| 摘要 |
PURPOSE:To decrease the out-of-focus by the contrast of an object by detecting the changing condition of a distance measuring signal and predicting an error of the distance measurement by a contrast pattern. CONSTITUTION:The outputs A, B of respective elements 4a, 4b of a photodetec tor 4 are integrated and the integration is interrupted at the time tau when for example, (A+B)/2 attains a specified level L. A difference A-B between the signals A and b is made and is converted to a digital quantity by an A/D con verter built in a signal processing circuit S, which determines a signal (y) by making the operation y=(A-B)/(A+B); i.e., (A-B)/(2L). The error by the contrast pattern is determined from the changing condition of the curve (A-B)/(A+B). A motor 6 is controlled at the parameter which does not depend on the contrast pattern, if the error is large. |
