MONITORING DEVICE AND PROGRAM

PROBLEM TO BE SOLVED: To provide a monitoring system capable of reducing a monitoring burden on a monitoring person when disappearance of an object is detected.SOLUTION: An event detector 22 reads and compares with each other a plurality of image frames in a memory 30 that are different from each other time-sequentially to detect event occurrence in a region in the image frames. A disappearance image processor 231 reads a past image frame in the memory 30 to extract an image in the past image frame. An MPEG processor 232 superposes the image extracted by the disappearance image processor 231 upon an input image frame to generate and output video data.