Patent ID: 6445812
Filing Date: 2002-09-03
Classification: G06K,G06T

Abstract:
A method for compensating for variations of illumination in an automatic visual inspection system, the method comprising the steps of:receiving image data; estimating an illumination component based on the image data; removing the estimated illumination component from the image data to provide illumination-compensated image data; and outputting the illumination-compensated image data to the visual inspection system for further processing, wherein the step of estimating an illumination component comprises the steps of: computing an image brightness function representing the image data, the image brightness function being the product of an irradiance function and a reflectance function; and estimating the irradiance function from the image data; and wherein the step of removing the estimated illumination component comprises the steps of: computing the reflectance function using the estimated irradiance function and the computed image brightness function, the computed reflectance function representing the illumination-compensated image data.