| 摘要 |
PURPOSE:To detect a moving body without impeding natural flows of people and vehicles by extracting the path of flow of the moving body by difference processing and binarization processing for image data which are inputted at different time and counting how many times a virtual gate is passed. CONSTITUTION:An observation area is prescribed and a camera photographs a moving body, e.g. a pedestrian in the area. Photographed image data are stored on an image memory such as a video tape and then sequential difference processing is performed to extract the path of flow. The difference processing is performed for all images between successive points of time to extract only changing images. The difference images which are thus obtained are ANDed to extract an image at a common point of time between the both, and this process is continuously carried out to trace the position of the center of gravity, thereby obtaining the path 21 of flow. When the passage state of the pedestrian is known, the virtual gate 23 is set. Once the pedestrian crosses the virtual gate 23, it is considered that the passage is completed and the frequency is counted. |
