以三維查表和插值之彩色掃瞄器至彩色映像管的色彩重現

Abstract

Colorimetric reproduction is becoming more common and available on allcomputer graphics systems. The objective of this thesis is to study the table-based colorimetric reproduction process for input and output devices rangingfrom color scanner to color CRT monitor. The colorimetric rerpoduction usesthe device-independent color space such as CIEXYZ or CIELUV as an intermediatestandard color space. Input and output devices such as scanners and CRT monitorsare calibrated separately with respect to the standard color space for accuratecolor information exchange. One way of the calibration process is to use a three-dimensional (3D) look-up table (LUT) and interpolation which map the device-dependent responses to the device-independent representations. In the study, atwo-step process of gray-balancing and a matrix transformation were used to characterize color scanners and to establish the LUT that stores the relatioshipsfrom RGB values to XYZ values. On the other hand, Berns's model was used to characterize color CRT monitors and to establish the reverse mapping from XYZvalues to control values in another LUT. Using these two LUTs, 3D interpolationtechniques for the color space transformation are simulated. Other colorimetricsimulations were also used to assess the suitability of interpolation functionmethod for the scanner and CRT monitor calibration. According to our simulations, the LUT model and the cubic interpolator used can well characterize color reproduction process from color scanners to color CRT monitors.