| 摘要 |
PROBLEM TO BE SOLVED: To lower the price by actualizing high-precision active range finding using visible light and composing the instrument of general light emitting and receiving elements. SOLUTION: The range finder is equipped with an arithmetic means 50 which computes only light reception data of light emitted by the light emitting element 40 and reflected by a subject with 1st light reception data obtained by receiving subject light, while the light emitting element 40 emits and 2nd light reception data obtained by receiving the subject light while the light emitting element is stopped from emitting the light, and takes an active distance measurement according to the computed arithmetic data. The arithmetic means 50 compares the level of the arithmetic data with a reference value, and sets a measured distance to a first previously set default distance when the level of the arithmetic data is less than the reference value. Even when which external light is obtained, a distance can be measured with high precision and, even if the external light varies in lightness, a proper default distance can be set following up the variation. |
