Digital Color Reproduction

Image characterization of potato chip appearance during frying

“…Although their resultant signals are also device-dependent, a constant illumination could be guarantied. Knowledge of the illuminant simplifies colour estimation and eliminates problems caused by the need to manage exposure duration and colour balancing (Wandell and Silverstein, 2003). Additionally, the scanner resolution and focusing are fixed which gives more reproducible results (Jeliń ski et al, 2007).…”

“…However, these advantages do not guarantee CIE values, and therefore, scanners could also need a previous RGB signal correction for suitable comparisons according to the CIE colour system as provided by a colorimeters or spectrophotometers. Modern digital cameras and scanners are designed to deliver different colour signals congruent with CIE colour spaces (XYZ or L*a*b*) using intrinsic compensations and corrections (Wandell and Silverstein, 2003). Therefore, for objective colour measurements and comparisons of colour data, these gamma-corrections or particular compensations need to be previously elucidated.…”

Concerning the calculation of the color gamut in a digital camera

“…The mathematical background for this procedure is linear algebra. 7,19,20,44 According to this formalism, color-matching functions T (41 rows by 3 columns, from 380 to 780 nm at 10 nm steps) and primary spectra P (41 rows by 3 columns) of any color space associated to additive color reproduction systems (device or human eye) are linked into a dual relationship as follows:…”

“…Color devices [1][2][3][4][5][6][7] are basically divided into input or capture devices (scanners and digital cameras) and output devices (softcopy, such as displays, and hardcopy, such as printers). Scanners, digital cameras, and displays (CRT, LCD/TFT, plasma, etc.)…”

“…perform by additive and subtractive color mixing. Successful color management [5][6][7][8][9][10][11] depends on knowing the color gamut and the color profile of the device used. Determining the gamut of output devices (displays, projectors, and printers) is relatively easy, both when colors in display or in paper are generated systematically 12 and when color profiles are applied.…”