An Illumination-Adaptive Colorimetric Measurement Using Color Image Sensor

Colorimetric Analysis Using Scene-Adaptive Color Conversion Matrix of Calibrated CIS

“…However, this requires phosphor chromaticity information for the RGB and white reference to be previously measured. An alternative method is color measurement based on multicharacterization and illuminant estimation [13]. First, the representative camera transfer matrix is measured for A, D50, and D65 illuminants.…”

“…The color-targetbased method uses reference colors obtained from their values on a color chart and thus is relatively simple and practical when compared to the spectral-sensitivity-based method that requires spectral analysis of the camera. The polynomial regression method based on least squares fitting has been widely adopted by many color researchers for calculation of the transfer matrix from the captured RGB values and their values [9][10][11][12][13]. However, camera characterization under the specific standard illuminant does not provide good estimations for the different ambient light conditions in which an image is captured.…”

“…Generally, most color images from CISs should be calibrated chromatically to remove specific color cast. The changed transfer matrix for any other white balance condition can be obtained based on the surrounding illumination and the phosphor primaries of a camera [12,13]. However, color measurement performance can be enhanced using a recalculated transfer matrix based on illuminant estimation techniques.…”