Method and System for 2D Detection of Localized Light Contributions

• US 20120281879A1
• Filed: 01/11/2011
• Published: 11/08/2012
• Est. Priority Date: 01/15/2010
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Vlutters, Ruud, De Bruijn, Frederik Jan, Feri, Lorenzo, Schenk, Tim Corneel Wilhelmus, Muijs, Remco Theodorus Johannes
• Granted Patent: US 8,755,561 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]
• CPC Class Codes: H05B 47/17 Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations

Abstract

The invention relates to a detection system for determining whether a light contribution of a light source is present at a selected position within a 2D scene. The light contribution includes an embedded code comprising a repeating sequence of N symbols. The detection system includes a camera and a processing unit. The camera is configured to acquire a series of images of the scene via specific open/closure patterns of the shutter. Each image includes a plurality of pixels, each pixel representing an intensity of the light output of the light source at a different physical position within the scene. The processing unit is configured to process the acquired series of images to determine whether the light contribution of the first light source is present at the selected physical position within the scene by e.g. correlating a sequence of pixels of the acquired series corresponding to the selected physical position with the first sequence of N symbols.

Claims

1. A detection system for determining whether a light contribution of a first light source of an illumination system is present at a selected position within a scene;

wherein the light contribution of the first light source includes a first embedded code comprising a repeating first sequence of N symbols, the detection system comprising;

a camera configured to acquire a series of images of the scene, wherein;

each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output of the illumination system comprising at least the light contribution of the first light source,

the series comprises at least N different images, and

each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols; and

a processing unit configured to process the acquired series of images to determine that the light contribution of the first light source is present at the selected physical position.

2. The detection system according to claim 1, wherein the processing of the acquired series of images to determine that the light contribution of the first light source is present at the selected physical position comprises:

correlating a sequence of pixels of the acquired series of images corresponding to the selected physical position with the first sequence of N symbols, and

determining that the light contribution of the first light source is present at the selected physical position when the correlation of the sequence of pixels of the acquired series of images corresponding to the selected physical position with the first sequence of N symbols produces a correlation peak.

3. The detection system according to claim 2, wherein, based on the correlation of the sequence of pixels of the acquired series of images corresponding to the selected physical position with the first sequence of N symbols, the processing unit is further configured to determine an intensity, or a derivative thereof, of the light contribution of the first light source at the selected physical position.

4. The detection system according to claim 1, wherein:

the illumination system further comprises a second light source;

a light contribution of the second light source includes a second embedded code comprising a repeating second sequence of N symbols;

the total light output of the illumination system further comprises the light contribution of the second light source; and

the processing unit is further configured to process the acquired series of images to determine that the light contribution of the second light source is present at the selected physical position.

5. The detection system according to claim 4, wherein the processing of the acquired series of images to determine that the light contribution of the second light source is present at the selected physical position comprises:

correlating the sequence of pixels of the acquired series of images corresponding to the selected physical position with the second sequence of N symbols, and

determining that the light contribution of the second light source is present at the selected physical position when the correlation of the sequence of pixels of the acquired series of images corresponding to the selected physical position with the second sequence of N symbols produces a correlation peak.

6. The detection system according to claim 4, wherein the selected physical position is included within a first part of the scene and the processing unit is further configured to:

for each acquired image, determine a sum of the pixels included in a part of the image corresponding to the first part of the scene,

correlate a sequence of the sums of the acquired series of images with the first sequence of N symbols, and

determine that the light contribution of the first light source is present within the first part of the scene when the correlation of the sequence of the image sums of the acquired series of images with the first sequence of N symbols produces at least one correlation peak above a first threshold value.

7. The detection system according to claim 6, wherein the processing unit is further configured to:

correlate the sequence of the sums of the acquired series of images with the second sequence of N symbols, and

determine that the light contribution of the second light source is present within the first part of the scene when the correlation of the sequence of the image sums of the acquired series of images with the second sequence of N symbols produces at least one correlation peak above a second threshold value.

8. The detection system according to claim 1, wherein the duration of each of the one or more exposure instances is equal to the duration of one symbol of the first sequence of N symbols.

9. The detection system according to claim 1, wherein the one or more exposure instances comprise a single exposure of two or more consecutive exposure instances.

10. The detection system according to claim 1, wherein the one or more exposure instances comprise two or more non-consecutive exposure instances.

11. A detection system for determining whether a light contribution of a first light source of an illumination system is present within a first part of a scene, wherein the light contribution of the first light source includes a first embedded code comprising a repeating first sequence of N symbols, the detection system comprising:

a camera configured to acquire a series of images of the scene, wherein;

each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output of the illumination system comprising at least the light contribution of the first light source,

the series comprises at least N different images, and

each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols; and

a processing unit configured to;

for each acquired image, determine a sum of the pixels included in a part of the image corresponding to the first part of the scene,

correlate a sequence of the sums of the acquired series of images with the first sequence of N symbols, and

determine that the light contribution of the first light source is present within the first part of the scene when the correlation of the sequence of the image sums of the acquired series of images with the first sequence of N symbols produces at least one correlation peak above a first threshold value.

12. A method for determining whether a light contribution of a first light source of an illumination system is present at a selected position within a scene, wherein the light contribution of the first light source includes a first embedded code comprising a repeating first sequence of N symbols, the method comprising:

acquiring a series of images of the scene, wherein;

each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output of the illumination system comprising at least the light contribution of the first light source,

the series comprises at least N different images, and

each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols; and

processing the acquired series of images to determine that the light contribution of the first light source is present at the selected physical position.

13. The method according to claim 12, wherein the processing of the acquired series of images to determine that the light contribution of the first light source is present at the selected physical position comprises:

correlating a sequence of pixels of the acquired series of images corresponding to the selected physical position with the first sequence of N symbols, and

determining that the light contribution of the first light source is present at the selected physical position when the correlation of the sequence of pixels of the acquired series of images corresponding to the selected physical position with the first sequence of N symbols produces a correlation peak.

14. A method for determining whether a light contribution of a first light source of an illumination system is present within a first part of a scene, wherein the light contribution of the first light source includes a first embedded code comprising a repeating first sequence of N symbols, the method comprising:

acquiring a series of images of the scene, wherein;

each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output if the illumination system comprising at least the light contribution of the first light source,

the series comprises at least N different images, and

each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols;

for each acquired image, determining a sum of the pixels included in a part of the image corresponding to the first part of the scene;

correlating a sequence of the sums of the acquired series of images with the first sequence of N symbols; and

determining that the light contribution of the first light source is present within the first part of the scene when the correlation of the sequence of the image sums of the acquired series of images with the first sequence of N symbols produces at least one correlation peak above a first threshold value.

15. (canceled)