US 12,322,128 B2
Method, system and apparatus for photometric stereo reconstruction of a surface
Arnaud Lina, Montreal (CA)
Assigned to Matrox Electronics Systems, Ltd., Quebec (CA)
Filed by Matrox Electronics Systems, Ltd., Lincolnshire, IL (US)
Filed on May 25, 2023, as Appl. No. 18/202,232.
Claims priority of provisional application 63/356,478, filed on Jun. 28, 2022.
Prior Publication US 2023/0419523 A1, Dec. 28, 2023
Int. Cl. G06T 7/586 (2017.01); H04N 13/106 (2018.01); H04N 13/207 (2018.01); H04N 13/254 (2018.01)
CPC G06T 7/586 (2017.01) [H04N 13/106 (2018.05); H04N 13/207 (2018.05); H04N 13/254 (2018.05); G06T 2207/10152 (2013.01); G06T 2207/30168 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A method of generating a photometric stereo reconstruction of a surface using an illumination system including a plurality of lights including a pair of lights, the pair of lights including a first light and a second light, the method comprising:
capturing a first image of the surface with the surface illuminated from a first direction along an axis of the pair of lights by the first light with each other light of the plurality of lights off, the first light oriented at a first elevation angle;
capturing a second image of the surface with the surface illuminated from a second direction along the axis of the pair of lights by the second light with each other light of the plurality of lights off, the second direction being opposite the first direction, the second light oriented at a second elevation angle, the second elevation angle being substantially identical to the first elevation angle;
processing the first image by taking a derivative of a first reflected light intensity along the axis of the pair of lights at each of a first plurality of pixel locations in the first image, respectively;
processing the second image by taking a derivative of a second reflected light intensity along the axis of the pair of lights at each of a second plurality of pixel locations in the second image, respectively, each one of the respective second plurality of pixel locations corresponding to a respective one of the first plurality of pixel locations;
employing both the derivative of the first reflected light intensity taken at each of the first plurality of pixel locations in the first image and the derivative of the second reflected light intensity taken at each of the second plurality of pixel locations in the second image to identify a set of invalid pixels where a photometric stereo condition is not satisfied; and
generating the photometric stereo reconstruction of the surface, the photometric stereo reconstruction based on a plurality of images including the first image and the second image and based on the identified set of invalid pixels.