| 摘要 |
PURPOSE:To improve accuracy for detecting the focusing state of a photographic lens and to shorten time required for automatically controlling focusing by detecting the focusing state of the photographic lens based on a picture element signal of a color largest in level change of the picture element signal. CONSTITUTION:Luminance change signals S6-S9 obtained in the process to find an AF signal are respectively obtained by differentiating respective chrominance signals G, Mg, Ye and Cy with respect to lateral picture elements and taking the absolute value of that differentiated value. The AF signal is obtained by integrating the luminance change signals with respect to lateral pixel. In this example, the AF signal based on the chrominance signal G shows most satisfactorily the difference (contrast) of luminance at the respective parts of the object, and the signal G contains most of a high frequency component. Therefore, the AF operation is performed by using the chrominance signal to obtain the AF signal showing the maximum value. Thus, the amount of the high frequency component contained in a reflected signal from the object can be detected with high accuracy, and the accuracy for detecting the focusing state can be improved. |
