| 摘要 |
<p>PURPOSE:To prevent issuance of wrong alarms when the lightness of monitoring places is wholly changed, etc., in case where picture information of continuous two pictures is compared on a picture element basis, by adding the average lightness of the picture to be compared to the comparing conditions. CONSTITUTION:Pictures of water level of a dam, etc., are taken by a TV camera and the picture signals are received by a receiving circuit 6 of a still picture monitoring device 5 through a transmitter 3 and a transmission line 4. The picture data are inputted into a picture memory 8 and average lightness computing circuit 9 under the control of a CPU15. After a prescribed time, the picture data in the picture memory 8 are transferred to another picture memory 11 under the control of the CPU15, and, at the same time, the computed result L1 of the average lightness computing circuit 9 is transferred to a lightness memory 12. Picture data of the next picture are inputted into the picture memory 8 and the average lightness computing circuit 9, and an average lightness L2 is computed. Prescribed operations are performed in adders 10, 13, and 14 on the basis of picture element, and differences in the lightness in which the average lightness of the pictures between picture elements is considered is inputted into a comparator 18 through a gate 17, and then, when the difference is larger than the threshold, the output is generated.</p> |
