| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a range finder capable of securing an attainment distance in the case that the luminance of external light is of low luminance and acquiring satisfactory range characteristics at a long distance. <P>SOLUTION: The range finder is provided with a light emitting means; a light receiving means; a clamp means for outputting a long-distance side signal or a clamp signal; an operation means for computing the ratio of close-distance side signals to signals outputted from the clamp means and outputting an output ratio signal; an external light luminance measuring means; a threshold value setting means for setting a farthest-distance determination threshold value as a threshold value corresponding to the side of a long distance when the luminance of external light is of low luminance; and a converting means for converting the output ratio signal into a distance signal by a conversion expression in the case that the value of the output ratio signal is on the close-distance side in comparison with the farthest-distance determination threshold value and into a distance signal of a fixed prescribed value in the case that it is not on the close-distance side. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
