Fingerprint recognition method and fingerprint sensing circuit thereof

Abstract

A fingerprint identification method and a fingerprint sensing circuit thereof are disclosed. The fingerprint identification method is used in a fingerprint sensing circuit and includes the following steps: performing a first fingerprint sensing procedure under a first light spot setting, the first fingerprint sensing procedure including a first exposure operation and a first readout operation; and performing a second fingerprint sensing procedure under a second light spot setting, the second fingerprint sensing procedure including a second exposure operation and a second readout operation. A host performs a first fingerprint identification corresponding to the first fingerprint sensing procedure, and the second light spot setting is performed simultaneously with the first fingerprint identification.

Description

Technical Field

[0001] This invention relates to a fingerprint recognition method and a related fingerprint sensing circuit, and more particularly to a fingerprint recognition method with fake fingerprint detection function and a related fingerprint sensing circuit. Background Technology

[0002] Fingerprint recognition is one of the most widely used biometric verification solutions in the industry. In recent years, product developers and researchers in this field have discovered the threat of fake fingerprints, which are artificial fingerprints made of rubber, paper, film, or other materials used to simulate real fingerprint textures. For security reasons, fingerprint recognition products should be able to identify fingerprint features and distinguish whether the received fingerprint is genuine or fake.

[0003] To effectively distinguish between real and fake fingerprints, fingerprint recognition products need to employ algorithms for fake fingerprint detection. However, performing fake fingerprint detection in addition to fingerprint feature recognition often consumes a significant amount of time, leading to a decline in the user experience of fingerprint sensing and recognition. Summary of the Invention

[0004] Therefore, the main objective of this invention is to provide a fingerprint recognition method with fake fingerprint detection function and its related fingerprint sensing circuit, wherein the timing of fingerprint recognition can be well controlled to reduce the overall time consumption, thereby improving the user experience.

[0005] An embodiment of the present invention discloses a fingerprint recognition method for a fingerprint sensing circuit. The method includes the following steps: executing a first fingerprint sensing process under a first light spot setting, the first fingerprint sensing process including a first exposure operation and a first readout operation; and executing a second fingerprint sensing process under a second light spot setting, the second fingerprint sensing process including a second exposure operation and a second readout operation. A host computer performs a first fingerprint recognition in response to the first fingerprint sensing process, and the second light spot setting is executed simultaneously with the first fingerprint recognition.

[0006] Another embodiment of the present invention discloses a fingerprint sensing circuit configured to perform the following steps: executing a first fingerprint sensing process under a first light spot setting, the first fingerprint sensing process including a first exposure operation and a first readout operation; and executing a second fingerprint sensing process under a second light spot setting, the second fingerprint sensing process including a second exposure operation and a second readout operation. A host performs a first fingerprint recognition in response to the first fingerprint sensing process, and the second light spot setting is performed simultaneously with the first fingerprint recognition. Attached Figure Description

[0007] Figure 1This is a schematic diagram of the fingerprint image processing system according to Embodiment 1 of the present invention.

[0008] Figure 2A A fingerprint image processing system integrating touch control and display driving functions is shown.

[0009] Figure 2B A multi-chip implementation of a fingerprint image processing system integrated with touch control and display driving functions is shown.

[0010] Figure 3 This is a schematic diagram of a general timing control scheme for fingerprint sensing and recognition applied to a fingerprint image processing system.

[0011] Figure 4 This is a schematic diagram of a timing control scheme for fingerprint sensing and recognition according to an embodiment of the present invention.

[0012] Figure 5 A detailed implementation of a segmentation method for the fingerprint recognition process used for user authentication is further illustrated.

[0013] Figure 6 This is a schematic diagram of a timing control scheme for fingerprint sensing and recognition according to another embodiment of the present invention.

[0014] Figure 7A This is a flowchart of a fingerprint sensing and recognition process that integrates touch detection with an embodiment of the present invention.

[0015] Figure 7B This is a flowchart of a fingerprint sensing and recognition process that integrates internal frequency display with touch detection.

[0016] Figure 8 This is a flowchart of the fingerprint sensing and recognition process according to Embodiment 1 of the present invention.

[0017] The reference numerals in the attached figures are explained as follows:

[0018] 10, 20, 25 fingerprint image processing system

[0019] 100 fingerprint sensors

[0020] 102 Fingerprint sensing circuit

[0021] 104 host

[0022] 200 display screens

[0023] 202 Fingerprint Touch Display Integrated Circuit

[0024] 252 Touch Display Driver Integrated Circuit

[0025] 253 Fingerprint Reading Integrated Circuit

[0026] P1 and P2 phases

[0027] 70, 75, and 80 fingerprint sensing and recognition processes

[0028] Steps 800-812 Detailed Implementation

[0029] Figure 1 This is a schematic diagram of the fingerprint image processing system 10 according to Embodiment 1 of the present invention. Figure 1 As shown, the fingerprint image processing system 10 includes a fingerprint sensor 100, a fingerprint sensing circuit 102, and a host 104. Generally, the fingerprint sensor 100 can be an optical fingerprint sensor, which includes a sensing pixel array, at least one light source, and a sensing pad for placing a finger. The intensity of light reflected by the contacting finger can be sensed by each sensing pixel to generate a fingerprint image signal, which is transmitted to the fingerprint sensing circuit 102 and then to the host 104 for fingerprint image recognition. The detailed structure of the fingerprint sensor 100 should be well known to those skilled in the art and will not be described in detail here.

[0030] The fingerprint sensing circuit 102 can be a fingerprint image processing integrated circuit implemented in a chip. Generally, the fingerprint sensing circuit 102 receives fingerprint image signals (usually voltage or current signals) from the fingerprint sensor 100 and converts the fingerprint image signals into digital form. This digital signal is then transmitted to the host 104 for subsequent fingerprint recognition and matching. In some embodiments, the fingerprint sensing circuit 102 can be used to process the fingerprint image signal, for example, by removing unwanted noise / offset and amplifying the signal to improve signal quality, so that the output image signal or data can be recognized more effectively.

[0031] In one embodiment, the fingerprint sensor 100 may be integrated into a display screen, and the fingerprint sensing circuit 102 may be integrated into a touch control device and / or a display driver device of the display screen, thereby realizing a fingerprint, touch and display integration (FTDI) circuit. Figure 2A A fingerprint image processing system 20 integrating touch control and display driving functions is shown. For example... Figure 2AAs shown, the fingerprint image processing system 20 includes a display screen 200, a fingerprint touch display integration circuit 202, and a host 104. The display screen 200 may integrate a fingerprint sensor 100. For example, the sensing pixels of the fingerprint sensor 100 may be disposed in a specific area on the display screen 200 or under the entire screen, making the display screen 200 a touchscreen that can receive the fingerprint image of the touched finger, thereby realizing under-display fingerprint sensing functionality. Alternatively, the fingerprint sensor 100 may also include a sensing pad disposed together with the screen of the display screen 200, which can be used to receive the fingerprint image of the touched finger.

[0032] The fingerprint touch display integrated circuit 202 can be a single chip integrating display, touch, and fingerprint functions. More specifically, the fingerprint touch display integrated circuit 202 may include a fingerprint sensing circuit (such as...). Figure 1 The display screen 200 includes a fingerprint sensing circuit 102, a touch control device, and a display driver. The fingerprint sensing circuit can be used to control the fingerprint sensing operation of the fingerprint sensor integrated with the display screen 200; the touch control device can be used to control touch sensing operations, such as finger touch and / or stylus touch; and the display driver can be used to output display data signals to the display screen 200 for related display control.

[0033] In another embodiment, the single-chip fingerprint touch display integrated circuit can also be replaced by a multi-chip implementation. Figure 2B A multi-chip implementation of a fingerprint image processing system 25 integrated with touch control and display driving functions is shown. For example... Figure 2B As shown, the fingerprint image processing system 25 differs from the fingerprint image processing system 20 in that it includes a Touch and Display Driving Integration (TDDI) circuit 252 and a fingerprint reader integrated circuit 253, which can replace the function of the fingerprint touch and display integration circuit 202 in the fingerprint image processing system 20. An interface can be provided between the touch and display driving integration circuit 252 and the fingerprint reader integrated circuit 253 to transmit necessary information (such as synchronization signals) to synchronize the functions of display driving, touch sensing, and fingerprint sensing.

[0034] In this example, the fingerprint touch display integrated circuit 202, the touch display driver integrated circuit 252, and the fingerprint reader integrated circuit 253 can all communicate with the host 104 through one or more interfaces, which may include, but are not limited to, a Serial Peripheral Interface (SPI), an Inter-Integrated Circuit (I2C) interface, and / or a Mobile Industry Processor Interface (MIPI).

[0035] Figure 2A and Figure 2B Host 104 in the middle is equivalent to Figure 1 The host 104 in the diagram is therefore represented by the same symbol. The host 104 can be the main processor of an electronic system, such as a Central Processing Unit (CPU), a Microcontroller Unit (MCU), an Application Processor (AP), and the like. For fingerprint recognition, the host 104 can be used to execute various fingerprint recognition procedures, including preprocessing, feature extraction, and matching, but is not limited to these. The host 104 then determines whether the fingerprint image from the fingerprint sensor 100 matches a registered fingerprint image, thereby verifying a specific function, such as device unlocking, payment, or logging into an application or webpage. Because fingerprint recognition operations require complex calculations and a large amount of storage space to store the registered fingerprint image, the fingerprint recognition algorithm must be performed within the host 104 to simplify the circuit area and cost of the fingerprint sensing circuit 102.

[0036] Figure 3 For application in a fingerprint image processing system (such as Figure 1 , Figure 2A or Figure 2BThe diagram illustrates a general timing control scheme for fingerprint sensing and recognition in a fingerprint image processing system 10, 20, or 25. When the host 104 needs to receive a fingerprint from a user, it can control the fingerprint sensing circuit 102 to execute the fingerprint sensing process. First, the host 104 can control the display driver to set the light spot. Generally, the light spot is required to have one or more specific wavelengths of light illuminating the fingerprint sensing area (such as a sensing pad or panel) to illuminate the finger on the sensing area. After the light spot is set (e.g., the target brightness is reached), the host 104 can send an image capture command to the fingerprint sensing circuit 102. The image capture command instructs the fingerprint sensing circuit 102 to start the exposure operation, and then read the fingerprint image signal from the fingerprint sensor 100. During the readout operation, the fingerprint sensing circuit 102 can first sample the fingerprint image signal, then process the fingerprint image signal (e.g., amplify the signal and / or remove unnecessary noise / offset), convert the fingerprint image signal into digital data, and then output the fingerprint image data to the host 104. Based on the fingerprint image data from the fingerprint sensing circuit 102, the host 104 can use a fingerprint recognition algorithm to perform fingerprint recognition, determine whether the fingerprint image matches any registered fingerprint, and perform user identity verification.

[0037] Since the fingerprint image processing system has a fake fingerprint detection function, after the fingerprint sensing circuit 102 and the host 104 execute the fingerprint sensing / recognition process for user authentication, they can further execute the fingerprint sensing / recognition process for fake fingerprint detection. More specifically, the host 104 can control the display driver to set the light spot for fake fingerprint detection, and the fingerprint sensing circuit 102 correspondingly performs exposure and readout operations, and then outputs fingerprint image data to the host 104. In response to the receipt of fingerprint image data, the host 104 can perform recognition for fake fingerprint detection according to the corresponding algorithm. It should be noted that the host 104 includes algorithms for user authentication and algorithms for fake fingerprint detection. In the first fingerprint recognition operation for user authentication, the host 104 can determine whether the received fingerprint belongs to a specific user; in the second fingerprint recognition operation for fake fingerprint detection, the host 104 can determine whether the received fingerprint is real or fake. After the above process is completed, the host 104 can determine whether the fingerprint is correct and real, so as to enable a specific function accordingly.

[0038] It is worth noting that fake fingerprint detection requires a special algorithm, which differs from the algorithms used for user authentication in the general fingerprint recognition process, such as preprocessing, thinning, feature point extraction, and matching. The special algorithm for fake fingerprint detection is specifically designed to distinguish between real and fake fingerprints. The light spots used for general fingerprint recognition and fake fingerprint detection are also different. For example, fake fingerprint detection only requires a small light spot to illuminate a portion of the finger area. This light spot has a characteristic that allows the host 104 to distinguish between real and fake fingerprints. Therefore, the light spot needs to be changed between the first and second exposure operations. The exposure time for fake fingerprint detection is also shorter than that for general fingerprint recognition because fake fingerprint detection typically only needs to distinguish between real and fake fingerprints on a small portion of the fingerprint.

[0039] Figure 4 This is a schematic diagram of a timing control scheme for fingerprint sensing and recognition according to an embodiment of the present invention. Figure 4 As shown, the operation of the host 104 and the fingerprint sensing circuit 102 is displayed separately for clearer explanation. The exposure and reading of the image signal are performed by the fingerprint sensing circuit 102, while the spot setting and fingerprint recognition are performed by the host 104. In this example, a general fingerprint sensing and recognition operation for user authentication can be performed first, followed by another fingerprint sensing and recognition operation for fake fingerprint detection.

[0040] To reduce overall time consumption, compared to Figure 3 Compared to general timing control schemes, this invention can perform the spot setting for fake fingerprint detection earlier. For example... Figure 4 As shown, the light spot setting for fake fingerprint detection and the fingerprint recognition process for user identity verification can be executed simultaneously. That is, while the host 104 is executing the fingerprint recognition process to determine whether the fingerprint belongs to the correct user, the light spot setting for subsequent fake fingerprint detection can also be executed at the same time.

[0041] More specifically, suppose that the fingerprint recognition process for user authentication is performed in a first period and the spot setting for fake fingerprint detection is performed in a second period, the second period and the first period may partially overlap.

[0042] like Figure 4As shown, an image capture command can be transmitted during the first fingerprint recognition process. More specifically, the host 104 can send an image capture command to the fingerprint sensing circuit 102 during the first fingerprint recognition process to instruct the fingerprint sensing circuit 102 to start the exposure operation and then output the fingerprint image. It should be noted that fingerprint sensing involves confidential operations and should be performed within a Trusted Execution Environment (TEE). Therefore, before the host 104 outputs the image capture command to instruct the fingerprint sensing circuit 102 to start the fingerprint sensing operation, the host 104's operating system must first enter the TEE. In one embodiment, the fingerprint recognition process can be divided into several stages, allowing the host 104 to enter the TEE between two different stages. For example, as... Figure 4 As shown, fingerprint recognition for user authentication includes two phases, P1 and P2, and the host 104 can enter the trusted execution environment at a point in time between phases P1 and P2. In this way, the host 104 can output image capture instructions between the two phases P1 and P2.

[0043] After the fingerprint sensing circuit 102 receives an image capturing instruction from the host 104, it can begin the exposure operation, allowing the exposure operation for fake fingerprint detection and the fingerprint recognition operation for user authentication to be performed simultaneously. For example, the fingerprint recognition process for user authentication is performed during the first period as described above, while the exposure operation for fake fingerprint detection is performed during a third period. In this case, the third period and the first period may partially overlap.

[0044] exist Figure 4 In one embodiment, the period for performing the exposure operation for fake fingerprint detection partially overlaps with the period of phase P2 of the fingerprint recognition process, while the period for performing the spot setting for fake fingerprint detection partially overlaps with the period of phase P1 of the fingerprint recognition process.

[0045] Figure 5 A detailed implementation of segmenting the fingerprint recognition process for user authentication is further illustrated. For example... Figure 5 As shown, the fingerprint recognition process for user authentication can be divided into, for example, image preprocessing, feature point extraction, and feature point matching. In this case, the host 104 can enter a trusted execution environment between two of these different operations, and the image acquisition instructions can be transmitted within the trusted execution environment. In other words, Figure 4 Phase P1 in the process may include preprocessing operations (called the preprocessing phase), and Figure 4 Phase P2 may include feature point extraction operations (referred to as the feature point extraction phase).

[0046] It should be noted that the above embodiments are merely examples illustrating a feasible segmentation method for fingerprint recognition algorithms. Those skilled in the art should understand that fingerprint recognition algorithms can also segment fingerprints in other ways and accordingly set the timing for entering a trusted execution environment.

[0047] To further reduce the overall time required for fingerprint recognition, this invention proposes an improvement method in which the fingerprint sensing circuit 102 can be used to perform fingerprint recognition for fake fingerprint detection to shorten the overall fingerprint sensing process, such as... Figure 5 As shown.

[0048] In detail, in a typical timing control scheme, fingerprint recognition for fake fingerprint detection is performed by the host 104. Therefore, the fingerprint sensing circuit 102 must transmit the fingerprint image data to the host 104 after exposure and reading. Due to the large amount of image data, this operation usually takes a significant amount of time. In contrast, in Figure 5 In this embodiment, the fingerprint sensing circuit 102 can independently perform fingerprint recognition for fake fingerprint detection and obtain the corresponding judgment result. Therefore, the fingerprint sensing circuit 102 can be equipped with a dedicated algorithm for fake fingerprint detection to determine whether the sensed fingerprint is genuine or fake. This dedicated algorithm can be implemented in hardware within the fingerprint sensing circuit 102. In this case, the fingerprint sensing circuit 102 only needs to send the judgment result to the host 104, saving the time spent outputting fingerprint image data in the fake fingerprint detection operation. It should be noted that the judgment result is only needed to indicate whether the fingerprint is genuine or fake, and its data volume is typically much smaller than the data volume of a single fingerprint image frame.

[0049] In this example, the readout operation performed by the fingerprint sensing circuit 102 can be considered as the fingerprint sensing circuit 102 receiving a fingerprint image signal from the fingerprint sensor 100. After receiving the fingerprint image signal, the fingerprint sensing circuit 102 can perform identification to determine whether the fingerprint data represents a real fingerprint or a fake fingerprint.

[0050] Figure 6 This is a schematic diagram of a timing control scheme for fingerprint sensing and recognition according to another embodiment of the present invention. Figure 6 This description aims to illustrate the timing of fingerprint sensing / recognition operations used for fake fingerprint detection; therefore, operations such as spot setting and exposure for user authentication are omitted. Figure 6As shown, the time required for spot setting is variable. Generally, the time required to complete spot setting varies depending on whether the system is busy or idle. For example, the time required to set the spot for fingerprint sensing on the display ranges from 30 milliseconds (ms) to 120 milliseconds. If the system is very busy, the spot will take longer to complete setting (e.g., 120 ms); if the system is less busy, the spot can be prepared more quickly (e.g., 30 ms). Although the spot setting time may not be easily controlled, the fingerprint recognition process can be appropriately divided into multiple stages to accommodate various possible spot setting times, allowing image acquisition commands to be transmitted at optimized times, thereby reducing wasted time.

[0051] like Figure 6 As shown in (a), the light spot setting takes less time to complete, so the image capture command can be transmitted in a trusted execution environment set between the preprocessing stage and the feature point extraction stage of fingerprint recognition. Figure 6 As shown in (b), spot setting requires a relatively long time and is completed after the preprocessing stage. Therefore, the image capture command should be delayed until a reliable execution environment is set between the feature point extraction stage and the feature point matching stage. In this case, the fingerprint sensing circuit 102 needs to start exposure later, thus increasing the overall time consumed by fingerprint recognition. To reduce the wasted time, the algorithm for fingerprint recognition can be rearranged so that the length of the preprocessing stage is slightly greater than or equal to the possible spot setting time, so that the spot setting for fake fingerprint detection is completed before the feature point extraction stage begins. In this way, the image capture command can be transmitted earlier to reduce wasted time and reduce the overall time consumed by the fingerprint recognition operation, such as... Figure 6 As shown in (c).

[0052] Therefore, with proper arrangement and segmentation of the fingerprint recognition algorithm, the spot setting for fake fingerprint detection and the preprocessing stage for fingerprint recognition for user authentication can be executed simultaneously. Furthermore, the exposure operation for fake fingerprint detection and the subsequent stages of fingerprint recognition for user authentication (such as the feature point extraction stage and / or feature point matching stage) can also be executed simultaneously.

[0053] In addition, the preprocessing stage, feature point extraction stage, and / or feature point matching stage can be divided into two or more sub-stages. Alternatively or additionally, the fingerprint recognition operation can also be divided into four, five, or any number of stages, allowing the trusted execution environment to be set between any two adjacent sub-stages or stages. In this case, by appropriately setting the trusted execution environment, image acquisition instructions can be transmitted at suitable times, thus improving the flexibility of the timing arrangement for fake fingerprint detection and further accelerating the fingerprint sensing and recognition process.

[0054] In one embodiment, the segmentation of the fingerprint recognition algorithm ensures that the host 104 enters a trusted execution environment before a specific point in time. If the image capturing instruction is transmitted at or before this point in time, causing the fingerprint sensing circuit 102 to initiate exposure for fake fingerprint detection, the fingerprint image data can be transmitted to the host 104 without any wasted time. In practice, the segmentation of the fingerprint recognition algorithm can be performed in any suitable manner, and is not limited to the segmentation method presented in this specification.

[0055] In some embodiments, the time required to set the light spot may vary depending on the application or environment. For example, when the ambient light is bright, only a weaker light spot is needed, so the light spot setting time is shorter. When the light spot setting time is controllable, its length can be well controlled so that the light spot setting for fake fingerprint detection can be completed before the feature point extraction stage begins, thus allowing subsequent exposure operations to start at the beginning of the feature point extraction stage, resulting in minimal time delay.

[0056] As described above, the fingerprint sensing circuit of the present invention can integrate a touch control device and a display driving device to realize a fingerprint touch display integrated circuit. The fingerprint touch display integrated circuit can combine touch detection operation and fingerprint sensing operation to realize a specific function, such as device unlocking.

[0057] Figure 7A This is a flowchart of a fingerprint sensing and recognition process 70 integrating touch detection according to an embodiment of the present invention. Figure 7A As shown, the touch control device first initiates touch detection to determine if a finger touch has occurred on the touchscreen. Upon detection, the fingerprint touch display integrated circuit notifies the host computer, which then wakes up the fingerprint sensing circuit (FPR). Simultaneously, the host computer instructs the display driver to begin setting the fingerprint spot. Once the spot is ready, the host computer instructs the fingerprint sensing circuit to receive a fingerprint image, for example, via an image capture command output from a trusted execution environment. In response to the received image capture command, the fingerprint sensing circuit performs exposure and then outputs the fingerprint image to the host computer. The host computer then performs fingerprint recognition and, if the fingerprint matches, controls the device to unlock (or triggers other functions).

[0058] Since the fingerprint touch display integrated circuit includes a display driving device, it can also be used to perform spot control in addition to touch detection and fingerprint sensing operations. In this case, the spot setting for fingerprint sensing for user authentication and / or the spot setting for fake fingerprint detection can be performed by the fingerprint touch display integrated circuit without host intervention. In one embodiment, when the fingerprint touch display integrated circuit detects a finger touch, spot setting can be initiated according to the internal clock display. The internal clock display is a display operation controlled by the internal clock of the fingerprint touch display integrated circuit, which can be performed without receiving any instructions and / or commands from the host. Furthermore, since the spot setting is controlled by the fingerprint touch display integrated circuit itself, the time variation of the spot setting can be reduced and the spot can be controlled more easily.

[0059] Figure 7B This is a flowchart of a fingerprint sensing and recognition process 75 integrating internal frequency display and touch detection. Figure 7B As shown, when the Fingerprint Touch Display Integration (FTDI) circuit detects a finger touch, it can wake up the fingerprint sensing circuit and related display module using its internal clock. Therefore, the FTDI circuit can automatically set and display the fingerprint spot without host intervention. Next, the fingerprint sensing circuit (FPR) within the FTDI circuit begins exposure and outputs a fingerprint image to the host. Finally, the host performs fingerprint recognition based on relevant algorithms and, if the fingerprint matches, controls the device to unlock (or triggers other functions). In this implementation, the host does not intervene in the fingerprint spot setting, thus simplifying the coordination and communication between the FTDI circuit and the host, significantly reducing the time spent in the fingerprint recognition process.

[0060] It is worth noting that, Figure 7B The internal frequency-based display process can be applied to fingerprint sensing and recognition operations for user authentication and fake fingerprint detection. In this way, all steps from finger detection to fingerprint sensing can be executed by the fingerprint touch display integrated circuit without host intervention, thereby reducing the communication and waiting time between the fingerprint touch display integrated circuit and the host. Simultaneously, the light spot setting can also be controlled automatically by the fingerprint touch display integrated circuit without being affected by the host's workload. Therefore, light spot setting can be executed more efficiently, making the timing control and placement / segmentation of the fingerprint recognition algorithm more convenient, effectively reducing time wastage in the fingerprint recognition process.

[0061] The above operations can be summarized as a fingerprint sensing and recognition process 80, such as... Figure 8 As shown. The fingerprint sensing and recognition process 80 can be implemented in a fingerprint image processing system, such as... Figure 1 Fingerprint image processing system 10 or Figure 2A The fingerprint image processing system 20. For example... Figure 8 As shown, the fingerprint sensing and recognition process 80 includes the following steps:

[0062] Step 800: Begin.

[0063] Step 802: The fingerprint touch display integrated circuit performs a first light spot setting according to the internal frequency display.

[0064] Step 804: The fingerprint touch display integrated circuit executes a first fingerprint sensing process under the first light spot setting. The first fingerprint sensing process includes a first exposure operation and a first readout operation.

[0065] Step 806: The host performs fingerprint recognition for user authentication in response to the first fingerprint sensing process, while the fingerprint touch display integration circuit performs a second spot setting according to the internal frequency display.

[0066] Step 808: The fingerprint touch display integrated circuit executes a second fingerprint sensing process under the second light spot setting. The second fingerprint sensing process includes a second exposure operation and a second readout operation.

[0067] Step 810: The fingerprint touch display integrated circuit or host performs fingerprint recognition for fake fingerprint detection based on the fingerprint image data obtained in the second fingerprint sensing process.

[0068] Step 812: End.

[0069] For detailed instructions and variations on the fingerprint sensing and recognition process 80, please refer to the above paragraphs; they will not be repeated here.

[0070] In summary, this invention proposes a fingerprint recognition method and its related fingerprint sensing circuit, which has the function of detecting fake fingerprints. In this invention, the operation time of fingerprint sensing and recognition for user authentication and fake fingerprint detection can be accelerated in various ways. In one embodiment, when the host performs fingerprint recognition for user authentication, spot setting for fake fingerprint detection can be performed simultaneously to reduce the overall time consumption. In one embodiment, the fingerprint recognition process for user authentication can be divided into several stages, and the image capturing instruction used to instruct the fingerprint sensing circuit to start the exposure operation can be appropriately arranged between two adjacent stages. In one embodiment, the fingerprint sensing circuit can independently perform fingerprint recognition for fake fingerprint detection and send the judgment result to the host. In one embodiment, the fingerprint sensing circuit integrates a touch display driving device to realize a fingerprint touch display integrated circuit, which can perform spot setting based on internal frequency display without host intervention. All the above embodiments can be selectively used and combined to improve the efficiency of timing control during fingerprint sensing and recognition, reduce the overall time consumption of fingerprint sensing and recognition, and thus improve the user experience.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fingerprint recognition method for use in a fingerprint sensing circuit, characterized in that, include: A first fingerprint sensing process is executed under a first light spot setting, the first fingerprint sensing process including a first exposure operation and a first readout operation; as well as A second fingerprint sensing process is executed under a second light spot setting, the second fingerprint sensing process including a second exposure operation and a second readout operation; In response to the first fingerprint sensing process, a host performs a first fingerprint recognition; The setting of the second light spot is performed simultaneously with the first fingerprint recognition.

2. The method as described in claim 1, characterized in that, The first fingerprint recognition is performed during a first period, while the second spot setting is performed during a second period, which partially overlaps with the first period.

3. The method as described in claim 1, characterized in that, The second exposure operation is performed simultaneously with the first fingerprint recognition.

4. The method as described in claim 3, characterized in that, The first fingerprint recognition is performed during a first period, while the second exposure operation is performed during a third period, which partially overlaps with the first period.

5. The method as described in claim 1, characterized in that, The first fingerprint sensing process is used for user authentication, while the second fingerprint sensing process is used for fake fingerprint detection.

6. The method as described in claim 1, characterized in that, The first fingerprint recognition includes a first stage and a second stage, and the method further includes: The second exposure operation begins at a point in time between the first and second phases.

7. The method as described in claim 6, characterized in that, The first fingerprint recognition includes a preprocessing operation, a feature point extraction operation, and a feature point matching operation, and the first stage includes the preprocessing operation, and the second stage includes the feature point extraction operation.

8. The method as described in claim 6, characterized in that, Also includes: At that point in time, an image capture instruction is received from the host, wherein the image capture instruction instructs the fingerprint sensing circuit to initiate the second exposure operation.

9. The method as described in claim 6, characterized in that, Also includes: Control the duration of time used to execute the second spot setting, so that the second spot setting is completed before the start of the second stage.

10. The method as described in claim 6, characterized in that, Also includes: The duration of the first phase is set so that the second spot is completed before the start of the second phase.

11. The method as described in claim 1, characterized in that, Also includes: In response to the second fingerprint sensing process, a second fingerprint recognition is performed.

12. The method as described in claim 11, characterized in that, Also includes: A judgment result is obtained by performing the second fingerprint recognition; as well as Output the judgment result to the host.

13. The method as described in claim 1, characterized in that, At least one of the first spot setting and the second spot setting is executed without the host's intervention.

14. The method as described in claim 1, characterized in that, At least one of the first light spot setting and the second light spot setting is executed by an internal clock of the fingerprint sensing circuit.

15. A fingerprint image processing system, characterized in that, include: One host computer; as well as A fingerprint sensing circuit is configured to perform the following steps: A first fingerprint sensing process is executed under a first light spot setting, the first fingerprint sensing process including a first exposure operation and a first readout operation; and A second fingerprint sensing process is executed under a second light spot setting, the second fingerprint sensing process including a second exposure operation and a second readout operation; In response to the first fingerprint sensing process, the host performs a first fingerprint recognition; The setting of the second light spot is performed simultaneously with the first fingerprint recognition.

16. The fingerprint image processing system as described in claim 15, characterized in that, The first fingerprint recognition is performed during a first period, while the second spot setting is performed during a second period, which partially overlaps with the first period.

17. The fingerprint image processing system as described in claim 15, characterized in that, The second exposure operation is performed simultaneously with the first fingerprint recognition.

18. The fingerprint image processing system as described in claim 17, characterized in that, The first fingerprint recognition is performed during a first period, while the second exposure operation is performed during a third period, which partially overlaps with the first period.

19. The fingerprint image processing system as described in claim 15, characterized in that, The first fingerprint sensing process is used for user authentication, while the second fingerprint sensing process is used for fake fingerprint detection.

20. The fingerprint image processing system as described in claim 15, characterized in that, The first fingerprint recognition includes a first stage and a second stage, and the fingerprint sensing circuit is also set to start the second exposure operation at a time point between the first stage and the second stage.

21. The fingerprint image processing system as described in claim 20, characterized in that, The first fingerprint recognition includes a preprocessing operation, a feature point extraction operation, and a feature point matching operation, and the first stage includes the preprocessing operation, and the second stage includes the feature point extraction operation.

22. The fingerprint image processing system as described in claim 20, characterized in that, The fingerprint sensing circuit is also configured to receive an image capture instruction from the host at that time point, wherein the image capture instruction instructs the fingerprint sensing circuit to initiate the second exposure operation.

23. The fingerprint image processing system as described in claim 20, characterized in that, The fingerprint sensing circuit is also configured to control the duration of time for performing the second spot setting, so that the second spot setting is completed before the start of the second stage.

24. The fingerprint image processing system as described in claim 20, characterized in that, The fingerprint sensing circuit is also configured to set a time length for the first stage, so as to control the second light spot to be set to complete before the start of the second stage.

25. The fingerprint image processing system as described in claim 15, characterized in that, The fingerprint sensing circuit or the host is also configured to respond to the second fingerprint sensing process and perform a second fingerprint recognition.

26. The fingerprint image processing system as described in claim 25, characterized in that, The fingerprint sensing circuit is also configured to obtain a judgment result by performing the second fingerprint recognition and output the judgment result to the host.

27. The fingerprint image processing system as described in claim 15, characterized in that, At least one of the first spot setting and the second spot setting is executed without the host's intervention.

28. The fingerprint image processing system as described in claim 15, characterized in that, At least one of the first light spot setting and the second light spot setting is executed by an internal clock of the fingerprint sensing circuit.

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