Acquiring the precise distance to or from an object is entrenched in so many devices we use these days that we often wonder how people used to live without them just a few years ago. From every cell phone that we use, to driverless cars that are now coming to streets, measuring proximity to a nearby object plays a pivotal role in engineering and data acquisition. A robot vacuum cleaner traverses living rooms and bedrooms avoiding objects while cleaning carpets and floors. Modern TVs understand and respond to hand gestures. Defining and recording the exact position of an object in space and its position relative to its neighboring objects has evolved very rapidly.
Even laser gun slinging exploding robots in movies need to measure distance to an object and move accordingly. Not all of that is Computer Generated Graphics. Acquiring the precise distance to an object ranges from a very simple number to extremely complicated GPS...