Children's Color Association for Digital Image Retrieval. Page: 26
View a full description of this dissertation.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
specifying color has been developed by the Commission Internationale de I'Eclairage
(CIE). Three monochromatic primaries are wavelengths 435.8, 546.1 and 700 nm and
perceived as color red, color green and color blue by the human eyes. Since, it is
impossible to match all the colors of the spectrum with these three primaries, CIE
invented the three imaginary additive primaries. Three numbers, known as CIE
tristimulus values, are derived by analyzing the relative amount of three imaginary
primary colors (red, green, blue) needed to match the energy of the wavelength of the
sample color. A CIE color specification is written CIE (x,y,Y); x and y are the fractional
amounts of red and green, Y is the luminance factor (Agoston, 1979).
Color Space
For content-based indexing, a color histogram is the standard representation of
color in images. Before constructing the color histogram, types of color space have to
be defined. In digital images, color pixels are most commonly given values using color-
coding systems such as CIELAB, RGB, CMYK, and ROMM RGB.
CIELAB Color Space
"The CIE tristimulus values x, y, and z can be transformed by simple calculations
to three quantities L, A, and B. These three quantities provide a different color space of
which the complete name is CIELAB (1976) uniform color space" (Agoston, 1979, p.83);
L is defined as brightness, A ordinate shows the redness to greenness, and the B
ordinate describes the yellowness to blueness of a color. "... equal distances between
colors in any parts of CIELAB color space represent approximately equal perceptual
differences; hence, it provides a useful measure for determining color differences
numerically. The formula used for calculating color differences in terms of CIELAB units26
Upcoming Pages
Here’s what’s next.
Search Inside
This dissertation can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Dissertation.
Chang, Yun-Ke. Children's Color Association for Digital Image Retrieval., dissertation, August 2003; Denton, Texas. (https://digital.library.unt.edu/ark:/67531/metadc4342/m1/39/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; .