Image sensors for monitoring of vehicle environment

3D mapping of surroundings for use in autonomous driving and mobile robotics

© Fraunhofer IIS
Single-photon detection measures when an object refl ects and sends back an emitted pulse of light.

LiDAR (light detection and ranging) technology is often used in sensors for distance measurement and environmental recognition. Sensors can use LiDAR to measure the distance to an object, and to a certain extent its velocity, all in real time. Instead of radio waves, light is used for detection, which permits higher resolution in the 3D recording of the environment, including the movement of people or cars.

For each application, we develop customized image sensors, including time-of-flight (ToF) image sensors for optical distance measurement, which can determine the position of objects with high precision. This involves detecting when an emitted pulse of light returns to a receiver after reflecting off an object (optical time-of-flight measurement). This is achieved using single-photon avalanche diode (SPAD) arrays, in which individual photons hit a sensor and trigger an avalanche of electrons. Because this makes individual photons detectable, it enables optical time-of-flight measurement. From this time of flight, the distance to an object is then calculated directly.