Patent ID: 9373052
Filing Date: 2016-06-21
CPC Classification: G01B,G01N,G06K,G06T

Claim Text:
1. A computer implemented method to estimate shape information and one or more photometric invariants of a location of a scene as represented in hyperspectral or multispectral image data, the image data being indexed by wavelength and polarisation filter angle, the method comprising: (a) for each wavelength index, estimating a polarisation angle from the image data by fitting intensity information of the image data to a function of the filter angle; (b) for each wavelength index, estimating a degree of polarisation based on intensity values of the function with reference to the estimated polarisation angle for that wavelength index; (c) estimating the zenith of a surface normal of the scene at the location based on the estimated degree of polarisation for each wavelength index; and (d) estimating multiple values of a photometric invariant based on the estimated degree of polarization, each of the multiple values of the photometric invariant being for a respective wavelength index, wherein estimating the multiple values of the photometric invariant is based on multiple constraints for the photometric invariant, each of the multiple constraints being a constraint for the photometric invariant for the respective wavelength index, each of the multiple constraints for the photometric invariant relates the photometric invariant to the respective wavelength index and is a function of a number of multiple constraint variables, the number of multiple constraint variables being smaller than the number of wavelength indices.