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
65
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 contaminate in paragraph 8 could best be replaced by
选项
A、make unforgettable.
B、make clean.
C、make large.
D、make impure.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/J2yO777K
0
托福(TOEFL)
相关试题推荐
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
MorseCodeMorsecodeisbeingreplacedbyanewsatellite-basedsystemforsendingdistresscallsatsea.Itsdotsanddashesh
ClassifythefollowinginformationasreferringtoAadoptedthewritingsystemfromanothercountryBusedorganicmaterialst
ClassifythefollowinginformationasreferringtoAadoptedthewritingsystemfromanothercountryBusedorganicmaterialst
TheEvolutionaryMystery:CrocodileSurvivesA.Eventhoughcrocodileshaveexistedfor200millionyears,they’reanything
TheEvolutionaryMystery:CrocodileSurvivesA.Eventhoughcrocodileshaveexistedfor200millionyears,they’reanything
随机试题
以下不属于总监理工程师职责的是()。
最早正式使用“班级”一词的是著名教育家()
某高血压病人频繁呕吐伴有突然头痛,意识不清,脉搏、呼吸减慢,左右瞳孔明显不等大,你考虑()
A.内侧丘系B.下丘脑-神经垂体束C.中央导水管D.垂体门脉系统E.锥外系统
A.风寒袭肺咳嗽B.风热犯肺咳嗽C.燥邪伤肺咳嗽D.肾虚作喘E.痰热壅肺喘咳疏散风寒,宣肺止咳法可以治疗
下列高压设备,一般只在屋外使用的是()。
购买长期债券时,计入长期债券初始投资成本的债券费用摊销的时点是()。
2013年10月5日,北方公司与西方公司签订了—份销售合同,双方约定,2014年1月10日,北方公司应按每台3万元的价格向两方公司提供A商晶15台。20l3年12月31日,北方公司A商品的单位成本为2.4万元,数量为10台,其账而价值(成本)为24万元。2
由上至下,屋顶由()组成。
无论是在入境旅游还是在出境旅游中,导游人员的一项重要职责是宣传社会主义中国,但是需注意的问题是在宣传中()。
最新回复
(
0
)