# US 2019/0377929 A1 · Cancelling out impairment data in fingerprint images > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0377929 A1 - Document ID: US20190377929A1 - Status: Published application - Kind: A1 - Application number: 16/485,293 - Filed: 2018-02-07 - Published: 2019-12-12 - Earliest claimed: 2017-02-17 - Assignees: Fingerprint Cards AB - Applicants: Fingerprint Cards AB - Inventors: Karl LUNDAHL; Erik SVENSSON; Morten Rolle HANSEN - Web page: https://patentgrep.com/patent/US20190377929A1 ## CPC - G06V 40/1306: {non-optical, e.g. ultrasonic or capacitive sensing} - G06V 10/30: Noise filtering - G06V 40/1347: {Preprocessing; Feature extraction} - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract The invention relates to a method of a fingerprint sensing system of enabling cancelling out impairment data present in an image captured by a fingerprint sensor of the fingerprint sensing system, a method of a fingerprint sensing system of cancelling out impairment data present in an image captured by a fingerprint sensor of the fingerprint sensing system, and a fingerprint sensing system performing the methods. ## Claims ### Claim 1 A method of a fingerprint sensing system of enabling cancelling out impairment data present in an image captured by a fingerprint sensor of the fingerprint sensing system, comprising: capturing an image of an object contacting the fingerprint sensor; detecting, from the captured image, impairment data caused by impairments that the fingerprint sensor is subjected to; fitting the detected impairment data to a selected mathematical model; and storing the mathematical model to which the detected impairment data is fitted, wherein the model can be used subsequently for at least partly cancelling out impairment data present in an image captured by the fingerprint sensor. ### Claim at position 2 -5. (canceled) ### Claim 6 A method of a fingerprint sensing system of cancelling out impairment data present in an image captured by a fingerprint sensor of the fingerprint sensing system comprising: capturing an image of an object contacting the fingerprint sensor; acquiring a stored predetermined mathematical model representing impairment data present in the captured image, which impairment data is caused by impairments that the fingerprint sensor is subjected to; and using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image. ### Claim 7 (depends on 6) The method of claim 6, wherein the step of using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image comprises: adjusting fingerprint sensor settings upon capturing the image in order to compensate for the impairment data represented by the acquired predetermined mathematical model, thereby at least partly cancelling out the impairment data present in the captured image. ### Claim 8 (depends on 7) The method of claim 7, wherein the adjusting of fingerprint sensor settings comprises adjusting sensitivity of pixels of the sensor to compensate for the impairment data. ### Claim 9 (depends on 8) The method of claim 8, wherein the adjusting of fingerprint sensor further comprises: adjusting sensitivity of pixels of the sensor such that different clusters of pixels are adjusted to have different pixel sensitivity. ### Claim 10 (depends on 6) The method of claim 6, wherein the step of using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image comprises: subtracting the impairment data represented by the acquired predetermined mathematical model from the impairment data present in the captured image. ### Claim 11 (depends on 6) The method of claim 6, wherein the step of using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image comprises: dividing the impairment data present in the captured image with the impairment data represented by the acquired predetermined mathematical model. ### Claim 12 (depends on 6) The method of claim 6, wherein the step of using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image comprises: assigning a lesser weight to fingerprint features extracted from areas of the captured image indicated by the acquired predetermined mathematical model to comprise impairment data. ### Claim 13 (depends on 6) The method of claim 6, wherein the step of using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image comprises: performing supplementary sensing of the object contacting the fingerprint sensor at areas of the fingerprint sensor indicated by the acquired predetermined mathematical model to comprise impairment data. ### Claim 14 (canceled) ### Claim 15 A fingerprint sensing system comprising a fingerprint sensor and a processing unit, the fingerprint sensing system being configured to enabling cancelling out impairment data present in an image captured by a fingerprint sensor of the fingerprint sensing system, the fingerprint sensor being configured to: capture an image of an object contacting the fingerprint sensor; the processing unit being configured to: detect, from the captured image, impairment data caused by impairments that the fingerprint sensor is subjected to; fit the detected impairment data to a selected mathematical model; and store the mathematical model to which the detected impairment data is fitted, wherein the model can be used subsequently for at least partly cancelling out impairment data present in an image captured by the fingerprint sensor. ### Claim at position 13 -19. (canceled) ### Claim 20 A fingerprint sensing system comprising a fingerprint sensor and a processing unit, the fingerprint sensing system being configured to cancelling out impairment data present in an image captured by a fingerprint sensor of the fingerprint sensing system, the fingerprint sensor being configured to: capture an image of an object contacting the fingerprint sensor; the processing unit being configured to: acquire a stored predetermined mathematical model representing impairment data present in the captured image, which impairment data is caused by impairments that the fingerprint sensor is subjected to; and use the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image. ### Claim 21 (depends on 20) The fingerprint sensing system of claim 20, the processing unit being configured to, when using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image: adjust fingerprint sensor settings upon capturing the image in order to compensate for the impairment data represented by the acquired predetermined mathematical model, thereby at least partly cancelling out the impairment data present in the captured image. ### Claim 22 (depends on 21) The fingerprint sensing system of claim 21, wherein the processing unit is configured to, when adjusting the fingerprint sensor settings: adjust sensitivity of pixels of the sensor to compensate for the impairment data. ### Claim 23 (depends on 21) The fingerprint sensing system of claim 21, wherein the processing unit is configured to, when adjusting the fingerprint sensor settings: adjust sensitivity of pixels of the sensor such that different clusters of pixels are adjusted to have different pixel sensitivity. ### Claim 24 (depends on 20) The fingerprint sensing system of claim 20, wherein the processing unit is configured to, when using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image: subtract the impairment data represented by the acquired predetermined mathematical model from the impairment data present in the captured image. ### Claim 25 (depends on 20) The fingerprint sensing system of claim 20, wherein the processing unit is configured to, when using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image: divide the impairment data present in the captured image with the impairment data represented by the acquired predetermined mathematical model. ### Claim 26 (depends on 20) The fingerprint sensing system of claim 20, wherein the processing unit is configured to, when using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image: assign a lesser weight to fingerprint features extracted from areas of the captured image indicated by the acquired predetermined mathematical model to comprise impairment data. ### Claim 27 (depends on 20) The fingerprint sensing system of claim 20, wherein the processing unit is configured to, when using the acquired predetermined mathematical model to at least partly cancel out the impairment data present in the captured image: perform supplementary sensing of the object contacting the fingerprint sensor at areas of the fingerprint sensor indicated by the acquired predetermined mathematical model to comprise impairment data. ### Claim at position 22 -29. (canceled) ### Claim 30 (depends on 6) A computer program comprising computer-executable instructions for causing the fingerprint sensing system to perform steps recited in claim 6 when the computer-executable instructions are executed on a processing unit included in the fingerprint sensing system. ### Claim 31 (depends on 30) A computer program product comprising a computer readable medium, the computer readable medium having the computer program according to claim 30 embodied thereon.