Conference Paper

Person Identification using Shadow Analysis.

DOI: 10.5244/C.24.35 Conference: British Machine Vision Conference, BMVC 2010, Aberystwyth, UK, August 31 - September 3, 2010. Proceedings
Source: DBLP
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Available from: Ryo Kurazume
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    • "Third, and most importantly, in the HS condition, we predicted an interference effect from the cast shadow action as hypothesised by Alearts et al (2009). Indeed, on the basis of the different findings regarding the cast shadow of the body (Galfano and Pavani 2005; Iwashita et al 2010; Pavani and Castiello 2004; Pavani and Galfano 2007), we expected that the mere observation of a cast shadow of a hand action could have a strong influence on the motor system of the observers. Specifically, our data should reveal an interference effect in the imitative behaviour in the condition in which the participants followed the hand regardless of whether they were asked to ignore the cast shadow. "
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    ABSTRACT: Observing actions performed by other persons can subsequently influence our own motor behaviours. However, it is unknown whether the shadows cast by such actions can also have an impact on the observers' actions. Here we show that the mere observation of a cast shadow can influence imitative behaviours. Specifically, participants were shown a hand picture and its associated cast shadow in a neutral position. In a 'compatible trial' the hand and the shadow that followed were turned in the same open or closed direction, whereas in an 'incompatible trial' the hand and the shadow were turned in different directions. We contrasted two experimental conditions: (i) 'hand-shadow' in which participants observed a hand and its cast shadow (the hand covered the shadow); (ii) 'hand-hand' in which participants observed a hand and another black hand (the shadow covered the hand). The participants' task was to imitate (ie by closing or opening their own hands) the hand or the cast shadow of an action. For both conditions results revealed interference (ie longer response latencies) for incompatible trials. This suggests for the first time that the mere observation of a cast shadow of a hand can influence imitative behaviours. However, time courses of the response latencies revealed that imitative effect in the hand-shadow condition was different than the imitative effect in the hand-hand condition. Therefore, we suggest considering the cast shadow of an action as an important feature during motor control for humans.
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    ABSTRACT: This chapter presents an overview and classification of security approaches based on computer analysis of human behavior. Overview of different methodologies is followed by an analysis of achieved accuracy rates, required equipment and prospects for future improvements. In particular the following broad categories of behavior-based authentication mechanisms are examined: Behavioral Biometrics (Authorship based, Human–Computer Interaction based, Motor Skill, and Purely Behavioral), Behavioral Passwords (syntactic, semantic, one-time methods and visual memory based), Biosignals (cognitive and semi-controllable biometrics) and Virtual Biometrics (representations of users in virtual worlds).
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    ABSTRACT: This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which identification of the subject followed. The experiments using the database show the effectiveness of the proposed method and further prove the superiority of using multiple viewpoints compared to a single viewpoint.
    Full-text · Article · May 2012 · Proceedings of SPIE - The International Society for Optical Engineering
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