| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect any variation in the direction of a fixed point observation camera due to an unexpected cause by analyzing images shot by the camera itself.SOLUTION: Images shot by a fixed point observation camera are inputted as frame-by-frame original images P(i) consecutively given in a time series, and foreground images F(i) resulting from extraction of only different parts from background images are generated and successively stored into a foreground image storage 130. A differential area between an (i-1)-th foreground image F(i-1) and an i-th foreground image F(i) is extracted to prepare a differential image D(i), and this differential image D(i) is divided into a plurality of blocks. Out of these blocks, blocks in which the occupying share of the differential area is not less than a first threshold are recognized as radically varying blocks, and the number of radically varying blocks in each individual differential area is counted. When a differential area in which the number of radically varying blocks is not less than a second threshold is obtained, a variation is determined to have occurred in the shooting field of view. |
