EP0508845A2
Expired / Lapsed
EP
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Method and apparatus for image processing
Assignee: NTT Inc
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Filing: 1992-03-11
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Granted: —
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Expires: 2012-03-11
Abstract
Abstract Method and apparatus for image processing for comparing fingerprints and the like. To avoid reducing the accuracy of the comparison due to the variations of the fingerprint lines when the fingerprint input is made, a method has been resolved wherein the line width of the registered fingerprint is narrowed more than the line width of the tested fingerprint. Reduction of the throughout of recording and comparison is solved by the selective utilization of the input of an activated fingerprint image, the judging of the fingerprint boundaries and the processing of only the activated division, and, additionally, in the comparison, by midway abandonment, midway decision, multi-step variation of the increment, and/or introduction of a sub-template jump search. By introducing the degree of discordance between two images, it becomes possible to compare two images based on a comparison of the black pixels of the registered image to those of the image undergoing testing As a result, the processing amount for position matching is reduced in comparison with the case when all black pixels of two images are checked, or the entire images, including black and white pixels, are checked. Reduction of the amount of processing required for registration and comparison is resolved by setting the black pixel address of the narrowed image of the registered fingerprint to recorded information as a subtemplate and a non sub-template, by creating a storage form which takes into consideration the narrowed image by means of the storage of registered information, and by carrying out the reduction of registered data. Reduction of the throughput of narrowization processing (including thinning) was resolved by the direct detection of the center point of a black pixel aggregation, and by a preformed judging table.
Inventors
- 👤 Tetsuji Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 02:40
CPC Classifications
G; G07; G07C; G07C9/00; G07C9/20; G07C9/22; G07C9/25; G07C9/257; G06; G06V; G06V10/00; G06V10/20; G06V10/34; G06V40/00; G06V40/10; G06V40/12
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
132 words
An image processing method for judging concordance of primary and secondary images, the primary and secondary images consisting of black pixels and white pixels, the method comprising the steps of: (a) defining lines by aggregations of black pixels; (b) redefining a majority of the lines in the primary image by narrowing the lines; (c) redefining a majority of the lines in the secondary image by narrowing the lines so as to be not wider than a predetermined width, the predetermined width being equal to or narrower than the width of the lines prior to narrowing; (d) changing the coordinates of the lines of at least one of the primary and secondary images; and (e) subsequently judging the concordance of the primary and secondary images by comparing the narrowed primary and secondary images.
Claim 2
Dependent Claim
28 words
An image processing method according to claim 1 wherein a majority of the line widths of the primary image are narrowed to have a width of one pixel.
Claim 3
Dependent Claim
28 words
An image processing method according to claim 1 wherein said predetermined width of the lines is smaller than the width of the widest lines in the secondary image.
Claim 4
Dependent Claim
44 words
An image processing method according to claim 1 wherein the line width of the primary image is narrowed to the width of one pixel, and said predetermined width of the lines is smaller than the width of the widest lines in the secondary image.
Claim 5
Dependent Claim
154 words
An image processing apparatus for judging the concordance of primary and secondary images, the primary and secondary images consisting of black pixels, forming lines, and white pixels, the image processing apparatus comprising: (a) a processing means for redefining a majority of the lines so that the lines are narrower than a predetermined width, the predetermined width being equal to or narrower than the width of the lines prior to narrowing; (b) a comparing means for narrowing a majority of the lines comprising the primary image, narrowing a majority of the lines comprising the secondary image so as to be not wider than a predetermined width, the predetermined width being equal to or narrower than the width of the lines prior to narrowing, translating the lines of at least one of the primary and secondary images, and subsequently judging the concordance of the primary and secondary images by comparing the narrowed primary and secondary images.
Claim 6
Dependent Claim
55 words
An image processing apparatus in accordance with claim 5 wherein the lines in the primary image are narrowed to a width of one pixel, and the lines in the secondary image are narrowed to be not wider than a predetermined width which is equal to or narrower than the width of the lines before narrowing.
Claim 7
Dependent Claim
34 words
An image processing apparatus in accordance with claim 5 wherein the predetermined width for narrowing the lines in the secondary image is less than the width of the widest line of the secondary image.
Claim 8
Dependent Claim
47 words
An image processing apparatus in accordance with claim 5 wherein the lines in the primary image are narrowed to the width of one pixel, and the predetermined width for narrowing the lines in the secondary image is the width of the widest line of the secondary image.
Claim 9
Dependent Claim
214 words
An image processing apparatus in accordance with claim 5 wherein the primary and secondary images consist of pixels having two brightness values, the image processing apparatus comprising, as a processing means, a means for performing a first process and a second process: the primary process being a process for predetermining the predetermined width wx; finding the number of pixels in the intersections of the lines and parallel straight lines Lx; and (a) for the intersections having more than wx pixels in the intersection, leaving the wx black pixels of the line segment black, and changing all other pixels to white, and (b) for the intersections having a number of black pixels less than wx, maintaining the black pixels as they are; and the second process being a process for predetermining the predetermined width wy; finding the number of pixels in the intersections of the lines with the rotated imaginary parallel straight lines Ly obtainable by rotating the imaginary parallel straight lines Lx; and (a) for the intersections having more than wx pixels in the intersection, leaving the wx black pixels of the line segment black and changing all other pixels to white, and (b) for the intersections having a number of black pixels less than wx, maintaining continuously arranged black pixels as they are.
Claim 10
Dependent Claim
82 words
An image processing apparatus for judging the concordance of primary and secondary images, the primary and secondary images consisting of black pixels forming lines and white pixels, the image processing apparatus comprising: a judging means for translating one of the images and comparing the translated image with the other image by calculating the degree of concordance, wherein the judging means abandons the comparison midway in regard to the translated images when the degree of concordance becomes lower than a predetermined threshold value.
Claim 11
Dependent Claim
88 words
An image processing apparatus for judging the concordance between primary and secondary images, the primary and secondary images consisting of black pixels, forming lines, and white pixels, the image processing apparatus comprising: a judging means for translating one of the images to be compared, and comparing the translated image to the non-translated image by calculating the degree of concordance, wherein the judging means judges that the secondary image being compared is concordant to the primary image, and abandons the comparison for the remaining translated images to be processed.
Claim 12
Dependent Claim
110 words
An image processing apparatus for judging the concordance of primary and secondary images, the primary and secondary images consisting of black pixels forming lines and white pixels, the image processing apparatus comprising: a judging means for translating one of the images and comparing the translated image to the non-translated other image by calculating the degree of concordance, wherein the translation and comparison comprise the processes of: translating an image by a first predetermined incremental value of translation in order to obtain a quasi-optimal translation position; and translating the image by a second predetermined incremental value of translation within the quasi-optimal translation position in order to obtain a best translated position.
Claim 13
Dependent Claim
185 words
An image processing apparatus for judging the concordance of primary and secondary images, the primary and secondary image consisting of black pixels, forming lines, and white pixels, the image processing apparatus comprising: (a) a processing means for redefining a majority of the lines so that the lines are narrower than a predetermined width, the predetermined width being equal to or narrower than the width of the lines prior to narrowing: (b) a comparison means for narrowing a majority of the lines constituting the primary image, narrowing a majority of the lines constituting the secondary image so as to be not wider than a predetermined width, the predetermined width being equal to or narrower than the width of the lines prior to narrowing, translating the lines of at least one of the primary and secondary images, and subsequently judging the concordance between the primary and secondary images by comparing the narrowed primary and secondary images, wherein the degree of discordance between the two images is approximately calculated approximately by comparing primary and secondary images which have been narrowed so that the lines have the same width.
Claim 14
Dependent Claim
24 words
An image processing apparatus according to claim 13 wherein the lines in the primary image are narrowed to have a width of one pixel.
Claim 15
Dependent Claim
103 words
An image processing apparatus for judging the concordance between primary and secondary images, the primary and secondary images consisting of black pixels, forming lines, and white pixels, the image processing apparatus comprising a translation means for judging the concordance between two images after translating one of the images to be compared, the image processing apparatus separating one the images into a sub-template area to be translated and compared to the non-translated image, and a non-subtemplate area which is not to be translated or compared, either the subtemplate area or the non-subtemplate area being divided into multiple portions separated by areas containing unused pixels.
Claim 16
Dependent Claim
106 words
An image processing apparatus for judging the concordance between primary and secondary images, the primary and secondary images consisting of black pixels, forming lines, and white pixels, the image processing apparatus comprising a translation means for judging the concordance between two images after translating one of the images to be compared the image processing apparatus separating one the images into one or more sub-template areas to be translated and compared to the non-translated image, and one or more non-subtemplate areas which is not to be translated or compared, at least one subtemplate area and at least one non-subtemplate area being separated by areas containing unused pixels.
Claim 17
Dependent Claim
38 words
An image processing apparatus comprising means for determining an approximate center of an image wherein an area is predetermined and if the approximate center falls outside the predetermined area, the approximate center is reset inside the predetermined area.
Claim 18
Dependent Claim
85 words
An image processing apparatus for processing images consisting of pixels having brightness values of two or more, the apparatus comprising: means for converting the image into a binary image consisting of black and white pixels in the case where the original image is a gray scale image; means for separating the binary image into two of more segments; judging means for judging whether each segment is valid or not by calculating an average brightness of the segment, and comparing the average brightness with predetermined values.
Claim 19
Dependent Claim
109 words
An image processing apparatus for processing images consisting of pixels having two or more brightness values, the apparatus comprising: means for inputting images consisting of two or more brightness values; means for converting the image into a binary image consisting of black and white pixels, in the case where the original image is a gray scale image; means for separating the binary image into one or more segments; judging means for judging whether each segment is valid or not by calculating an average brightness of the segment and comparing the average brightness with predetermined values, and finalizing the image when the number of valid segments exceeds a predetermined number.
Claim 20
Dependent Claim
122 words
An image processing method for recording black and white images, each image consisting of black and white pixels each having an address according to the X and Y axes, the method comprising the processes of: (a) selecting either the black pixels or the white pixels as the pixels to constitute a desired image; (b) segmenting the image into a plurality of segments each segment consisting of a representative pixel and other pixels, checking whether there is a selected black or white pixel in the segment, and when the check result is affirmative storing the X coordinate value of the representative pixel, whether the representative pixel is black or white, and whether each of the pixels in the segment is black or white.
Claim 21
Dependent Claim
71 words
An image processing apparatus for determining the optimum translation of an image by judging concordance between primary and secondary images, the images consisting of black and white pixels, the apparatus comprising: a first pattern translation means for consecutively translating an image at a first translation increment, and further obtaining the black pixels in the translated image by a jump search wherein the jump number is equal to or larger than 2.
Claim 22
Dependent Claim
102 words
An image processing apparatus for generating data regarding one of either the black pixels or the white pixels forming an image, the image consisting of black and white pixels, each constituting pixel having an X and Y value according to the X and Y axes, the image processing apparatus comprising: means for selecting one of either the black pixels or the white pixels as the object of comparison; and judging means for judging the concordance of two images after translating at least one of the images, and changing some of the selected black or white pixels into unselected white or black pixels.
Claim 23
Dependent Claim
126 words
An image processing method for processing an image consisting of pixels having brightness values of two or more, the images being stored in image memory, the method comprising: a first process of classifying pixels along parallel straight lines into narrowed black pixels, narrowed white pixels, and unresolved pixels; maintaining the connectivity regarding black pixels, and unresolved pixels according to the continuity of the original un-narrowed images; and a second process of changing the classification of the unresolved pixels along rotated parallel straight lines into black pixels and white pixels by using unresolved pixel judgement data that uses pixel aggregations, including the unresolved pixels to be processed; maintaining the connectivity regarding black pixels in the vicinity of the unresolved pixels and black pixels changed form unresolved pixels.
Claim 24
Dependent Claim
19 words
An image processing method according to claim 23 wherein a narrowing method is used instead of the second process.
Claim 25
Dependent Claim
20 words
An image processing method according to claim 23 wherein connectivity maintenance is at least partially omitted in the first process.
Claim 26
Dependent Claim
17 words
An image processing method according to claim 23 wherein the connectivity maintenance is a least partially omitted.
Claim 27
Dependent Claim
20 words
An image processing method according to claim 23 wherein the image stored in the image memory is a binary image.
References Cited (Backward Citations)
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