PURPOSE: To obtain a highly accurate out of focus signal by making use of the peak level of the high frequency component in the video signal from an image sensor.
CONSTITUTION: The video signal from an image sensor 8 is made into the signal corresponding to contrast through an amplifier 11, a sample holding circuit 12, a differentiation circuit 13 and an absolute value circuit 14. The signal thereof is multipled by the extraction function from a generation circuit 16 for an extraction function and is inputted to an integration circuit 17 and an envelope circuit 20. The (rear focus) signal from the left half part and the (front focus) signal from the right half of the video in the sensor 8 are integrated by an integrator 17 and the output of the circuit 20 by an integrator 21, alternately. The output of the integrator 17 is divided by the output of an integrator 21. The output signal thereof is inputted through sample holding circuits 23, 24 to an adder 25 and dividers 26, 27, and is divided by the output of the adder 26. The highly accurate out of focus signal is obtd. by the differential output signal with a differential amplifier 28.
OGAWA HIDEHIRO
KAWAHARA ATSUSHI
| JPS5576310A | 1980-06-09 | |||
| JP39005265A | ||||
| JPS5228340A | 1977-03-03 |