| 摘要 |
PURPOSE:To attain automatic focus control with reduced video signal change points by temprarily storing a video signal for the share of one frame in a frame memory, reading out the stored video signal for each pixel, rearranging the pixel data in order of amplitude, and storing the rearranged pixel data in a RAM. CONSTITUTION:A video signal amplified by an amplifier 4 is converted in an A/D converter 11 into a digital signal representing an amplitude for each pixel to be temporarily stored in a frame memory 12. A CPU 13 reads video signal from the frame memory 12 for every (mXn) pixels. The read-out data are rearranged in order from low amplitude data (i.e., black data) to high amplitude data (i.e., white data) before being stored in a RAM 15. The data stored in the RAM 15 is repeatedly read out and differentiated to obtain a hill-like differential waveform. To obtain automatic focus control of an optical lens, the driving of a motor 20 is controlled such as to reduce the width of the hill-like waveform and increase the crest of the waveform. |
