MATLAB for Psychologists by Mauro Borgo Alessandro Soranzo & Massimo Grassi

Author:Mauro Borgo, Alessandro Soranzo & Massimo Grassi
Language: eng
Format: epub
Publisher: Springer New York, New York, NY

To get a color image, we need to superpose different colors, for example Red, Green, and Blue in the RGB system. In color images, each coordinate has n intensity values, one for each of color of the system in use. For example, each pixel of an RGB image is a triplet of intensity values, one for red, one for green, and one for blue. By default, MATLAB represents these triplets with 8 bits, for a total of 24 bits, yielding 224 colors. This type of image is usually called TrueColor.

There is also another method of treating color images: indexing images. Each pixel has a value that represents not a color but the index in a color map matrix. The color map (or color palette) is a list of all the colors used in that image. Such indexing images occupy less memory than RGB images, so they are a good option for saving space. The indexing concept is graphically illustrated in Fig. 6.2.2 Each image has a zoomed area of 17  ×  17 pixels. Each zoomed area shows the intensity for the gray-scale image and the RGB values for the color image. The indexed image is obtained from the RGB image using a palette with the 60 colors included in the RGB image.

Fig. 6.2Three different digital representations of the same image

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.