Patent ID: 7471376

Claim:
A method of calibrating a time-of-flight (TOF) system of the type that emits light of a known phase, detects a portion of said light reflected from a target object a distance Z away, and determines Z by examining phase shift in detected reflected light relative to said known phase of emitted 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 known phase of said emitted light by at least two known phase values; (c) for each known phase value of said emitted light, determining from detected reflected light a corresponding phase shift relative to said known phase; (d) using corresponding relative phase shift determined at step (c) to form an electrical model of detection characteristics of said TOF system; and (e) storing data representing said electrical model; wherein data stored at step (e) is acquirable using only optical energy emitted by said TOF system and traversing said distance Z x and is useable during run-time operation of said TOF system to provide calibrated values of Z responsive to phase shift in detected reflected light.