Image encoding apparatus
View Patent ↗Provided is a moving picture coding apparatus for increasing a compression ratio of a moving picture signal while maintaining high image quality. To minimize the number of bits required for a residual block, quantized transform coefficients are adaptively divided into a plurality of subsets according to a size of a transform block, and non-zero quantized transform coefficients of each subset are scanned and encoded. Also, an intra prediction mode of the current block is determined using reference pixels obtained by filtering reference pixels of the current block. Accordingly, it is possible to minimize the amount of data required for the residual block of the current block.
1. An image encoding method, comprising:
determining, by a coding mode determiner, a size and a prediction mode of each predictive coding block for image or video data;
transforming and quantizing, by a transform/quantization unit, a residual block generated by intra prediction to generate a quantized block;
inversely quantizing and inversely transforming, by an inverse quantization/transform unit, the quantized block;
performing, by a deblocking filter, a deblocking filtering process to image data received from the inverse quantization/transform unit;
determining, by an intra predictor, an intra prediction mode;
generating, by the intra predictor, a prediction block according to the intra prediction mode; and
entropy-coding, by an entropy coder, quantized coefficients of the quantized block,
wherein, when a size of the quantized block is equal to 8×8, the coefficients of the quantized block are divided into a plurality of subsets, and the plurality of subsets are scanned according to a scan pattern determined by the intra prediction mode and coefficients of each subset are scanned according to the scan pattern determined by the intra prediction mode to be entropy-coded.
2. The method of claim 1 , wherein the quantized coefficients of each subset are scanned in a reverse direction according to the scan pattern.
3. The method of claim 1 , wherein the plurality of subsets are scanned in a reverse direction.
4. The method of claim 1 , wherein when the intra prediction mode is a vertical mode, the scan pattern is a horizontal scan.
5. The method of claim 1 , wherein when the intra prediction mode is a horizontal mode, the scan pattern is a vertical scan.
6. The method of claim 1 , further comprising generating, by the intra predictor, reference pixels when unavailable reference pixels exist.
7. The method of claim 1 , wherein the intra prediction mode is coded using an upper intra prediction mode and a left intra prediction mode.
8. The method of claim 7 , wherein when the upper intra prediction is unavailable, the upper intra prediction mode is set to a DC mode.