Sokkia Company Limited

Futoshi Osada

Koji Sasaki

Yutaka Nakamura

Hayami Kikawa

Akihiro Aoki

Toshihiro Uchimura

An electric optical distance meter is provided that makes an input power level of a reference light entering a light receiving device via an internal optical path comparable between low and high reflectivity targets. The electric optical distance meter has a shutterfor switching between an external optical path Po, through which a distance measuring light emitted by a light source is placed to and from a target, and the internal optical path Pi is placed from the light source to the light receiving device, where the shutter has: a rotating axis; blocking plateswhich are arranged at two locations symmetric with respect to the rotating axis, and alternately block the respective distance measuring lights L entering the external optical path and the internal optical path; and an attenuation platewhich is placed at one of the two locations where the blocking plates are not arranged and between the blocking plates, and attenuates the distance measuring light entering the internal optical path when the target is of a low reflectivity.

Electric optical distance meter

A distance measuring device is provided that reduces the time required for a distance measurement without degrading accuracy of the measured value. The distance measuring device includes a reference signal oscillator () that generates a reference signal (K), a light source () that emits a distance measuring light (L) modulated based on the reference signal, a light receiving element () that receives the distance measuring light reflected from a target () and converts the distance measuring light to a distance measuring signal (M), a frequency converter () that converts the distance measuring signal to an intermediate frequency signal, an A/D converter () that samples the intermediate frequency signal in synchronization with the reference signal, a memory () that stores data of the sampled intermediate frequency signal, and a CPU () that calculates a distance based on the intermediate frequency signal data, the CPU calculates amplitude of each frequency of the intermediate frequency signal based on the intermediate frequency signal data, determines an average of the amplitude, and ends sampling to calculate a distance when the number of pieces of the intermediate frequency signal data is equal to or more than a minimum required number and the average has become equal to or more than a predetermined value.

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Kanagawa, Japan

Futoshi Osada