| 摘要 |
PURPOSE:To detect a focusing direction on the basis of a focusing state and chromatic aberration and to attain rapid focusing by providing the titled device with a means for changing an image forming state, a means for converting object image information into two chrominance signals and a means for detecting the focusing state of an image corresponding to the two colors. CONSTITUTION:An image is focused by a lens 101 on an optical axis, a focal distance is changed by a lens 1-2, the position of the lens 1-2 is detected by a position detector 3 and the aberration comparing information C' of color G with colors R, B and the chromatic aberration direction AC of the color G are stored in a ROM15. The color information of the object is converted into three chromatic signals and a luminance signal Y by an image pickup element 4 and either one C of R and B is selected by an analog SW5 by controlling a microprocessor 16 to extract signals corresponding to the center of a screen through gates 6, 8. The intensity of their HF components is normalized, sharpness QC, QG are outputted through sharpness detectors 7, 9, the peaks of the output signals are held, the shaded degree is evaluated by a microprocessor 16, the size of the HF component of the object image is detected by the luminance signal or through prescribed processing and the invalidity of focusing direction decision due to large out-of-focus is processed by the signal F. Thus, rapid focusing can be attained by holding the image surface S at the intermediate state between G and C (R or B). |
