Method of searching recorded digital video for areas of activity

摘要

A method of scanning recorded video images of a scene to locate those images in which there is a predetermined amount of activity. Images (I) of the scene are obtained over a period of time. Each of the images (SI) is compared to a reference image (RI) of the scene and a difference image (DI) is created for each comparison. A threshold test is applied to each image as a measure of the activity occurring in the scene at the time the image is obtained and the results of the test are stored with the image in a memory (18) of an image processing system (10). When the images are subsequently viewed, a viewing threshold related to the amount of activity occurring in the scene is established by the viewer. The test results for each stored image are then scanned to determine if the image meets the viewing criteria. If it does, the image is either displayed for viewing on a monitor (24) or a file (F2) is created for analysis. Since the viewing threshold criteria can be rapidly determined for a large number of stored images, it is not necessary to view the images in their sequential order. This saves a substantial amount of time and allows the user to quickly locate pertinent information related to activities at a monitored site.