| 摘要 |
PURPOSE:To identify a high-brightness flare and to make target detection accurate by calculating the maximum absolute brightness level in each area of a video signal from the maximum brightness and gain coefficient in the area and selecting a target among significant areas. CONSTITUTION:An image pickup element 4 scans image forming light 3 and sends out the video signal 5. The signal 5 is multiplied 17 by the gain coefficient 18 and the result is A/D-converted 6; and then a detecting circuit 8 calculates the maximum brightness and coordinates of the center of gravity in each area of the video signal to generate signals 9 and 10. The maximum value in one image plane is detected 21 from the signal 9 and sent to a control circuit 24. The circuit 24 sends a trigger signal 25 to a gain control circuit 23 only once only when the maximum value 22 reaches the saturation level of a converter 6 and the circuit 23 sends out the coefficient 18. Then when the maximum value 22 is smaller than the saturation level, on the other hand, the circuit 24 stops the circuit 23 and actuates an arithmetic circuit 28 to calculate the maximum absolute brightness levels of respective areas from the number 27 of times of the operation of the circuit 23 and the signal 9. Therefore, the target in a significant area is accurately detected.
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