US 12,288,375 B2
Acquisition of optical characteristics
Abhijeet Ghosh, Orpington (GB); Gaurav Chawla, Shenfield (GB); Yiming Lin, London (GB); Jayanth Kannan, Colchester (GB); and Ekin Ozturk, London (GB)
Assigned to Lumirithmic Limited, Winchester (GB)
Filed by Lumirithmic Limited, Winchester (GB)
Filed on Oct. 18, 2021, as Appl. No. 17/504,070.
Claims priority of application No. 2110738 (GB), filed on Jul. 26, 2021.
Prior Publication US 2023/0022108 A1, Jan. 26, 2023
Int. Cl. G06V 10/60 (2022.01); G06T 7/55 (2017.01); G06T 15/04 (2011.01); G06T 15/50 (2011.01); G06V 10/141 (2022.01)
CPC G06V 10/60 (2022.01) [G06T 7/55 (2017.01); G06T 15/04 (2013.01); G06T 15/506 (2013.01); G06V 10/141 (2022.01); G06T 2207/10048 (2013.01)] 21 Claims
OG exemplary drawing
 
1. Apparatus comprising:
two or more colour displays arranged to provide piece-wise continuous illumination of a volume;
one or more cameras, each camera arranged to image the volume;
wherein the apparatus is configured to control the two or more colour displays and the one or more cameras:
to illuminate the volume with each of two or more illumination conditions, wherein each illumination condition is intensity modulated across the area of the two or more colour displays so as to simulate emission from an area of a spherical surface, a parabolic surface, or an ellipsoidal surface;
to obtain two or more sets of images, each set of images being obtained during illumination of the volume with one or more corresponding illumination conditions;
wherein the two or more sets of images comprise sufficient information for direct calculation of a specular reflectance map, a diffuse reflectance map, and a photometric normal map of an object or subject positioned within the volume;
wherein viewed from the volume, the apparatus only provides direct illumination of the volume from angles within a zone of a hemisphere, the zone being less than a hemisphere and corresponding to a first range of latitudinal angles and a second range of longitudinal angles, wherein each of the first and second ranges is no more than 17π/18;
further comprising one or more additional light sources arranged to provide illumination of the volume, each additional light source configured to provide direct illumination of the volume only from angles within the zone;
wherein the apparatus is configured to control the two or more colour displays and the one or more additional light sources, and wherein at least one of the illumination conditions comprises or consists of light emitted by an additional light source;
wherein the additional light sources comprise one or more area light sources and/or one or more point light sources;
wherein the two or more illumination conditions comprise three or more illumination conditions including at least first and second spectrally resolvable illumination conditions;
wherein the first spectrally resolvable illumination condition consists of light provided by the two or more colour displays;
wherein the second spectrally resolvable illumination condition consists of light provided by all of the one or more additional light sources or a subset of the one or more additional light sources;
wherein the apparatus is configured to illuminate the volume with the first and second spectrally resolvable illumination conditions concurrently;
wherein one set of images of the two or more sets of images takes the form of a first set of spectrally multiplexed images corresponding to a superposition of the first and second spectrally resolvable illumination conditions.