Accurate Silhouette Extraction of a Person in Video Data by Shadow Evaluation

This paper presents a new shadow detecting method for silhouette extraction of a person in gray-level video sequences. We use a shadow evaluator to verify each raw shadow pixel which was detected by Gaussian distribution analysis. The evaluator considers a raw shadow pixel initially to be a fake shadow pixel, and marks it as a silhouette pixel if it is enclosed or semienclosed by moving occlusion boundaries of a person. Those were extracted by subtracting edges in the current frame from edges of the background. We also propose a silhouette-compensation technique to recover some missing (i.e. removed) silhouette pixels by using a similarity criterion between silhouette pixels and their neighbors. Experimental results show us that the proposed algorithm keeps a silhouette of a person more accurate compared to other methods. Methods advocated by other researchers in YUV or RGB color space, typically remove silhouette pixels as shadow if the color of these pixels is similar to that of the surrounding background. Keywords—Shadow removal, silhouette detection, shadow evaluator, silhouette compensation

[1]  Jörn Ostermann,et al.  Detection of Moving Cast Shadows for Object Segmentation , 1999, IEEE Trans. Multim..

[2]  Rita Cucchiara,et al.  Detecting Moving Objects, Ghosts, and Shadows in Video Streams , 2003, IEEE Trans. Pattern Anal. Mach. Intell..

[3]  Oliver Schreer,et al.  Fast and robust shadow detection in videoconference applications , 2002, International Symposium on VIPromCom Video/Image Processing and Multimedia Communications.

[4]  N. Kanopoulos,et al.  Design of an image edge detection filter using the Sobel operator , 1988, IEEE J. Solid State Circuits.

[5]  Jörn Ostermann,et al.  Shadow detection for moving humans using gradient-based background subtraction , 2009, 2009 IEEE International Conference on Acoustics, Speech and Signal Processing.

[6]  Reinhard Koch,et al.  A Color Similarity Measure for Robust Shadow Removal in Real Time , 2003, VMV.

[7]  Wilhelm Burger,et al.  Digital Image Processing - An Algorithmic Introduction using Java , 2008, Texts in Computer Science.

[8]  Nigel J. B. McFarlane,et al.  Segmentation and tracking of piglets in images , 1995, Machine Vision and Applications.

[9]  Xi Chen,et al.  Adaptive Silouette Extraction and Human Tracking in Complex and Dynamic Environments , 2006, 2006 International Conference on Image Processing.

[10]  Jonathan H. Connell,et al.  A Statistical Approach for Real-time Robust Background Subtrac tion and Shadow Detection , 2014 .

[11]  Xi Chen,et al.  Adaptive Silhouette Extraction and Human Tracking in Complex and Dynamic Environments , 2006 .

[12]  Supavadee Aramvith,et al.  An adaptive real-time background subtraction and moving shadows detection , 2004, 2004 IEEE International Conference on Multimedia and Expo (ICME) (IEEE Cat. No.04TH8763).

[13]  Antoine Manzanera,et al.  A Robust and Computationally Efficient Motion Detection Algorithm Based on Sigma-Delta Background Estimation , 2004, ICVGIP.

[14]  Mubarak Shah,et al.  A hierarchical approach to robust background subtraction using color and gradient information , 2002, Workshop on Motion and Video Computing, 2002. Proceedings..

[15]  Thomas B. Moeslund,et al.  Detection and removal of chromatic moving shadows in surveillance scenarios , 2009, 2009 IEEE 12th International Conference on Computer Vision.

[16]  Soraia Raupp Musse,et al.  Background Subtraction and Shadow Detection in Grayscale Video Sequences , 2005, XVIII Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI'05).

[17]  Hans-Hellmut Nagel,et al.  Model-based object tracking in monocular image sequences of road traffic scenes , 1993, International Journal of Computer 11263on.

[18]  Tieniu Tan,et al.  Cast Shadow Removal with GMM for Surface Reflectance Component , 2006, 18th International Conference on Pattern Recognition (ICPR'06).

[19]  Giancarlo Iannizzotto,et al.  A vision-based system for elderly patients monitoring , 2010, 3rd International Conference on Human System Interaction.