METHOD FOR TIME OF FLIGHT MODULATION FREQUENCY DETECTION AND ILLUMINATION MODULATION FREQUENCY ADJUSTMENT

• US 20140152974A1
• Filed: 12/04/2012
• Published: 06/05/2014
• Est. Priority Date: 12/04/2012
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: KO, Dong-Ik
• Granted Patent: US 9,823,340 B2
• Time in Patent Office: Days
• US Class Current: 356/5.01
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 17/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/493 Extracting wanted echo signals

Abstract

A method removing adjecent frequency interference from a Time Of Flight sensor system by adaptively adjusting the infrared illumination frequency of the TOF sensor by measuring the interfering infrared illuminating frequencies and dynamicaly adjusting the illuminating infrared frequency of the TOF sensor to eliminate the interference.

Claims

1. A method of interference rejection in a Time of Flight (TOF) measurement system comprising the steps of:

receiving all ambient infrared illumination;

measuring the modulation frequencies of said received infrared illumination;

comparing duration of said measured modulation frequencies to a preset threshold;

adjusting the infrared illumination modulating frequency of the Time of Flight measurement system if the preset threshold is exceeded.

2. The method of claim 1 wherein:

the TOF measurement system'"'"'s infrared illumination modulation frequency is dynamically adjusted to a value that is offset from the strongest detected ambient infrared modulation frequency.

3. The method of claim 1 wherein:

the TOF measurement system'"'"'s infrared illumination modulation frequency is dynamically adjusted to a value that is offset from a plurality of the detected ambient infrared modulation frequencies.