Robots don't have to solve problems the same way as humans. The system is trained by showing the object to the TV camera, resulting in all potentially useful shape descriptions being automatically calculated and stored. A click of sound reflects from an object and returns to the sender. The time required for it to return is converted to a measurement of distance or range. This kind of range finding goes under alternate names of sonar, ultrasonic sensing or ultrasound.
Authors describing range finding technologies are quick to point out their limitations.
Nevertheless, as I look out the window I see a bicycle down the street. Using my human vision system I estimate it to be 100 ft. away. I have no doubt that sonar or laser could do better. Such efforts try to use the cues in two-dimensional photographs to estimate depth as humans do with the naked eye. However, I would think that in the long run such computational approaches will be no more accurate than the human eye and that researchers will do better by perfecting sonar, laser etc.