APPARATUS AND METHOD FOR CAMERA-BASED COLOR MEASUREMENTS

• US 20090185185A1
• Filed: 01/22/2008
• Published: 07/23/2009
• Est. Priority Date: 01/22/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Shakespeare, John F., Shakespeare, Tarja T.
• Granted Patent: US 8,049,892 B2
• Time in Patent Office: Days
• US Class Current: 356/406
• CPC Class Codes: G01J 2003/1213 Filters in general, e.g. dichroic, band
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01N 21/3563 for analysing solids; Preparation of samples therefor

Abstract

A method includes receiving light from a material at a digital imaging device. The method also includes filtering the light into at least three spectral bands using a filter, where different regions of the filter pass different spectral bands. The method further includes measuring the light in each of the spectral bands and determining at least one color associated with the material using the measured light in the spectral bands. The different regions of the filter could include multiple masks (where each mask passes one of the spectral bands), different areas of a linear variable filter, and/or individual filters (where each individual filter passes one of the spectral bands). The digital imaging device could include a digital camera. The filter could be formed on a detector in the digital camera, and/or a component of the digital camera could be replaced with the filter.

Claims

1. A method comprising:

receiving light from a material at a digital imaging device;

filtering the light into at least three spectral bands using a filter, wherein different regions of the filter pass different spectral bands;

measuring the light in each of the spectral bands; and

determining at least one calorimetric quantity associated with the material using the measured light in the spectral bands.

2. The method of claim 1, wherein measuring the light in each of the spectral bands comprises taking multiple measurements of the light in each of the spectral bands.

3. The method of claim 1, wherein the different regions of the filter comprise multiple masks, each of the masks passing one of the spectral bands.

4. The method of claim 1, wherein the different regions of the filter comprise different areas of a linear variable filter.

5. The method of claim 1, wherein the different regions of the filter comprise individual filters each passing one of the spectral bands.

6. The method of claim 1, wherein the digital imaging device comprises a digital camera, the filter formed on a detector in the digital camera.

7. The method of claim 1, wherein the digital imaging device comprises a digital camera;

and

further comprising replacing a component of the digital camera with the filter.

8. The method of claim 1, wherein the spectral bands comprise wavelength bands that are 20 nm in width and that include one or more of:

350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, and 750 nm.

9. The method of claim 1, further comprising:

adjusting a process associated with the material based on the at least one determined calorimetric quantity.

10. The method of claim 9, wherein:

the material comprises a still or moving paper sheet; and

the process comprises one or more of;

a paper production process, a plastic production process, and a paper or textile printing process.

11. An apparatus comprising:

a filter configured to receive light associated with a material and to filter the light into at least three spectral bands, different regions of the filter passing different spectral bands;

a detector configured to generate a measurement of the light in each of the spectral bands; and

an interface configured to output the measurements for use in determining at least one calorimetric quantity associated with the material.

12. The apparatus of claim 11, wherein the detector is configured to generate multiple measurements of the light in each of the spectral bands.

13. The apparatus of claim 11, wherein the different regions of the filter comprise multiple masks, each of the masks passing one of the spectral bands.

14. The apparatus of claim 11, wherein the different regions of the filter comprise different areas of a linear variable filter.

15. The apparatus of claim 11, wherein the different regions of the filter comprise individual filters each passing one of the spectral bands.

16. The apparatus of claim 11, wherein the detector comprises a plurality of pixels each configured to measure the light in one of the spectral bands.

17. The apparatus of claim 11, wherein the detector comprises at least one of:

a charge-coupled device, a complimentary metal oxide semiconductor device, and a charge injection device in a digital camera.

18. The apparatus of claim 11, wherein the filter is disposed on a surface of the detector.

19. A system comprising:

an illumination source configured to illuminate a material; and

a color sensor comprising;

a filter configured to receive light associated with the material and to filter the light into at least three spectral bands, different regions of the filter passing different spectral bands;

a detector configured to generate measurements of the light in each of the spectral bands; and

an interface configured to output the measurements for use in determining at least one colorimetric quantity associated with the material.

20. The system of claim 19, further comprising:

one or more controllers configured to determine the at least one calorimetric quantity associated with the material and to control a processing or production system based on the at least one determined calorimetric quantity.

21. The system of claim 19, wherein the at least one calorimetric quantity comprises at least one of:

a spatial calorimetric quantity based on an image of the material; and

an average color of the material.