Abstract: An image compression method employing a conditional quadtree split method includes inputting image data in frame or field units as blocks having a predetermined size; generating an average value for all of the pixels in each block and a sub-block code value for determining whether to perform sequential quad-splitting operations on the block into a suitable sub-block according to image type; and outputting a quadtree map drawn according to the sub-block code value and the average value of each block, as a bit stream. An apparatus employing the method can transmit good quality image data having no distortion at a high transmission rate.

Abstract: A method and an apparatus for encoding a digital audio signal are provided. The method comprises the steps of: mapping the digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; allocating a number of bits to each sub-band signal according to human psychoacoustic properties, on the basis of the mapped sub-band signals; compensating each sub-band signal by receiving a transmitted previous quantized error, quantizing the compensated sub-band signals according to the corresponding allocated bit number, and transferring the current quantized error to the next quantization; and forming a transmit bit stream in frame units from the quantized data. Therefore, the quantized error generated during encoding of the audio signal is can be minimized.

Abstract: A bi-directional motion estimation method and apparatus thereof in a low bit-rate moving video codec system, for filtering motion vectors by performing a bi-directional motion estimation in units of objects having the same motion in a constant domain and for compensating the motion using the motion vectors generated as the result of forward or backward motion prediction in accordance with the motion prediction mode of previously set frames, can determine the precise motion vector compared to the existing block matching algorithm and depict the inter-frame motion with a smaller amount of information. Therefore, markedly less data (for compression) is used and reconstructed picture quality is improved.

Abstract: The present invention relates to a color correction method for dividing a color space and producing a color correction coefficient for respective regions. The method comprises the steps of receiving image data, discriminating a region to which the input data pertains and selecting a color correction coefficient in accordance with the region so as to produce the selected one, performing color correction by operating the selected color correction coefficient and the input data, and outputting the color-corrected image data.