Method and system for monitoring and controlling workpieces
View Patent ↗Methods and systems for monitoring the delivery of workpieces to a position by: storing a digital reference image of the position prior to the delivery of workpieces; storing a digital operating image of the position during delivery of workpieces; performing image arithmetic on the reference image and the operating image to produce a digital evaluation image comprised of a plurality of pixels; establishing a threshold image condition for the evaluation image that correlates to the existence of an operating condition relevant to the control of the delivery of workpieces; and examining the pixels in the evaluation image to determine whether the threshold image condition is met.
1. A method for monitoring the delivery of workpieces to a position comprising the steps of:
storing a digital reference image of the position prior to the delivery of workpieces;
storing a digital operating image of the position during delivery of workpieces;
performing image arithmetic on the reference image and the operating image to produce a digital evaluation image comprised of a plurality of pixels;
establishing a threshold image condition for the evaluation image that correlates to the existence of an operating condition relevant to the control of the delivery of workpieces;
examining the pixels in the evaluation image to determine whether the threshold image condition is met.
2. The method of claim 1 , wherein the step of performing image arithmetic comprises the step of producing a difference image.
3. The method of claim 1 , wherein the step of performing image arithmetic comprises the step of producing an unsigned difference image.
4. The method of claim 1 , wherein the step of storing a digital reference image comprises the step of storing a plurality of different digital reference images corresponding to different environmental conditions and the step of performing image arithmetic comprises the selection of the digital reference image that is expected to correspond most closely to the operating image.
5. The method of claim 4 , wherein different reference images are stored at different times of day and wherein the step of performing image arithmetic comprises selecting the reference image corresponding to the time of day when the operating image was stored.
6. The method of claim 1 , further comprising the step of controlling the ambient light condition in the vicinity of the position.
7. The method of claim 1 wherein the threshold image condition comprises a pixel value threshold and the step of examining the pixels in the evaluation image to determine whether the threshold image condition is met comprises the step of assigning a value to a pixel in the evaluation image based upon the brightness of the pixel.
8. The method of claim 1 wherein the threshold image condition comprises a pixel value threshold and the step of examining the pixels in the evaluation image to determine whether the threshold image condition is met comprises the step of assigning a value to a pixel in the evaluation image based upon the brightness of the pixel and the brightness of at least one adjacent pixel.
9. The method of claim 1 , further comprising the step of checking a camera position reference.
10. The method of claim 9 , wherein the step of checking a camera position reference comprises the step of examining a portion of the evaluation image that corresponds to a portion of the reference image that contains a camera position target.
11. A method for controlling the delivery of packages from a package source to a plurality of lanes on a slide comprising the steps of:
storing a digital reference image of at least a portion of the lanes prior to the delivery of packages;
storing a digital operating image of at least a portion of the lanes during delivery of workpieces;
performing image arithmetic on the reference image and the operating image to produce a digital evaluation image comprised of a plurality of pixels;
establishing a threshold image condition for the evaluation image that correlates to whether a specified capacity of the lane has been exceeded;
examining the pixels in the evaluation image to determine whether the threshold image condition is met; and
generating a signal corresponding to whether the threshold image condition is met.
12. The method of claim 11 , wherein the step of performing image arithmetic comprises the step of producing a difference image.
13. The method of claim 11 , wherein the step of performing image arithmetic comprises the step of producing an unsigned difference image.
14. The method of claim 11 , wherein the step of storing a digital reference image comprises the step of storing a plurality of different digital reference images corresponding to different environmental conditions and the step of performing image arithmetic comprises the selection of the digital reference image that is expected to correspond most closely to the operating image.
15. The method of claim 14 , wherein different reference images are stored at different times of day and wherein the step of performing image arithmetic comprises selecting the reference image corresponding to the time of day when the operating image was stored.
16. The method of claim 11 , further comprising the step of controlling the ambient light condition in the vicinity of the lanes.
17. The method of claim 11 wherein the threshold image condition comprises a pixel value threshold and the step of examining the pixels in the evaluation image to determine whether the threshold image condition is met comprises the step of assigning a value to a pixel in the evaluation image based upon the brightness of the pixel.
18. The method of claim 11 wherein the threshold image condition comprises a pixel value threshold and the step of examining the pixels in the evaluation image to determine whether the threshold image condition is met comprises the step of assiging a value to a pixel in the evaluation image based upon the brightness of the pixel and the brightness of at least one adjacent pixel.
19. The method of claim 11 , further comprising the step of checking a camera position reference.
20. The method of claim 19 , wherein the step of checking a camera position reference comprises the step of examining a portion of the evaluation image that corresponds to a portion of the reference image that contains a camera position target.
21. The method of claim 11 , wherein the step of establishing a threshold image condition comprises the step of establishing a plurality of threshold image conditions.
22. A system for monitoring the flow of packages from a package source to a lane comprising the steps of:
means for storing a digital reference image of at least a portion of the lane prior to the delivery of packages;
means for storing a digital operating image of at least a portion of the lane during delivery of workpieces;
means for performing image arithmetic on the reference image and the operating image to produce a digital evaluation image comprised of a plurality of pixels;
means for storing a threshold image condition for the evaluation image that correlates to whether a specified capacity of the lane has been exceeded;
means for examining the pixels in the evaluation image to determine whether the threshold image condition is met.
23. The system of claim 22 , further comprising means for controlling changes in the ambient light condition in the vicinity of the lane.
24. The system of claim 22 wherein the means for examining the pixels in the evaluation image comprises means for assigning a value to a pixel in the evaluation image based upon the brightness of the pixel.
25. The system of claim 22 wherein the means for examining the pixels in the evaluation image comprises means for assigning a value to a pixel in the evaluation image based upon the brightness of the pixel and the brightness of at least one adjacent pixel.
26. The system of claim 22 , further comprising means for checking a camera position reference.
27. The system of claim 26 , wherein means for checking a camera position reference comprises means for examining a portion of the evaluation image that corresponds to a portion of the reference image that contains a camera position target.