METHOD AND APPARATUS FOR ESTIMATING ILLUMINATION LIGHT SPECTRAL CHARACTERISTIC, AND INFORMATION-RECORDING MEDIUM RECORDING SPECTRAL CHARACTERISTIC ESTIMATION PROGRAM

摘要

PROBLEM TO BE SOLVED: To estimate a spectral characteristic of an illumination light with the utilization of an image pickup system without using a special measuring device by estimating the spectral characteristic of the illumination light irradiating a standard plate with the use of an optimization method. ;SOLUTION: According to this method, a standard plate 1 having a plurality of color chips of different spectral reflectances set on the same plane is arranged at a specific position in a space, an image of the standard plate is picked up by an image pickup means 2, and a spectral characteristic of an illumination light irradiating the standard plate 1 is estimated from the obtained image data with the use of an optimization method. More specifically, a pickup response value corresponding to each color chip on the standard plate 1 is extracted from the image data and set as a target variable. Either before or after the extraction of the target variable, an explanation variable is formed from the spectral reflectance of each color chip and a spectral sensitivity characteristic of the image pickup means 2. The optimization method is carried out with the use of the target variable and the explanation variable, so that an optimal solution representing the spectral characteristic of the illumination light irradiating the standard plate 1 is obtained. The spectral characteristic of the illumination light is thus estimated.;COPYRIGHT: (C)1999,JPO