US 11,810,329 B2
Method, system, and device for color measurement of a surface
Yuanhao Yu, Markham (CA); Shuhao Li, Unionville (CA); Juwei Lu, North York (CA); and Jin Tang, Markham (CA)
Assigned to Huawei Technologies Co., Ltd., Shenzhen (CN)
Filed by Yuanhao Yu, Markham (CA); Shuhao Li, Unionville (CA); Juwei Lu, North York (CA); and Jin Tang, Markham (CA)
Filed on Nov. 19, 2020, as Appl. No. 16/953,029.
Prior Publication US 2022/0156979 A1, May 19, 2022
Int. Cl. G06T 7/90 (2017.01); G06N 3/084 (2023.01); G06T 7/521 (2017.01); G06T 7/557 (2017.01)
CPC G06T 7/90 (2017.01) [G06N 3/084 (2013.01); G06T 7/521 (2017.01); G06T 7/557 (2017.01)] 18 Claims
OG exemplary drawing
 
1. A method of measuring a color of a target surface using a color measuring device, comprising:
capturing a plurality of digital images of the target surface using a camera of the color measuring device as the target surface is illuminated with constant color light emitted by a controlled light source of the color measuring device that is in a fixed position relative to the camera and a constant intensity, constant color environmental light, wherein the intensity of the light illuminating the target surface is varied by a known amount between the capturing of the images;
generating, image data included in the plurality of images, a plurality of linear equations based on the image data from each image in the plurality of images, the image data comprising a sum of a product of the color of the controlled light source and a surface color of the target surface and a product of the environmental light source and the surface color of the target surface;
determining a color feature tensor that corresponds to the product of the color of the light emitted by the controlled light source and the surface color of the target surface from the plurality of linear equations using linear regression; and
inferring the surface color of the target surface based on the color feature tensor.