ABSTRACT
Storage and transmission are essential processes in image processing. As discussed in Chapter 1, images are generally stored in the bitmap format, and the memory in spatial dimensions could be very large if images are stored directly without preprocessing. For example, the data of an 8-bit grey-scale image with the resolution 256 × 256 requires a total memory of 65536 bytes (or 64 kilobytes). The memory required for a true colour image increases to 64 kilobytes × 3 = 192 kilobytes. Under the National Television Standard Committee (NTSC) standard, 30 frames of images are played in one second to ensure continuous vision effect. Suppose the images are true colour having a resolution of 720 × 576, the images played in one second would require the storage size of 720 × 576 × 3 × 30 = 37324800 bytes = 36 megabytes. Such a huge amount of data would cause enormous difficulties during storage or transmission. Therefore, compression of original images is inevitable to facilitate transmission or other processes.
