Abstract: This paper presents a system based on image processing and dedicated to count the number of pedestrians walking across subway corridors. Results of its evaluation in real conditions and on a significant amount of passengers are given. The paper describes the experimental prototype able to deal with several cameras and working in real time on a PC. It shows difficulties met in the field trial procedure. The system can process images issued from several cameras hanging from the ceiling (the number of these cameras is a function of the corridor width). Detection is achieved using cooperative techniques: a particular texture is laid on the ground and viewed by the camera(s). This method allows us to enhance detection accuracy, especially in poor lighting conditions. The local destruction of this texture in the corresponding image gives us relevant information about the presence of people. Segmentation of the moving parts is performed: mathematical morphology operators are implemented. Detected pixels are thresholded and filtered. Finally, all the connected parts are labelled. The last step consists in tracking the moving parts provided by the previous step. Sequential analysis on images of the objects is done and a movement prediction is performed. Finally, this tracking allows us to compute the number of passengers passing a fictive line in both directions. This research has been undertaken jointly by INRETS and RATP (French subway operator for Paris). !5
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