Band compression device for shaded image

摘要

A band compression method for a shaded image in which a sample input picture element value and an estimation error obtained from an estimation value of the input picture element are converted into quantization values and coded. First codes are temporarily stored in at least one block of buffer memories according to a quantization step number. The estimation errors are converted into quantization values corresponding to the input picture element values. Each quantization value is converted into the first code when the estimation error is quantized corresponding to the estimation error and quantization value. The next picture element value is estimated in accordance with the quantization value.