| 摘要 |
PURPOSE:To reduce misses of measurement by increasing the aperture ratio of an object which forms an optical path and decreasing depth of field, calculating the differential value of the brightness signal of a formed image, and comparing a distribution of points where the differential value exceeds a specific value. CONSTITUTION:Lenses 1 and 2 which form an environmental image on photosensor arrays 3 and 4 are held by a frame 5 and coupled together mechanically, and moved forth and back by a motor 5 as shown by an arrow 6. Then, the lenses 1 and 2 have large aperture ratios and are made relatively small in depth of field. The lenses 1 and 2 are moved by a moving means 28 for focusing and synchronized with a driving circuit 5 for the photosensors 3 and 4 so that a time period longer than, for example, a distance calculation time is obtained. An output image signal is differentiated by differentiation circuits 6 and 7 with time and a distribution of points where the differential value exceeds the specific value is compared. Consequently, the distance distribution is measured within a practical time and misses of measurements resulting from an erroneous assumption of corresponding points of a right and left images are reduced greatly. |
