Abstract: An improved technique for processing a color or gray scale pixel map representing a document is disclosed. The pixel map is decomposed into a three-plane representation, a reduced-resolution “upper” plane, a reduced-resolution “lower” plane, and a high-resolution binary selector plane. The “upper” and “lower” planes contain the color or gray scale for the page as well as the continuous tone pictures that are contained on the page. The selector plane stores information for selecting from either the foreground plane or background plane during decompression. Information contained in the selector plane is first used to pre-process the upper and lower planes to reduce the amount of data on each of the other two planes that will be subjected to further processing. Each of the pre-processed planes is compressed using a compression technique optimal for the type of data that resides upon it.

Abstract: An improved technique for processing a color or gray scale pixel map representing a document is disclosed. The pixel map is decomposed into a three-plane representation, a reduced-resolution “upper” plane, a reduced-resolution “lower” plane, and a high-resolution binary selector plane. The “upper” and “lower” planes contain the color or gray scale for the page as well as the continuous tone pictures that are contained on the page. The selector plane stores information for selecting from either the foreground plane or background plane during decompression. Information contained in the selector plane is first used to pre-process the upper and lower planes to reduce the amount of data on each of the other two planes that will be subjected to further processing. Each of the pre-processed planes is compressed using a compression technique optimal for the type of data that resides upon it.

Abstract: A method and apparatus for insertion of a secondary digital image, such as a digital image of a photograph or the like, into a base digital image without requiring the base document image data to be decompressed for purposes of locating the appropriate paste location or to perform the actual electronic pasting operation. The JPEG or otherwise compressed base digital image is segmented into information areas and background areas without decompressing the base digital image so that each background area is identified as a potential paste location for the compressed secondary digital image. The segmentation operation is performed on the basis of the encoding “cost” of each block and the DC coefficient of the block. Without decompressing the base digital image, a select background area is identified therein which is sufficiently large to receive the compressed secondary digital image.

Abstract: A method detects if an image is compressed. The method determines a block grid within the image and establishes blocks from the determined grid. The method then computes differences between samples inside the established blocks and differences between samples across the established blocks. The method determines that the image is compressed based on characteristics derived from statistics of the computed differences.

Abstract: A method and apparatus for efficiently transmitting digital image data is disclosed. More specifically, the present invention accomplishes fast data transmission by analyzing the content of input data, and then retrieving data that closely matches that which would be produced if the data were subjected to some form of data compression from storage. The retrieved data is transmitted to the retrieving device, thereby eliminating the need for very time consuming data compression processes.

Abstract: An improved technique for processing a color or gray scale pixel map representing a document is disclosed. The pixel map is decomposed into a three-plane representation, a reduced-resolution “upper” plane, a reduced-resolution “lower” plane, and a high-resolution binary selector plane. The “upper” and “lower” planes contain the color or gray scale for the page as well as the continuous tone pictures that are contained on the page. The selector plane stores information for selecting from either the foreground plane or background plane during decompression. Information contained in the selector plane is first used to pre-process the upper and lower planes to reduce the amount of data on each of the other two planes that will be subjected to further processing. Each of the pre-processed planes is compressed using a compression technique optimal for the type of data that resides upon it.

Abstract: A method and apparatus for compressing a mixed raster content image that represents a color or gray scale a document is disclosed. The pixel map is decomposed into a three-plane representation—a reduced-resolution “upper” plane, a reduced-resolution “lower” plane, and a high-resolution binary selector plane. An iterative smoothing technique is then used to pre-process the upper and lower planes using the information contained in the selector plane, thereby reducing the amount of data that will be subjected to further processing.

Abstract: A method detects if an image is compressed. The method determines a block grid within the image and establishes blocks from the determined grid. The method then computes differences between samples inside the established blocks and differences between samples across the established blocks. The method determines that the image is compressed based on characteristics derived from statistics of the computed differences.

Abstract: Color printing systems frequently use multiresolution analysis, which creates intermediate lower resolution images, in applications such as descreening and filtering. The typical steps are to decompose the original image into sub bands, apply the application to one or more sub bands and then recompose the image, prior to color correction and color space transformation. This disclosure describes applying the color correction to one of the lower resolution sub bands and a simpler color space transformation to the final image as a way to reduce the amount of computation. The described multiresolution analysis is a wavelet transform.

Abstract: A method detects if an image is compressed. The method determines a block grid within the image and establishes blocks from the determined grid. The method then computes differences between samples inside the established blocks and differences between samples across the established blocks. The method determines that the image is compressed based on characteristics derived from statistics of the computed differences.

Abstract: A decompressor and decompression methods rotate and decompress compressed images for devices with asymmetric resolution. A compressed data file is transmitted and/or input to a decompressor. The decompressor receives a group of consecutive image blocks of the compressed data file and separately scaled-inverse-transforms each image block in the group. Then, each block is placed in a macroblock. Accordingly, the combination of the scaled blocks provides the required global scaling for image rotation. Thus, time and effort spent in scaling the decompressed image is avoided.

Abstract: A method and apparatus for compressing digital image data to improve the efficiency of serial data transmission is disclosed. More specifically, the present invention accomplishes image compression by performing the most complex portions of a standard compression technique on a subset of the originally provided data. The invention includes a fast JPEG compressor based on a modified two-dimensional discrete cosine transform.

Abstract: The present invention is a method for the color correction of digital images that have been compressed. In a preferred embodiment, aspects of the color correction are carried out on the compressed image data to improve computational efficiency. One of a number of alternative methods is employed to accomplish the color correction on lossy or losslessly compressed images. The color transformation process accomplishes color correction on compressed image data in conjunction with compression or decompression operations. A second, simplified phase of the color correction may be applied subsequently to the decompressed image data in certain embodiments.

Abstract: An apparatus, method and system optimizes Huffman codes within the Huffman tables without requiring buffering an entire uncompressed original image. Compression of a whole image is performed prior to storage in a buffer. Therefore, the necessary buffer size for performing computation of symbol frequencies in order to optimize Huffman codes is reduced. Default Huffman codes are used to pre-compress the image for storage in the buffer. Simultaneously, the input symbol frequency is determined to produce optimized Huffman codes. The optimized Huffman codes are used to optimally re-encode the encoded image data to reduce the space of the re-encoded data. The optimally encoded image data can then be stored and/or transmitted.

Abstract: The present invention is directed to a method and apparatus for improving the efficiency of color correcting subsampled color image data. More specifically, the present invention is directed to taking advantage of a method of applying a full conversion between color spaces on a master set of pixels in an image. New values are assigned to the remaining pixel subset by interpolating from the converted master set of pixels. The interpolation error is then added to the pixel subset, and the master set and subset are merged to produce a full converted color image set, which is subjected to further processing as a single unit.

Abstract: A method for processing compressed digital data derived from an original image sequence, the data being organized as a set of image frames, each image frame comprising a set of blocks, each block including a string of bits corresponding to an area of the original image frame in the original image sequence. A cost function is derived as a number related to the amount of bits spent to encode a block, sets of blocks, an image frame, or sets of image frames. A segmentation technique is applied to the map with cost functions. Temporal segmentation is performed by analyzing cost functions associated with each image frame. In both cases auxiliary functions can be used to improve the segmentation quality. The segmented regions of a image frame or sets of image frames can be identified, replaced, printed, or processed in special manners.

Abstract: The present invention is a method for the color correction of digital images that have been compressed. In a preferred embodiment, aspects of the color correction are carried out on the compressed image data to improve computational efficiency. One of a number of alternative methods is employed to accomplish the color correction on lossy or losslessly compressed images. The color transformation process accomplishes color correction on compressed image data in conjunction with compression or decompression operations. A second, simplified phase of the color correction may be applied subsequently to the decompressed image data in certain embodiments. Accordingly, the technique has application to any number of color imaging systems, including digital printers and copiers where there is a necessity to color correct compressed digital images.

Abstract: The present invention is a method and apparatus for automatically detecting the characteristics of a document object placed on the platen of a digital copier or similar scanning system. The invention accomplishes the detection by processing a digitized image in a highly efficient manner using binary moments, and using the moments characterizes the shape of a boundary about the object. Once determined, the shape of the object may be employed to further process the image to automatically crop, derotate, and register the image at a predefined location in an output image suitable for rendering on a document substrate.

Abstract: The present invention is a method and apparatus for the processing of images that have been compressed using a discrete cosine transform operation, and particularly JPEG compressed images. In a preferred embodiment, the rotation of image blocks is accomplished by sign inversion and transposition operations to accomplish intrablock operations. Subsequently, one of a number of alternative methods is employed to accomplish the same image processing on an interblock level, thereby enabling the rotation or mirroring of compressed images. The two stage process allows the use of either a standardized JPEG system with enhancements or a hybrid processing method, thereby accomplishing the image processing in conjunction with compression or decompression operations and minimizing the need for large memory buffers to accomplish the image processing.

Abstract: An enhancement to the standard JPEG image data compression technique includes a step of recording the length of each string of bits corresponding to each block of pixels in the original image at the time of compression. The list of lengths of each string of bits in the compressed image data is retained as an "encoding cost map" or ECM. The ECM, which is considerably smaller than the compressed image data, can be transmitted or retained in memory separate from the compressed image data along with some other accompanying information and is used as a "key" for editing or segmentation of the compressed image data. The ECM, in combination with a map of DC components of the compressed image, can also be used for substituting background portions of the image with blocks of pure white data, in order to compress certain types of images even further.