| 摘要 |
PURPOSE:To detect a repetitive pattern which is hard to detect accurately by a simple device by correcting a photoelectrically converted signal at the time of use of auxiliary light by using the output of a photoelectric converted signal in the absence of the auxiliary light. CONSTITUTION:The photoelectric conversion output 201 of a sensor 101 in the absence of the auxiliary light is A/D-converted 102 and stored in a memory 104 with a control signal 208 through a multiplexer 103. Then, an auxiliary light source 108 ius energized with a control signal 210and the output of the sensor 101 is A/D-converted and inputted to a multiplexer 103. The signal of this time is subtracted 105 from the signal stored in the memory 104 last time with a control signal 208. Further, the result is divided 106 by a signal 105 from the memory 104 to obtain a signal 207, which drives a focus adjusting device 107 to drive a lens by a lens driving device 109, thereby making a display on a display device 110. Consequently, even a repetitive pattern which is hard to detect a focus can be detected accurately by the easy modification of software. |
