# US 2017/0286746 A1 · Efficient determination of biometric attribute for fast rejection of enrolled templates and other applications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0286746 A1 - Document ID: US20170286746A1 - Status: Published application - Kind: A1 - Application number: 15/086,906 - Filed: 2016-03-31 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: Synaptics Incorporated - Applicants: Synaptics Incorporated - Inventors: Kinh Tieu; Bob Lee Mackey - Web page: https://patentgrep.com/patent/US20170286746A1 ## CPC - G06V 40/1359: {Extracting features related to ridge properties; Determining the fingerprint type, e.g. whorl or loop} - G06V 30/248: {involving plural approaches, e.g. verification by template match; Resolving confusion among similar patterns, e.g. "O" versus "Q" (G06V30/242 takes precedence)} - G06V 40/1376: {Matching features related to ridge properties or fingerprint texture} - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract A biometric input system includes: a biometric sensor, configured to generate a biometric image comprising features of an input biometric object; and a processing system, configured to receive the biometric image, generate a feature map from the biometric image, perform a distance transform on the feature map, and determine an attribute of the biometric image from the distance transform. The processing system is further configured to compare the determined attribute of the biometric image with corresponding attributes of enrolled biometric images, and, based on the comparison, to eliminate enrolled biometric images from a matching process for the biometric image, wherein the matching process is performed after the elimination and comprises comparison of the biometric image to remaining enrolled biometric images based on one or more attributes of the biometric image other than the determined attribute. ## Claims ### Claim 1 A biometric input system, comprising: a biometric sensor, configured to generate a biometric image comprising features of an input biometric object; and a processing system, configured to receive the biometric image, generate a feature map from the biometric image, perform a distance transform on the feature map, and determine an attribute of the biometric image from the distance transform; wherein the processing system is further configured to compare the determined attribute of the biometric image with corresponding attributes of enrolled biometric images, and, based on the comparison, to eliminate enrolled biometric images from a matching process for the biometric image, wherein the matching process is performed after the elimination and comprises comparison of the biometric image to remaining enrolled biometric images based on one or more attributes of the biometric image other than the determined attribute. ### Claim 2 (depends on 1) The system according to claim 1, wherein the input biometric object is a fingerprint, and the feature map is a skeletonized ridge representation of the fingerprint. ### Claim 3 (depends on 2) The system according to claim 2, wherein generating the feature map from the biometric image comprises: generating a binary image from the received biometric image; and thinning each ridge of the binary image to a single pixel width. ### Claim 4 (depends on 2) The system according to claim 2, wherein the performed distance transform indicates a distance-to-nearest-ridge for each pixel of the feature map. ### Claim 5 (depends on 4) The system according to claim 4, wherein determining the attribute of the biometric image from the distance transform further comprises: identifying local maxima based on the performed distance transform; and determining the attribute of the biometric image based on the identified local maxima. ### Claim 6 (depends on 5) The system according to claim 5, wherein the determined attribute comprises a median or mean half ridge spacing value. ### Claim 7 (depends on 5) The system according to claim 5, wherein the determined attribute comprises a distribution of half ridge spacing values. ### Claim 8 (depends on 1) The system according to claim 1, wherein the processing system is further configured to determine an age, gender, or ethnicity corresponding to the input biometric object based on the determined attribute. ### Claim 9 A biometric input method, comprising: obtaining, by a processing system, a biometric image of an input biometric object; generating, by the processing system, a skeletonized ridge representation of the input biometric object based on the obtained biometric image; performing, by the processing system, a distance transform on the skeletonized ridge representation to determine a distance-to-nearest-ridge for each pixel of the skeletonized ridge representation; identifying local maxima based on the performed distance transform; and determining an attribute of the biometric image based on the performed distance transform and the identified local maxima. ### Claim 10 (depends on 9) The method according to claim 9, further comprising: comparing, by the processing system, the determined attribute of the biometric image with corresponding attributes of enrolled biometric images; eliminating, by the processing system, based on the comparing, enrolled biometric images from a matching process for the biometric image; and performing, by the processing system, the matching process for the biometric image, wherein performing the matching process comprises comparing one or more attributes of the biometric image other than the determined attribute to enrolled biometric images remaining after the elimination. ### Claim 11 (depends on 9) The method according to claim 9, wherein the obtained biometric image is a full or partial view of a fingerprint, and wherein the method further comprises: identifying one or more fingers corresponding to the obtained biometric image based on the determined attribute. ### Claim 12 (depends on 9) The method according to claim 9, wherein the obtained biometric image is a partial view of a fingerprint, and wherein the method further comprises: determining a localization of the partial view of the fingerprint within the fingerprint based on the determined attribute. ### Claim 13 (depends on 9) The method according to claim 9, further comprising: determining an age, gender, or ethnicity corresponding to the input biometric object based on the determined attribute. ### Claim 14 (depends on 9) The method according to claim 9, wherein the determined attribute is based on a ridge spacing-related value or a distribution of ridge spacing-related values. ### Claim 15 A non-transitory, computer-readable medium having processor-executable instructions stored thereon for biometric input, the processor-executable instructions, when executed, facilitating performance of the following: generating a skeletonized ridge representation of an input biometric image corresponding to an input biometric object; performing a distance transform on the skeletonized ridge representation to determine a distance-to-nearest-ridge for each pixel of the skeletonized ridge representation; identifying local maxima based on the performed distance transform; and determining an attribute of the biometric image based on the performed distance transform and the identified local maxima. ### Claim 16 (depends on 15) The non-transitory, computer-readable medium according to claim 15, wherein the processor-executable instructions, when executed, further facilitate: comparing the determined attribute of the biometric image with corresponding attributes of enrolled biometric images; eliminating, based on the comparing, enrolled biometric images from a matching process for the biometric image; and performing the matching process for the biometric image, wherein performing the matching process comprises comparing one or more attributes of the biometric image other than the determined attribute to enrolled biometric images remaining after the elimination. ### Claim 17 (depends on 15) The non-transitory, computer-readable medium according to claim 15, wherein the obtained biometric image is a full or partial view of a fingerprint, and wherein the processor-executable instructions, when executed, further facilitate: identifying one or more fingers corresponding to the obtained biometric image based on the determined attribute. ### Claim 18 (depends on 15) The non-transitory, computer-readable medium according to claim 15, wherein the obtained biometric image is a partial view of a fingerprint, and wherein the processor-executable instructions, when executed, further facilitate: determining a localization of the partial view of the fingerprint within the fingerprint based on the determined attribute . ### Claim 19 (depends on 15) The non-transitory, computer-readable medium according to claim 15, further comprising: determining an age, gender, or ethnicity corresponding to the input biometric object based on the determined attribute. ### Claim 20 (depends on 15) The non-transitory, computer-readable medium according to claim 15, wherein the determined attribute is based on a ridge spacing-related value or a distribution of ridge spacing-related values.