首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The Evolution of the Photofit Security technology: A new type of computerised photofit system takes a novel evolutionary app
The Evolution of the Photofit Security technology: A new type of computerised photofit system takes a novel evolutionary app
admin
2011-01-15
48
问题
The Evolution of the Photofit
Security technology: A new type of computerised photofit system takes a novel evolutionary approach to generating images of suspects. If you have ever tried to describe someone’s face in detail, you will understand why the "photofit" composite images used by the police look so dodgy. In recent years, computerised "E-Fit" systems have helped improve the accuracy of these images by allowing witnesses to choose from a wider range of facial features. But researchers at the University of Stirling in Scotland found that, despite these improvements, people still have a hard time constructing recognisable faces--especially if there is a delay of more
The problem is that people tend to recoguise faces as whole entities, rather than as separate features. So picking from a range of eyes, noses and mouths is not necessarily the most suitable approach, says Charlie Frowd, a psychologist at the University of Stifling. Next year, however, British police are expected to begin trials of a new computerised system, called EvoFIT, developed by Dr. Frowd and his colleague Peter Hancock. It uses an evolutionary approach, known as a genetic algorithm, to "evolve" faces rather than piece them together.
"The process is entirely non-verbal and takes a fraction of the normal time," claims Dr. Frowd. A witness is shown an array of 60 different faces with random features. Having studied them closely, the witness is asked to choose the six images that most closely resemble the person they are trying to describe. These six are then used to generate another set of 60, by switching featurees between some of the images and by making random changes to others. The witness is then asked to repeat the task, whereupon a new batch of faces is generated, and so on. In evolutionary terms, this process is known as "genetic crossover and mutation", and is a powerful way to search a large number of possibilities for a particular solution. By allowing the user to steer the selection process, the program is able to generate a good likeness for the original face after just a few cycles.
In one of its early versions, EvoFIT was used by police in Northampton shire who were trying to catch a violent attacker. The attacker was never caught, but the senior investigating officer, Superintendent Paul Spick, says the witness involved found the new software much quicker and easier to use than traditional E-Fit systems. It was also more accurate: the final image caused the witness visible distress when displayed. A further important advantage of EvoFIT over traditional composites is that an image can be generated even if the witness can only provide a sketchy verbal description.
The researchers have since made a number of further improvements to their system and are now in the process of commercializing it in partnership with ABM, a British firm which supplies police forces with photofit, one of the leading computerized composite systems. The images are more realistic, and the system can generate three-quarter angle views of the face, which are easier to distinguish than direct frontal views, says Dr. Frowd.
A His team has also found that by combining the images generated by different witnesses, or even from a single witness, it is possible to get an even better likeness. B This could be particularly useful when multiple witnesses come forward and the police are unsure which of the images they produce is the most accurate. C In the latest version, witnesses are given a selection of face shapes to choose from before facial features are added. D This makes it less likely that the correct facial features will be rejected simply because they are on the wrong-shaped face.
These modifications appear to make all the difference. In recent experiments, Dr. Frowd and Dr. Hancock compared EvoFIT with the computerized systems currently in use by asking volunteers to construct an image of a face two days after seeing it, and then showing the resulting image to people who were familiar with the person depicted. With traditional composites, the person was correctly identified about 4% of the time; the figure rose to 25% with EvoFIT images.
Next year ABM will perform inhouse evaluations of the system and will then team up with police forces for further trials. Although things look promising so far, two things in particular need further testing, says Leslie Bowie, ABM’s director of research. Do the EvoFIT images distract witnesses or contaminate their memories of the face they are trying to recall? And while EvoFIT has performed well in the calm conditions of the laboratory, how will it cope with real-life witnesses, who are often traumatized by their experiences? If it can address these two questions, EvoFIT could be the next step in the evolution of the photofit.
The word its in paragraph 4 refers to
选项
A、EvoFIT.
B、Photofit.
C、person.
D、attacker.
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/C2yO777K
0
托福(TOEFL)
相关试题推荐
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
ClassifythefollowinginformationasreferringtoAadoptedthewritingsystemfromanothercountryBusedorganicmaterialst
ClassifythefollowinginformationasreferringtoAadoptedthewritingsystemfromanothercountryBusedorganicmaterialst
Inthelastdecadearevolutionhasoccurredinthewaythatscientiststhinkaboutthebrain.Wenowknowthatthedecisionshu
TheEvolutionaryMystery:CrocodileSurvivesA.Eventhoughcrocodileshaveexistedfor200millionyears,they’reanything
TheEvolutionaryMystery:CrocodileSurvivesA.Eventhoughcrocodileshaveexistedfor200millionyears,they’reanything
TheEvolutionaryMystery:CrocodileSurvivesA.Eventhoughcrocodileshaveexistedfor200millionyears,they’reanything
随机试题
"见红"一般发生在分娩开始前的
A.患者的权利B.患者的义务C.医生的权利D.医生的义务E.患者和医生共同的义务患者检举经治医生收受红包是()
在某工程双代号网络计划中,如果其计划工期等于计算工期,且工作i-j的完成节点j在关键线路上,则工作i-j的自由时差()。
托管业务准人条件中要求,基金托管部门拟从事基金清算、核算、投资监督、信息披露等业务的执业人员应不少于5人,并具有证券从业资格。()
教师进行人格修养最好的策略是()。
大学期间对你最有挑战的事情是什么?你有什么收获?
中国的城市发展已经进入软实力竞争时代。单靠粗放式的资源消耗、廉价劳动力来换取硬实力发展的模式已经_________。填入划横线部分最恰当的一项是()。
根据下列资料,回答126~130题。2010年,我国共投入研究与试验发展(R&D,以下简称R&D)经费7062.6亿元,比上年增21.7%;R&D经费投入强度(与国内生产总值之比)为1.76%,比上年的1.70%有所提高。分活动类型看
设随机变量X的概率密度为f(x),则随机变量|X|的概率密f1(x)为
结构化程序设计主要强调的是()。
最新回复
(
0
)