文档介绍：Chapter 3 Data Representation 《计算机科学导论》puter Science Illuminated 《计算机科学导论》课程组 2 /62 Contents Data puter Representing Numeric Data Representing Text Representing Audio Information Representing Images and Graphics Representing puter Science Illuminated 《计算机科学导论》课程组 3 /62 Chapter 3 Goals 1. Distinguish between analog and digital information . 2. Explain pression and calculate compression ratio s. 3. Explain the binary formats for negative and floating-point values. 4. Describe the characteristics of the ASCII and Unicode character set s. Computer Science Illuminated 《计算机科学导论》课程组 4 /62 Chapter 3 Goals 5. Perform various types of text compression . * (not required) 6. Explain the nature of sound and its representation. 7. Explain how RGB values define a color . 8. Distinguish between raster and vector graphics . 9. Explain temporal and spatial video compression . * (not required) Computer Science Illuminated 《计算机科学导论》课程组 5 /62 Contents - Goals Data puters(Goals 1,2) Representing Numeric Data (Goals 3) Representing Text (Goals 4,5) Representing Audio Information(Goals 6) Representing Images and Graphics (Goals 7,8) Representing Video (Goals 9) Computer Science Illuminated 《计算机科学导论》课程组 6 /62 Data puters ? Computers are multimedia devices, managing and manipulating data in many forms . ? Numbers ? Text ? Audio ? Images and graphics ? Video ? All forms of data must be represented in binary form . pression is also involved as well. Computer Science Illuminated 《计算机科学导论》课程组 7 /62 Brief Introduction to pression ? pression (P54) ? What? Reducing the amount of space ? Why? ? storage limitations, ? bandwidth 带宽 restrictions ? How much? compression ratio 压缩比? Technique categories: ? lossless compression 无损压缩, ? lossy compression puter Science Illuminated 《计算机科学导论》课程组 8 /pression Tools ? The two mon utilities ? WinRAR : create and press .rar format ? WinZip: crea