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Image and Videl Comoression P2

After the introduction to image and video compression presented in Chapter 1, we now address several fundamental aspects of image and video compression in the remaining chapters of Section I. Chapter 2, the first chapter in the series, concerns quantization. Quantization is a necessary component in lossy coding and has a direct impact on the bit rate and the distortion of reconstructed images or videos. We discuss concepts, principles and various quantization techniques which include uniform and nonuniform quantization, optimum quantization, and adaptive quantization. 2.1 QUANTIZATION AND THE SOURCE ENCODER Recall Figure 1.1, in which the functionality of image and video compression. | 2 Quantization After the introduction to image and video compression presented in Chapter 1 we now address several fundamental aspects of image and video compression in the remaining chapters of Section I. Chapter 2 the first chapter in the series concerns quantization. Quantization is a necessary component in lossy coding and has a direct impact on the bit rate and the distortion of reconstructed images or videos. We discuss concepts principles and various quantization techniques which include uniform and nonuniform quantization optimum quantization and adaptive quantization. 2.1 QUANTIZATION AND THE SOURCE ENCODER Recall Figure 1.1 in which the functionality of image and video compression in the applications of visual communications and storage is depicted. In the context of visual communications the whole system may be illustrated as shown in Figure 2.1. In the transmitter the input analog information source is converted to a digital format in the A D converter block. The digital format is compressed through the image and video source encoder. In the channel encoder some redundancy is added to help combat noise and hence transmission error. Modulation makes digital data suitable for transmission through the analog channel such as air space in the application of a TV broadcast. At the receiver the counterpart blocks reconstruct the input visual information. As far as storage of visual information is concerned the blocks of channel channel encoder channel decoder modulation and demodulation may be omitted as shown in Figure 2.2. If input and output are required to be in the digital format in some applications then the A D and D A converters are omitted from the system. If they are required however other blocks such as encryption and decryption can be added to the system Sklar 1988 . Hence what is conceptualized in Figure 2.1 is a fundamental block diagram of a visual communication system. In this book we are mainly concerned with source encoding and source .