-cure—while others consider a cure unnecessary or unethical, or feel that autism conditions are not harmful or detrimental. For example, it may be seen as an evolutionary adaptation to an ecological niche by some environmentalists and the more radical autism rights campaigners.

Autistic culture and community

With the recent increases in autism recognition and new approaches to educating and socializing autistics, an autistic culture has begun to develop. Autistic culture is based on a belief that autism is a unique way of being and not a disorder to be cured. The Aspie world, as it is sometimes called, contains people with Asperger syndrome (AS) and high functioning autism (HFA), and can be linked to three historical trends: the emergence of AS and HFA as labels, the emergence of the disability rights movement, and the rise of the Internet. Autistic communities exist both online and offline; many people use these for support and communication with others like themselves, as the social limitations of autism sometimes make it difficult to make friends, to establish support within general society, and to construct an identity within society.

Because many autistics find it easier to communicate online than in person, a large number of online resources are available. Some autistic individuals learn sign language, participate in online chat rooms, discussion boards, and websites, or use communication devices at autism-community social events such as Autreat. The Internet helps bypass non-verbal cues and emotional sharing that some autistics tend to have difficulty with. It gives autistic individuals a way to communicate and form online communities.

Conducting work, conversation and interviews online in chat rooms, rather than via phone calls or personal contact, help level the playing field for many autistics. A New York Times article said "the impact of the Internet on autistics may one day be compared in magnitude to the spread of sign language among the deaf" because it opens new opportunities for communication by filtering out "sensory overload that impedes communication among autistics."

Globally

Autistic people may be perceived differently from country to country. For example, many Africans have spiritual beliefs about psychiatric disorders, which extends into perceived causes of autism. In one survey of Nigerian pediatric or psychiatric nurses, 40% cited preternatural causes of autism such as ancestral spirits or the action of the devil.

Events and public recognition

World Autism Day

Minnesota governor Mark Dayton declared the World Autism Awareness Day on 2 April 2013

World Autism Day, also called World Autism Awareness Day, is marked on 2 April. It was designated by the United Nations General Assembly at the end of 2007. On 2 April 2009, activists left 150 strollers near Central Park in New York City to raise awareness that one in 150 children is estimated to be autistic. There are many celebration activities all over the world on 2 April—World Autism Day. "Autism knows no geographic boundaries—it affects individuals and families on every continent and in every country," said Suzanne Wright, co-founder of the group Autism Speaks. "The celebration of World Autism Awareness Day is an important way to help the world better understand the scope of this health crisis and the need for compassion and acceptance for those living with autism. This remarkable day—the first of many to come—promises to be a time of great hope and happiness as we work to build a global autism community."

Light It Up Blue

In 2010, Autism Speaks launched the Light It Up Blue initiative. Light It Up Blue sees prominent buildings across the world—including the Empire State Building in New York City and the CN Tower in Toronto, Ontario, Canada—turn their lights blue to raise awareness for autism and to commemorate World Autism Awareness Day. However, the Autism Speaks group is not well received by most autism rights activists, due to their lack of incorporation of perspectives of actual autistic people in their work, and their focus on searching for a 'cure'.

Autism Sunday

Autism Sunday is a global Christian event, observed on the second Sunday of February. It is supported by church leaders and organisations around the world. The event started as a small idea in the front room of British autism campaigners, Ivan and Charika Corea. It is now a huge event celebrated in many countries. Autism Sunday was launched in London in 2002 with a historic service at St. Paul's Cathedral.

Autism Awareness Year

Autism awareness ribbon - not supported by many autistic people.

The year 2002 was declared Autism Awareness Year in the United Kingdom—this idea was initiated by Ivan and Charika Corea, parents of an autistic child, Charin. Autism Awareness Year was led by the British Institute of Brain Injured Children, Disabilities Trust, The Shirley Foundation, National Autistic Society, Autism London and 800 organizations in the United Kingdom. It had the personal backing of British Prime Minister Tony Blair. This was the first ever occasion of partnership working on autism on such a huge scale. 2002 Autism Awareness Year helped raise awareness of the serious issues concerning autism and Asperger's Syndrome across the United Kingdom. A major conference, Autism 2002 was held at the King's Fund in London with debates in the House of Commons and the House of Lords in Westminster. Autism awareness ribbons were worn to mark the year.

British autism advocates want autistic people acknowledged as a minority rather than as disabled, because they say that "disability discrimination laws don't protect those who are not disabled but who 'still have something that makes them look or act differently from other people.'" But the autism community is split over this issue, and some view this notion as radical.

Autistic Pride Day

Autistic Pride Day is an Aspies For Freedom initiative celebrated on 18 June each year. It is a day for celebrating the neurodiversity of autistic people. Modeled after gay pride events, they often compare their efforts to the civil rights and LGBT social movements.

Autistics Speaking Day

Autistics Speaking Day (ASDay), 1 November, is a self-advocacy campaign run by autistic people to raise awareness and challenge negative stereotypes about autism by speaking for themselves and sharing their stories. The first one was held in 2010. According to one of the founders, Corina Becker, the main goal of ASDay is "to acknowledge our difficulties while sharing our strengths, passions, and interests." The idea for the event developed out of opposition to a "Communication Shutdown" fundraising campaign led by Autism Speaks that year, which had asked for participants to "simulate" having autism by staying away from all forms of online communication for one day.

Autism Acceptance Project

In 2006 the Autism Acceptance Project was founded by Estée Klar, the mother of an autistic child, with help from an autistic advisory and board. The project's mission statement is, "The Autism Acceptance Project is dedicated to promoting acceptance of and accommodations for autistic people in society." The project is primarily supported by autistic people and their supporters. The goal is to create a positive perspective of autism and to accept autism as a part of life with its trials and tribulations. The project is also working to enable autistic people to gain the right to advocate for themselves (along with their supporters) in all policy decision formats from government to a general committee. By providing an abundance of resources, the project is able to reach a multitude of audiences using a Web site along with lectures and exhibitions.

Autism Acceptance Day

In 2011, the first Autism Acceptance Day celebrations were organized by Paula Durbin Westby, as a response to traditional "Autism Awareness" campaigns which the Autistic community found harmful and insufficient. Autism Acceptance Day is now held every April. "Awareness" focuses on informing others of the existence of autism while "acceptance" pushes towards validating and honoring the autism community. By providing tools and educational material, people are encouraged to embrace the challenges autistic people face and celebrate their strengths. Rather than making autism into a crippling disability, acceptance integrates those on the autistic spectrum into everyday society. Instead of encouraging people to wear blue as Autism Awareness Day does, Autism Acceptance Day encourages people to wear red.

Autreat

At Autreat—an annual autistic gathering—participants compared their movement to gay rights activists, or the Deaf culture, where sign language is preferred over surgery that might restore hearing. Other local organizations have also arisen: for example, a European counterpart, Autscape, was created around 2005.

Twainbow

Twainbow is an advocacy organization that provides awareness, education, and support for autistic people who identify as lesbian/gay/bisexual/transgender (LGBT). According to its founder, "Twainbow is a portmanteau of 'twain' (meaning 'two') and 'rainbow.' Those who are both LGBT and autistic live under two rainbows—the rainbow flag and the autism spectrum." The company also introduced an LGBT-autism Gay Pride flag representing the population.

History

Donald Triplett was the first person diagnosed with autism. He was diagnosed by Kanner after being first examined in 1938, and was labeled as "case 1". Triplett was noted for his savant abilities, particularly being able to name musical notes played on a piano and to mentally multiply numbers. His father, Oliver, described him as socially withdrawn but interested in number patterns, music notes, letters of the alphabet, and U.S. president pictures. By the age of two, he had the ability to recite the 23rd Psalm and memorized 25 questions and answers from the Presbyterian catechism. He was also interested in creating musical chords.

Scholarship

Autism spectrum disorders received increasing attention from social-science scholars in the early 2000s, with the goals of improving support services and therapies, arguing that autism should be tolerated as a difference not a disorder, and by how autism affects the definition of personhood and identity. Sociological research has also investigated how social institutions, particularly families, cope with the challenges associated with autism.

Media portrayals

Much of the public perception of autism is based on its portrayals in biographies, movies, novels, and TV series. Many of these portrayals have been inaccurate, and have contributed to a divergence between public perception and the clinical reality of autism. For example, in the movie Mozart and the Whale (2005), the opening scene gives four clues that a leading character has Asperger syndrome, and two of these clues are extraordinary savant skills. The savant skills are not needed in the film, but in the movies savant skills have become a stereotype for the autism spectrum, because of the incorrect assertion that most autistic people are savants.

Some works from the 1970s have autistic characters, who are rarely labeled. In contrast, in the BBC2 television miniseries The Politician's Husband (2013), the impact of Noah Hoynes' Aspergers on the boy's behavior and on his family, and steps Noah's loved ones take to accommodate and address it, are prominent plot points in all three episodes.

Popular media have depicted special talents of some autistic people, including exceptional abilities as seen in the 1988 movie Rain Man. Such portrayals have been criticized by both scientific studies and media analysts over the years for fostering a pigeonholing image of autism that leads to false expectations about real-life autistic individuals, with Rain Man being singled out for popularizing it.

Since the 1970s, fictional portrayals of autistic people, Asperger syndrome, and other ASCs have become more frequent. Public perception of autism is often based on these fictional portrayals in novels, biographies, movies, and TV series. These depictions of autism in media today are often made in a way that brings pity to the public and their concern of the topic, because their viewpoint is never actually shown, leaving the public without knowledge of autism and its diagnosis. Portrayals in the media of characters with atypical abilities (for example, the ability to multiply large numbers without a calculator) may be misinterpreted by viewers as accurate portrayals of all autistic people and of autism itself. Additionally, the media frequently depicts autism as only affecting children, which promotes the misconception that autism does not affect adults.

Notable individuals

Some notable figures like American food animal handling systems designer and author Temple Grandin, American Pulitzer Prize-winning music critic and author Tim Page, Australian musician, lead singer and only constant member of rock band the Vines Craig Nicholls, English actor and filmmaker Paddy Considine and Swedish environmental activist Greta Thunberg are autistic.

Thunberg, who in August 2018 started the "School strike for climate" movement, has explained how the "gift" of living with Asperger syndrome helps her "see things from outside the box" when it comes to climate change. In an interview with presenter Nick Robinson on BBC Radio 4's Today, the then-16-year-old activist said that autism helps her see things in "black and white". She went on to say:

It makes me different, and being different is a gift, I would say. It also makes me see things from outside the box. I don't easily fall for lies, I can see through things. I don't think I would be interested in the climate at all, if I had been like everyone else. Many people say that it doesn't matter, you can cheat sometimes. But I can't do that. You can't be a little bit sustainable. Either you're sustainable, or not sustainable. For way too long the politicians and people in power have got away with not doing anything at all to fight the climate crisis and ecological crisis, but we will make sure that they will not get away with it any longer.

Scottish singer Susan Boyle was diagnosed with Aspergers at the age of 51. Boyle was originally believed to have had slight brain damage at birth. Boyle rose to fame after appearing on the talent show Britain's Got Talent in 2009. Her debut album I Dreamed a Dream, released in 2009, became the fastest selling debut by a UK artist of all time. American actress Daryl Hannah, star of movies such as Splash, Steel Magnolias and Wall Street, was diagnosed as being on the autism spectrum as a child. Diagnosed at fifteen, Heather Kuzmich appeared on America's Next Top Model in 2007. Although she did not win the competition, Kuzmich was voted the viewers' favourite eight weeks in a row. She has since been signed to Elite Model Management. New Zealand-born musician Ladyhawke and gold medal-winning British Paralympic swimmer Jessica-Jane Applegate are also autistic. In June 2021, autistic Scottish strongman Tom Stoltman won the World's Strongest Man competition. Welsh actor Anthony Hopkins is the first openly autistic actor to win an Academy Award.

Additionally, media speculation of contemporary figures as being on the autism spectrum has become popular in recent times. New York magazine reported some examples, which included that Time magazine suggested that Bill Gates is autistic, and that a biographer of Warren Buffett wrote that his prodigious memory and "fascination with numbers" give him "a vaguely autistic aura." The magazine also reported that on Celebrity Rehab, Dr. Drew Pinsky deemed basketball player Dennis Rodman a candidate for an Asperger's diagnosis, and the UCLA specialist consulted "seemed to concur". Nora Ephron criticized these conclusions, writing that popular speculative diagnoses suggest autism is "an epidemic, or else a wildly over-diagnosed thing that there used to be other words for." The practice of diagnosing autism in these cases is controversial.

Some historical personalities are also the subject of speculation about being autistic, e.g. Michelangelo.

3D scanning

From Wikipedia, the free encyclopedia
 
Making a 3D-model of a Viking belt buckle using a hand held VIUscan 3D laser scanner.

3D scanning is the process of analyzing a real-world object or environment to collect data on its shape and possibly its appearance (e.g. color). The collected data can then be used to construct digital 3D models.

A 3D scanner can be based on many different technologies, each with its own limitations, advantages and costs. Many limitations in the kind of objects that can be digitised are still present. For example, optical technology may encounter many difficulties with dark, shiny, reflective or transparent objects. For example, industrial computed tomography scanning, structured-light 3D scanners, LiDAR and Time Of Flight 3D Scanners can be used to construct digital 3D models, without destructive testing.

Collected 3D data is useful for a wide variety of applications. These devices are used extensively by the entertainment industry in the production of movies and video games, including virtual reality. Other common applications of this technology include augmented reality, motion capture, gesture recognition, robotic mapping, industrial design, orthotics and prosthetics, reverse engineering and prototyping, quality control/inspection and the digitization of cultural artifacts.

Functionality

The purpose of a 3D scanner is usually to create a 3D model. This 3D model consists of a polygon mesh or point cloud of geometric samples on the surface of the subject. These points can then be used to extrapolate the shape of the subject (a process called reconstruction). If colour information is collected at each point, then the colours or textures on the surface of the subject can also be determined.

3D scanners share several traits with cameras. Like most cameras, they have a cone-like field of view, and like cameras, they can only collect information about surfaces that are not obscured. While a camera collects colour information about surfaces within its field of view, a 3D scanner collects distance information about surfaces within its field of view. The "picture" produced by a 3D scanner describes the distance to a surface at each point in the picture. This allows the three dimensional position of each point in the picture to be identified.

In some situations, a single scan will not produce a complete model of the subject. Multiple scans, from different directions are usually helpful to obtain information about all sides of the subject. These scans have to be brought into a common reference system, a process that is usually called alignment or registration, and then merged to create a complete 3D model. This whole process, going from the single range map to the whole model, is usually known as the 3D scanning pipeline.

Technology

There are a variety of technologies for digitally acquiring the shape of a 3D object. The techniques work with most or all sensor types including optical, acoustic, laser scanning, radar, thermal, and seismic. A well established classification divides them into two types: contact and non-contact. Non-contact solutions can be further divided into two main categories, active and passive. There are a variety of technologies that fall under each of these categories.

Contact

A Coordinate Measuring Machine (CMM) with scanning head.
 
3D scanning of a fin whale skeleton in the Natural History Museum of Slovenia (August 2013)

Contact 3D scanners work by physically probing (touching) the part and recording the position of the sensor as the probe moves around the part.

There are two main types of contact 3D scanners:

  • Coordinate measuring machines (CMMs) which traditionally have 3 perpendicular moving axis with a touch probe mounted on the Z axis. As the touch probe moves around the part, sensors on each axis record the position to generate XYZ coordinates. Modern CMMs are 5 axis systems, with the two extra axes provided by pivoting sensor heads. CMMs are the most accurate form of 3D measurement achieving micron precision. The greatest advantage of a CMM after accuracy is that it can be run in autonomous (CNC) mode or as a manual probing system. The disadvantage of CMMs is that their upfront cost and the technical knowledge required to operate them.
  • Articulated Arms which generally have multiple segments with polar sensors on each joint. As per the CMM, as the articulated arm moves around the part sensors record their position and the location of the end of the arm is calculated using complex math and the wrist rotation angle and hinge angle of each joint. While not usually as accurate as CMMs, articulated arms still achieve high accuracy and are cheaper and slightly easier to use. They do not usually have CNC options.

Both modern CMMs and Articulated Arms can also be fitted with non-contact laser scanners instead of touch probes.

Non-contact active

Active scanners emit some kind of radiation or light and detect its reflection or radiation passing through object in order to probe an object or environment. Possible types of emissions used include light, ultrasound or x-ray.

Time-of-flight

This lidar scanner may be used to scan buildings, rock formations, etc., to produce a 3D model. The lidar can aim its laser beam in a wide range: its head rotates horizontally, a mirror flips vertically. The laser beam is used to measure the distance to the first object on its path.

The time-of-flight 3D laser scanner is an active scanner that uses laser light to probe the subject. At the heart of this type of scanner is a time-of-flight laser range finder. The laser range finder finds the distance of a surface by timing the round-trip time of a pulse of light. A laser is used to emit a pulse of light and the amount of time before the reflected light is seen by a detector is measured. Since the speed of light is known, the round-trip time determines the travel distance of the light, which is twice the distance between the scanner and the surface. If is the round-trip time, then distance is equal to . The accuracy of a time-of-flight 3D laser scanner depends on how precisely we can measure the time: 3.3 picoseconds (approx.) is the time taken for light to travel 1 millimetre.

The laser range finder only detects the distance of one point in its direction of view. Thus, the scanner scans its entire field of view one point at a time by changing the range finder's direction of view to scan different points. The view direction of the laser range finder can be changed either by rotating the range finder itself, or by using a system of rotating mirrors. The latter method is commonly used because mirrors are much lighter and can thus be rotated much faster and with greater accuracy. Typical time-of-flight 3D laser scanners can measure the distance of 10,000~100,000 points every second.

Time-of-flight devices are also available in a 2D configuration. This is referred to as a time-of-flight camera.

Triangulation

Principle of a laser triangulation sensor. Two object positions are shown.

Triangulation based 3D laser scanners are also active scanners that use laser light to probe the environment. With respect to time-of-flight 3D laser scanner the triangulation laser shines a laser on the subject and exploits a camera to look for the location of the laser dot. Depending on how far away the laser strikes a surface, the laser dot appears at different places in the camera's field of view. This technique is called triangulation because the laser dot, the camera and the laser emitter form a triangle. The length of one side of the triangle, the distance between the camera and the laser emitter is known. The angle of the laser emitter corner is also known. The angle of the camera corner can be determined by looking at the location of the laser dot in the camera's field of view. These three pieces of information fully determine the shape and size of the triangle and give the location of the laser dot corner of the triangle. In most cases a laser stripe, instead of a single laser dot, is swept across the object to speed up the acquisition process. The National Research Council of Canada was among the first institutes to develop the triangulation based laser scanning technology in 1978.

Strengths and weaknesses

Time-of-flight and triangulation range finders each have strengths and weaknesses that make them suitable for different situations. The advantage of time-of-flight range finders is that they are capable of operating over very long distances, on the order of kilometres. These scanners are thus suitable for scanning large structures like buildings or geographic features. The disadvantage of time-of-flight range finders is their accuracy. Due to the high speed of light, timing the round-trip time is difficult and the accuracy of the distance measurement is relatively low, on the order of millimetres.

Triangulation range finders are exactly the opposite. They have a limited range of some meters, but their accuracy is relatively high. The accuracy of triangulation range finders is on the order of tens of micrometers.

Time-of-flight scanners' accuracy can be lost when the laser hits the edge of an object because the information that is sent back to the scanner is from two different locations for one laser pulse. The coordinate relative to the scanner's position for a point that has hit the edge of an object will be calculated based on an average and therefore will put the point in the wrong place. When using a high resolution scan on an object the chances of the beam hitting an edge are increased and the resulting data will show noise just behind the edges of the object. Scanners with a smaller beam width will help to solve this problem but will be limited by range as the beam width will increase over distance. Software can also help by determining that the first object to be hit by the laser beam should cancel out the second.

At a rate of 10,000 sample points per second, low resolution scans can take less than a second, but high resolution scans, requiring millions of samples, can take minutes for some time-of-flight scanners. The problem this creates is distortion from motion. Since each point is sampled at a different time, any motion in the subject or the scanner will distort the collected data. Thus, it is usually necessary to mount both the subject and the scanner on stable platforms and minimise vibration. Using these scanners to scan objects in motion is very difficult.

Recently, there has been research on compensating for distortion from small amounts of vibration and distortions due to motion and/or rotation.

Short-range laser scanners can't usually encompass a depth of field more than 1 meter. When scanning in one position for any length of time slight movement can occur in the scanner position due to changes in temperature. If the scanner is set on a tripod and there is strong sunlight on one side of the scanner then that side of the tripod will expand and slowly distort the scan data from one side to another. Some laser scanners have level compensators built into them to counteract any movement of the scanner during the scan process.

Conoscopic holography

In a conoscopic system, a laser beam is projected onto the surface and then the immediate reflection along the same ray-path are put through a conoscopic crystal and projected onto a CCD. The result is a diffraction pattern, that can be frequency analyzed to determine the distance to the measured surface. The main advantage with conoscopic holography is that only a single ray-path is needed for measuring, thus giving an opportunity to measure for instance the depth of a finely drilled hole.

Hand-held laser scanners

Hand-held laser scanners create a 3D image through the triangulation mechanism described above: a laser dot or line is projected onto an object from a hand-held device and a sensor (typically a charge-coupled device or position sensitive device) measures the distance to the surface. Data is collected in relation to an internal coordinate system and therefore to collect data where the scanner is in motion the position of the scanner must be determined. The position can be determined by the scanner using reference features on the surface being scanned (typically adhesive reflective tabs, but natural features have been also used in research work) or by using an external tracking method. External tracking often takes the form of a laser tracker (to provide the sensor position) with integrated camera (to determine the orientation of the scanner) or a photogrammetric solution using 3 or more cameras providing the complete six degrees of freedom of the scanner. Both techniques tend to use infrared light-emitting diodes attached to the scanner which are seen by the camera(s) through filters providing resilience to ambient lighting.

Data is collected by a computer and recorded as data points within three-dimensional space, with processing this can be converted into a triangulated mesh and then a computer-aided design model, often as non-uniform rational B-spline surfaces. Hand-held laser scanners can combine this data with passive, visible-light sensors — which capture surface textures and colors — to build (or "reverse engineer") a full 3D model.

Structured light

Structured-light 3D scanners project a pattern of light on the subject and look at the deformation of the pattern on the subject. The pattern is projected onto the subject using either an LCD projector or other stable light source. A camera, offset slightly from the pattern projector, looks at the shape of the pattern and calculates the distance of every point in the field of view.

Structured-light scanning is still a very active area of research with many research papers published each year. Perfect maps have also been proven useful as structured light patterns that solve the correspondence problem and allow for error detection and error correction. (See Morano, R., et al. "Structured Light Using Pseudorandom Codes," IEEE Transactions on Pattern Analysis and Machine Intelligence.)

The advantage of structured-light 3D scanners is speed and precision. Instead of scanning one point at a time, structured light scanners scan multiple points or the entire field of view at once. Scanning an entire field of view in a fraction of a second reduces or eliminates the problem of distortion from motion. Some existing systems are capable of scanning moving objects in real-time.

A real-time scanner using digital fringe projection and phase-shifting technique (certain kinds of structured light methods) was developed, to capture, reconstruct, and render high-density details of dynamically deformable objects (such as facial expressions) at 40 frames per second. Recently, another scanner has been developed. Different patterns can be applied to this system, and the frame rate for capturing and data processing achieves 120 frames per second. It can also scan isolated surfaces, for example two moving hands. By utilising the binary defocusing technique, speed breakthroughs have been made that could reach hundreds  to thousands of frames per second.

Modulated light

Modulated light 3D scanners shine a continually changing light at the subject. Usually the light source simply cycles its amplitude in a sinusoidal pattern. A camera detects the reflected light and the amount the pattern is shifted by determines the distance the light travelled. Modulated light also allows the scanner to ignore light from sources other than a laser, so there is no interference.

Volumetric techniques

Medical

Computed tomography (CT) is a medical imaging method which generates a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images, similarly magnetic resonance imaging is another medical imaging technique that provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. These techniques produce a discrete 3D volumetric representation that can be directly visualised, manipulated or converted to traditional 3D surface by mean of isosurface extraction algorithms.

Industrial

Although most common in medicine, industrial computed tomography, microtomography and MRI are also used in other fields for acquiring a digital representation of an object and its interior, such as non destructive materials testing, reverse engineering, or studying biological and paleontological specimens.

Non-contact passive

Passive 3D imaging solutions do not emit any kind of radiation themselves, but instead rely on detecting reflected ambient radiation. Most solutions of this type detect visible light because it is a readily available ambient radiation. Other types of radiation, such as infrared could also be used. Passive methods can be very cheap, because in most cases they do not need particular hardware but simple digital cameras.

  • Stereoscopic systems usually employ two video cameras, slightly apart, looking at the same scene. By analysing the slight differences between the images seen by each camera, it is possible to determine the distance at each point in the images. This method is based on the same principles driving human stereoscopic vision.
  • Photometric systems usually use a single camera, but take multiple images under varying lighting conditions. These techniques attempt to invert the image formation model in order to recover the surface orientation at each pixel.
  • Silhouette techniques use outlines created from a sequence of photographs around a three-dimensional object against a well contrasted background. These silhouettes are extruded and intersected to form the visual hull approximation of the object. With these approaches some concavities of an object (like the interior of a bowl) cannot be detected.

Photogrammetric non-contact passive methods

Images taken from multiple perspectives such as a fixed camera array can be taken of a subject for a photogrammetric reconstruction pipeline to generate a 3D mesh or point cloud.

Photogrammetry provides reliable information about 3D shapes of physical objects based on analysis of photographic images. The resulting 3D data is typically provided as a 3D point cloud, 3D mesh or 3D points. Modern photogrammetry software applications automatically analyze a large number of digital images for 3D reconstruction, however manual interaction may be required if the software cannot automatically determine the 3D positions of the camera in the images which is an essential step in the reconstruction pipeline. Various software packages are available including PhotoModeler, Geodetic Systems, Autodesk ReCap, RealityCapture and Agisoft Metashape (see comparison of photogrammetry software).

  • Close range photogrammetry typically uses a handheld camera such as a DSLR with a fixed focal length lens to capture images of objects for 3D reconstruction. Subjects include smaller objects such as a building facade, vehicles, sculptures, rocks, and shoes.
  • Camera Arrays can be used to generate 3D point clouds or meshes of live objects such as people or pets by synchronizing multiple cameras to photograph a subject from multiple perspectives at the same time for 3D object reconstruction.
  • Wide angle photogrammetry can be used to capture the interior of buildings or enclosed spaces using a wide angle lens camera such as a 360 camera.
  • Aerial photogrammetry uses aerial images acquired by satellite, commercial aircraft or UAV drone to collect images of buildings, structures and terrain for 3D reconstruction into a point cloud or mesh.

Acquisition from acquired sensor data

Semi-automatic building extraction from lidar data and high-resolution images is also a possibility. Again, this approach allows modelling without physically moving towards the location or object. From airborne lidar data, digital surface model (DSM) can be generated and then the objects higher than the ground are automatically detected from the DSM. Based on general knowledge about buildings, geometric characteristics such as size, height and shape information are then used to separate the buildings from other objects. The extracted building outlines are then simplified using an orthogonal algorithm to obtain better cartographic quality. Watershed analysis can be conducted to extract the ridgelines of building roofs. The ridgelines as well as slope information are used to classify the buildings per type. The buildings are then reconstructed using three parametric building models (flat, gabled, hipped).

Acquisition from on-site sensors

Lidar and other terrestrial laser scanning technology offers the fastest, automated way to collect height or distance information. lidar or laser for height measurement of buildings is becoming very promising. Commercial applications of both airborne lidar and ground laser scanning technology have proven to be fast and accurate methods for building height extraction. The building extraction task is needed to determine building locations, ground elevation, orientations, building size, rooftop heights, etc. Most buildings are described to sufficient details in terms of general polyhedra, i.e., their boundaries can be represented by a set of planar surfaces and straight lines. Further processing such as expressing building footprints as polygons is used for data storing in GIS databases.

Using laser scans and images taken from ground level and a bird's-eye perspective, Fruh and Zakhor present an approach to automatically create textured 3D city models. This approach involves registering and merging the detailed facade models with a complementary airborne model. The airborne modeling process generates a half-meter resolution model with a bird's-eye view of the entire area, containing terrain profile and building tops. Ground-based modeling process results in a detailed model of the building facades. Using the DSM obtained from airborne laser scans, they localize the acquisition vehicle and register the ground-based facades to the airborne model by means of Monte Carlo localization (MCL). Finally, the two models are merged with different resolutions to obtain a 3D model.

Using an airborne laser altimeter, Haala, Brenner and Anders combined height data with the existing ground plans of buildings. The ground plans of buildings had already been acquired either in analog form by maps and plans or digitally in a 2D GIS. The project was done in order to enable an automatic data capture by the integration of these different types of information. Afterwards virtual reality city models are generated in the project by texture processing, e.g. by mapping of terrestrial images. The project demonstrated the feasibility of rapid acquisition of 3D urban GIS. Ground plans proved are another very important source of information for 3D building reconstruction. Compared to results of automatic procedures, these ground plans proved more reliable since they contain aggregated information which has been made explicit by human interpretation. For this reason, ground plans, can considerably reduce costs in a reconstruction project. An example of existing ground plan data usable in building reconstruction is the Digital Cadastral map, which provides information on the distribution of property, including the borders of all agricultural areas and the ground plans of existing buildings. Additionally information as street names and the usage of buildings (e.g. garage, residential building, office block, industrial building, church) is provided in the form of text symbols. At the moment the Digital Cadastral map is built up as a database covering an area, mainly composed by digitizing preexisting maps or plans.

Cost

  • Terrestrial laser scan devices (pulse or phase devices) + processing software generally start at a price of €150,000. Some less precise devices (as the Trimble VX) cost around €75,000.
  • Terrestrial lidar systems cost around €300,000.
  • Systems using regular still cameras mounted on RC helicopters (Photogrammetry) are also possible, and cost around €25,000. Systems that use still cameras with balloons are even cheaper (around €2,500), but require additional manual processing. As the manual processing takes around 1 month of labor for every day of taking pictures, this is still an expensive solution in the long run.
  • Obtaining satellite images is also an expensive endeavor. High resolution stereo images (0.5 m resolution) cost around €11,000. Image satellites include Quikbird, Ikonos. High resolution monoscopic images cost around €5,500. Somewhat lower resolution images (e.g. from the CORONA satellite; with a 2 m resolution) cost around €1,000 per 2 images. Note that Google Earth images are too low in resolution to make an accurate 3D model.

Reconstruction

From point clouds

The point clouds produced by 3D scanners and 3D imaging can be used directly for measurement and visualisation in the architecture and construction world.

From models

Most applications, however, use instead polygonal 3D models, NURBS surface models, or editable feature-based CAD models (aka solid models).

  • Polygon mesh models: In a polygonal representation of a shape, a curved surface is modeled as many small faceted flat surfaces (think of a sphere modeled as a disco ball). Polygon models—also called Mesh models, are useful for visualisation, for some CAM (i.e., machining), but are generally "heavy" ( i.e., very large data sets), and are relatively un-editable in this form. Reconstruction to polygonal model involves finding and connecting adjacent points with straight lines in order to create a continuous surface. Many applications, both free and nonfree, are available for this purpose (e.g. GigaMesh, MeshLab, PointCab, kubit PointCloud for AutoCAD, Reconstructor, imagemodel, PolyWorks, Rapidform, Geomagic, Imageware, Rhino 3D etc.).
  • Surface models: The next level of sophistication in modeling involves using a quilt of curved surface patches to model the shape. These might be NURBS, TSplines or other curved representations of curved topology. Using NURBS, the spherical shape becomes a true mathematical sphere. Some applications offer patch layout by hand but the best in class offer both automated patch layout and manual layout. These patches have the advantage of being lighter and more manipulable when exported to CAD. Surface models are somewhat editable, but only in a sculptural sense of pushing and pulling to deform the surface. This representation lends itself well to modelling organic and artistic shapes. Providers of surface modellers include Rapidform, Geomagic, Rhino 3D, Maya, T Splines etc.
  • Solid CAD models: From an engineering/manufacturing perspective, the ultimate representation of a digitised shape is the editable, parametric CAD model. In CAD, the sphere is described by parametric features which are easily edited by changing a value (e.g., centre point and radius).

These CAD models describe not simply the envelope or shape of the object, but CAD models also embody the "design intent" (i.e., critical features and their relationship to other features). An example of design intent not evident in the shape alone might be a brake drum's lug bolts, which must be concentric with the hole in the centre of the drum. This knowledge would drive the sequence and method of creating the CAD model; a designer with an awareness of this relationship would not design the lug bolts referenced to the outside diameter, but instead, to the center. A modeler creating a CAD model will want to include both Shape and design intent in the complete CAD model.

Vendors offer different approaches to getting to the parametric CAD model. Some export the NURBS surfaces and leave it to the CAD designer to complete the model in CAD (e.g., Geomagic, Imageware, Rhino 3D). Others use the scan data to create an editable and verifiable feature based model that is imported into CAD with full feature tree intact, yielding a complete, native CAD model, capturing both shape and design intent (e.g. Geomagic, Rapidform). For instance, the market offers various plug-ins for established CAD-programs, such as SolidWorks. Xtract3D, DezignWorks and Geomagic for SolidWorks allow manipulating a 3D scan directly inside SolidWorks. Still other CAD applications are robust enough to manipulate limited points or polygon models within the CAD environment (e.g., CATIA, AutoCAD, Revit).

From a set of 2D slices

3D reconstruction of the brain and eyeballs from CT scanned DICOM images. In this image, areas with the density of bone or air were made transparent, and the slices stacked up in an approximate free-space alignment. The outer ring of material around the brain are the soft tissues of skin and muscle on the outside of the skull. A black box encloses the slices to provide the black background. Since these are simply 2D images stacked up, when viewed on edge the slices disappear since they have effectively zero thickness. Each DICOM scan represents about 5 mm of material averaged into a thin slice.

CT, industrial CT, MRI, or micro-CT scanners do not produce point clouds but a set of 2D slices (each termed a "tomogram") which are then 'stacked together' to produce a 3D representation. There are several ways to do this depending on the output required:

  • Volume rendering: Different parts of an object usually have different threshold values or greyscale densities. From this, a 3-dimensional model can be constructed and displayed on screen. Multiple models can be constructed from various thresholds, allowing different colours to represent each component of the object. Volume rendering is usually only used for visualisation of the scanned object.
  • Image segmentation: Where different structures have similar threshold/greyscale values, it can become impossible to separate them simply by adjusting volume rendering parameters. The solution is called segmentation, a manual or automatic procedure that can remove the unwanted structures from the image. Image segmentation software usually allows export of the segmented structures in CAD or STL format for further manipulation.
  • Image-based meshing: When using 3D image data for computational analysis (e.g. CFD and FEA), simply segmenting the data and meshing from CAD can become time-consuming, and virtually intractable for the complex topologies typical of image data. The solution is called image-based meshing, an automated process of generating an accurate and realistic geometrical description of the scan data.

From laser scans

Laser scanning describes the general method to sample or scan a surface using laser technology. Several areas of application exist that mainly differ in the power of the lasers that are used, and in the results of the scanning process. Low laser power is used when the scanned surface doesn't have to be influenced, e.g. when it only has to be digitised. Confocal or 3D laser scanning are methods to get information about the scanned surface. Another low-power application uses structured light projection systems for solar cell flatness metrology, enabling stress calculation throughout in excess of 2000 wafers per hour.

The laser power used for laser scanning equipment in industrial applications is typically less than 1W. The power level is usually on the order of 200 mW or less but sometimes more.

From photographs

3D data acquisition and object reconstruction can be performed using stereo image pairs. Stereo photogrammetry or photogrammetry based on a block of overlapped images is the primary approach for 3D mapping and object reconstruction using 2D images. Close-range photogrammetry has also matured to the level where cameras or digital cameras can be used to capture the close-look images of objects, e.g., buildings, and reconstruct them using the very same theory as the aerial photogrammetry. An example of software which could do this is Vexcel FotoG 5. This software has now been replaced by Vexcel GeoSynth. Another similar software program is Microsoft Photosynth.

A semi-automatic method for acquiring 3D topologically structured data from 2D aerial stereo images has been presented by Sisi Zlatanova. The process involves the manual digitizing of a number of points necessary for automatically reconstructing the 3D objects. Each reconstructed object is validated by superimposition of its wire frame graphics in the stereo model. The topologically structured 3D data is stored in a database and are also used for visualization of the objects. Notable software used for 3D data acquisition using 2D images include e.g. Agisoft Metashape, RealityCapture, and ENSAIS Engineering College TIPHON (Traitement d'Image et PHOtogrammétrie Numérique).

A method for semi-automatic building extraction together with a concept for storing building models alongside terrain and other topographic data in a topographical information system has been developed by Franz Rottensteiner. His approach was based on the integration of building parameter estimations into the photogrammetry process applying a hybrid modeling scheme. Buildings are decomposed into a set of simple primitives that are reconstructed individually and are then combined by Boolean operators. The internal data structure of both the primitives and the compound building models are based on the boundary representation methods

Multiple images are used in Zeng's approach to surface reconstruction from multiple images. A central idea is to explore the integration of both 3D stereo data and 2D calibrated images. This approach is motivated by the fact that only robust and accurate feature points that survived the geometry scrutiny of multiple images are reconstructed in space. The density insufficiency and the inevitable holes in the stereo data should then be filled in by using information from multiple images. The idea is thus to first construct small surface patches from stereo points, then to progressively propagate only reliable patches in their neighborhood from images into the whole surface using a best-first strategy. The problem thus reduces to searching for an optimal local surface patch going through a given set of stereo points from images.

Multi-spectral images are also used for 3D building detection. The first and last pulse data and the normalized difference vegetation index are used in the process.

New measurement techniques are also employed to obtain measurements of and between objects from single images by using the projection, or the shadow as well as their combination. This technology is gaining attention given its fast processing time, and far lower cost than stereo measurements.

Applications

Space experiments

3D scanning technology has been used to scan space rocks for the European Space Agency.

Construction industry and civil engineering

  • Robotic control: e.g. a laser scanner may function as the "eye" of a robot.
  • As-built drawings of bridges, industrial plants, and monuments
  • Documentation of historical sites
  • Site modelling and lay outing
  • Quality control
  • Quantity surveys
  • Payload monitoring 
  • Freeway redesign
  • Establishing a bench mark of pre-existing shape/state in order to detect structural changes resulting from exposure to extreme loadings such as earthquake, vessel/truck impact or fire.
  • Create GIS (geographic information system) maps and geomatics.
  • Subsurface laser scanning in mines and karst voids.
  • Forensic documentation

Design process

  • Increasing accuracy working with complex parts and shapes,
  • Coordinating product design using parts from multiple sources,
  • Updating old CD scans with those from more current technology,
  • Replacing missing or older parts,
  • Creating cost savings by allowing as-built design services, for example in automotive manufacturing plants,
  • "Bringing the plant to the engineers" with web shared scans, and
  • Saving travel costs.

Entertainment

3D scanners are used by the entertainment industry to create digital 3D models for movies, video games and leisure purposes. They are heavily utilized in virtual cinematography. In cases where a real-world equivalent of a model exists, it is much faster to scan the real-world object than to manually create a model using 3D modeling software. Frequently, artists sculpt physical models of what they want and scan them into digital form rather than directly creating digital models on a computer.

3D photography

3D selfie in 1:20 scale printed by Shapeways using gypsum-based printing, created by Madurodam miniature park from 2D pictures taken at its Fantasitron photo booth.
 
Fantasitron 3D photo booth at Madurodam

3D scanners are evolving for the use of cameras to represent 3D objects in an accurate manner. Companies are emerging since 2010 that create 3D portraits of people (3D figurines or 3D selfie).

An augmented reality menu for the Madrid restaurant chain 80 Degrees

Law enforcement

3D laser scanning is used by the law enforcement agencies around the world. 3D models are used for on-site documentation of:

  • Crime scenes
  • Bullet trajectories
  • Bloodstain pattern analysis
  • Accident reconstruction
  • Bombings
  • Plane crashes, and more

Reverse engineering

Reverse engineering of a mechanical component requires a precise digital model of the objects to be reproduced. Rather than a set of points a precise digital model can be represented by a polygon mesh, a set of flat or curved NURBS surfaces, or ideally for mechanical components, a CAD solid model. A 3D scanner can be used to digitise free-form or gradually changing shaped components as well as prismatic geometries whereas a coordinate measuring machine is usually used only to determine simple dimensions of a highly prismatic model. These data points are then processed to create a usable digital model, usually using specialized reverse engineering software.

Real estate

Land or buildings can be scanned into a 3D model, which allows buyers to tour and inspect the property remotely, anywhere, without having to be present at the property. There is already at least one company providing 3D-scanned virtual real estate tours. A typical virtual tour Archived 2017-04-27 at the Wayback Machine would consist of dollhouse view, inside view, as well as a floor plan.

Virtual/remote tourism

The environment at a place of interest can be captured and converted into a 3D model. This model can then be explored by the public, either through a VR interface or a traditional "2D" interface. This allows the user to explore locations which are inconvenient for travel. A group of history students at Vancouver iTech Preparatory Middle School created a Virtual Museum by 3D Scanning more than 100 artifacts.

Cultural heritage

There have been many research projects undertaken via the scanning of historical sites and artifacts both for documentation and analysis purposes.

The combined use of 3D scanning and 3D printing technologies allows the replication of real objects without the use of traditional plaster casting techniques, that in many cases can be too invasive for being performed on precious or delicate cultural heritage artifacts. In an example of a typical application scenario, a gargoyle model was digitally acquired using a 3D scanner and the produced 3D data was processed using MeshLab. The resulting digital 3D model was fed to a rapid prototyping machine to create a real resin replica of the original object.

Creation of 3D models for Museums and Archaeological artifacts.

Michelangelo

In 1999, two different research groups started scanning Michelangelo's statues. Stanford University with a group led by Marc Levoy used a custom laser triangulation scanner built by Cyberware to scan Michelangelo's statues in Florence, notably the David, the Prigioni and the four statues in The Medici Chapel. The scans produced a data point density of one sample per 0.25 mm, detailed enough to see Michelangelo's chisel marks. These detailed scans produced a large amount of data (up to 32 gigabytes) and processing the data from his scans took 5 months. Approximately in the same period a research group from IBM, led by H. Rushmeier and F. Bernardini scanned the Pietà of Florence acquiring both geometric and colour details. The digital model, result of the Stanford scanning campaign, was thoroughly used in the 2004 subsequent restoration of the statue.

Monticello

In 2002, David Luebke, et al. scanned Thomas Jefferson's Monticello. A commercial time of flight laser scanner, the DeltaSphere 3000, was used. The scanner data was later combined with colour data from digital photographs to create the Virtual Monticello, and the Jefferson's Cabinet exhibits in the New Orleans Museum of Art in 2003. The Virtual Monticello exhibit simulated a window looking into Jefferson's Library. The exhibit consisted of a rear projection display on a wall and a pair of stereo glasses for the viewer. The glasses, combined with polarised projectors, provided a 3D effect. Position tracking hardware on the glasses allowed the display to adapt as the viewer moves around, creating the illusion that the display is actually a hole in the wall looking into Jefferson's Library. The Jefferson's Cabinet exhibit was a barrier stereogram (essentially a non-active hologram that appears different from different angles) of Jefferson's Cabinet.

Cuneiform tablets

The first 3D models of cuneiform tablets were acquired in Germany in 2000. In 2003 the so-called Digital Hammurabi project acquired cuneiform tablets with a laser triangulation scanner using a regular grid pattern having a resolution of 0.025 mm (0.00098 in). With the use of high-resolution 3D-scanners by the Heidelberg University for tablet acquisition in 2009 the development of the GigaMesh Software Framework began to visualize and extract cuneiform characters from 3D-models. It was used to process ca. 2.000 3D-digitized tablets of the Hilprecht Collection in Jena to create an Open Access benchmark dataset and an annotated collection of 3D-models of tablets freely available under CC BY licenses.

Kasubi Tombs

A 2009 CyArk 3D scanning project at Uganda's historic Kasubi Tombs, a UNESCO World Heritage Site, using a Leica HDS 4500, produced detailed architectural models of Muzibu Azaala Mpanga, the main building at the complex and tomb of the Kabakas (Kings) of Uganda. A fire on March 16, 2010, burned down much of the Muzibu Azaala Mpanga structure, and reconstruction work is likely to lean heavily upon the dataset produced by the 3D scan mission.

"Plastico di Roma antica"

In 2005, Gabriele Guidi, et al. scanned the "Plastico di Roma antica", a model of Rome created in the last century. Neither the triangulation method, nor the time of flight method satisfied the requirements of this project because the item to be scanned was both large and contained small details. They found though, that a modulated light scanner was able to provide both the ability to scan an object the size of the model and the accuracy that was needed. The modulated light scanner was supplemented by a triangulation scanner which was used to scan some parts of the model.

Other projects

The 3D Encounters Project at the Petrie Museum of Egyptian Archaeology aims to use 3D laser scanning to create a high quality 3D image library of artefacts and enable digital travelling exhibitions of fragile Egyptian artefacts, English Heritage has investigated the use of 3D laser scanning for a wide range of applications to gain archaeological and condition data, and the National Conservation Centre in Liverpool has also produced 3D laser scans on commission, including portable object and in situ scans of archaeological sites. The Smithsonian Institution has a project called Smithsonian X 3D notable for the breadth of types of 3D objects they are attempting to scan. These include small objects such as insects and flowers, to human sized objects such as Amelia Earhart's Flight Suit to room sized objects such as the Gunboat Philadelphia to historic sites such as Liang Bua in Indonesia. Also of note the data from these scans is being made available to the public for free and downloadable in several data formats.

Medical CAD/CAM

3D scanners are used to capture the 3D shape of a patient in orthotics and dentistry. It gradually supplants tedious plaster cast. CAD/CAM software are then used to design and manufacture the orthosis, prosthesis or dental implants.

Many Chairside dental CAD/CAM systems and Dental Laboratory CAD/CAM systems use 3D Scanner technologies to capture the 3D surface of a dental preparation (either in vivo or in vitro), in order to produce a restoration digitally using CAD software and ultimately produce the final restoration using a CAM technology (such as a CNC milling machine, or 3D printer). The chairside systems are designed to facilitate the 3D scanning of a preparation in vivo and produce the restoration (such as a Crown, Onlay, Inlay or Veneer).

Creation of 3D models for Anatomy and Biology education and cadaver models for educational neurosurgical simulations.

Quality assurance and industrial metrology

The digitalisation of real-world objects is of vital importance in various application domains. This method is especially applied in industrial quality assurance to measure the geometric dimension accuracy. Industrial processes such as assembly are complex, highly automated and typically based on CAD (computer-aided design) data. The problem is that the same degree of automation is also required for quality assurance. It is, for example, a very complex task to assemble a modern car, since it consists of many parts that must fit together at the very end of the production line. The optimal performance of this process is guaranteed by quality assurance systems. Especially the geometry of the metal parts must be checked in order to assure that they have the correct dimensions, fit together and finally work reliably.

Within highly automated processes, the resulting geometric measures are transferred to machines that manufacture the desired objects. Due to mechanical uncertainties and abrasions, the result may differ from its digital nominal. In order to automatically capture and evaluate these deviations, the manufactured part must be digitised as well. For this purpose, 3D scanners are applied to generate point samples from the object's surface which are finally compared against the nominal data.

The process of comparing 3D data against a CAD model is referred to as CAD-Compare, and can be a useful technique for applications such as determining wear patterns on moulds and tooling, determining accuracy of final build, analysing gap and flush, or analysing highly complex sculpted surfaces. At present, laser triangulation scanners, structured light and contact scanning are the predominant technologies employed for industrial purposes, with contact scanning remaining the slowest, but overall most accurate option. Nevertheless, 3D scanning technology offers distinct advantages compared to traditional touch probe measurements. White-light or laser scanners accurately digitize objects all around, capturing fine details and freeform surfaces without reference points or spray. The entire surface is covered at record speed without the risk of damaging the part. Graphic comparison charts illustrate geometric deviations of full object level, providing deeper insights into potential causes.

Circumvention of shipping costs and international import/export tariffs

3D scanning can be used in conjunction with 3D printing technology to virtually teleport certain object across distances without the need of shipping them and in some cases incurring import/export tariffs. For example, a plastic object can be 3D-scanned in the United States, the files can be sent off to a 3D-printing facility over in Germany where the object is replicated, effectively teleporting the object across the globe. In the future, as 3D scanning and 3D printing technologies become more and more prevalent, governments around the world will need to reconsider and rewrite trade agreements and international laws.

Object reconstruction

After the data has been collected, the acquired (and sometimes already processed) data from images or sensors needs to be reconstructed. This may be done in the same program or in some cases, the 3D data needs to be exported and imported into another program for further refining, and/or to add additional data. Such additional data could be gps-location data, ... Also, after the reconstruction, the data might be directly implemented into a local (GIS) map or a worldwide map such as Google Earth.

Software

Several software packages are used in which the acquired (and sometimes already processed) data from images or sensors is imported. Notable software packages include:

Politics of Europe

From Wikipedia, the free encyclopedia ...