Measuring lighting levels using a visible light sensor

Patent metadata

Field	Value
Publication number	US-12439494-B2
Application number	US-202318199143-A
Country	US
Kind code	B2
Filing date	May 18, 2023
Priority date	Dec 9, 2016
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A visible light sensor may be configured to sense environmental characteristics of a space using an image of the space. The visible light sensor may be controlled in one or more modes, including a daylight glare sensor mode, a daylighting sensor mode, a color sensor mode, and/or an occupancy/vacancy sensor mode. In the daylight glare sensor mode, the visible light sensor may be configured to decrease or eliminate glare within a space. In the daylighting sensor mode and the color sensor mode, the visible light sensor may be configured to provide a preferred amount of light and color temperature, respectively, within the space. In the occupancy/vacancy sensor mode, the visible light sensor may be configured to detect an occupancy/vacancy condition within the space and adjust one or more control devices according to the occupation or vacancy of the space. The visible light sensor may be configured to protect the privacy of users within the space via software, a removable module, and/or a special sensor.

First claim

What is claimed is:

1. A method of controlling at least one lighting load in a space, the method comprising:
storing a plurality of images of the space, wherein each image of the plurality of images comprises a contribution of artificial light provided by the at least one lighting load at a different respective intensity in the space;
retrieving at least one first image of the space from the plurality of images of the space based on a present intensity of the at least one lighting load in the space;
retrieving a second image of the space comprising a contribution of daylight and artificial light in the space;
removing the contribution of artificial light in the at least one first image from the second image to determine a contribution of daylight; and
generating control instructions for controlling the at least one lighting load in the space, the control instructions based on the contribution of daylight determined by removing the contribution of artificial light in the at least one first image from the second image.

2. The method of claim 1 , further comprising applying a daylighting mask to the second image to focus on a portion of the second image prior to removing the contribution of artificial light of the at least one lighting load in the space.

3. The method of claim 2 , further comprising determining an average lighting level metric calculated over an unmasked portion of the space, wherein the average lighting level metric indicates the contribution of daylight.

4. The method of claim 3 , further comprising transmitting the average lighting level metric.

5. The method of claim 2 , wherein the method comprises applying the daylighting mask to focus on a portion of the second image that is above or below a contrast threshold.

6. The method of claim 1 , further comprising applying a subtraction process to the second image prior to removing the contribution of artificial light of the at least one lighting load in the space, the subtraction process comprising at least one of removing bright spots above a brightness threshold from the second image or removing dark spots below a darkness threshold from the second image.

7. The method of claim 6 , wherein the subtraction process further comprises:
converting the second image to a grayscale image; and
removing portions of the grayscale image that are above the brightness threshold or below the darkness threshold.

8. The method of claim 6 , further comprising, after applying the subtraction process, backfilling removed bright spots or removed dark spots with a backfill value that is based on pixels adjacent to the removed bright spots or the removed dark spots.

9. The method of claim 8 , wherein the backfill value comprises an average lighting intensity value of the pixels adjacent to the removed bright spots or the removed dark spots.

10. The method of claim 1 , wherein removing the contribution of artificial light in the at least one first image from the second image to determine a contribution of daylight comprises removing a contribution of artificial light in at least one pixel of the at least one first image from at least one associated pixel of the second image.

11. The method of claim 1 , wherein the at least one lighting load is in a minimally-controlled zone of one or more lighting fixtures within the space.

12. The method of claim 1 , wherein the at least one lighting load comprises a plurality of lighting loads in the space, wherein each lighting load of the plurality of lighting loads is associated with a respective set of images of the plurality of images of the space, wherein the respective set of images for each lighting load of the plurality of lighting loads represents contributions of artificial light for the respective lighting load at different intensities, wherein retrieving the at least one first image of the space based on the present intensity of the at least one lighting load further comprises retrieving separate first images for each lighting load of the plurality of lighting loads based on the present intensity of the lighting load, the method further comprising:
adding the contribution of artificial light from each of the first images to determine a total contribution of artificial light, and wherein removing the contribution of artificial light in the at least one first image from the second image to determine the contribution of daylight comprises removing the total contribution of artificial light from the second image to determine the contribution of daylight.

13. An apparatus for controlling at least one lighting load in a space, the apparatus comprising:
a control circuit configured to:
store a plurality of images of the space, wherein each image of the plurality of images comprises a contribution of artificial light provided by the at least one lighting load at a different respective intensity in the space;
retrieve at least one first image of the space from the plurality of images of the space based on a present intensity of the at least one lighting load in the space;
remove the contribution of artificial light in the at least one first image from a second image to determine a contribution of daylight; and
generate control instructions for controlling the at least one lighting load in the space, the control instructions based on the contribution of daylight determined by removing the contribution of artificial light in the at least one first image from the second image.

14. The apparatus of claim 13 , wherein the control circuit is further configured to apply a daylighting mask to the second image prior to removal of the contribution of artificial light of the at least one lighting load in the space.

15. The apparatus of claim 14 , wherein the control circuit is further configured to determine an average lighting level metric calculated over an unmasked portion of the space, wherein the average lighting level metric indicates the contribution of daylight.

16. The apparatus of claim 15 , further comprising a communication circuit, the communication circuit configured to transmit the average lighting level metric.

17. A computer-readable medium having stored thereon instructions that, when executed by a control circuit, are configured to cause the control circuit to:
store a plurality of images of a space, wherein each image of the plurality of images comprises a contribution of artificial light provided by at least one lighting load at a different respective intensity in the space;
retrieve at least one first image of the space from the plurality of images of the space based on a present intensity of the at least one lighting load in the space;
remove the contribution of artificial light in the at least one first image from a second image to determine a contribution of daylight; and
generate control instructions for controlling the at least one lighting load in the space, the control instructions based on the contribution of daylight determined by removing the contribution of artificial light in the at least one first image from the second image.

18. A method of controlling at least one lighting load in a space, the method comprising:
retrieving at least one first image of the space, wherein the at least one first image comprises a contribution of artificial light from at least one lighting load;
determining a present intensity of the at least one lighting load;
scaling the at least one first image according to the present intensity of at least one lighting load in the space;
retrieving a second image of the space comprising a contribution of daylight and a

Assignees

• Lutron Tech Co Llc

Inventors

• Casey Craig Alan
• Protzman Brent
• Steiner James P

Classifications

• G05B15/02

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• H04N2201/0084

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• H04N1/40012

  Conversion of colour to monochrome · CPC title

• G06T2207/30232

  Surveillance · CPC title

• G06T2207/30196

  Human being; Person · CPC title