Image sensors and optical devices

What is the measurement principle of a ToF (time-of-flight) sensor?

  1. ADistance is calculated from the time it takes emitted light to reflect off an object and return
  2. BTemperature is calculated from sound reflections
  3. CDistance is estimated from the color of the object
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Answer: A. Distance is calculated from the time it takes emitted light to reflect off an object and return

A ToF sensor measures the time for light from its source to reflect off an object and return to the sensor (or the phase shift of modulated light) and calculates distance from the speed of light. It is used for face authentication and AR in smartphones and for sensing the surroundings of robots and cars.

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