Apparatus and method for measuring a distance

摘要

A distance measuring apparatus according to the present invention comprises two types of distance measuring units, which are a first distance measuring unit of the active method for receiving reflected light of measuring light returning from an object and performing distance measurement based on a focused position thereof, and a second distance measuring unit of the passive method for receiving the natural light reflected by the object through two optical systems and performing the distance measurement based on two optical images thus obtained. The apparatus further has a luminance determining unit for determining a luminance of the external field from a photometry result, and a distance selecting device for selecting and outputting either one of distance measurement results obtained by the first distance measuring unit and second distance measuring unit as a proper distance value, based on the luminance of the external field determined by the luminance determining unit. This distance selecting device may be so arranged that the luminance of external field obtained by the luminance determining unit is determined in two levels of high level and low level. Then it selects the distance measurement result of the first distance measuring unit when the luminance of external field is determined as a low level or selects the distance measurement result of the second distance measuring unit when the luminance of external field is determined as a high level.