LiDAR and ToF (Time-of-Flight), refer to a measurement principle based on a signal leaving a source and a detector measuring the time it takes for a detector to receive the same signal back. The distance to any given object can be determined by factoring in the speed of the signal itself. Optical systems play a critical role when the signal is based on light, and the most common systems are referred to as LiDARs and ToF cameras. ToF-cameras illuminate a scene with a modulated signal, and the phase shift between the send and receive signal determines the depth ranging. 

Many industries and applications have leveraged these technologies for decades, from topology and meteorology to medical and industrial robotics applications. In recent years, ToF cameras have also entered high-volume consumer and automotive markets. Many established and new companies are pushing the boundaries to reduce costs and advance performance for long- and short-range systems.