Time-of-Flight Cameras: How They Work and Their Limits

A third depth-sensing approach that splits the difference between LiDAR and stereo vision.

A time-of-flight (ToF) camera illuminates a scene with modulated infrared light and measures the phase shift (effectively, the time delay) of the light bouncing back at every pixel simultaneously, producing a full depth image in a single capture rather than by scanning point by point like LiDAR.

Strengths

ToF cameras are compact, work in the dark (since they provide their own illumination), and don't need textured surfaces the way stereo matching does, making them a solid choice for close-range perception like hand-eye coordination during manipulation.

Limits

They generally have shorter effective range than LiDAR, lower resolution than a good stereo pair, and can struggle with strong ambient infrared (direct sunlight is a common failure case) and with highly reflective or absorptive surfaces that distort the returned signal.