Adaptive fingerprint enrollment using local under-display fingerprint sensor in electronic devices

Abstract

This document describes methods and systems for adaptive fingerprint enrollment of a finger characteristic using an under-display fingerprint sensor (UDFPS) in an electronic device. The electronic device includes an adaptive enrollment module that determines a characteristic of a fingerprint based on information corresponding to touch inputs detected by the touch display device, including the size and shape of the area of the touch inputs. Based on the fingerprint characteristic, the number and location of enrollment touches used to complete enrollment of the fingerprint are adjusted to minimize the number of enrollment touches needed to complete enrollment, minimize the amount of time needed to complete enrollment, and maximize coverage of the fingerprint. The adaptive enrollment module also provides visual guidance to direct the user to touch the adjusted locations of the enrollment touches, and if needed, provides feedback to instruct the user to adjust the position of their finger to align with the visual guidance.

Description

Background Technology

[0001] Fingerprint authentication systems are a useful way to authenticate users to electronic devices. To reduce manufacturing costs, electronic devices can use under-display fingerprint sensors (UDFPS), which are continuously being developed in increasingly smaller sizes. Due to their size, these smaller UDFPS may be able to capture only a portion of a user's fingerprint. Therefore, multiple images of different parts of the fingerprint can be captured and stitched together to create a complete fingerprint enrollment. Existing fingerprint scanners typically have a uniform enrollment scheme with a fixed number of enrollment images. Because different users and different fingers have different fingerprint sizes, the enrollment experience can vary from finger to finger or user to user. For example, large fingerprints may be under-enrolled (e.g., their fingerprint template may not be fully covered, and gaps may exist between enrollment images), and / or small fingerprints may be over-enrolled (e.g., they may be required to provide more enrollment than is needed to fully cover their fingerprint template), thus degrading and weakening the user experience. Summary of the Invention

[0002] This document describes a method and system for adaptive fingerprint registration of finger characteristics using an under-display fingerprint sensor in an electronic device. The electronic device includes an adaptive registration module that determines fingerprint characteristics based on information corresponding to touch input detected by a touch display device, including the size and shape of the area of ​​the touch input. Based on the fingerprint characteristics, the number and location of registration touches used to complete fingerprint registration are adjusted to minimize the number of registration touches required to complete registration, minimize the amount of time required to complete registration, and maximize fingerprint coverage. The adaptive registration module also provides visual guidance to guide the user to touch the adjusted location of the registration touches and, if necessary, provides feedback to instruct the user to adjust the position of their finger to align with the visual guidance. In some aspects, a method for adaptive fingerprint registration of finger characteristics using an under-display fingerprint sensor in an electronic device is disclosed. The method includes providing a first visual guidance via a touch display device at a location corresponding to an effective area of ​​the under-display fingerprint sensor, the effective area being smaller than the typical size of a user's fingerprint. A first fingerprint image of a portion of the fingerprint of a user's finger is captured, the user's finger touching the touch display device at the location of the first visual guidance. The fingerprint contact area of ​​the user's finger touching the touch display device is determined, and one or more characteristics corresponding to the fingerprint are also determined based on the fingerprint contact area. Based on one or more characteristics of a fingerprint, the number of registration touches and the target location of the registration touches for registering the fingerprint in the fingerprint registration system are adjusted. Additionally, visual guidance is provided based on the adjusted number and target location of the registration touches to indicate the sequence of positions on the touch display device for the user to touch with their finger, thereby completing fingerprint registration with the adjusted number of registration touches.

[0003] In other aspects, a mobile electronic device is disclosed. The mobile electronic device includes a touch display device, an under-display fingerprint sensor located beneath the touch display device, one or more processors, and a memory. The memory is configured to store instructions that, when executed by the one or more processors, cause the one or more processors to implement an adaptive registration module to: provide an adaptive registration scheme adapted to one or more characteristics of the fingerprint during fingerprint registration; and provide visual guidance and feedback to guide the user through a sequence for placing the user's finger to provide a target location for registration touch. The visual guidance is output by the electronic device by performing the methods described above.

[0004] In other respects, a computer-readable medium comprising instructions that, when executed by one or more processors, cause one or more processors to perform the methods described above.

[0005] This invention is provided to introduce a simplified concept of adaptive fingerprint registration based on finger characteristics using a fingerprint sensor under a partial display in an electronic device, which will be further described in the following detailed description and accompanying drawings. This invention is not intended to identify the essential features of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter. Attached Figure Description

[0006] This document describes in detail one or more aspects of adaptive fingerprint registration based on finger characteristics using a fingerprint sensor under a local display in an electronic device, with reference to the accompanying drawings. Throughout the drawings, the same reference numerals are used to refer to similar features and components:

[0007] Figure 1 An example implementation of an electronic device capable of implementing adaptive fingerprint registration according to the technology described herein is shown;

[0008] Figure 2 Show in more detail Figure 1 Example implementation of electronic devices in the;

[0009] Figure 3 Show in more detail Figure 1 Example implementation of a fingerprint authentication system;

[0010] Figure 4 Showing via Figure 1 An example implementation of a touch display device detecting the size of a fingerprint corresponding to a touch input;

[0011] Figure 5 An example implementation of visual guidance provided during adaptive fingerprint registration is shown;

[0012] Figure 6 An example of a visually guided position sequence adapted to fingerprint size is shown during adaptive fingerprint registration;

[0013] Figure 7 Example diagrams are shown corresponding to the details of the algorithms used to determine fingerprint size, the number of registered touches, and the location of the registered touches;

[0014] Figure 8 An example method is described for determining the number and location of visual guides for adaptive fingerprint registration;

[0015] Figure 9 An example sequence of captured images stitched together during adaptive fingerprint registration according to the techniques described herein is shown;

[0016] Figure 10 An example implementation of error calculation between the target location of the registered touch and the detected location of the touch input is shown; and

[0017] Figure 11 and 12 An example method is described for adaptive fingerprint registration based on finger characteristics using a fingerprint sensor under a local display in an electronic device. Detailed Implementation

[0018] Overview

[0019] This document describes a method and system for adaptive fingerprint registration using a fingerprint sensor under a local display in an electronic device to assess fingerprint characteristics. The adaptive fingerprint registration described herein utilizes touch information obtained through a touch display, including an estimation of the contact area of ​​the touch. The contact area of ​​the touch has a general shape (e.g., an ellipse). The shape is used to determine the major and minor axes, which can be used to approximate the size of the fingerprint of the finger providing the touch. In some aspects, the orientation of the touch (e.g., an ellipse) relative to the touch display can be determined based on the touch information detected by the touch display.

[0020] The registration process is tailored to the characteristics of a specific finger to minimize the total number of registration templates required to complete registration, reduce overlap between images captured during registration, increase the non-overlapping area for each new registration step, and maximize the coverage of the registered fingerprint area relative to the ideal fingerprint. Furthermore, the electronic device can provide user-friendly visual guidance, instructing users where to place their fingers for each registration touch. If the user follows the registration instructions, the registration process can be completed in a short time. In contrast, some fingerprint systems using unguided registration processes (e.g., requiring users to touch the display at random locations) may result in users repeatedly touching the same locations, providing redundant registration data and thus requiring additional touches and time to complete the registration.

[0021] The electronic device can also provide accurate feedback to users when they do not follow the registration instructions. Such feedback can help optimize the registration process by reducing errors and the time spent during registration. Therefore, visual guidance and feedback can be used to instruct users on how to register the ideal fingerprint area for each touch. This guidance is specifically tailored to how the user's finger lands on the touchscreen and is therefore personalized for each user and each finger.

[0022] Since visual guidance can be viewed as a game, the adaptive fingerprint registration described in this paper can also increase user engagement. For example, visual guidance provides a series of locations for the user to touch in sequence, and can notify the user of feedback when their finger is not placed at the target location or is within a threshold distance of the target location. These features can increase user interaction to achieve the desired outcome.

[0023] While the features and concepts of the described method and system for adaptive fingerprint registration using a fingerprint sensor under a local display in an electronic device can be implemented in any number of different environments, aspects are described in the following example scenarios.

[0024] Example device

[0025] Figure 1 An example implementation 100 of an electronic device (e.g., electronic device 102) capable of implementing adaptive fingerprint registration according to the techniques described herein is shown. Electronic device 102 is shown as including a processor 104, a touch-sensitive display (e.g., a touch display device 106), a local display fingerprint sensor 108 (UDFPS 108), and a fingerprint authentication system 110, which can be used to provide a guided fingerprint registration process that adapts one or more characteristics of the fingerprint (e.g., size, shape, orientation). In various aspects, fingerprint authentication system 110 includes an adaptive registration module 112 that, when executed by processor 104, customizes the registration scheme based on the characteristics of the user's fingerprint to reduce the total number of user-performed registration touches required to complete the user's fingerprint registration.

[0026] The local UDFPS 108 is embedded beneath the touch display device 106, allowing users to place their fingers (e.g., fingers, thumbs, or palms) on the touch display device 106 of the electronic device 102 for authentication. The local UDFPS 108 can be implemented as any suitable sensor, including complementary metal-oxide-semiconductor (CMOS) image sensors, capacitive image sensors, charge-coupled devices (CCDs), ultrasonic image sensors, quantum image sensors (QIS), thin-film transistors (TFTs), optical sensors, and so on.

[0027] The fingerprint authentication system 110 is configured to scan small images of different parts of a user's finger using local UDFPS 108 and stitch the images together to create a template of the user's fingerprint. The template is stored locally or remotely and is subsequently used to authenticate the user to the electronic device 102.

[0028] The local UDFPS108, due to its size, can only scan small areas (e.g., effective area 114), which typically cannot capture a user's entire fingerprint in a single scan or image. For example, the typical size of a fingerprint (e.g., average size) is approximately 225 mm. 2 The effective region 114 can be significantly smaller, for example, 50% to 80% smaller. Figure 1A simplified example is shown where a user touches the touch display device 106 with their finger 116 at a first position 118 (represented by a dashed ellipse) corresponding to and centered on the effective area 114 of the local UDFPS 108. As shown in Example 120-1, the user's fingerprint 122 is significantly larger than the effective area 114 of the local UDFPS 108. When the user places their finger at the first position 118, the local UDFPS 108 scans the central portion of the fingerprint 122. Then, in Example 120-2, the user places their finger 116 at a different position (e.g., a second position 124) that is not centered on the effective area 114 of the local UDFPS 108. In this example, the second position 124 is offset from the central position (e.g., the first position 118). This second position 124 allows the local UDFPS 108 to scan another portion of the fingerprint 122. Then, at instance 120-3, the user places their finger 116 at another location (e.g., a third location 126) so that the local UDFPS 108 can scan additional portions of the fingerprint 122. After scanning a sufficient number of different portions of the fingerprint 122, the fingerprint authentication system 110 can stitch the scans together to create a template of the user's fingerprint for subsequent authentication attempts against the electronic device 102.

[0029] In more detail, consider Figure 2 , Figure 2 Show Figure 1 Example embodiment 200 of the electronic device 102. Figure 2 The electronic device 102 is shown in various example devices including a smartphone 102-1, a tablet computer 102-2, a laptop computer 102-3, a desktop computer 102-4, a computing watch 102-5, computing glasses 102-6, a gaming system 102-7, a home automation and control system 102-8, and a microwave oven 102-9. The electronic device 102 may also include other devices such as televisions, entertainment systems, audio systems, automobiles, drones, touchpads, drawing tablets, netbooks, e-readers, home security systems, and other home appliances. It should be noted that the electronic device 102 can be mobile, wearable, non-wearable but mobile, or relatively fixed (e.g., desktop computers and appliances).

[0030] The electronic device 102 also includes one or more computer processors 202 (e.g., processor 104) and one or more computer-readable media 204 including memory medium 206 and storage medium 208. An application 210 and / or operating system 212, implemented as computer-readable instructions on the computer-readable medium 204, can be executed by the computer processor 202 to provide some or all of the functions described herein. For example, the computer-readable medium 204 may include a fingerprint authentication system 110. Figure 3 The fingerprint authentication system 110 is described in detail below. The fingerprint authentication system 110 is configured to adapt the fingerprint registration process to the characteristics of the user's finger and provide visual guidance and feedback to help the user provide an optimized tactile experience for the fingerprint registration process.

[0031] Electronic device 102 may also include network interface 214. Electronic device 102 can use network interface 214 to transmit data via wired, wireless, or optical networks. By way of example and not limitation, network interface 214 can transmit data via local area network (LAN), wireless local area network (WLAN), personal area network (PAN), wide area network (WAN), intranet, Internet, peer-to-peer network, point-to-point network, or mesh network.

[0032] Various implementations of the fingerprint authentication system 110 may include a system-on-a-chip (SoC), one or more integrated circuits (ICs), a processor having embedded processor instructions or configured to access processor instructions stored in memory, hardware with embedded firmware, a printed circuit board with various hardware components, or any combination thereof.

[0033] The electronic device 102 also includes one or more sensors 216, which may include any of a variety of sensors, including audio sensors (e.g., microphones), touch input sensors (e.g., touchscreens), image capture devices (e.g., cameras or video cameras), proximity sensors (e.g., capacitive sensors), ambient light sensors (e.g., photodetectors), or local UDFPS 108.

[0034] Electronic device 102 may also include a display device (e.g., touch display device 106). Touch display device 106 may include any suitable touch-sensitive display device, such as a touch screen, liquid crystal display (LCD), thin-film transistor (TFT) LCD, in-situ switching (IPS) LCD, capacitive touch screen display, organic light-emitting diode (OLED) display, active-matrix organic light-emitting diode (AMOLED) display, super AMOLED display, etc. Touch display device 106 may be referred to as a display or screen, allowing content to be displayed on the screen.

[0035] Figure 3 Show in more detail Figure 1 Example implementation 300 of the fingerprint authentication system 110. Although Figure 3 Various entities and components are shown as part of the fingerprint authentication system 110, but any one of these entities and components may be detached from the fingerprint authentication system 110, allowing the fingerprint authentication system 110 to access and / or communicate with these entities and components to manage adaptive fingerprint registration on the electronic device 102.

[0036] exist Figure 3 In this context, the touch display device 106 detects touch events (e.g., touch input 302). The touch display device 106 provides one or more characteristics of the touch input 302. At least one of the characteristics may represent a parameter of the fingerprint of the finger used to provide the touch input 302. In various aspects, the characteristics may include one or more of the size 304 and / or shape 306 of the contact area of ​​the touch input 302. For example, the size 304 may be used to approximate the size or shape of a fingerprint. In some embodiments, the characteristics may include the orientation 308 of the touch input 302, which may indicate the direction in which the user's finger is pointing relative to one or more axes (e.g., vertical axis, horizontal axis) of the touch display device 106. The characteristics may also include the amount of pressure 310 of the touch input 302 on the touch display device 106. Because the size of the contact area of ​​the touch input 302 can vary with the flatness of the finger contacting the touch display device 106, the pressure 310 may indicate how accurately the size of the contact area represents the size of the fingerprint. Pressure 310 can be estimated based on the thermal image of touch input 302 and can be used to determine whether to instruct the user to press harder to increase the coupling between the user's finger and the touch display device 106, thereby improving the image quality of the fingerprint image captured by local UDFPS 108.

[0037] The touch display device 106 provides the characteristics of the touch input 302 to the adaptive registration module 112 of the fingerprint authentication system 110. The adaptive registration module 112 includes a registration control module 312 and a visual guidance module 314. The registration control module 312 receives information (e.g., at least size 304) from the touch display device 106 and creates an adaptive registration scheme 316 using the characteristics of the touch input 302, which adapts to the specific finger providing the touch input 302. In various respects, the adaptive registration scheme 316 defines, based on the characteristics of the touch input 302, the minimum number of registration touches required to optimize the registration process for a specific finger (e.g., T). min318) and a corresponding target touch position 320. Furthermore, an adaptive registration scheme 316 is created to provide sufficient overlap (e.g., substantially within the range of 0.1% to 2%) between consecutive images of registered touches for stitching the images together, while also avoiding potentially redundant excessive overlap. The target touch position 320 is determined to effectively increase (e.g., substantially maximize) the non-overlapping area of ​​each newly registered touch and reduce the total number of registrations required to achieve fingerprint coverage within a threshold tolerance of approximately fingerprint size (e.g., 1%, 1.5%, 2.2%, 5%). Therefore, characteristics of the touch input 302 representing the contact area of ​​a finger on the touch display device 106 (e.g., major axis, minor axis, tilt or rotation relative to the vertical axis of the touch display device) are used to optimize fingerprint coverage.

[0038] The visual guidance module 314 is configured to use an adaptive registration scheme 316 to provide visual guidance 322 corresponding to the target touch position 320. Visual guidance 322 can be taken via the touch display device 106. Figure 1 The visual guide 322 is presented in a form that indicates where the user should place their finger. The visual guide 322 can act as a moving target, which moves to a new location after the user has successfully touched the touch display device 106 at the target location (within acceptable misalignment tolerance). As described herein, the visual guide 322 visually indicates a sequence of positions following a progressively moving path (e.g., a spiral path), which reduces overlap between successive fingerprint images while increasing the non-overlapping area of ​​each fingerprint image and maximizing fingerprint coverage.

[0039] When the placement of a finger is substantially misaligned with the target touch location 320 (e.g., beyond an acceptable tolerance), the visual guidance module 314 can also provide feedback 324 to the user. Feedback 324 can be provided in any suitable form for instructing the user and guiding the user to align their finger with the visual guidance 322. In one example, feedback 324 may include a message with text instructing the user to move their finger in a certain direction, press harder, etc. In another example, feedback 324 may include requesting the user to press harder on the touch display device 106 (e.g., apply greater pressure) when pressure 310 is below a pressure threshold, to cover more area of ​​the fingerprint during registration, or to enable the local UDFPS 108 to capture a high-quality image of the fingerprint. Another example includes determining, based on a thermal map of the touch input, that the image quality of the captured image of a portion of the fingerprint is below a quality threshold and responsively estimating the pressure 310 of the touch input on the touch display device 106. If the pressure 310 is below the pressure threshold, feedback 324 can be provided to the user to request the user to increase the pressure 310 of the touch input. This can increase the coupling between the user's finger and the touch display device, thereby improving the image quality of the image captured by the fingerprint sensor under the local display. See below for reference. Figure 5 and 6 To describe more details. In some respects, visual guidance 322 can be dynamically adjusted based on one or more of the registered touches throughout the registration process to maximize the total area of ​​the fingerprint to be registered.

[0040] These and other features and configurations will be discussed in more detail below, as well as Figure 1-3 The ways in which entities function and interact. These entities can be further divided, combined, and so on. Figure 1 Implementation method 100 and Figures 2 to 12 The detailed illustrations show some of the many possible environments, apparatuses, and methods in which the described techniques can be employed.

[0041] Figure 4 Showing via Figure 1 An example embodiment 400 describes a touch display device 106 that detects the size of a fingerprint corresponding to a touch input. The touch display device 106 can be used to approximate the size of a user's fingerprint. For example, the touch display device 106 may include a sensor grid to enable complex inputs, such as the contact area of ​​a finger. In this example, the touch display device 106 can determine the size of the contact area, which corresponds to an approximate size of the fingerprint.

[0042] The illustrated example shows a portion of the touch display device 106 based on the response to a finger touch. For example, a shaded square 402 (e.g., a pixel) indicates the absence of a finger, while an unshaded square 404 (e.g., a pixel) indicates the presence of a finger. Pixels indicating the presence of a finger can be aggregated to provide the contact area of ​​the finger. The contact area can be used to generate a thermal map 406. Existing touch displays can generate a thermal map 406 of the contact area of ​​a touch input. In an implementation, the thermal map 406 can serve as a representation of the extent to which each pixel covers the finger, since the thermal map 406 is related to the amount of capacitance detected at that pixel location in the touch display device 106. Using the thermal map 406, the fingerprint authentication system 110 can estimate one or more characteristics of the fingerprint 122 of the finger, including the size and / or shape of the fingerprint 122. Any suitable two-dimensional shape can be used to approximate the shape of the fingerprint 122, including ellipses, rectangles, squares, trapezoids, etc. In the example shown, the shape of the fingerprint 122 is approximated as an ellipse (e.g., ellipse 408) with a major axis 410 and a minor axis 412. By estimating the shape based on the heatmap 406, the major axis 410 and minor axis 412 can be calculated to approximate the size of the fingerprint 122. Additionally, the centroid 414 of the fingerprint can be determined, which can be used to determine the target touch location 320 for registration. The size of the fingerprint 122 is used to adjust the adaptive registration scheme 316.

[0043] Figure 5 This illustrates the visual guidance provided during adaptive fingerprint registration (e.g., Figure 3 Example implementation 500 of the visual guidance 322. Based on the adaptive registration scheme 316, the fingerprint authentication system 110 can provide visual guidance (e.g., visual guide 502, shown as “X” for illustrative purposes) regarding the specific location where a user places their finger. The user places their finger by using the visual guide 502 such that the centroid of their finger touches or approaches the visual guide 502. Alternatively, the visual guide 502 can be an ellipse touched by the user, such that the contact area of ​​the finger substantially fills the ellipse. Any suitable visual artifact (e.g., icon, shape, object) can be implemented as a visual guide to indicate to the user where to touch the touch display device 106. Different portions of the fingerprint 122 are registered by touching the touch display device 106 at different locations based on the visual guide 502.

[0044] For example, touch display device 106 is shown as having an effective area 114 of local UDFPS 108. Examples 506-1, 506-2, and 506-3 illustrate different registrations based on different touch positions on touch display device 106. Example 506-1 shows a first registration of fingerprint 122 centered on the effective area 114 of local UDFPS 108. In this way, when electronic device 102 provides guidance to the center of the effective area 114 of local UDFPS 108, the user registers the center of their fingerprint 122. For example, visual guidance 502 (shown as “X”) can be based on the centroid positioning of fingerprint 122 calculated according to the size and shape of fingerprint 122. When visual guidance 502 is above the effective area 114 of local UDFPS 108, as shown in example 506-2, the user registers the lower portion of their fingerprint 122. When visual guidance 502 is below the effective area 114, as shown in example 506-3, the user registers the upper portion of their fingerprint 122. Therefore, assuming the user successfully follows the instructions with the centroid of their fingerprint (e.g., the middle of their finger) and registers different parts of the fingerprint 122 by moving the position of the visual guide 502.

[0045] The visual guide 502 can be adapted to the characteristics of the fingerprint (e.g., size, shape, orientation). For example, for a larger fingerprint size, the visual guide 502 can be enlarged to make it easier for the user to track the visual guide 502 or align their finger with it. Furthermore, the visual guide 502 can be provided relative to the finger landing (e.g., touch location), the local UDFPS 108, and the touch display device 106. Therefore, the visual guide 502 can be dynamic, as it can depend on the fingerprint size, the tilt of the fingerprint relative to the touch display device 106 (e.g., orientation 308), and its position relative to the local UDFPS 108 and the touch display device 106. Additionally, if the contact area of ​​the touch input is rotated relative to the vertical axis of the touch display device 106, the visual guide 502 can be rotated and / or translated. For example, if the user rotates their finger from one registration touch to the next, the adaptive registration scheme 316 and therefore the visual guide 502 can adapt to the new orientation of the fingerprint.

[0046] Existing fingerprint registration systems may use unguided registration schemes, requiring users to continuously touch the display until the device indicates registration is complete. Therefore, users touch the display at random locations, sometimes returning to the same or similar locations, resulting in redundant registration, which in turn increases the number of touches required to complete registration and the time required. Using random locations for registration touches may capture areas of the finger with smaller values ​​relative to the fingerprint (e.g., the outer edge of the fingerprint) and / or may result in gaps between non-overlapping scans. Figure 6The adaptive fingerprint registration technology described in detail can solve and minimize at least some of these problems.

[0047] Figure 6 Examples 600 and 610 illustrate visually guided position sequences adapted to fingerprint size during adaptive fingerprint registration. Examples 600 and 610 are shown for large fingerprints (e.g., approximately 256 square millimeters (mm²)). 2 Large fingerprints (e.g., approximately 361mm) and large fingerprints. 2 This compares the adaptive registration schemes provided. For example, Example 600 uses fewer registration touches for large fingerprints, while Example 610 uses more registration touches for large fingerprints. Visual guidance 502 indicates the target location for each sequential registration touch (e.g., Figure 3 The target touch position 320 in the middle). In operation, a visual guide 502 is displayed one at a time to indicate the specific position where the user places their finger, thereby enabling the electronic device 102 to ( Figure 1 In the local UDFPS108, a specific portion of the user's fingerprint is scanned over the effective area 114. In this example, visual guidance 502 indicates the centroid where the user places their finger (e.g., Figure 4 The location of the centroid 414 in the image. In Example 600, the adaptive registration scheme can use seven registration touches to complete the registration process with sufficient coverage for a large fingerprint. In contrast, Example 610 shows the use of 15 registration touches to achieve sufficient coverage for a large fingerprint to complete the registration process.

[0048] Additionally, note that the visual guides 502 are ordered to sequentially form spiral patterns (e.g., spiral pattern 602, spiral pattern 612). The positional sequence used by the visual guides 502 can form any suitable pattern or shape, including ovals, rectangles, stars, trapezoids, triangles, and so on. In the example shown, a spiral pattern is used, which allows the user's finger to make small incremental movements between registered touches (e.g., moving from one target location to an adjacent target location). These small increments allow for more accurate fingerprint localization, where there is an appropriate level of overlap between successive scans. Furthermore, user engagement is enhanced because the user follows the moving target (e.g., visual guides 502) with their finger to achieve visual guidance, similar to playing a game.

[0049] In some respects, the pattern formed by the sequence of visual guidance 502 can be a predefined pattern of the target touch point. In this way, the visual guidance can be generalizable for average finger size. In other respects, the pattern can be an algorithmically defined pattern of the target touch point. Based on the identified characteristics of a particular finger, the algorithmically defined pattern can be adapted to that particular finger. It can be based on the first registered touch (e.g., Figure 3The initial calculation of the characteristics of the touch input 302 in the touch input determines the position of the visual guide 502 (e.g., target touch position 320). However, if a subsequent registration has a new orientation that is substantially different from the orientation of the first registered touch, the visual guide 502 can be refitted to align with the new orientation.

[0050] Additionally, visual guidance can be dynamically adjusted during registration. For example, at any time after the first registration touch, the adaptive registration module 112 can adjust the adaptive registration scheme 316 by, for example, adding additional registration touches and / or adjusting the position of the registration touches (e.g., target touch position 320). Figure 3 (in the middle) to dynamically optimize fingerprint coverage.

[0051] Figure 7 Example Figure 700 illustrates details corresponding to the algorithm used to determine the fingerprint size, number of registered touches, and location of the registered touches for adaptive fingerprint registration. In the illustrated example, the first ellipse is determined (e.g., based on...). Figure 4 The heatmap 406 in the image is an ellipse 408 approximating the fingerprint 122. Based on the characteristics of the first ellipse, one or more additional smaller ellipses (e.g., new ellipse 702) are calculated and used to determine the number of registered touches and target locations for adaptive fingerprint registration.

[0052] In the example shown, the adaptive registration module 112 determines the major ellipse dimension a1 and the minor ellipse dimension b1 of the contact area of ​​the touch input. The major ellipse dimension a1 can correspond to the touch input-based heatmap 406. Figure 4 The major axis 410 of the ellipse 408 approximating the fingerprint 122 is defined by the heatmap 406 based on the touch input. The minor ellipse dimension b1 can correspond to the minor axis 412 of the ellipse 408 approximating the fingerprint 122 based on the touch input. The ellipse 408 (also referred to as the "fingerprint ellipse") can be subdivided into smaller ellipses. For example, the adaptive registration module 112 can construct a new ellipse 702 with an offset 704 from the fingerprint ellipse (e.g., ellipse 408). In some respects, the offset 704 can be related to the effective region 114 of the local UDFPS 108. Figure 1 The dimensions of the ellipse (in the middle) are somewhat correlated. The new ellipse 702 includes a long ellipse dimension 706a2 and a short ellipse dimension 708b2. Based on the fingerprint size (e.g., represented by ellipse 408), the adaptive registration module 112 can infer a location (e.g., location 710) that provides sufficient overlap (e.g., at least threshold overlap) between consecutive images (e.g., scans) of the fingerprint and provides sufficient total coverage of the fingerprint (e.g., within a threshold tolerance, such as regarding...). Figure 3(As described) for use in registration. Can be based on Figure 1 The location 710 is determined by the correlation between the size of the effective region 114 of the local UDFPS 108 and the regions of the ellipse (e.g., regions 712 and 714). In the example, the region of ellipse 408 is the difference between the area of ​​ellipse 408 and the area of ​​ellipse 702. Furthermore, it can be determined by following the principle of... Figure 6 The defined pattern (e.g., a spiral pattern) is presented to the user in an ordered sequence at position 710. Figure 8 More details describing this process, Figure 8 refer to Figure 7 The characteristics described.

[0053] Figure 8 An example method is described for determining the number and location of visual guides for adaptive fingerprint registration. At 802, the dimensions a1 of the major ellipse and b1 of the minor ellipse are determined. As an example, the major axis 410 and minor axis 412 are determined for an ellipse 408 approximated by a touch-input-based heatmap 406. At 804, the adaptive registration module 112 constructs one or more new ellipses, each having an offset Δ from ellipse 408 (e.g., offset 704). Each new ellipse is also concentric with ellipse 408. The offset 704 can be different for each new ellipse. In some respects, the offset 704 increases for each new ellipse such that each new ellipse is smaller than the previous ellipse.

[0054] At 806, the major ellipse dimension a2 and the minor ellipse dimension b2 are determined for each new ellipse. For example, the major ellipse dimension 706a2 and the minor ellipse dimension 708b2 of the new ellipse 702 are determined. To ensure that the new ellipse 702 is usable by the algorithm, constraints can be applied to the new ellipse. For example, if the major ellipse dimension a2 or the minor ellipse dimension b2 of any given new ellipse is less than zero, the new ellipse is not recorded and is not used in subsequent steps of method 800. However, if both a2 and b2 of a given new ellipse are greater than zero, and at least one of a2 or b2 is less than a threshold H, the given new ellipse is recorded and used in subsequent steps of method 800. If both a2 and b2 are greater than the threshold H, method 800 can return to 804 to construct another new ellipse with a different offset.

[0055] At point 808, determine the number of segments for each ellipse. For example, determine each elliptical region (e.g., Figure 7 The area of ​​zone 712 or zone 714 in the diagram is then calculated. Each area is then divided by the square of the corresponding offset (e.g., Δ). 2The result is rounded to a higher integer representing the number of segments of the ellipse. In all respects, the minimum number of segments can be three (for example, if the number of segments is less than three, the number of segments is set to three). If the number of segments of a given ellipse is greater than the minimum number, that larger number is set to the number of segments of the given ellipse.

[0056] At 810, the position of each visual guide 502 is determined for each elliptical region. In some respects, the first point is located centered on the effective region 114 of the local UDFPS108 (e.g., Figure 6 The point (0,0) is shown in Examples 600 and 610. At least some of the positions 710 are located on the midpoint of the elliptical region. Additionally, positions 710 include points located on a specific number of segments dividing each elliptical region. Furthermore, positions 710 are ordered from the center, small ellipse to large ellipse. This order allows the user to provide small incremental movements of their finger between consecutive registered touches, which can increase the accuracy of registration.

[0057] At 812, visual guidance is provided via a touch display device in a sorted sequence. For example, visual guidance 502 is displayed one at a time in a pattern (e.g., a predefined pattern or an algorithmically defined pattern) according to position 710. The pattern may be a spiral pattern starting from the center of the effective area 114 of the local UDFPS 108. The display of visual guidance 502 follows a sorted sequence based on touch input. For example, if a touch input corresponding to a first visual guidance is received, the first visual guidance is removed, and a second visual guidance in the sorted sequence is displayed. Further details of these features are described below.

[0058] Figure 9 An example sequence 900 of captured images stitched together during adaptive fingerprint registration according to the techniques described herein is shown. For example, when a user registers according to a guided registration scheme and visual guidance (e.g., ...) as described herein... Figure 5The visual guidance 502 provides instructions for registering a touch, during which the local UDFPS 108 scans portions of the fingerprint and stitches the scans together to complete the fingerprint registration. In Example 902-1, the user provides a first touch such that the centroid of the finger is located on the effective area 114 of the local UDFPS 108, and the local UDFPS 108 scans the finger to obtain a first portion 904 of the fingerprint (e.g., the central portion). In Example 902-2, the user provides a second touch such that the centroid of the finger is positioned at a location offset from the center of the effective area 114 (e.g., to the left), and the local UDFPS 108 scans a second portion 906 of the fingerprint. In Example 902-3, the user provides a third touch such that the centroid of the finger is located at yet another location offset from the center of the effective area 114 (e.g., the upper left corner), and the local UDFPS 108 scans a third portion 908 of the fingerprint. Each new registration has minimal overlap with the previous registration, and there are no gaps between consecutive images, which reduces the total number of registrations required to complete fingerprint registration with sufficient coverage. In this example, each newly scanned portion follows a spiral pattern. However, it can follow any suitable pattern. The user continues to provide registration touches based on the provided visual guidance until, for example, at instance 902-n, the scanning sequence provides sufficient coverage of the fingerprint to complete registration.

[0059] Figure 10 An example implementation 1000 is shown, illustrating the calculation of the error between the target location of the registered touch and the detected location of the touch input. Example implementation 1000 includes a touch display (e.g., Figure 1 A portion of the touch display device 106 in the vicinity of the effective area 114 of the local UDFPS 108. This portion of the touch display has touch pixels 1002 with no signal (e.g., no touch detected) and touch pixels 1004 with signal (e.g., a detected touch). Touch pixels 1004 are used to define an ellipse (e.g., ellipse 408) approximating the size of a fingerprint. The center of ellipse 408 is determined, and this center represents the centroid of the fingerprint (e.g., ...). Figure 4 (centroid 414 in the fingerprint). Although visual guidance 502 can be provided, users may not accurately position their fingers to align the centroid of their fingerprint with the visual guidance 502. Therefore, a certain degree of error tolerance can be implemented.

[0060] The accuracy with which a user follows visual instructions (e.g., visual guide 502) can be quantified and used to dynamically adjust the registration scheme (e.g., the number and location of registered touches). For example, the position of visual guide 502 can be compared with the positioning of the finger's centroid 414 relative to the touch display device 106 to determine a distance d (e.g., distance 1006). Distance 1006 can be compared with a threshold th. The threshold th allows a user to experience some jitter when placing their finger's center on visual guide 502. The threshold th represents a bias threshold, which provides an indication of whether the user is substantially following the instruction or has deviated significantly from it. For example, if distance d is less than the threshold th, the user is considered to have followed the instruction correctly. However, if distance d is greater than the threshold th, feedback (e.g., a visual or audio message) can be provided to instruct the user to place their finger's center (e.g., centroid 414) on visual guide 502. The fingerprint centroid position and ellipse orientation can be used as initial estimates to stitch together a fingerprint image to construct the entire fingerprint template.

[0061] Figure 11 and 12 Example methods 1100 and 1200 are described respectively for adaptive fingerprint registration using a fingerprint sensor under a local display in an electronic device to assess finger characteristics. Methods 1100 and 1200 can be performed by an electronic device 102, which uses an adaptive registration module 112 to adapt the number and location of registered touches to the characteristics of the fingerprint. Method 1200 is complementary to method 1100 and can optionally be performed in conjunction with method 1100.

[0062] Methods 1100 and 1200 are shown as a set of boxes specifying the operations to be performed, but are not necessarily limited to the order or combination of operations performed by the corresponding boxes shown. Furthermore, any one or more operations may be repeated, combined, rearranged, or linked to provide a wide variety of additional and / or alternative methods. References can be found in the sections discussed below. Figure 1 Example implementation 100 or reference Figures 2 to 10 The entities or processes described in detail are for illustrative purposes only. The technology is not limited to the performance of one or more entities operating on a device.

[0063] At 1102, a first visual guide is presented via a touch display device at a location corresponding to the effective area of ​​the local UDFPS. The visual guide (e.g., visual guide 502) is configured to instruct the user where to place a finger on the touch display device 106 so that the size of the fingerprint 122 of the finger can be detected and a first fingerprint image of a first portion (e.g., first portion 904) of the fingerprint 122 can be captured.

[0064] At 1104, UDFPS captures a first fingerprint image of a portion of the fingerprint of the finger touching the location of the visual guide. Assuming the user follows the instructions of the visual guide 502, the first fingerprint image may include the central portion of the fingerprint 122, which includes the centroid 414 in the fingerprint 122.

[0065] At 1106, a fingerprint contact area and one or more characteristics corresponding to the fingerprint are determined. For example, the touch display device 106 may generate a thermal map (e.g., thermal map 406) corresponding to the area of ​​the touch display device that is in contact with the finger. The thermal map may be used to approximate the fingerprint contact area (e.g., ellipse 408), which may be used to estimate fingerprint characteristics, including one or more of size 304, shape 306, and orientation 308. Step 1106 is not necessarily limited to being performed after step 1104. In some embodiments, for example, step 1106 may be performed before or in parallel with step 1104.

[0066] At 1108, the adaptive registration module adjusts the number of registration touches and the target locations of the registration touches for registering the fingerprint in the fingerprint authentication system (e.g., fingerprint authentication system 110) based on one or more characteristics of the fingerprint. In each aspect, the target locations sequentially follow a pattern to complete registration with the minimum number of registration touches. A minimum number of registration touches (e.g., Figure 3 T in min The pattern is based on one or more characteristics of the fingerprint, including at least size. Step 1108 may include... Figure 8 One or more steps in the process include one or more of the following: determining the long and short elliptical dimensions of the fingerprint contact area (e.g., at 802); constructing one or more new ellipses, each new ellipse having an offset from the fingerprint contact area (e.g., at 804); determining the long and short dimensions of the new ellipses (e.g., at 806); determining the number of segments of each ellipse (e.g., at 808); and determining the position of each visual guide on each elliptical region (e.g., 810). In some aspects, the pattern is a spiral pattern (clockwise or counterclockwise). The pattern may begin at a location that allows the central portion of the fingerprint to be captured by the local UDFPS 108. For example, spiral pattern 602 or spiral pattern 612 may include a first visual guide configured to align the centroid 414 of the fingerprint with the center of the effective area 114 of the local UDFPS 108.

[0067] At 1110, the error counter is set to zero to indicate a user error in following visual guidance instructions. The error counter is used to count the number of times the user fails to follow visual guidance instructions. If the error counter reaches or exceeds a limit (e.g., MaxError), the adaptive registration module 112 can determine that the user is not interested in completing the registration.

[0068] continue Figure 12 1202 displays the i-th visual guide, where i = 2:N. In the case of i = 2, a second visual guide is displayed that is offset from the center of the effective region 114 of the local UDFPS 108. The second visual guide (e.g., visual guide 502) may be located within the effective region 114 (e.g., near the edge of the effective region 114). Alternatively, the second visual guide may be located outside the effective region 114.

[0069] At 1204, a fingerprint image (e.g., the i-th image) is captured. For example, local UDFPS 108 can scan a portion of the fingerprint located on the effective region 114.

[0070] At 1206, the distance d between the fingerprint centroid and the location of the visual guide is determined. The fingerprint centroid (e.g., centroid 414) can be determined based on the fingerprint contact area detected by the touch display device 106.

[0071] At 1208, the adaptive registration module 112 determines whether the distance d between the fingerprint centroid (e.g., centroid 414) and the visual guide 502 is greater than a threshold distance D. th Any suitable threshold distance D can be used. th This includes threshold distances that are essentially in the range of zero millimeters (mm) to 2.0 mm. Threshold distance D th Sets a permissible limit (e.g., maximum distance) for the positional misalignment of the fingerprint centroid with the visual guide 502 for acceptable registration touches. This applies if the distance d between the fingerprint centroid 414 and the visual guide 502 is less than a threshold distance D. th If "No" is set at 1208, then method 1200 returns to 1202 to display the next visual guide (e.g., the i+1 visual guide).

[0072] If the distance d between the fingerprint centroid and the visual guide 502 is greater than the threshold distance D th If 1208 is "Yes", then at 1210, the adaptive registration module 112 determines that the user has not followed the instruction. In this case, feedback is provided to the user via the touch display device 106 to adjust the position of their finger above the visual guide 502. Additionally, the error counter is incremented by 1.

[0073] At 1212, the adaptive registration module 112 determines whether the error counter is greater than MaxError. Any suitable integer can be used for MaxError, including, for example, 3, 4, 5, 6, 7, etc. If the error counter does not exceed MaxError ("No" at 1212), then at 1214, feedback is provided to the user to reposition their finger on the visual guide 502. At 1216, the i-th fingerprint image is recaptured, and method 1200 returns to 1206 to recheck the distance d between the fingerprint centroid 414 and the position of the visual guide 502.

[0074] If the error counter exceeds MaxError ("Yes" at 1212) at 1212, then adaptive fingerprint registration can end at 1218. For example, an error counter exceeding MaxError indicates that the user has not followed the guided registration instructions. Therefore, it can be assumed that the user is not interested in feedback or adaptive fingerprint registration. Therefore, method 1200 can end. In some aspects, the adaptive fingerprint registration process can transition to a regular registration scheme, which allows the user to touch their finger at random locations on the touch display device 106 and does not provide feedback to guide the user on where to position their finger to reduce the number of registration touches. In another example, the adaptive fingerprint registration process can restart. Alternatively, the adaptive fingerprint registration process can end, and the application running the adaptive fingerprint registration process can be closed.

[0075] Generally, any component, module, method, and operation described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of the example methods can be described in a general context of executable instructions stored on computer-readable storage memory local and / or remote on a computer processing system, and implementations may include software applications, programs, functions, etc. Alternatively or additionally, any functionality described herein can be performed at least in part by one or more hardware logic components, including but not limited to field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip (SoCs), complex programmable logic devices (CPLDs), and so on.

[0076] The following describes some examples:

[0077] A method for adaptive fingerprint registration using an under-display fingerprint sensor in an electronic device, the method comprising: providing first visual guidance via a touch display device at a location corresponding to an effective area of ​​the under-display fingerprint sensor, the effective area being smaller than the typical size of a user's fingerprint; capturing a first fingerprint image of a portion of the fingerprint of a user's finger, the user's finger touching the touch display device at the location of the first visual guidance; determining the fingerprint contact area touched by the user's finger on the touch display device, and determining one or more characteristics corresponding to the fingerprint based on the fingerprint contact area; adjusting the number of registration touches and the target location of the registration touches for registering the fingerprint in a fingerprint registration system based on the one or more characteristics of the fingerprint; and providing visual guidance based on the adjusted number and target location of the registration touches to indicate a sequence of positions on the touch display device for the user to touch with their finger to complete fingerprint registration with the adjusted number of registration touches.

[0078] One or more characteristics of a fingerprint may include one or more of size, shape, and orientation.

[0079] One or more characteristics of a fingerprint may include the amount of pressure applied to the fingerprint contact area on a touch display device.

[0080] Adjusting the number of registered touches and the target location of the registered touches can include reducing the number of registered touches for large fingerprints or increasing the number of registered touches for large fingerprints.

[0081] Adjusting the number of registered touches and the target location of the registered touches can include reducing the total number of registered touches, reducing the overlap between consecutive images of registered touches, increasing the non-overlapping area of ​​each new registered touch, and increasing the coverage of the approximate area of ​​the fingerprint.

[0082] Adjusting the number of registered touches and the target location of the registered touches may include adjusting the number of registered touches to a number that produces consecutive fingerprint images with a threshold overlap and achieves a total coverage of the fingerprint within a threshold tolerance.

[0083] Each location in the sequence of registered touch locations can be determined based on the estimated centroid of the fingerprint.

[0084] Visual guidance can include predefined patterns for touch points.

[0085] Visual guidance may include patterns of touch points adapted to the user's fingers, which are represented by one or more characteristics of touch input.

[0086] The location sequence may include a spiral pattern centered on the effective area of ​​the fingerprint sensor under the local display.

[0087] The method may further include: determining that the image quality of the captured image of an additional portion of a fingerprint captured by a local display fingerprint sensor is below a quality threshold; in response to determining that the image quality of the captured image is below the threshold, estimating the finger pressure of a user's finger touching the touch display device based on a thermal map of the fingerprint contact area; determining that the finger pressure is below a pressure threshold; and providing feedback to the user to press more forcefully to increase the coupling between the user's finger and the touch display device and increase the image quality of the image captured by the local display fingerprint sensor.

[0088] The method may further include: determining the long ellipse dimension and short ellipse dimension of the fingerprint ellipse corresponding to the fingerprint contact area; constructing one or more new ellipses, each of which has an offset from the fingerprint ellipse and is concentric with the fingerprint ellipse; determining the long dimension and short dimension of each new ellipse; and inferring the target location of the registered touch based on the size of the fingerprint ellipse.

[0089] Inferring the target location of a registered touch may include: determining the number of segments of each ellipse that do not overlap with smaller ellipses in one or more new ellipses; associating the target location of the registered touch with segments in each ellipse; and sorting the target locations to form a location sequence.

[0090] A mobile electronic device includes: a touch display device; an under-display fingerprint sensor located beneath the touch display device; one or more processors; and a memory storing: instructions that, when executed by the one or more processors, cause the one or more processors to implement an adaptive registration module to: provide an adaptive registration scheme adapted to one or more characteristics of a fingerprint during the registration of a user's fingerprint; and provide visual guidance and feedback to guide the user through a sequence of steps for placing their finger to provide a target location for the registration touch, the visual guidance being output by the electronic device by performing the methods described above.

[0091] A computer-readable medium comprising instructions that, when executed by one or more processors, cause one or more processors to perform the methods disclosed above.

[0092] in conclusion

[0093] Although aspects of adaptive fingerprint registration using a fingerprint sensor under a local display in an electronic device to assess finger characteristics have been described in language specific to features and / or methods, the subject matter of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as exemplary embodiments of the claimed adaptive fingerprint registration, and other equivalent features and methods are intended to be within the scope of the appended claims. Furthermore, various different aspects have been described, and it should be understood that each described aspect may be implemented independently or in combination with one or more other described aspects.

Claims

1. A method for adaptive fingerprint registration based on finger characteristics using a fingerprint sensor under a local display in an electronic device, the method comprising: A first visual guide is provided via a touch display device at a location corresponding to the effective area of ​​the fingerprint sensor under the partial display, the effective area being smaller than the typical size of the user's fingerprint; A first fingerprint image is captured, representing a portion of the fingerprint of the user's finger, which touches the touch display device at the location indicated by the first visual guidance. Determine that the user's finger touches the fingerprint contact area of ​​the touch display device, and determine one or more fingerprint contact area characteristics corresponding to the fingerprint based on the fingerprint contact area; Based on the characteristics of one or more fingerprint contact areas of the fingerprint, the number of registration touches and the target location of the registration touches for registering the fingerprint in the fingerprint registration system are adjusted, wherein adjusting the number of registration touches includes adjusting the number of registration touches to a specified number of registration touches that meet the threshold coverage. as well as Visual guidance is provided based on the adjusted number and target position of the registered touches to indicate the sequence of positions on the touch display device for the user to touch with their finger, thereby completing the fingerprint registration through the adjusted number of registered touches.

2. The method according to claim 1, wherein, The characteristics of the one or more fingerprint contact areas include one or more of size, shape, and orientation.

3. The method according to claim 1, wherein, The characteristics of the one or more fingerprint contact areas include the amount of pressure applied to the fingerprint contact areas on the touch display device.

4. The method according to claim 1, wherein, Adjusting the number of registered touches and the target location of the registered touches includes: reducing the number of registered touches for small fingerprints or increasing the number of registered touches for large fingerprints to meet the threshold coverage.

5. The method according to claim 1, wherein, Adjusting the number of registered touches and the target location of the registered touches includes one or more of the following: reducing the total number of registered touches required for the threshold coverage, reducing the overlap between consecutive images of the registered touches, increasing the non-overlapping area of ​​each new registered touch, and increasing the coverage of the approximate area of ​​the fingerprint.

6. The method according to claim 1, wherein, Adjusting the number of registered touches and the target location of the registered touches includes: The number of registered touches is adjusted to a number that generates consecutive fingerprint images with a threshold overlap and achieves a total coverage of the fingerprints within a threshold tolerance.

7. The method according to claim 1, wherein, Each location in the sequence of locations of the registered touch is determined based on the estimated centroid of the fingerprint.

8. The method according to claim 1, wherein, The visual guidance includes predefined patterns for touch points.

9. The method according to claim 1, wherein, The visual guidance includes a pattern adapted to the touch points of the user's finger, which is represented by the characteristics of one or more fingerprint contact areas of the touch input.

10. The method according to claim 1, wherein, The sequence of positions includes a spiral pattern centered on the effective area of ​​the fingerprint sensor under the local display.

11. The method of claim 1, further comprising: The image quality of the captured image of an additional portion of the fingerprint captured by the fingerprint sensor under the local display is determined to be below a quality threshold; In response to determining that the image quality of the captured image is below the threshold, the finger pressure of the user's finger touching the touch display device is estimated based on the thermal map of the fingerprint contact area; It is determined that the finger pressure is below the pressure threshold; as well as The system provides feedback to the user to press harder, thereby increasing the coupling between the user's finger and the touch display device and increasing the image quality of the image captured by the fingerprint sensor under the local display.

12. The method according to any one of claims 1-11, further comprising: Determine the long and short ellipse dimensions of the fingerprint ellipse corresponding to the fingerprint contact area; Construct one or more new ellipses, each of which has an offset from the fingerprint ellipse and is concentric with the fingerprint ellipse; Determine the long and short dimensions of each new ellipse; as well as The target location of the registered touch is inferred based on the size of the fingerprint ellipse.

13. The method according to claim 12, wherein, Inferring the target location of the registered touch includes: Determine the number of segments of each ellipse that do not overlap with smaller ellipses in the one or more new ellipses; Associate the target location of the registered touch with the segment in each ellipse; and The target locations are sorted to form a sequence of locations.

14. A mobile electronic device, comprising: Touch display device; A partial display under-display fingerprint sensor, wherein the partial display under-display fingerprint sensor is located below the touch display device; One or more processors; as well as The memory stores: Instructions, which, when executed by the one or more processors, cause the one or more processors to implement an adaptive registration module to: During the registration of a user's fingerprint, an adaptive registration scheme adapted to one or more characteristics of the fingerprint is provided; as well as The electronic device provides visual guidance and feedback to guide the user through a sequence of actions for placing their fingers to provide target locations for registered touches, the visual guidance being output by the electronic device by performing the method described in any one of claims 1-13.

15. A non-volatile computer-readable storage medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform the method according to any one of claims 1 to 13.

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