OPTICAL PROCESSING OF SURFACES TO DETERMINE CLEANLINESS

• US 20100328476A1
• Filed: 12/01/2009
• Published: 12/30/2010
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Ecolab, Inc.
• Inventors: Wagner, Christopher C.
• Granted Patent: US 8,229,204 B2
• Time in Patent Office: Days
• US Class Current: 348/222.1
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/30124 Fabrics; Textile; Paper
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: G06V 10/141 Control of illumination

Abstract

Techniques are described for determining cleanliness of various surfaces by processing images of the surfaces. The surfaces may comprise, for example, drinking glasses, dishes, fabric swatch arrays, Tosi plates, ceramic tiles, or stainless steel coupons. In one example, a system includes a camera to capture a digital image of a surface, a light source to illuminate the surface, a housing to enclose the surface, the camera, and the light source in a light-tight environment, and an analysis computer to receive the digital image, calculate a luminosity value for the surface from the digital image, and determine a cleanliness value for the surface from the calculated luminosity value. The analysis computer may automatically configure an environment in which to capture the digital image such that the environment is suited for the particular surface to be analyzed. The analysis computer may also cause the camera to automatically capture the digital image.

Claims

1. A method comprising:

receiving, with a computing device, a digital image of a surface;

calculating a luminosity value for the surface from the digital image; and

determining, with the computing device, a cleanliness value for the surface from the calculated luminosity value.

2. The method of claim 1, wherein the digital image of the surface comprises a digital representation of the surface captured in an environment suited to the surface.

3. The method of claim 1, further comprising receiving, with the computing device, an identification of a ware type corresponding to the surface.

4. The method of claim 3, further comprising sending, with the computing device, electrical signals to automatically configure an environment in which to capture the digital image of the surface based on the identification of the ware type, wherein the environment comprises at least one of a lighting arrangement, a lighting position relative to the surface, a housing, an internal coloring of the housing, a camera position relative to the surface, a camera aperture, and a camera shutter speed.

5. The method of claim 4,

wherein receiving the identification comprises receiving an identification that the ware type comprises one of a drinking glass, a plate, and a stainless steel coupon, and

wherein sending electrical signals comprises sending a first electrical signal to position an array of light-emitting diodes (LEDs) such that light emitted by the LEDs of the array is aimed at the surface and a second electrical signal to enable the LEDs of the array.

6. The method of claim 4,

wherein receiving the identification comprises receiving an identification that the ware type comprises one of a fabric swatch array and a ceramic tile, and

wherein sending electrical signals comprises sending at least one electrical signal to an array of light-emitting diodes (LEDs) to enable the LEDs of the array, wherein the array of LEDs is configured to provide diffused lighting to illuminate the surface.

7. The method of claim 1, further comprising:

sending a first electrical signal to a camera to cause the camera to capture the digital image of the surface;

sending a second electrical signal to the camera to retrieve the captured digital image from the camera; and

receiving the digital image from the camera.

8. The method of claim 1, wherein calculating the luminosity value for the surface comprises:

calculating a histogram from luminosity values of pixels of the digital image, wherein the histogram comprises a plurality of bins corresponding to a range of the luminosity values, and wherein each bin of the histogram comprises a bin index and a bin value representative of a number of pixels in the digital image that have the luminosity value corresponding to the bin index; and

calculating an average luminosity value from the histogram.

9. The method of claim 1, wherein determining a cleanliness value comprises correlating the calculated luminosity value to predetermined cleanliness values.

10. The method of claim 9, wherein the predetermined cleanliness values correspond to known cleanliness values for control surfaces of the same type as the surface depicted in the digital image.

11. The method of claim 1, further comprising:

determining a threshold luminosity value; and

counting a number of pixels in the digital image for which corresponding luminosity values exceed the threshold luminosity value,

wherein determining the cleanliness value further comprises determining the cleanliness value from the luminosity value for the surface and the counted number of pixels.

12. A system comprising:

a camera to capture a digital image of a surface;

a light source to illuminate the surface;

a housing to enclose the surface, the camera, and the light source in a light-tight environment; and

an analysis computer to receive the digital image, calculate a luminosity value for the surface from the digital image, and determine a cleanliness value for the surface from the calculated luminosity value.

13. The system of claim 12, wherein the analysis computer is configured to automatically enable the light source and send electrical signals to the camera to capture the digital image and to retrieve the digital image from the camera.

14. The system of claim 12, further comprising a light source actuator coupled to the light source to control an angle of the light source with respect to the surface, wherein the analysis computer is configured to send electrical signals to the light source actuator to control the angle of the light source.

15. The system of claim 12, further comprising a camera actuator coupled to the camera and to control a height of the camera with respect to the surface, wherein the analysis computer is configured to send electrical signals to the camera actuator to control the height of the camera.

16. The system of claim 12, wherein the surface corresponds to a stainless steel coupon, and wherein the housing comprises an interior color of white.

17. The system of claim 12, wherein the surface corresponds to a drinking glass, and wherein the housing comprises an interior color of black.

18. The system of claim 12, wherein the surface corresponds to one of a fabric swatch array or a ceramic tile, and wherein the housing comprises an interior color of black.

19. The system of claim 12, wherein the surface corresponds to a dish, wherein the housing comprises an interior color of black.

20. The system of claim of claim 12, wherein the analysis computer is configured to calculate the luminosity value for the digital image by calculating a histogram from luminosity values of pixels of the digital image, wherein the histogram comprises a plurality of bins corresponding to a range of the luminosity values, and wherein each bin of the histogram comprises a bin index and a bin value representative of a number of pixels in the digital image that have the luminosity value corresponding to the bin index, and calculating an average luminosity value from the histogram.

21. The system of claim 12, wherein the surface corresponds to a ware type, wherein the analysis computer is configured to determine the cleanliness value by correlating the calculated luminosity value to predetermined cleanliness values, wherein the predetermined cleanliness values correspond to known cleanliness values for control wares of the same ware type as the ware type corresponding to the surface depicted in the digital image.

22. The system of claim 12, wherein the light source comprises a direct-lighting array of light-emitting diodes (LEDs) and a diffused-lighting array of LEDs.

23. The system of claim 22, wherein the analysis computer enables the direct-lighting array of LEDs when a ware corresponding to the surface comprises one of a drinking glass, a stainless steel coupon, or a dish.

24. The system of claim 22, wherein the analysis computer enables the diffused-lighting array of LEDs when a ware corresponding to the surface comprises one of a fabric swatch array or a ceramic tile.

25. The system of claim 12, further comprising a washing apparatus to wash the surface, wherein the analysis computer is configured to automatically disable the washing apparatus when the analysis computer determines that the surface has achieved a cleanliness value that exceeds a threshold.

26. A computer-readable medium encoded with instructions for causing a programmable processor to:

receive a digital image of a surface;

calculate a luminosity value for the surface from the digital image; and

determine a cleanliness value for the surface from the calculated intensity value.

27. The computer-readable medium of claim 26, wherein the digital image of the surface comprises a digital representation of the surface captured in an environment suited to the surface.

28. The computer-readable medium of claim 26, further comprising receiving, with the computing device, an identification of a ware type corresponding to the surface.

29. The computer-readable medium of claim 28, further encoded with instructions to send electrical signals to automatically configure an environment in which to capture the digital image of the surface based on the identification of the ware type, wherein the environment comprises at least one of a lighting arrangement, a lighting position relative to the surface, a housing, an internal coloring of the housing, a camera position relative to the surface, a camera aperture, and a camera shutter speed.

30. The computer-readable medium of claim 29,

wherein the instructions to receive the identification comprise instructions to receive an identification that the ware type comprises one of a drinking glass, a plate, and a stainless steel coupon, and

wherein the instructions to send electrical signals comprise instructions to send a first electrical signal to position an array of light-emitting diodes (LEDs) such that light emitted by the LEDs of the array is aimed at the surface and a second electrical signal to enable the LEDs of the array.

31. The computer-readable medium of claim 29,

wherein the instructions to receive the identification comprise instructions to receive an identification that the ware type comprises one of a fabric swatch array and a ceramic tile, and

wherein the instructions to send electrical signals comprise instructions to send at least one electrical signal to an array of light-emitting diodes (LEDs) to enable the LEDs of the array, wherein the array of LEDs is configured to provide diffused lighting to illuminate the surface.

32. The computer-readable medium of claim 26, further encoded with instructions to:

send a first electrical signal to a camera to cause the camera to capture the digital image of the surface;

send a second electrical signal to the camera to retrieve the captured digital image from the camera; and

receive the digital image from the camera.

33. The computer-readable medium of claim 26, wherein the instructions to calculate a luminosity value for the surface comprise instructions to:

calculate a histogram from luminosity values of pixels of the digital image, wherein the histogram comprises a plurality of bins corresponding to a range of the luminosity values, and wherein each bin of the histogram comprises a bin index and a bin value representative of a number of pixels in the digital image that have the luminosity value corresponding to the bin index; and

calculate an average luminosity value from the histogram.

34. The computer-readable medium of claim 26, wherein the surface corresponds to a ware type, wherein the instructions to determine a cleanliness value comprise instructions to correlate the calculated luminosity value with predetermined cleanliness values, wherein the predetermined cleanliness values correspond to known cleanliness values for control wares of the same ware type as the ware type corresponding to the surface depicted in the digital image.