| 摘要 |
PURPOSE:To measure a range to an object to be photographed accurately by detecting a beam loss with a beam loss detection circuit and compensating the measured results according to the detection. CONSTITUTION:A part of light reflected on an object to be photographed is collected again by a light receiving lens 21, and made incident on a PSD 22 of a range detection circuit 20. The two outputs from the PSD 22 are output to a multiplexer 3 through I-V converters 25 and 28, respectively. Also a part of another reflected light is made incident on a PSD 32 of a beam loss detection circuit 30 through a light receiving lens 31. The outputs from the PSD 32 are output to the multiplexer 3 through I-V converters 35 and 38, respectively. The multiplexer 3 selects one of these four outputs basing on signals from a CPU 1, and outputs it to an A/D converter 2. The 4D converter 2 converts an input analog voltage into a digital signal, and outputs it to the CPU 1. The CPU 1 processes the input signal in time series, and stores the input signals as range information in a RAM 6. |
