1. Chap 4 Color image processing

2. Chapter 6 Color Image Processing • Two major areas: full color and pseudo color • 6.1 Color fundamentals • Primary color of light: R, G, B • Secondary color of light: magenta, cyan and yellow • Pigment or colorant-subtract or absorbs a primary color • of light and reflect or transmit the other two • HIS model • Chromaticity include hue and saturation • Hue: dominant color as perceived by a observer • Saturation:the relative purity or the amount of white light • mixed with a hue

3. Chapter 6 Color Image Processing

4. Brightness: embody the chromatic notion of intensity • Three basic properties used to describe the quality of chromatic light source: source, radiance, and brightness • Tri-stimulus values: X, Y and Z • Tri-chromatic coefficients: • CIE chromaticity diagram • Shows color as a function of x (red) and y(green) • useful for color mixing • Boundary :fully saturated • Equal energy point 6.2 Color models • Purpose: facilitate the specification of colors in some standard • A specification of a coordinate system and a subspace within that system where each color is represented a single point • Two applied directions for color models: hardware and applications (color graphics)

5. RGB models--color monitors • CMY (CMYK)--color printing • YIQ--color television • HIS--humans describe and interpret color • The RGB Color model • Have a depth of 24bits • The CMY color model • The YIQ model • The HIS color model • Brightness-- is a subjective descriptor that is practically impossible to measure • Ideal tool for developing image processing algorithm

6. Converting colors from RGB to HIS • Converting colors from HIS to RGB • Procedures • multiply H by 360o; • (1) When H is in RG sector, the RGB components are given by

7. (2) GB sector • (3) BR sector • Manipulating HIS component images • Change the individual color of any region in the RGB image • 6.3 Pseudo image processing • Assign colors to gray values based on a specification criterion • Assign colors to monochrome images from the process associated with true color images

8. Chapter 6 Color Image Processing

9. Chapter 6 Color Image Processing

10. Chapter 6 Color Image Processing