| 摘要 |
PURPOSE:To eliminate the adverse influence in the tracking process arising from the level difference of a video signal in a scanning direction by adding a vertical line multiplexer, BPF and a target area detector to process the video signal. CONSTITUTION:A vertical line multiplexer 16 reads out a video signal from a frame memory 11 in order of the arranging direction of a photodetectors 9. The BPF17 changes a cut-off frequency by the size of a target. A target area detector 18 is provided for the purpose of measuring a target area. The video signal in a picture element unit is taken out of the memory 11 from the direction in arranging order of the photodetectors 9, i.e., from the direction vertical to a scanning direction to obtain the video signal contg. mixedly offset components caused by the sensitivity difference among the respective photodetectors 9. The signal is then passed through the BPF17 to assure such a band allowing the passage of only the frequency near the frequency component of the target and the unnecessary low band component and high frequency band component of disturbance existing mixedly therein are suppressed. The output signal from a comparator 14 which is subjected to a threshold processing and binary coding is further inputted to said area detector to measure the area of the target and control the cut-off frequency of the BPF17. |
