# US 5,345,517 A · Image reduction apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,517 A - Document ID: US5345517A - Status: Granted - Kind: A - Application number: 07/895,241 - Filed: 1992-06-08 - Granted: 1994-09-06 - Earliest claimed: 1989-04-10 - Assignees: Canon Kabushiki Kaisha - Inventors: Akihiro Katayama; Mitsuru Maeda; Yasuji Hirabayashi; Tadashi Yoshida - Web page: https://patentgrep.com/patent/US5345517A ## CPC - H04N 1/4172: {Progressive encoding, i.e. by decomposition into high and low resolution components} - H04N 1/40062: {Discrimination between different image types, e.g. two-tone, continuous tone} - H04N 1/40068: {Modification of image resolution, i.e. determining the values of picture elements at new relative positions (H04N1/3935 takes precedence)} - H04N 1/409: Edge or detail enhancement; Noise or error suppression - H04N 1/4105: {for halftone screened pictures} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An image reduction apparatus includes a smoothing unit for smoothing binary image data, a binarization unit for binarizing an output from the smoothing unit, a detection unit for detecting an attribute of the binary image data smoothed by the smoothing unit, a plurality of correction units corresponding to a plurality of attributes, and a selector for selecting one of the correction units in accordance with the attribute detected by the detection unit. An output from the binarization unit is corrected by the correction unit selected by the selector. ## Claims ### Claim 1 An image reduction apparatus comprising: input means for inputting image data representing an image; and processing means for executing a reduction process on the image data input by the input means and outputting reduced image data, wherein said processing means further comprises: detection means for detecting first and second attributes of the image represented by the image data input by said input means; correction means for correcting the reduction process on the basis of a first attribute detected by said detection means; and correction means for correcting the reduction process on the basis of a second attribute detected by said detection means. ### Claim 2 (depends on 1) An apparatus according to claim 1, wherein at least one of said correction means is adapted to reverse reduced image data obtained by the reduction process. ### Claim 3 (depends on 1) An apparatus according to claim 1, wherein said processing means includes smoothing means for smoothing the image data by filter-processing the image data of peripheral pixels of a pixel of interest. ### Claim 4 An image reduction apparatus comprising: input means for inputting image data representing an image; and processing means for executing a reduction process on the image data input by the input means and outputting reduced image data, wherein said processing means further comprises: reduction means for executing a reduction process on the image data input by said input means; memory means for storing reduced image data obtained by a previous reduction-process operation of said reduction means; first correction means for correcting the reduction process in a first way on the basis of a pattern of an image represented by both the image data on which the reduction process is to be executed and the reduced image data stored in said memory means; second correction means for correcting the reduction process in a second way on the basis of a pattern of an image represented by both the image data on which the reduction process is to be executed and the reduced image data stored in said memory means; and selection means for selecting said first or second correction means. ### Claim 5 (depends on 4) An apparatus according to claim 4, wherein said selection means further comprises discrimination means which discriminates as to whether a pattern corresponds to one of a plurality of predetermined patterns. ### Claim 6 (depends on 4) An apparatus according to claim 4, wherein at least one of said correction means is adapted to reverse reduced image data obtained by the reduction process. ### Claim 7 (depends on 4) An apparatus according to claim 4, wherein said reduction means includes smoothing means for smoothing the image data by filter-processing the image data of peripheral pixels of a pixel of interest. ### Claim 8 (depends on 3) An apparatus according to claim 3, further comprising binarization means for binarizing an output from said smoothing means. ### Claim 9 (depends on 8) An apparatus according to claim 8, further comprising sub-sampling means for sub-sampling an output from said binarization means. ### Claim 10 (depends on 1) An apparatus according to claim 1, wherein said detection means detects whether or not image represented by the image data is a negative image or a positive image. ### Claim 11 (depends on 1) An apparatus according to claim 1, wherein said detection means detects whether or not the image represented by the image data is a pseudo half tone image. ### Claim 12 (depends on 1) An apparatus according to claim 1, wherein at least one of said correction means discriminates as to whether the image disappears as a result of the reduction process. ### Claim 13 (depends on 5) An apparatus according to claim 5, wherein said discrimination means discriminates as to whether a pattern contained within the image disappears as a result of the reduction process. ### Claim 14 (depends on 7) An apparatus according to claim 7, further comprising binarization means for binarizing an output from said smoothing means. ### Claim 15 (depends on 14) An apparatus according to claim 14, further comprising sub-sampling means for sub-sampling an output from said binarization means. ### Claim 16 An image reduction method comprising the steps of: inputting image data representing an image; detecting first and second attributes of the image represented by the image data; and selecting a first or a second mode for executing a reduction process, wherein, in said first mode, the reduction process is executed on the basis of a first attribute detected in said detecting step, and in said second mode, the reduction process is executed on the basis of a second attribute detected in said detecting step. ### Claim 17 (depends on 16) A method according to claim 16, wherein said selecting step includes the step of discriminating as to whether the reduction process is inadequate for the different attributes. ### Claim 18 (depends on 16) A method according to claim 16, wherein said detection step detects whether the image represented by the image data is a negative image or a positive image. ### Claim 19 (depends on 16) A method according to claim 16, wherein said detection step detects whether or not the image represented by the image data is a pseudo half tone image. ### Claim 20 (depends on 17) A method according to claim 17, wherein, in said discrimination step, discrimination is performed as to whether a pattern within the image disappears as a result of the reduction process. ### Claim 21 (depends on 16) A method according to claim 16, wherein said reduction process includes a smoothing step for smoothing the image data by filter-processing the image data of peripheral pixels of a pixel of interest. ### Claim 22 (depends on 21) A method according to claim 21, further comprising a binarization step for binarizing an output obtained by said smoothing step. ### Claim 23 (depends on 22) A method according to claim 22, further comprising a sub-sampling step for sub-sampling an output obtained by said binarization step. ### Claim 24 An image reduction method comprising the steps of: executing a reduction process on image data representing an image; storing reduced image data obtained by the previous reduction process; and selecting a first or a second mode for executing a reduction process, wherein, in said first mode, the reduction process is executed in a first way on the basis of a first pattern of an image represented by both the image data for which the reduction process is to be executed and the previously reduced image data, and in said second mode, the reduction process is executed in a second way on the basis of a second pattern of an image represented by both the image data for which the reduction process is to be executed and the previously reduced data. ### Claim 25 (depends on 24) A method according to claim 24, wherein said discrimination step discriminates as to whether a pattern corresponds to one of a plurality of predetermined patterns. ### Claim 26 (depends on 24) A method according to claim 24, wherein said reduction process includes a smoothing step for smoothing the image data by filter-processing the image data of peripheral pixels of a pixel of interest. ### Claim 27 (depends on 26) A method according to claim 26, further comprising a binarization step for binarizing an output obtained by said smoothing step. ### Claim 28 (depends on 27) A method according to claim 27, further comprising a sub-sampling step for sub-sampling an output obtained by said binarization step. ### Claim 29 An image reduction apparatus comprising: input means for inputting image data representing an image; generating means for generating a signal indicating whether the image represented by the image data input by said input means is a positive image or a negative image; and processing means for executing a reduction process on the image data input by the input means and outputting reduced image data, wherein said processing means executes a reduction process so that a black line of the image is preserved when the signal indicates that the image represented by the image data input by said input means is a positive image and so that a white line of image is preserved when the signal indicates that the image is a negative image. ### Claim 30 (depends on 29) An apparatus according to claim 29, wherein said processing means further comprises smoothing means for smoothing the image data by filter-processing the image data of peripheral pixels of a pixel of interest. ### Claim 31 (depends on 30) An apparatus according to claim 30, further comprising binarization means for binarizing an output from said smoothing means. ### Claim 32 (depends on 31) An apparatus according to claim 31, further comprising sub-sampling means or sub-sampling an output from said binarization means. ### Claim 33 An image reduction method comprising the steps of: inputting image data representing an image; generating a signal indicating whether the image represented by the image data is a positive image or a negative image; and executing a reduction process on the image data input in said inputting step and outputting reduced image data, wherein, in said executing step, a reduction process is executed so that a black line of the image is preserved when the signal indicates that the image represented by the image data input in said inputting step is a positive image and so that a white line of image is preserved when the signal indicates that the image is a negative image. ### Claim 34 (depends on 33) A method according to claim 33, wherein the reduction process includes a smoothing step for smoothing the image data by filter-processing the image data of peripheral pixels of a pixel of interest. ### Claim 35 (depends on 34) A method according to claim 34, further comprising a binarization step for binarizing an output obtained by said smoothing step. ### Claim 36 (depends on 35) A method according to claim 35, further comprising a sub-sampling step for sub-sampling an output obtained by said binarizing step. ### Claim 37 (depends on 24) A Method according to claim 24, further comprising the step of discriminating as to whether an inadequate reduction process is expected to be executed, on the basis of a pattern of an image represented by both the image data for which the reduction process is to be executed and the previously reduced image data, wherein said discrimination step discriminates as to whether a pattern within the image disappears as a result of the reduction process.