| 摘要 |
PURPOSE:To enable focusing to be performed with a simple circuit by Fourier-transforming the subject image with a Fourier transformation lens and using this information as the focus control information of the taking lens. CONSTITUTION:The image of a subject 1 imaged on a screen 4 by a taking lens 2 is trasformed by using a Fourier trasformation lens 6 and the image thereof is formed on a Fourier information imaging plane 7. This information is transformed in a photoelectric transforming part 8 and the luminances PA, PB of the low-frequency section and high-frequency section of space frequencies are measured. Next, the operation of PB/PA is performed by an arithmetic circuit 9, then the point where the results of the operation become maximum is the point where the focus has matched. Hence, the displaying of the moving direction of the taking lens or its automatic focusing may be performed. In this way, the focusing may be performed with the simple circuit. |
