| 摘要 |
PURPOSE:To make distance measurement no matter where a subject exists in a photographing field by deciding the infinite region in the photographing field in the shorter time than the time required for the distance measurement prior to the distance measurement, then measuring the distance in the region of finite distances. CONSTITUTION:A timer means for measuring the prescribed time shorter than the time required for ascending integration to detect the change state of the ratio of the plural outputs of a signal receiver for receiving a reflection signal and a detecting means for detecting whether the amt. of the reflection signal received by the signal receiving means attains a prescribed level or not are provided. A signal is then projected to either of the central region or peripheral region in the field. The signal of a projecting means is projected to the region where the signal is not projected and the distance to said region is measured upon detection of the detecting means that the amt. of the reflection signal does not attains the prescribed level within the prescribed time. The quick distance measurement is thereby permitted and the cost is reduced. |
