Laser rangefinder Laser rangefinder

Distance measurement

There are various methods of optical distance measurement, including TOF (Time-of-Flight) and triangulation. They are used for various applications, such as detecting surroundings in autonomous vehicles, detecting obstacles in robots, and in laser rangefinders. Hamamatsu offers a wide range of photosensors and light emitters for these distance measurement mechanisms. We can also offer devices with custom specifications that meet such requirements.

Types of optical distance measurement

Direct TOF method

The direct TOF method calculates distance to an object by measuring the time it takes for a light pulse from the light source to be reflected by the object and return to the sensor. Its features include a wide range for distance measurement and compact optical system.

Indirect TOF method

Indirect TOF method calculates the distance to the target object by measuring the phase difference between light reception timing and light emission timing. It provides higher accuracy for short-distance measurements than the direct TOF method. It does not require a time measurement circuit, so the circuit can be miniaturized. 

Triangulation method

Triangulation distance measurement method calculates the distance to the target object by receiving light reflected on the target object with a photosensor and detecting the position of light incident on its light reception surface. This method features high accuracy for short-distance measurement.

Hamamatsu devices for distance measurement


Lineup of Hamamatsu photosensors for distance measurement and application examples.

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distance_measurement_map CMOS linear image sensor PSD Photo IC for distance measurement Distance image sensor Si PIN photodiode Si APD Si APD with front-end IC MPPC InGaAs APD

Light emitters

Infrared LEDs for short distance measurement.

Related applications

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