For example, a robot can use them to follow a white line. The robot sends out a beam of infrared light, some of which bounces off of an obstacle and returns to a light sensor on the robot. Hans Moravec explains some of the difficulties involved in making robots do simple tasks. For more complex vision systems, light sensors are not enough. Robots that find and remove imperfect products from a conveyor belt need to be able to resolve complex, changing images quickly.
Robotic vision is one of the greatest challenges for engineers.
It is difficult to program a robot to see what's important and ignore what isn't. A robot has trouble interpreting things like glare, lighting changes, and shadows. Also, for a robot to have depth perception, it needs stereoscopic vision like our own. Resolving two slightly different images to make one 3D image requires large amounts of computer memory.