Patent ID: 8189932

Claim:
An image processing apparatus comprising: horizontal analysis filtering means for receiving image data in units of lines and for generating a low-frequency component and a high-frequency component by performing horizontal low-pass analysis filtering and horizontal high-pass analysis filtering every time a number of samples in a horizontal direction reaches a predetermined value; vertical analysis filtering means for generating coefficient data of a plurality of subbands by performing vertical low-pass analysis filtering and vertical high-pass analysis filtering every time a number of lines in a vertical direction of low-frequency and high-frequency components generated by the horizontal analysis filtering means reaches a predetermined value, and quantization means for determining an adaptive quantization step size with respect to each line block and for quantizing the coefficient data of the plurality of subbands generated by the vertical analysis filtering means by weights, the weights being chosen such that a weighted quantization step size is smaller for a low-frequency component and is higher for a high-frequency component for each line block, the quantizing generating quantized coefficient data, wherein the line block includes a line of a lowest-frequency subband and a plurality of lines of other subbands necessary for generating the line of the lowest-frequency subband.