Patent ID: 8587771

Claim:
A method of self-calibrating a time-of-flight (TOF) system to reduce error, the TOF system emitting optical energy of a known modulation frequency phase, detecting a portion of said optical energy reflected from a target object a distance Z away using an array of pixels, and determining depth Z by examining phase shift in detected reflected optical energy relative to phase of emitted said optical energy, the method comprising the following steps: (a) acquiring detection data from said array of pixels using a number N of acquisitions, wherein N is selected from a group consisting of (i) even integers, and (ii) odd integers; (b) causing said TOF system to operate during runtime in a mode selected from a group consisting of (i) detection gain modification mode, (ii) detection integration time modification mode, and (iii) digital value modification mode, wherein a selected said mode provides self-calibration data for said TOF system; (c) storing self-calibration data obtained during one said mode in a first and second memory location; and (d) using stored said self-calibration data during runtime operation of said TOF system to reduce calibration error; wherein said method reduces at least one of (i) bias error due to higher order harmonics, (ii) bias error due to variation in wave-shape of optical energy emitted by said TOF system, and (iii) bias errors due to variations in waveforms received by said pixels in said array.