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Evaluation of Intrinsic Image Algorithms to Detect the Shadows Cast by Static Objects Outdoors
CICATA Qro., Instituto Politécnico Nacional, Cerro Blanco 141, Col. Colinas del Cimatario, Santiago de Queretaro, C.P. 76090, Mexico
Computer Vision Center, UAB Campus, Bellaterra 08193, Barcelona, Spain
* Author to whom correspondence should be addressed.
Received: 29 July 2012; in revised form: 7 September 2012 / Accepted: 17 September 2012 / Published: 1 October 2012
Abstract: In some automatic scene analysis applications, the presence of shadows becomes a nuisance that is necessary to deal with. As a consequence, a preliminary stage in many computer vision algorithms is to attenuate their effect. In this paper, we focus our attention on the detection of shadows cast by static objects outdoors, as the scene is viewed for extended periods of time (days, weeks) from a fixed camera and considering daylight intervals where the main source of light is the sun. In this context, we report two contributions. First, we introduce the use of synthetic images for which ground truth can be generated automatically, avoiding the tedious effort of manual annotation. Secondly, we report a novel application of the intrinsic image concept to the automatic detection of shadows cast by static objects in outdoors. We make both a quantitative and a qualitative evaluation of several algorithms based on this image representation. For the quantitative evaluation, we used the synthetic data set, while for the qualitative evaluation we used both data sets. Our experimental results show that the evaluated methods can partially solve the problem of shadow detection.
Keywords: video sequences; shadow detection; intrinsic images; illumination component
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Isaza, C.; Salas, J.; Raducanu, B. Evaluation of Intrinsic Image Algorithms to Detect the Shadows Cast by Static Objects Outdoors. Sensors 2012, 12, 13333-13348.
Isaza C, Salas J, Raducanu B. Evaluation of Intrinsic Image Algorithms to Detect the Shadows Cast by Static Objects Outdoors. Sensors. 2012; 12(10):13333-13348.
Isaza, Cesar; Salas, Joaquín; Raducanu, Bogdan. 2012. "Evaluation of Intrinsic Image Algorithms to Detect the Shadows Cast by Static Objects Outdoors." Sensors 12, no. 10: 13333-13348.