own in Figure 2-17. Red, green, and blue are called the primary colors, because as colors they form the basis for the creation of all other colors. It is a well known fact that if three white lights are covered with red, green, and blue color gels respectively, and the lights are shined at roughly the same spot as shown in Figure 2-18, the result will be a light spot for each color, but where the three colors intersect the result will be white light. The combination of the three primary colors creates white. Each primary color also has a complimentary color in the overall spec- trum. As Figure 2-19 shows, the complementary color for red is cyan, while the complimentary colors for green and blue are magenta and yel- low, respectively. Table 2-2 shows the relationships that exist between the primary and complementary colors. For full-color, uncompressed images, each of the red, green, and blue elements requires eight bits, or 24 bits per pixel. This yields what is known as "256-bit color" (28). Now consider the storage requirements for an image that is 640 by 480 pixels in size. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Protocols Protocols 640 X 480 = 307,200 pixels 307,200 pixels X 24 bits/pixel = 7,372,800 bits 7,372,800 bits 8 bits per byte = 921,600 bytes per image In other words, an uncompressed, relatively low quality image requires one megabyte of storage. A larger 1,024 by 768 pixel image requires 6.3 MB of storage capacity in its uncompressed form. Given Figure 2-17 The red, green, and blue (RGB) components of a pixel Green Figure 2-18 Green Red, green, and blue light, shining on the same place, create white light. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the web