nt use of video recording Sampling is the process used to create the image devices is still warranted, e.g., the main reason movie sequences used for video and digital video applications. camera panning is done very slowly is to minimize tem- Spatial sampling and quantization of a natural video signal poral aliasing. digitizes the image plane into a two dimensional set of In many cases where fast motions or moving edges are digital pixels that define a digital image. Temporal sam- not well resolved due to temporal aliasing, the human pling of a natural video signal creates a sequence of image visual system will interpolate such motion and provide its frames typically used for motion pictures and television. own perceived reconstruction. The HVS is very tolerant The combination of spatial and temporal sampling of temporal aliasing by using its own knowledge of natural creates a sequence of digital images termed digital video. motion to provide motion estimation and compensation As described earlier, the digital video signal intensity is to the image sequences generated by temporal sampling. defined as I(i, j, k), where 0 i M, 0 < j N are the The combination of temporal filtering in sampling horizontal and vertical spatial coordinates, and 0 < k is systems and the mechanisms of human visual perception, the temporal coordinate. reduce the affects of temporal aliasing such that The standard digital video formats introduced here temporal under sampling (sub-Nyquist sampling) is are used in the broadcast for both analog and digital acceptable in the generation of typical image sequences television, as well as computer video applications. intended for general purpose use. Composite television signal digital broadcasting formats Video compression CHAPTER 7.4 are included here due to their use in video compression standards, digital broadcasting, and standards format Table 7.4-3 Digital video component television parameters for CCIR 601. conversion applications. Knowledge of these digital video formats provides background