Patent ID: 7133494
Filing Date: 2006-11-07
Classification: A61B

Abstract:
1. A method for examining an object comprising at least two categories of materials in order to determine a value of a physical parameter of each of said materials, the method comprising the steps of: applying radiation through the object, the radiation belonging to a broadband energy spectrum; taking a plurality, of measurements of the radiation after having passed through the object, said measurements being taken at respective energy bands in said spectrum; selecting a plurality of pairs of said energy bands; defining, for each of said materials and each of said pairs, a function of an intermediate parameter ({circumflex over (M)}) based on the measurements in the energy bands in the pair and on coefficients obtained in a previous calibration, each of said intermediate parameters being an estimation of the value of the physical parameter for one of said materials, and calculating values of said intermediate parameters; defining a weighted sum of said intermediate parameters for each of said materials, the intermediate parameters ({circumflex over (M)}) being weighted by weighting coefficient; calculating values of said weighting coefficients by minimizing a variance of said weighted sum; and calculating, for each of the materials, said value of said physical parameter with the weighted sum based on said values of said weighted coefficients and said values of said intermediate parameters.