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公开(公告)号：EP0149120B1
公开(公告)日：1991-02-27
申请号：EP84115007.1
申请日：1984-12-11
IPC分类号： G06F15/62
CPC分类号： G06T3/4023
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公开(公告)号：EP0381129A1
公开(公告)日：1990-08-08
申请号：EP90101777.2
申请日：1990-01-30
IPC分类号： H04N1/41
CPC分类号： H04N1/4105
摘要： A system is described for reformatting halftone data for compression, wherein an original bilevel image is reformatted to produce another bilevel image that allows vertical correlations to be recognized by the compression technique, thus improving compressibility dramatically, with particular suitability for facsimile transmissions. In reformatting it is assumed that a selected halftone frequency H will satisfactorily describe an entire document, and each of successive sets of H consecutive lines are concatenated to form respective single lines. The thus reformatted lines have a clearer halftone periodicity offering greater correlation and permit more efficient coding by well-known standard bilevel compression algorithms (e.g., CCITT G3 (MR) or G4 (MMR)). For an image with unknown pattern frequency, a technique for readily estimating the frequency for use in reformatting the image is described.
摘要翻译： 描述了用于重新格式化半色调数据以进行压缩的系统，其中原始双层图像被重新格式化以产生允许垂直相关被压缩技术识别的另一双层图像，因此显着提高了压缩率，并且特别适合于传真传输。 在重新格式化时，假定选定的半色调频率H将令人满意地描述整个文档，并且连续H个连续行中的每个连续行被连接以形成相应的单行。 这样重新格式化的线具有更清晰的半色调周期性，提供更大的相关性，并允许通过众所周知的标准双层压缩算法（例如CCITT G3（MR）或G4（MMR））进行更高效的编码。 对于具有未知图案频率的图像，描述了用于容易地估计用于重新格式化图像的频率的技术。
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3.发明公开A method for converting a bit map of an image to a run length or run end representation 失效一种用于将图像的位图转换为运行长度或运行结束表示的方法
公开(公告)号：EP0149122A3
公开(公告)日：1987-07-15
申请号：EP84115009
申请日：1984-12-11
IPC分类号： H04N01/419
摘要： 57 A method for converting an image from a bit map to a run end or run length representation includes the steps of: storing said image as a bit map representation; initializing all variables to be used in the conversion process; converting by table lookup, each run of continuous color to a run end; storing, in a run end buffer, as a count value, each run end; repeating the steps of converting and storing for each run of continuous color to the end of the image.
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公开(公告)号：EP0147701A3
公开(公告)日：1986-07-30
申请号：EP84115010
申请日：1984-12-11
IPC分类号： G06F15/62
CPC分类号： G06T3/606
摘要： 57 A method for rotation of a binary image by 180 degrees, includes the steps of: positioning first (Pl) and second (P2) address pointers at the center or at the beginning and end respectively of an image to be rotated; indexing the first pointer in a first direction through said image; indexing the second pointer in a second direction through said image; exchanging, for each index step, a first image word at the first pointer with a second image word, at the second pointer if the first image word and the second image word have any two bits with different values; reversing all exchanged words; storing the reversed, exchanged words at said pointer locations; repeating the above steps until the first pointer and the second pointer have been indexed through all words in the image at which point the image has been rotated by 180 degrees.
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5.发明授权
公开(公告)号：EP0154860B1
公开(公告)日：1991-01-09
申请号：EP85101927.3
申请日：1985-02-22
IPC分类号： H03M7/42
CPC分类号： H03M7/4006
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公开(公告)号：EP0188193A3
公开(公告)日：1989-04-19
申请号：EP86100035.4
申请日：1986-01-02
IPC分类号： H04N1/40
CPC分类号： G06T5/009 , G06T5/40 , H04N1/401 , H04N1/4074
摘要： A method and apparatus for processing images using gray scale techniques includes means (40) for obtaining a histogram of levels in an image; means (42) for analyzing said histogram to identify one or more ranges of background in said image; means (44, 48, 52) for converting each of said ranges of background to a constant value to achieve flat backgrounds in said image; means for generating a dynamic range expansion table for each image; means for correcting said image data for dynamic range compression due to coring during processing of said image data by reference to said dynamic range expansion table. The process may also include means for encoding (54) said processed image using gray scale encoding techniques, means (46) for filtering all nonbackground pixels in said image, means for generating for said image a shading correction for each pixel in said image; means for correcting each pixel for shading employing said shading correction generated for each pixel, means for determining if said image is a graphics image; means for generating a dynamic range expansion table for each graphics image; means for correcting said image data for dynamic range compression by reference to said dynamic range expansion table, means for creating a second table of values from parameters contained in said encoded image data; and means for translating decoded image pixel values by reference to said second table to correct for quantization noise.
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公开(公告)号：EP0149124A3
公开(公告)日：1987-08-19
申请号：EP84115016
申请日：1984-12-11
IPC分类号： H04N01/417
CPC分类号： H04N1/4175 , G06T9/005
摘要： A method for encoding and decoding digital image data, includes the steps of testing the data for a vertical relationship between adjacent lines of the image, generating directly a reference code word representative of the vertical relationship for each successful test, generating by table lookup a run code word for a stream of data bits of common value for each unsuccessful test, wherein a data element representing a number of bits in a code word is stored at a predetermined offset from a table entry for the code word, merging the vertical reference code words and the run code words generated by the above steps to form an encoded data stream, testmg an encoded data stream for a reference code, decoding directly the vertical relationship from the reference code for each successful test: decoding by table lookup a run of bits of common value by serial examination of said encoded data stream for each unsuccessful test and storing data decoded by the above steps in a predetermined relationship
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公开(公告)号：EP0149120A2
公开(公告)日：1985-07-24
申请号：EP84115007.1
申请日：1984-12-11
IPC分类号： G06F15/62
CPC分类号： G06T3/4023
摘要： A method for expanding a binary image includes the steps of: storing the image in bit sequence; inserting for each string of 5 bits along a first axis one or more expansion bits, to convert each said string of 5 bits to a string of 6 bits; assigning a value to each expansion bit generated by the above step; inserting one or more rows of expansion bits for each 5 rows of bits along a second axls of the image to convert each 5 rows of bits to 6 rows of bits along the second axis of the image; assigning a value to each expansion bit generated by the above steps; storing the enlarged image generated by the above steps.
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10.发明授权A method for converting a bit map of an image to a run length or run end representation 失效一种用于将图像的位图转换为运行长度或运行结束表示的方法
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