Depth from Time-of-Flight Imaging

In this chapter, we discuss techniques that use temporally coded light sources for measuring scene depths. The light source is modeled as a point source whose intensity can be modulated over time at high speeds. Examples of such sources are lasers that can emit light pulses of short duration (few picoseconds to a few nanoseconds) and light-emitting diodes (LEDs) whose intensity can be modulated at high temporal frequencies (tens of MHz to GHz). In all cases, the objective is to measure the total time it takes for light to travel from the source to a scene point and from the scene point back to a sensor, which is typically co-located with the source. This time duration is referred to as time-of-flight (ToF) and is proportional to the distance between the scene point and the sensor.