Systems and methods for sensing occupancy

1. A computer implemented method for sensing occupancy of a workspace, comprising:

creating a difference image that represents luminance differences of pixels between past and current images of the workspace resulting from motion in the workspace;

determining motion occurring in regions of the workspace based on the difference image;

altering a workspace environment based at least in part on the determined motion;

determining which pixels in the difference image represent persistent motion that can be ignored;

determining which pixels representing motion in the difference image are invalid because the pixels are isolated from other pixels representing motion;

determining the number of pixels representing motion in each of a plurality of regions in the workspace and creating a trigger representative of the region having the most pixels representing motion;

evaluating the trigger based on a pre-set priority; and

updating a state machine using a signal representing the evaluated trigger, the state machine controlling the workspace environment.

2. The method of claim 1 , wherein creating the difference image includes comparing an absolute value of the difference in luminance between the images to a threshold value, setting a corresponding pixel in the difference image to 1 if the difference is greater than the threshold value, and setting the corresponding pixel in the difference image to 0 if the difference is less than the threshold value.

3. The method of claim 1 , further comprising:

comparing every pixel representing motion to immediate neighboring pixels, and if the immediate neighboring pixels are not pixels representing motion, changing a value of the compared pixel representing motion.

4. The method of claim 1 , further comprising:

creating a persistence image having a pixel corresponding to each pixel in the difference image, the pixels in the persistence image being incremented in value each time a pixel in the difference image is determined to represent motion.

5. The method of claim 1 , further comprising:

creating a motion history image representing how recently motion was detected in each pixel representing motion in the difference image.

6. The method of claim 5 , further comprising:

assigning a pixel value to pixels in the motion history image corresponding to pixels in the difference image representing motion, and subtracting from the pixel value each time a pixel in the current image is determined to not represent motion.

7. A computer implemented method for sensing occupancy of a workspace, comprising:

creating a difference image that represents luminance differences of pixels in two sequential images of the workspace resulting from motion in the workspace, the difference image including motion pixels and non-motion pixels;

determining which motion pixels are invalid by comparing the motion pixels to adjacent pixels and changing the motion pixels to non-motion pixels if the adjacent pixels are not also motion pixels;

creating an updated difference image with the pixels changed from motion pixels to non-motion pixels;

altering a workspace environment based at least in part on the updated difference image;

determining the number of motion pixels in each of a plurality of regions in the workspace, and creating a trigger representative of the region which has the most motion pixels; and

updating a state machine using the trigger, the state machine controlling the workspace environment.

8. The method of claim 7 , further comprising:

creating a persistence image having a pixel corresponding to each pixel in the difference image, the pixels in the persistence image being incremented in value each time a pixel in the difference image is determined to represent motion.

9. The method of claim 7 , further comprising:

creating a motion history image representing how recently motion was detected in each motion pixel.

10. A computer implemented method for sensing occupancy of a workspace, comprising:

creating a difference image that represents luminance differences of pixels in two sequential images of the workspace resulting from motion in the workspace, the difference image including motion pixels and non-motion pixels;

creating a persistence image having pixels corresponding to pixels of the difference image, a value of the pixels in the persistence image being increased each time a corresponding motion pixel is identified in the difference image, the value being decreased when a corresponding non-motion pixel is identified in the difference image, wherein the pixels in the persistence image are ignored when the value exceeds a threshold value; and

altering a workspace environment based at least in part on the persistence and difference images.

11. The method of claim 10 , further comprising:

determining motion occurring in regions of the workspace based at least in part on the persistence and difference images.

12. The method of claim 10 , further comprising:

creating a motion history image representing how recently motion was detected in each motion pixel.

13. The method of claim 11 , further comprising:

determining the number of pixels representing motion in each of the regions in the workspace and creating a trigger representative of the region having the most pixels representing motion.

14. The method of claim 13 , further comprising:

evaluating the trigger based on a pre-set priority.

15. The method of claim 13 , further comprising:

updating a state machine using a signal representing the trigger, the state machine controlling alterations to the workspace environment.