Apparatus and method for measuring color

• US 20070076206A1
• Filed: 09/18/2006
• Published: 04/05/2007
• Est. Priority Date: 01/02/1996
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: JJL Technologies, L.L.C.
• Inventors: Jung, Wayne, Jung, Russell, Loudermilk, Alan
• Granted Patent: US 7,400,404 B2
• Time in Patent Office: Days
• US Class Current: 356/406
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/0233 Optical standards
• CPC Class Codes: A61C 19/10 Supports for artificial teeth for transport or for comparison of the colour
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/0297 Constructional arrangements for removing other types of optical noise or for performing calibration
• CPC Class Codes: G01J 3/04 Slit arrangements slit adjustment
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/508 measuring the colour of teeth
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G01J 3/524 Calibration of colorimeters
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 21/474 : Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/57 : Measuring gloss

Abstract

Color measuring systems and methods are disclosed. Perimeter receiver fiber optics are spaced apart from a central source fiber optic and receive light reflected from the surface of the object being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object being measured. Under processor control, the color measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention.

Claims

1. (canceled)

2. A method in a color measurement apparatus for determining a color characteristic based on light returned from an object or material comprising the steps of:

generating and supplying light of a plurality of wavelengths or spectral bands to the object or material;

receiving light returned from the object or material with a sensor, wherein the sensor generates one or more output signals having a frequency proportional to an intensity of light received by the sensor;

generating at least a first signal having a frequency proportional to an intensity of light received by the sensor of a first wavelength or spectral band;

generating at least a second signal having a frequency proportional to an intensity of light received by the sensor of a second wavelength or spectral band; and

generating at least a third signal having a frequency proportional to an intensity of light received by the sensor of a third wavelength or spectral band;

wherein the color characteristic of the received light is determined based on at least the first, second and third signals.

3. The method of claim 2, wherein the sensor outputs one or more digital signals.

4. The method of claim 3, wherein the one or more digital signals comprise TTL or CMOS compatible signals.

5. The method of claim 4, wherein the one or more digital signals are coupled to a microprocessor or logic circuitry without analog-to-digital conversion.

6. The method of claim 2, wherein one or more signals output from the sensor are coupled to a processing element, wherein the color characteristic is determined based on measuring a frequency of the one or more signals.

7. The method of claim 2, wherein one or more signals output from the sensors are coupled to a processing element, wherein the color characteristic is determined based on measuring a period of the one or more signals.

8. The method of claim 2, wherein the color measurement apparatus comprises a spectrometer.

9. The method of claim 2, wherein the color measurement apparatus comprises a colorimeter.

10. The method of claim 2, wherein light is coupled to or from the object or material via one or more fiber optics.

11. The method of claim 2, wherein the color characteristic is determined based on a calibration measurement.

12. The method of claim 2, wherein the color characteristic is used to determine a closest color among a set of stored colors.

13. The method of claim 2, wherein the light is generated via a broadband light source and the sensor comprises a plurality of sensing elements.

14. The method of claim 2, wherein the light is generated via a plurality of colored light sources and the sensor comprises a single sensor.

15. The method of claim 2, wherein a processing element receives the first, second and third signals, wherein the processing element determines a plurality of data values from the first, second and third signals at a predetermined timing, wherein, based on the plurality of data values determined from the first, second and third signals, a frequency or period determination is made for each of the first, second and third signals.

16. The method of claim 2, wherein the sensor comprises an array of photodiodes.

17. The method of claim 2, wherein the color characteristic is used to determine one or more closest matches to a plurality of stored colors or shades, wherein the stored colors or shades comprise shades of one or more dental shade guide systems.

18. A method in a color measurement apparatus for determining a color characteristic based on light returned from an object or material comprising the steps of:

generating and supplying light of a plurality of wavelengths or spectral bands to the object or material;

receiving light returned from the object or material with a sensor, wherein the sensor generates one or more output signals having a frequency proportional to an intensity of light received by the sensor;

generating at least a first signal having a frequency proportional to an intensity of light received by the sensor of a first wavelength or spectral band;

generating at least a second signal having a frequency proportional to an intensity of light received by the sensor of a second wavelength or spectral band; and

generating at least a third signal having a frequency proportional to an intensity of light received by the sensor of a third wavelength or spectral band;

wherein the color characteristic of the received light is determined based on at least the first, second and third signals;

wherein the color characteristic is used to determine a closest color or shade among a set of stored colors or shades.

19. The method of claim 18, wherein the light is generated via a broadband light source and the sensor comprises a plurality of sensing elements.

20. The method of claim 18, wherein the light is generated via a plurality of colored light sources and the sensor comprises a single sensor.

21. The method of claim 18, wherein the stored colors or shades comprises shades of one or more dental shade guide systems.

22. The method of claim 18, wherein the color measurement apparatus comprises a spectrometer.

23. The method of claim 18, wherein the color measurement apparatus comprises a calorimeter.

24. A method in a color measurement apparatus for determining a color characteristic based on light returned from an object or material comprising the steps of:

generating and supplying light of a plurality of wavelengths or spectral bands to the object or material;

receiving light returned from the object or material with a sensor, wherein the sensor generates one or more output signals having a frequency proportional to an intensity of light received by the sensor;

generating at least a first signal having a frequency proportional to an intensity of light received by the sensor of a first wavelength or spectral band;

generating at least a second signal having a frequency proportional to an intensity of light received by the sensor of a second wavelength or spectral band;

generating at least a third signal having a frequency proportional to an intensity of light received by the sensor of a third wavelength or spectral band;

wherein the color characteristic of the received light is determined based on at least the first, second and third signals;

wherein the first, second and third signals are generated via one or more photodiodes coupled to an integrator;

wherein the first, second and third signals are coupled to a processing element, wherein the color characteristic is determined based on measuring a frequency or period of the at least first, second and third signals.

25. The method of claim 24, wherein the color characteristic is used to determine one or more closest matches to a plurality of stored colors or shades, wherein the stored colors or shades comprise shades of one or more dental shade guide systems.

26. The method of claim 24, wherein the color measurement apparatus comprises a spectrometer.

27. The method of claim 24, wherein the color measurement apparatus comprises a calorimeter.

28. The method of claim 24, wherein the light is generated via a broadband light source and the sensor comprises a plurality of sensing elements.

29. The method of claim 24, wherein the light is generated via a plurality of colored light sources and the sensor comprises a single sensor.