摘要:
According to this invention, encoded data of a target data amount is generated by one image input operation while both lossless encoding and lossy encoding are adopted. For this purpose, a first memory stores encoded data of a shorter encode length among encoded data generated by a first encoding unit which performs lossy encoding and encoded data generated by a second encoding unit which performs lossless encoding. A second memory stores encoded data from a second encoding unit. When an encoding sequence control unit determines that the encoded data amount in the first memory has exceeded the target data amount, the encoding sequence control unit discards data in the first memory, sets a quantization parameter for a higher compression ratio for the first encoding unit, and causes the first encoding unit to execute encoding. Encoded data before the encoded data amount is determined to have exceeded the target data amount is re-encoded by a re-encoding unit.
摘要:
According to this invention, encoded data of a target data amount is generated by one image input operation while both lossless encoding and lossy encoding are adopted. For this purpose, a first memory stores encoded data of a shorter encode length among encoded data generated by a first encoding unit which performs lossy encoding and encoded data generated by a second encoding unit which performs lossless encoding. A second memory stores encoded data from a second encoding unit. When an encoding sequence control unit determines that the encoded data amount in the first memory has exceeded the target data amount, the encoding sequence control unit discards data in the first memory, sets a quantization parameter for a higher compression ratio for the first encoding unit, and causes the first encoding unit to execute encoding. Encoded data before the encoded data amount is determined to have exceeded the target data amount is re-encoded by a re-encoding unit.
摘要:
Resolution interpolation data is generated by relatively simple processing. This enables image encoding by simple and quick processing to attain high image quality and high compression performance. To do this, a tile divider extracts tile data of 32×32 pixels from encoding target original image data. A resolution converter samples one pixel of a block of 2×2 pixels in the tile data, thereby generating reduced tile data of a reduced image. An interpolation data generator generates interpolation data to be used to generate tile data having the original resolution from the reduced tile data. Based on the interpolation data of a tile of interest, an encoding method selector outputs a control signal indicating which one of lossless encoding and lossy encoding should be executed for the reduced tile data. A code stream generator outputs the generated encoded data and interpolation data as encoded image data.
摘要:
Resolution interpolation data is generated by relatively simple processing. This enables image encoding by simple and quick processing to attain high image quality and high compression performance. To do this, a tile divider extracts tile data of 32×32 pixels from encoding target original image data. A resolution converter samples one pixel of a block of 2×2 pixels in the tile data, thereby generating reduced tile data of a reduced image. An interpolation data generator generates interpolation data to be used to generate tile data having the original resolution from the reduced tile data. Based on the interpolation data of a tile of interest, an encoding method selector outputs a control signal indicating which one of lossless encoding and lossy encoding should be executed for the reduced tile data. A code stream generator outputs the generated encoded data and interpolation data as encoded image data.
摘要:
This invention generates efficient encoded data to restore original image data from reduced image data. An input unit inputs block data of 2×2 pixels from original image data. A converter generates reduced image data having a size smaller than the original image data by sampling one pixel data at a preset position in the input block data. A generator generates encoded data to restore three non-sampling target pixel data in each block data so as to restore the original image data from the reduced image data generated by the resolution converter. To do this, the generator determines whether all non-sampling target pixels in a block of interest are restorable from a sampling target pixel in the block of interest or from sampling target pixels in three blocks adjacent to the block of interest, and generates and outputs three kinds of additional information based on the determination result.
摘要:
This invention generates efficient encoded data to restore original image data from reduced image data. An input unit inputs block data of 2×2 pixels from original image data. A converter generates reduced image data having a size smaller than the original image data by sampling one pixel data at a preset position in the input block data. A generator generates encoded data to restore three non-sampling target pixel data in each block data so as to restore the original image data from the reduced image data generated by the resolution converter. To do this, the generator determines whether all non-sampling target pixels in a block of interest are restorable from a sampling target pixel in the block of interest or from sampling target pixels in three blocks adjacent to the block of interest, and generates and outputs three kinds of additional information based on the determination result.
摘要:
According to this invention, while the encoding efficiency of image data (e.g., a natural image) substantially maintains the conventional one, an image (e.g., a CG image or text document) having a small number of appearance colors is losslessly encoded at higher compression ratio. For this purpose, pixel data are input in the raster order and temporarily stored in a buffer. Pixel data at positions having undergone encoding are stored. A neighborhood matching determination unit generates first information representing whether a pixel having the same color as that of the pixel of interest exists in neighboring pixels a, b, and c, and second information for specifying whether a pixel having the same color as that of the pixel of interest exists, and if the pixel having the same color exists, specifying the neighboring pixel. A pixel matching detection unit counts the number of colors contained in the neighboring pixels a, b, and c, and generates information representing whether the number of colors is two or less, or three or less. On the basis of the first information and second information, a code generation unit outputs one or both of encoded data from a matched-pixel position encoding unit and prediction error encoding unit.
摘要:
An image coding apparatus for efficient coding on image data having discrete pixel values such as a CG image or a limited color image as well as a natural image where pixel value changes are mild. For this purpose, a tile dividing unit divides multi-valued image data into tiles. An occurred level count unit outputs the result of counting of the number of brightness values in the tile to a comparison unit and outputs the existing brightness values to an index table generation unit. The index table generation unit allocates continuous index values to the existing brightness values, and stores the result of allocation into an index memory table. An index conversion unit replaces the input pixel values in the tile with index values, and outputs the index values to a selector. The selector selects one of the brightness values in the tile or the index values based on the result of comparison by the comparison unit, and outputs the selected values to a tile data predictive coding unit so as to perform predictive coding processing.
摘要:
Image data is efficiently encoded using a predict coding unit and a run-length coding unit. The predict coding unit encodes a target pixel X on the basis of difference between the value of the target pixel and a predict value calculated from pixels neighboring the target pixel. The run-length coding unit starts the measuring the run when the number of colors contained in four pixels “a”, “b”, “c”, and “d” near the target pixel X is 1, and outputs encoded data of the run when the target pixel is different from an immediately preceding pixel “a”. Then, the predict coding unit starts the encoding. At this time, since the target pixel is different from the preceding pixel, the preceding pixel is excluded from references for generating the predict value. Instead of the preceding pixel, an pixel, which has been encoded, satisfying a specific condition is referred to.
摘要:
An image having few colors can be losslessly encoded at a higher compression ratio. For this purpose, pixel data are input in raster order and temporarily stored in a buffer. A neighborhood matching determination unit generates first information representing whether a pixel having the same color as that of the pixel of interest exists in neighboring pixels and second information specifying whether a pixel having the same color as that of the pixel of interest exists, and if the pixel having the same color exists, specifying the neighboring pixel. A pixel matching detection unit counts the number of colors contained in the neighboring pixels and generates information representing whether the number of colors is two or less, or three or less. On the basis of the information, a code generation unit outputs one or both of encoded data from a matched-pixel position encoding unit and a prediction error encoding unit.