Time-of-flight camera system and method to improve measurement quality of weak field-of-view signal regions

Patent metadata

Field	Value
Publication number	US-2016182789-A1
Application number	US-201414579243-A
Country	US
Kind code	A1
Filing date	Dec 22, 2014
Priority date	Dec 22, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A time-of-flight camera system is described. The time-of-flight camera system includes an illuminator to illuminate a region within the time-of-flight camera system's field of view. The time-of-flight camera system includes an image sensor to receive optical signals from the illumination for determining depth profile information within the field of view using time-of-flight measurement techniques. The image sensor has circuitry to determine one or more regions within the field of view where a received optical signal from the illuminating was weak. The illuminator is also to re-illuminate the one or more regions with stronger light than the one or more regions received during the illuminating. Each of the one or more regions being smaller than the region. The image sensor is also to receive optical signals from the re-illumination for determining depth profile information within the one or more regions.

First claim

1 . A method, comprising:
illuminating a region within a time-of-flight camera system's field of view; determining depth profile information within said field of view using time-of-flight measurement techniques; determining one or more regions within said field of view where a received signal from said illuminating was weak; re-illuminating said one or more regions with stronger light than said one or more regions received during said illuminating, each of said one or more regions being smaller than said region; and, determining depth profile information within said one or more regions using time-of-flight measurement techniques.

2 . The method of claim 1 wherein said region is said time-of-flight's entire field of view.

3 . The method of claim 1 wherein said re-illuminating further comprises re-illuminating a partition with said field of view.

4 . The method of claim 3 wherein a light source that illuminates said partition emits stronger light during said re-illuminating than during said illuminating.

5 . The method of claim 1 wherein said re-illuminating further comprises directing light directly to each of said one or more regions.

6 . The method of claim 5 wherein said light is shaped in size to respectively encompass each of said one or more regions during said re-illuminating.

7 . The method of claim 6 wherein a light source that illuminates said region and said one or more regions does not emit stronger light when re-illuminating at least one of said one or more regions than when illuminating said region.

8 . A machine readable storage medium comprising stored program code, and not transitory electromagnetic signals, that when processed by a digital processing system causes a method to be performed by a time-of-flight camera system, said method comprising:
illuminating a region within time-of-flight camera system's field of view; determining depth profile information within said field of view using time-of-flight measurement techniques; determining one or more regions within said field of view where a received signal from said illuminating was weak; re-illuminating said one or more regions with stronger light than said one or more regions received during said illuminating, each of said one or more regions being smaller than said region; and, determining depth profile information within said one or more regions using time-of-flight measurement techniques.

9 . The machine readable storage medium of claim 8 wherein said region is said time-of-flight's entire field of view.

10 . The machine readable storage medium of claim 8 wherein said re-illuminating further comprises re-illuminating a partition with said field of view.

11 . The machine readable storage medium of claim 10 wherein a light source that illuminates said partition emits stronger light during said re-illuminating than during said illuminating.

12 . The machine readable storage medium of claim 8 wherein said re-illuminating further comprises directing light directly to each of said one or more regions.

13 . The machine readable storage medium of claim 12 wherein said light is shaped in size to respectively encompass each of said one or more regions during said re-illuminating.

14 . The machine readable storage medium of claim 13 wherein a light source that illuminates said region and said one or more regions does not emit stronger light when re-illuminating at least one of said one or more regions than when illuminating said region.

15 . An apparatus, comprising:
a time-of-flight camera system comprising: an illuminator to illuminate a region within said time-of-flight camera system's field of view; an image sensor to receive optical signals from said illumination for determining depth profile information within said field of view using time-of-flight measurement techniques, said image sensor having circuitry to determine one or more regions within said field of view where a received optical signal from said illuminating was weak; said illuminator to also re-illuminate said one or more regions with stronger light than said one or more regions received during said illuminating, each of said one or more regions being smaller than said region; and, said image sensor to also receive optical signals from said re-illumination for determining depth profile information within said one or more regions using time-of-flight measurement techniques.

16 . The apparatus of claim 15 wherein said one-or-more regions are defined with pixels of said image sensor.

17 . The apparatus of claim 15 wherein said region is said time-of-flight's entire field of view.

18 . The apparatus of claim 15 wherein said illuminator has an optical component and a light source designed to partition illumination of said time-of-flight camera's field of view.

19 . The apparatus of claim 18 wherein said re-illumination of said one or more regions is performed by individually illuminating respective one or more partitions where said one or more regions reside.

20 . The apparatus of claim 15 wherein said illuminator has a movable optical component to individually direct said re-illumination to said one or more regions.

21 . A computing system, comprising:
an applications processor having a plurality of processing cores and a memory controller, a system memory being coupled to said memory controller; a time-of-flight camera system coupled to said applications processor, said time-of-flight camera system including: an illuminator to illuminate a region within said time-of-flight camera system's field of view; an image sensor to receive optical signals from said illumination for determining depth profile information within said field of view using time-of-flight measurement techniques, said image sensor having circuitry to determine one or more regions within said field of view where a received optical signal from said illuminating was weak; said illuminator to also re-illuminate said one or more regions with stronger light than said one or more regions received during said illuminating, each of said one or more regions being smaller than said region; and, said image sensor to also receive optical signals from said re-illumination for determining depth profile information within said one or more regions using time-of-flight measurement techniques.

22 . The computing system of claim 21 wherein said one-or-more regions are defined with pixels of said image sensor.

23 . The computing system of claim 21 wherein said region is said time-of-flight's entire field of view.

24 . The computing system of claim 21 wherein said illuminator has an optical component and a light source designed to partition illumination of said time-of-flight camera's field of view.

25 . The computing system of claim 21 wherein said re-illumination of said one or more regions is performed by individually illuminating respective one or more partitions where said one or more regions reside.

26 . The computing system of claim 21 wherein said illuminator has a movable optical component to individually direct said re-illumination to said one or more regions.

Assignees

• Google Inc

Inventors

• Wan Chung Chun
• Ko Jamyuen

Classifications

• H04N23/56 Primary

  provided with illuminating means · CPC title

• H04N23/74

  by influencing the scene brightness using illuminating means · CPC title

• H04N23/00

  Cameras or camera modules comprising electronic image sensors; Control thereof · CPC title

• H04N23/60

  Control of cameras or camera modules · CPC title

• G01S17/894

  Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar · CPC title