US-20260127766-A1 - COLOR AND SHADE DETECTION DEVICE AND METHOD

Abstract

A device includes one or more homogenous telecentric illuminators, a 3D digital scanner arranged to scan the physical object and provide a 3D scan of the physical object, a 2D digital image detector arranged to generate a 2D digital image of the physical object and an object platform arm arranged to translate and rotate the physical object. Calibration includes determining a 3D digital scanner transform, a 2D digital image transform, and a color calibration matrix. A method includes receiving a 3D digital model of a physical object, arranging the physical object in a plane of detection of a 2D digital image detector, illuminating at least the pre-marked best color determination region with a unique light wavelength, taking a 2D digital image of at least the pre-marked best color determination region at the unique light wavelength, repeating illuminating and taking a 2D digital image for multiple unique light wavelengths, and determining a spectral response for each pixel in the 2D digital image.

Inventors

• Kunal Patil

Assignees

• JAMES R. GLIDEWELL DENTAL CERAMICS, INC.

Dates

Publication Date

20260507

Application Date

20251105

Claims (20)

1. 1 . A device for detecting color and shade, comprising: one or more homogenous telecentric illuminators; a 3 dimensional scanner (3D digital scanner) arranged to scan the physical object and provide a 3D scan of the physical object; a 2D digital image detector arranged to generate a 2D digital image of the physical object; and an object platform arm arranged to translate and rotate the physical object.
2. 2 . The device of claim 1 , wherein each of the one or more homogenous telecentric illuminators comprises a light source and a bi-telecentric lens.
3. 3 . The device of claim 2 , wherein the light source comprises one or more light emitters emitting light at a unique light wavelength.
4. 4 . The device of claim 2 , wherein each of the one or more homogenous telecentric illuminators comprise a first light guide to receive light emitted from the light source and transmit a homogenous and diffused light.
5. 5 . The device of claim 4 , further comprising a second light guide that receives the homogenous and defused light and transmits further homogenized and diffused light to the bi-telecentric lens.
6. 6 . The device of claim 1 , further comprising a flux detector attached to an output lens of the bi-telecentric lens of each homogenous telecentric illuminator.
7. 7 . The device of claim 1 , further comprising a polarizing lens attached to an output lens of the bi-telecentric lens of each homogenous telecentric illuminator to output polarized light.
8. 8 . The device of claim 1 , further comprising an enclosure to block outside light during operation.
9. 9 . A computer-implemented method of calibrating a device for color and shade detection, comprising: determining a 3D digital scanner to machine coordinate system transform; determining a 2D digital image detector to machine coordinate transform; and determining a color calibration matrix.
10. 10 . The method of claim 9 , wherein determining the color calibration matrix comprises using one or more certified color calibration tiles.
11. 11 . The method of claim 10 , wherein determining the color calibration matrix comprises taking a 2D digital image of each certified tile at a particular unique light wavelength to generate a recorded tile pixel value.
12. 12 . The method of claim 9 , further comprising determining a base glossiness.
13. 13 . The method of claim 12 , wherein determining base glossiness comprises detecting a 2D image of a physical object illuminated by light of a wavelength greater than a maximum polarizing wavelength.
14. 14 . A computer-implemented method of determining color and shade, comprising: receiving a 3D digital model of a physical object comprising a pre-marked best color determination region; arranging the physical object so that the pre-marked best color determination region is in a plane of detection of a 2D digital image detector; illuminating at least the pre-marked best color determination region with a unique light wavelength; taking a 2D digital image of at least the pre-marked best color determination region at the unique light wavelength; repeating illuminating and taking a 2D digital image for multiple unique light wavelengths; and determining a spectral response for each pixel in the best color determination pixel region in the 2D digital image.
15. 15 . The method of claim 14 , further comprising determining an absolute color for each pixel in the best color determination region.
16. 16 . The method of claim 14 , further comprising determining a current white tile image.
17. 17 . The method of claim 14 , wherein illuminating the physical object comprises using one or more homogenous telecentric illuminators.
18. 18 . The method of claim 17 , wherein each of the one or more homogenous telecentric illuminators comprises a light source comprising one or more light emitters.
19. 19 . The method of claim 18 , wherein each light emitter of the one or more light emitters emits light at a unique wavelength.
20. 20 . The method of claim 18 , wherein each of the one or more homogenous telecentric illuminators comprises a polarizer to polarize emitted light.

Description

RELATED APPLICATIONS The present application claims priority to and the benefit of co-pending U.S. Provisional Patent Application Ser. No. 63/717,639, entitled Color And Shade Detection Device And Method, filed on November 7, 2024, which is herein incorporated by reference in its entirety. BACKGROUND Historically, physical objects such as dental restorations are checked for color and shade by human observations. One issue with the human observation approach is color and shade determination is subjective, not quantitative. Spectrometers are typically not suited for measuring color and shade on uneven surfaces. Spectrometric measurement of uneven shiny or textured surfaces—such as those found on many physical objects, including dental restoration surfaces--can be very challenging. Moreover if the surface exhibits translucency behavior, the thickness of the surface can affect the reflectance. Even spectrophotometric devices that can measure the color of the surface of a physical object such as dental restorations do not accommodate for change in shade due to thickness of the walls of the physical object/dental restoration, which can change the translucency. Measurements can also be affected due to the angle between the normal to the target surface and axis of the light from light source(s). Maintaining the sensor/camera axis parallel to the symmetry plane of the light source(s) can be challenging and time consuming, particularly in mass production environments. In the mass production environment, it can also be challenging to maintain the homogeneity of the light onto the target by keeping the distance between the object/ dental restoration surface and the light source constant. Additionally, many devices available in the market do not account for fluorescence effects. Light Emitting Diode (“LED”) flux can change over time with respect to the temperature, which can have implications on the production floor, and requires calibration. Finally, existing devices may not be adaptable for quality control (“QC”). Existing devices typically output the closest matching shade based on weighted distance approach, delta E difference from selected shade or raw lab color values. Full volumetric surface color measurement is not performed. SUMMARY Disclosed is a device for detecting color and shade. The device can include one or more homogenous telecentric illuminators, a 3 dimensional scanner (3D digital scanner) arranged to scan the physical object and provide a 3D scan of the physical object, a 2D digital image detector arranged to generate a 2D digital image of the physical object and an object platform arm arranged to translate and rotate the physical object. Also disclosed is a computer-implemented method of calibrating a device for color and shade detection. The method can include determining a 3D digital scanner to machine coordinate system transform, determining a 2D digital image detector to machine coordinate transform and determining a color calibration matrix. Also disclosed is a computer-implemented method of determining color and shade. The method can include receiving a 3D digital model of a physical object comprising a pre-marked best color determination region, arranging the physical object so that the pre-marked best color determination region is in a plane of detection of a 2D digital image detector, illuminating at least the pre-marked best color determination region with a unique light wavelength, taking a 2D digital image of at least the pre-marked best color determination region at the unique light wavelength, repeating illuminating and taking a 2D digital image for multiple unique light wavelengths, and determining a spectral response for each pixel in the best color determination pixel region in the 2D digital image. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing the outside of a color and shade detection device in some embodiments. FIG. 2 is a perspective view showing the inside of a color and shade detection device from a front side in some embodiments. FIG. 3 is a perspective view showing the inside of a color and shade detection device from a back side in some embodiments. FIG. 4 is an top orthogonal view of a diagram of the inside of a color and shade detection device in some embodiments. FIG. 5 is a diagram of the inside of a light source in some embodiments. FIG. 6 is a cross-sectional side view of an illustration of a bi-telecentric lens in some embodiments. FIG. 7 is a table of wavelengths to absolute color mappings in some embodiments. FIG. 8 is a top view diagram of a portion of the inside of a color and shade detection device configured for glossiness detection in some embodiments. FIG. 9 is a flow diagram in some embodiments. FIG. 10 is a diagram of a computing environment in some embodiments. DETAILED DESCRIPTION For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The disclo