| 摘要 |
PROBLEM TO BE SOLVED: To exclude influences on an image caused by a sunshine without installing an appended apparatus, such as, an illuminance meter, and thereby monitor at low price and with high accuracy. SOLUTION: At every hour on the hour with 0 minute, an image of a monitoring target institution is captured by a camera 1, and time stamp information representing the date and the time when the image is captured is added to the monitoring image data, which are stored successively in a storage unit 4. Whenever up-to-date monitoring image data are obtained, the up-to-date monitoring image data and monitoring image data, at the same time, on the previous day are read out from the storage unit 4, and these monitoring image data are corrected in the brightness (density) for each pixel so that an average of the brightness becomes an arbitrary common value. Next, the difference between the monitoring image data after the brightness is corrected is acquired for each pixel to generate an absolute differential image; the generated absolute differential image is compared with the threshold for each pixel; and it is determined based on the result whether there is a change between the monitoring image data. COPYRIGHT: (C)2009,JPO&INPIT
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