METHOD AND SYSTEM FOR CODING IMAGES

摘要

PURPOSE: A method and a system for coding images are provided to compress a motion picture in consideration of a luminance component and a color component to accomplish high-efficiency compression. CONSTITUTION: An image coding system includes a motion compensator for compensating for a motion of a source image to output a difference image, a discrete cosine transformer(4) for discrete-cosine-transforming the difference image, a quantizer(5) for quantizing the difference image at a predetermined quantizing interval, and a variable-length-coder for variable-length-coding the quantized signal, and a buffer(14) for outputting the variable-length-coded signal as bit streams. The coding system further includes a macro block classifier(17), and a rate controller(18). The macro block classifier classifies the macro block of a source image into n macro black classes on the basis of color signal characteristic and complexity characteristic of a video signal existing in the macro block of the source image. The rate controller controls the quantizing interval according to the macro block classes and a degree of fullness of the buffer.