Patent ID: 8295578

Claim:
A method of processing image data, the method comprising: receiving image data indicative of an optical response of a plurality of materials of an object in a plurality of wavelength bands each having a pre-selected bandwidth in the range from about two nanometers to about forty nanometers, wherein the image data comprises image data for a plurality of image pixels; comparing the image data to reference data corresponding to a plurality of candidate materials, the reference data comprising data indicative of an optical response of each of the candidate materials for the plurality of wavelength bands; determining an identity of a first material of the plurality of materials corresponding to a first image pixel of the plurality of image pixels based on the comparing; and determining an identity of a second material of the plurality of materials corresponding to a second image pixel of the plurality of image pixels based on the comparing, wherein the reference data comprises data indicative of an optical response of each of the candidate materials for the plurality of different wavelength bands collected at one or both of a plurality of different reflection, angles and/or a plurality of different light illumination intensities, wherein the comparing comprises determining a higher order error amount using a difference between a derivative with respect to wavelength of the image data for each of the plurality of wavelength bands and a derivative with respect to wavelength of the data indicative of the optical response of at least some of the candidate materials for the plurality of wavelength bands.