METHOD FOR DECIDING HUMAN VISUAL SENSITIVITY BY IMAGE OBJECTS AND HIGH-EFFICIENCY IMAGE CODING SYSTEM USING THE SAME

摘要

PURPOSE: A method for deciding human visual sensitivity by image objects and a high-efficiency image coding system using the method are provided to reflect human visual sensitivity on determination of a quantizing step size so as to decide the quantizing step size such that quantization error is minimized. CONSTITUTION: Digital image is inputted to form a perceptual color tolerance look-up table(21). Image objects of the digital image are classified using Y color component value of the digital image and a perceptual color tolerance range defined in the look-up table(22). Brightness sensitivity of each of the image objects is determined using visual sensitivity contrast effect. Color sensitivity of each image object is determined using an average allowable perceptual color tolerance of the image objects, and a degree of quantizing color variation with respect to each image object is decided using the average quantizing step size and the perceptual color tolerance look-up table. Visual sensitivity complexity of each image object is determined using a perceptual color tolerance relation with neighboring pixels. Human visual sensitivity with respect to each image object is decided using the bright sensitivity, color sensitivity, degree of quantizing color variation and visual sensitivity complexity.