Patent ID: 7936449

Claim:
A method of calibrating a time-of-flight (TOF) system of the type that emits modulated light of a known phase, detects a portion of emitted said modulated light reflected from a target object a distance Z away, and determines Z by examining phase shift in detected reflected modulated light relative to said known phase of emitted modulated light, the method comprising the following steps: (a) disposing a target object a distance Z x from said TOF system, said distance Z x being within operating distance range of said TOF system; (b) altering said phase of said emitted said modulated light by at least one known phase value; (c) for each phase value of emitted said modulated light, determining from detected reflected light a corresponding phase shift relative to each said phase value; (d) using corresponding relative phase shift determined at step (c) to form an electrical model of detection characteristics of said TOF system, said electrical model representing distance-vs-phase characteristics of said TOF system, which characteristics are substantially independent of physical characteristics of at least one detector detecting said reflected modulated light relative to at least one source of said modulated light; and (e) storing data representing said electrical model; wherein data stored at step (e) is useable during run-time operation of said TOF system to provide calibrated values of Z responsive to phase shift in detected reflected light.