A new perceptual model for video sequence encoding

A method of encoding monochrome video sequences is presented. This method is applicable to slow-moving scenes with a zoom factor close to unity. It incorporates a perceptual model for the detection and tracking of image blocks perceived to be in apparent motion. The perceptual model is a threshold model based on contrast. Weber fractions in the spatiotemporal domain are used to set the threshold for the detection of motion. The threshold is determined on a scene-adaptive basis. The information content of the scene is derived from the spectral distribution of image data and the masking characteristics of the human visual system. The perceptual model is used in the block-classification process, which in turn determines the coding strategy used for each block type. The discrete cosine transform is used for encoding image blocks which have changed beyond a perceptual threshold. A comparison of the perceptually encoded image sequence with that using no perceptual model indicates substantially improved quality and performance of the perceptual encoder for compression ratios up to 100:1