Document image entry system
First Claim
1. An image input apparatus comprising:
- an image scanning unit for effecting a scanning on a surface of a sheet of paper to convert an optical image on the sheet into halftone or multivalue digital image data;
a local recognition unit for effecting a scanning on an image attained by said image scanning unit by use of a window including M×
N (M and N are integers) pixels such that a feature value is extracted depending on a state of a density distribution of pixels in the window and a recognition to determine whether each of said pixels belongs to a binary domain or a halftone domain is effected according to said feature value; and
a large scale recognition unit for subdividing the image in block each including P×
Q (P and Q are integers and P>
M, Q>
N) pixels such that depending on a feature value represented by an output result from said local recognition unit with respect to each pixel of each block, whether said each block belongs to a binary domain or a halftone domain is recognized in a real-time processing;
wherein recognition of whether each portion of said image belongs to a binary domain or halftone domain is effected only depending on partial data of said image.
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Accused Products
Abstract
For halftone digital image data, an edge portion of the image is extracted for each pixel, and based on a density of each pixel or an average density of each group of a plurality of adjacent or neighboring pixels, there are extracted pixels of a background other than the edge portion of the image. Thereafter, the image data is subdivided into a plurality of blocks each including a predetermined number of pixels. Based on distribution states of the pixels of the block judged to belong to the edge and those of the block judged to belong to the background, a domain recognition is conducted to determine whether the block is a binary block or a halftone block. In addition, for each block, a state of areas in blocks encircling the block is examined such that depending on the state, an expansion/contraction processing is repeatedly achieved a predetermined times for the halftone domain, thereby separating the image data into a binary domain and a halftone domain in a real-time fashion.
96 Citations
16 Claims
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1. An image input apparatus comprising:
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an image scanning unit for effecting a scanning on a surface of a sheet of paper to convert an optical image on the sheet into halftone or multivalue digital image data; a local recognition unit for effecting a scanning on an image attained by said image scanning unit by use of a window including M×
N (M and N are integers) pixels such that a feature value is extracted depending on a state of a density distribution of pixels in the window and a recognition to determine whether each of said pixels belongs to a binary domain or a halftone domain is effected according to said feature value; anda large scale recognition unit for subdividing the image in block each including P×
Q (P and Q are integers and P>
M, Q>
N) pixels such that depending on a feature value represented by an output result from said local recognition unit with respect to each pixel of each block, whether said each block belongs to a binary domain or a halftone domain is recognized in a real-time processing;wherein recognition of whether each portion of said image belongs to a binary domain or halftone domain is effected only depending on partial data of said image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An image input apparatus comprising:
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(a) means for inputting an image and for converting the image into halftone or multivalue digital image data; (b) binarize means for binarizing said halftone digital image data; (c) dither means for converting said halftone digital image data into guasi-halftone data; (d) domain recognize means for determining whether said halftone digital image data belongs to a binary domain or to a halftone domain; and (e) select means for selecting either an output from said binarize means or an output from said dither means based on are result from said domain recognize means wherein said domain recognize means includes; (i) means for processing said halftone digital image data so as to extract an edge portion of the image for each pixel, (ii) means for extracting pixels associated with a background of the image other than the edge portion of the image based on a density of each pixel or an average density for each group of a plurality of adjacent or neighboring pixels, and (iii) means for subdividing said image data into a plurality of blocks each including a predeterned number of pixels such that a domain recognition is effected for each said block to determine whether said each block belongs to a binary block or a halftone block based on distribution states of pixels of said block judged to belong to the edge and pixels of said block judged to belong to the background.
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10. An image input apparatus comprising:
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means for inputting an image including a character or a pattern area and a photographic area and for converting said image into multivalue digital image data; binarize means for binarization processing of a binary image such as a character and a pattern for said inputted multivalue image data; dither means for dithering processing of a halftone image such as a photographic for said inputted multivalue image data; local domain decision means for deciding whether a pixel corresponding to said multivalue digital data belongs to a binary image domain or to a halftone image domain based on detecting the condition of density distribution of pixels in a predetermined range located in a periphery of said pixel; global domain decision means including block decision means for deciding whether a block consisting of an adjacent plurality of said pixel belongs to a binary image domain or to a halftone image domain based on decision results for each pixel generated by said local domain decision means and rewriting means for correcting the decision results of a block decision results of blocks adjacent to said block according to a predetermined rule; selection means for alternatively selecting data generated by said binarize means or said dither means according to the decision results for each block generated by said global domain decision means. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification