Structured light-based non-contact three-dimensional palm print acquisition device and method

Abstract

The invention discloses a non-contact three-dimensional palm print acquisition device and method based on structured light. The device comprises a supporting assembly, a structured light projection device, an image acquisition device, a triggering unit, a light supplementing device and a control and processing unit, the supporting assembly is used for installing the devices. The optical axes of the light projection device and the image acquisition device intersect in an acquisition area. The structured light projection device, the image acquisition device and the trigger unit are respectively in communication connection with the control and processing unit; the trigger unit is used for detecting a target signal in an acquisition area and sending a trigger instruction to the control and processing unit, and the control and processing unit is configured to control the structured light projection device to project a structured light pattern according to the trigger instruction; the trigger output end of the structured light projection device is electrically connected with the trigger input end of the image acquisition device, and the structured light projection device is configured to synchronously trigger the image acquisition device to perform image acquisition when projecting the structured light pattern. According to the invention, non-contact high-precision three-dimensional palm print acquisition is realized.

Description

Technical Field

[0001] This invention belongs to the field of biometric acquisition technology, and specifically relates to a non-contact three-dimensional palmprint acquisition device and method based on structured light. Background Technology

[0002] Palm prints refer to the various lines on the surface of the palm between the wrist and fingers. The morphology of palm prints is controlled by genetics; even if the epidermis peels off for some reason, the newly formed palm print lines retain the original structure. Palm print recognition is a relatively new biometric identification technology that identifies individuals by recognizing the image of the palm from the fingertips to the wrist. It features simple sampling, rich image information, high user acceptance, difficulty in forgery, and low susceptibility to noise interference. Palm print recognition technology is a relatively new biometric identification technology proposed in recent years. Palm prints refer to the image of the palm from the fingertips to the wrist. Many features can be used for identification, such as main lines, wrinkles, fine textures, ridges, and bifurcation points. Palm print recognition technology is also a non-invasive identification method, making it relatively easy for users to accept.

[0003] Biometric technology, with its unique stability, uniqueness, and convenience, is finding increasingly widespread application. Palmprint recognition, as an emerging biometric technology, has attracted widespread attention from researchers both domestically and internationally due to its rich image information, high user acceptance, difficulty in forgery, and low susceptibility to noise interference. However, because palmprint recognition technology started relatively late, it is still in the stage of learning from and drawing on other biometric recognition technologies. Palmprint recognition technology is a biometric technology for identity verification and identification based on the characteristics of human palm prints. It utilizes the unique ridge distribution, ridge details, and ridge spacing features in palmprint images, and through computer image processing and pattern recognition algorithms, it achieves automatic identification and comparison of individual palm prints. Palmprint recognition technology has already been widely applied in many fields, including security, mobile payment, and access control.

[0004] Chinese invention patent application CN101196986A discloses a three-dimensional palmprint identification device and its identification method. The device includes a chassis, a projector, a camera, and a control microcomputer. Its features are: a palm placement area is provided on the chassis, and a light-transmitting hole and a palm positioning device for fixing the palm are provided on the palm placement area; the projector and camera are set inside the chassis and connected to a transformer; the camera is perpendicular to the plane where the palm is placed and connected to the control microcomputer; the central light column of the projector and the camera intersects at a 30-45 degree angle in the center area of ​​the palm placement area; and the projector is connected to the control microcomputer through a VGA interface.

[0005] This solution is highly susceptible to bacterial transmission in public settings, raising hygiene concerns among users. Furthermore, the compression and deformation of muscles and skin during hand pressure can cause the acquired 3D depth information to mismatch with the natural state of the hand, affecting the accuracy of recognition and the realism of the 3D model. Additionally, the solution relies on soft triggering via computer software—"playing stripes - waiting - controlling the camera to take a picture"—which is highly delayed and unstable. Without a fixed device, physiological hand tremors can cause the projected stripes to mismatch with the shooting timing, resulting in phase calculation errors. Summary of the Invention

[0006] This invention provides a non-contact three-dimensional palmprint acquisition device and method based on structured light, aiming to solve the problems of hygiene, three-dimensional distortion, imaging blur and data misalignment in the existing technology.

[0007] To solve the above-mentioned technical problems, on the one hand, the present invention proposes a non-contact three-dimensional palmprint acquisition device based on structured light, including a support component, a structured light projection device, an image acquisition device, a triggering unit, a supplementary lighting device, and a control and processing unit; The support assembly is used to install the various devices, and the optical axes of the structured light projection device and the image acquisition device are configured to intersect at the image acquisition area. The structured light projection device, image acquisition device, and triggering unit establish communication connections with the control and processing unit, respectively. The triggering unit is used to detect the target signal within the image acquisition area and send a trigger command to the control and processing unit. The control and processing unit is configured to control the structured light projection device to project a structured light pattern according to the trigger command. The trigger output terminal of the structured light projection device is electrically connected to the trigger input terminal of the image acquisition device, and is configured to synchronously trigger the image acquisition device to acquire images when projecting a structured light pattern.

[0008] Preferably, the structured light projection device is a DLP projector, and the image acquisition device is an industrial camera; in particular, a CCD industrial camera may be selected. The DLP projector is configured to project a sinusoidal stripe pattern or a Gray code pattern onto the image acquisition area; the industrial camera is configured to perform exposure acquisition upon receiving the rising edge of the synchronization trigger signal.

[0009] Preferably, the triggering unit includes a microcontroller and a sensing sensor; The sensing sensor is used to detect whether the palm has entered the image acquisition area and transmits the detection signal to the microcontroller; the microcontroller is connected to the control and processing unit via serial communication.

[0010] Preferably, the microcontroller is an ESP32C3 microcontroller; The triggering unit also includes a USB serial port cable. The ESP32C3 microcontroller is connected to the control and processing unit via the USB serial port cable and is configured to obtain a +5V operating voltage from the control and processing unit via the USB serial port cable and send a trigger signal to the control and processing unit via the USB serial port cable.

[0011] Preferably, the support assembly includes a fixed bracket and an angle adjustment mechanism; The angle adjustment mechanism connects the structured light projection device and the image acquisition device, and is used to adjust the pitch angle of both, so that the optical axis of the structured light projection device and the optical axis of the image acquisition device are on the same plane and intersect at the location of the trigger unit.

[0012] Preferably, the supplementary lighting device is an anti-flicker light source, which is mounted on the support assembly and has its central optical axis perpendicular to the bottom plane of the device, in order to provide a uniform lighting environment.

[0013] Preferably, the specific method of the communication connection is as follows: The structured light projection device is connected to the control and processing unit via a USB interface; The image acquisition device is connected to the control and processing unit via a USB interface; The triggering unit is connected to the control and processing unit via a USB-to-serial cable.

[0014] Preferably, the control and processing unit is configured with an image processing module, which is used to perform the following steps: Receive a set of two-dimensional images with structured light stripes acquired by the image acquisition device, and a two-dimensional image without stripes; Phase resolution is performed on the two-dimensional image to calculate the depth map and generate point cloud data; Based on point cloud data and 2D images without stripes, 3D reconstruction and texture mapping are performed to generate a 3D model file containing texture information and mesh data.

[0015] Preferably, the lens of the structured light projection device and the lens of the image acquisition device have different specifications, and the depth of field of both covers the image acquisition area.

[0016] On the other hand, the present invention also proposes a non-contact three-dimensional palmprint acquisition method based on structured light, the method using the apparatus described in the first aspect of the present invention, comprising the following steps: The trigger unit monitors the image acquisition area and sends a trigger command to the control and processing unit when it detects a target object signal. The control and processing unit responds to the trigger command and controls the structured light projection device to project a preset structured light pattern sequence onto the image acquisition area; When the structured light projection device projects each frame of the pattern, it sends a synchronous trigger signal to the image acquisition device through the trigger output terminal. The image acquisition device exposes upon receiving a synchronization trigger signal, captures a two-dimensional image with structured light stripes projected onto the surface of the target object, and transmits the image data to the control and processing unit. The control and processing unit acquires a two-dimensional image sequence, calculates phase and depth information using a structured light three-dimensional reconstruction algorithm, and generates point cloud data. A three-dimensional mesh model is constructed based on the point cloud data, and the texture of the two-dimensional image is mapped onto the three-dimensional mesh model to generate a visualized three-dimensional palm print model.

[0017] Compared with the prior art, the present invention has the following technical effects: 1. The palmprint acquisition device proposed in this invention achieves completely non-contact acquisition using a high-sensitivity trigger. This avoids direct contact between the user's skin and the device surface, cutting off the transmission routes of bacteria and viruses, making it particularly suitable for scenarios with high public health requirements, such as medical and security applications. It eliminates the muscle compression and texture deformation caused by hand pressure in traditional contact acquisition methods, enabling the capture of true texture lines, wrinkle depth, and subtle morphological changes in the palm when it is naturally extended, thus improving the fidelity of three-dimensional data.

[0018] 2. The palmprint acquisition device proposed in this invention abandons the traditional VGA video stream projection or software asynchronous triggering mode, and adopts a design in which the trigger output of the structured light projection device is directly connected to the trigger input of the image acquisition device. This hard-connection synchronization mechanism ensures strict synchronization (microsecond-level response) between stripe projection and camera exposure, effectively solving the problem of image blurring or phase misalignment caused by physiological hand tremors in a non-contact, suspended state, and significantly improving the accuracy of point cloud generation and the success rate of 3D reconstruction.

[0019] 3. The palmprint acquisition device proposed in this invention, through algorithm optimization of the control and processing unit, can generate universal 3D model files containing high-precision triangular mesh data (such as PLY format) and clear texture maps (such as PNG format). These files are directly compatible with mainstream 3D processing software such as MeshLab and Blender, enabling this device to be used not only for biometrics but also for a wide range of applications in fields such as medical hand rehabilitation analysis and virtual reality modeling.

[0020] 4. The palmprint acquisition device proposed in this invention features an angle adjustment mechanism, ensuring that the optical axes of the projector and camera precisely intersect at the acquisition center where the trigger is located. Compared to the fixed optical path design in existing technologies, this invention allows for flexible adjustment of the device angle according to different lens specifications (different focal lengths, different depths of field), ensuring optimal depth-of-field coverage and illumination uniformity at different working distances. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the device described in this invention; Figure 2 This is a schematic diagram of the system hardware connection relationship according to an embodiment of the present invention; Figure 3 This is an example image of the three-dimensional palm print result described in an embodiment of the present invention.

[0022] Reference numerals: 1. Image acquisition device; 2. Structured light projection device; 3. Supplemental lighting device; 4. Image acquisition area. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present application and with reference to the accompanying drawings.

[0024] Example 1 This embodiment describes a non-contact three-dimensional palmprint acquisition device based on structured light, such as... Figure 1 , 2 As shown, it includes a support component, a structured light projection device 1, an image acquisition device 2, a triggering unit, a supplementary lighting device 3, and a control and processing unit.

[0025] The support assembly is used to mount the various devices, and the optical axes of the structured light projection device and the image acquisition device are configured to intersect at the image acquisition area 4. The support assembly includes a fixed bracket and an angle adjustment mechanism. The fixed bracket is used to stably mount the entire system, ensuring that the positions of each component are accurate and fixed. The angle adjustment mechanism connects the structured light projection device 2 and the image acquisition device 1, and is used to adjust the pitch angle of both, so that the optical axis of the structured light projection device 2 and the optical axis of the image acquisition device 1 are on the same plane and intersect at the location of the trigger unit.

[0026] Specifically, the fixed bracket is used to construct the physical framework of the entire system and ensure system stability. The angle adjustment mechanism is mounted on the fixed bracket, and the structured light projection device 2 and the image acquisition device 1 are respectively mounted on the angle adjustment mechanism.

[0027] By adjusting the angle adjustment mechanism, the center line (optical axis) of the lens of the structured light projection device 2 and the center line (optical axis) of the lens of the image acquisition device 1 are made to lie in the same plane, and the two optical axes intersect at a preset acquisition point (i.e., the sensing area where the trigger is located). Those skilled in the art will understand that after fixing the relative angle and position of the structured light projection device 2 and the image acquisition device 1 by adjusting the angle adjustment mechanism, the software algorithm still needs to perform calibration of the camera (image acquisition device 1) and the projector (structured light projection device 2). The core function is to determine the internal and external parameters of each device, as well as the interrelationships between them. The projector's internal parameters include: projection focal length, projection center point, projection distortion, etc.; the camera's internal parameters include: focal length, distortion coefficient, etc.; the external parameters are: the rotation and translation relationship between the camera coordinate system and the projector coordinate system. Only by combining all the parameters obtained from the calibration can accurate point cloud data be calculated.

[0028] Regarding the depth-of-field configuration, the lens specifications of the structured light projection device 2 and the image acquisition device 1 may be inconsistent (e.g., different focal lengths), but the depth-of-field range of both must be adjusted to cover the image acquisition area 4, ensuring that both the projected stripes and the captured image are clear in the image acquisition area 4. In one embodiment of the present invention, the lens specifications of the structured light projection device and the image acquisition device are inconsistent, and the depth-of-field range of both covers the image acquisition area 4.

[0029] In terms of lighting layout, the light source is mounted above the bracket, with its center line perpendicular to the bottom plane of the device, providing a uniform and stable lighting environment and avoiding shadow interference. Specifically, the supplementary lighting device is an anti-flicker light source, which is mounted on the support assembly, and its central optical axis is perpendicular to the bottom plane of the device, used to provide a uniform lighting environment.

[0030] The structured light projection device, image acquisition device, and triggering unit each establish a communication connection with the control and processing unit; the specific method of the communication connection is as follows: The structured light projection device is connected to the control and processing unit via a USB interface; The image acquisition device is connected to the control and processing unit via a USB interface, and is powered by the control and processing unit through this interface; The triggering unit is connected to the control and processing unit via a USB-to-serial cable. In this embodiment, the triggering unit obtains the power supply required for operation from the control and processing unit through this interface.

[0031] The triggering unit is used to detect the target signal within the image acquisition area 4 and send a trigger command to the control and processing unit. The control and processing unit is configured to control the structured light projection device to project a structured light pattern according to the trigger command.

[0032] The trigger output terminal of the structured light projection device is electrically connected to the trigger input terminal of the image acquisition device, and is configured to synchronously trigger the image acquisition device to acquire images when projecting a structured light pattern.

[0033] In a preferred embodiment, the structured light projection device 2 is a DLP projector, and the image acquisition device 1 is an industrial camera, which is suitable for 3D palmprint acquisition due to its high speed, low noise, and high dynamic range. In a further embodiment, a CCD camera is preferred because it has higher photosensitive consistency and is suitable for acquiring the texture details of palmprints. The DLP projector is configured to project a sinusoidal stripe pattern or a Gray code pattern onto the image acquisition area 4; the industrial camera is configured to perform exposure acquisition upon receiving the rising edge of the synchronization trigger signal.

[0034] A DLP projector internally includes a lens, projection light source, DMD core components, and drive circuitry. It connects to a computer via USB to receive projection commands and pre-stored stripe patterns, and is independently powered by an external +12V power supply. Additionally, the DLP projector is equipped with a trigger output line that outputs a +12V or +5V square wave signal.

[0035] The industrial camera includes a lens and a high-sensitivity image sensor. It connects to a computer via a USB 3.0 cable, enabling high-speed data transfer while the computer provides a +5.0V operating voltage. The industrial camera's trigger input line (IO input) is directly connected to the trigger output line of the DLP projector. The camera is set to external trigger mode and configured to trigger an image capture upon detecting a rising edge of a signal.

[0036] The triggering unit includes a microcontroller and a sensing sensor; the sensing sensor is used to detect whether the palm enters the image acquisition area 4 and transmits the detection signal to the microcontroller; the microcontroller is connected to the control and processing unit via serial communication.

[0037] This embodiment employs a trigger composed of an ESP32C3 microcontroller and a proximity sensor. The trigger detects the sensor input signal and sends a trigger signal to the computer, which then controls the DLP projector to project a sinusoidal stripe pattern or a Gray code pattern. The trigger unit also includes a USB serial cable. The ESP32C3 microcontroller is connected to the control and processing unit via the USB serial cable, configured to obtain a +5V operating voltage from the control and processing unit and send the trigger signal to the control and processing unit through the same USB serial cable.

[0038] The control and processing unit is equipped with an image processing module, which is used to perform the following steps: The image acquisition device receives a set of two-dimensional images with structured light stripes and a two-dimensional image without stripes, which is used for texture mapping. Phase resolution is performed on the two-dimensional image to calculate the depth map and generate point cloud data; Based on point cloud data and 2D images without stripes, 3D reconstruction and texture mapping are performed to generate a 3D model file containing texture information and mesh data.

[0039] In one embodiment of the present invention, the control and processing unit is a computer (PC) running an image processing program. The image processing program acquires a set of two-dimensional palm images with structured light stripes and a two-dimensional palm image without structured light stripes from the image acquisition device 1. After steps such as calculating the phase map, calculating the depth map based on the phase map combined with the intrinsic and extrinsic parameters of the camera and projector, generating point clouds, 3D reconstruction, and texture mapping, a 3D visualization model is finally generated and saved as a universal format file with texture and triangular mesh data, such as a combination file of a PLY 3D image and a PNG 2D image. The file can be opened and edited by commonly used 3D processing software such as MeshLab, CloudCompare, and Blender.

[0040] Example 2 This embodiment is a non-contact three-dimensional palmprint acquisition method based on structured light. The method uses the device described in Embodiment 1 and includes the following steps: The trigger unit monitors the image acquisition area 4, and when it detects a target object signal, it sends a trigger command to the control and processing unit. The control and processing unit responds to the trigger command and controls the structured light projection device to project a preset structured light pattern sequence onto the image acquisition area 4; When the structured light projection device projects each frame of the pattern, it sends a synchronous trigger signal to the image acquisition device through the trigger output terminal. The image acquisition device exposes upon receiving a synchronization trigger signal, captures a two-dimensional image with structured light stripes projected onto the surface of the target object, and transmits the image data to the control and processing unit. The control and processing unit acquires a two-dimensional image sequence, calculates phase and depth information using a structured light three-dimensional reconstruction algorithm, and generates point cloud data. A three-dimensional mesh model is constructed based on the point cloud data, and the texture of the two-dimensional image is mapped onto the three-dimensional mesh model to generate a visualized three-dimensional palm print model.

[0041] When implementing this method on the device described in Embodiment 1, firstly, an image processing program is started on a computer to pre-write a set of structured light coded patterns (such as sinusoidal stripes, phase-shifted stripes, or Gray code patterns) onto the DLP projector. The DLP projector is set to trigger output mode, and the exposure time and trigger delay are set. The DLP projector and the industrial camera are synchronized via a hardware trigger line. Through a precisely set trigger delay, it is ensured that the exposure time window of the industrial camera is completely within the stable display period of the striped image projected by the DLP projector, thereby avoiding motion blur caused by image switching and ensuring the accuracy of phase calculation. The industrial camera is set to trigger input mode, and the aperture, gain, and exposure time are adjusted to appropriate values ​​to accommodate the reflectivity of the palm.

[0042] When the user places their palm into the image acquisition area 4, the sensor in the trigger unit detects the object signal and transmits the signal to the ESP32C3 microcontroller. The ESP32C3 microcontroller then sends a trigger command to the computer to start acquisition via the serial port.

[0043] After receiving the instruction, the computer controls the DLP projector to begin projecting a preset stripe sequence frame by frame. The DLP projector projects the Nth frame of the stripe pattern; simultaneously, the DLP projector's trigger output line emits a square wave signal (rising edge). The industrial camera's trigger input receives this rising edge signal and immediately activates the shutter, capturing the Nth frame image of a hand with the projected stripes. This process repeats until the entire set of stripe patterns is projected and captured. Compared to software triggering, this method of directly triggering the camera via the projector hardware significantly reduces latency, ensures accurate phase of the stripe pattern in each frame, and effectively prevents texture blurring caused by slight hand tremors.

[0044] The computer receives a set of raw two-dimensional images transmitted from an industrial camera via a USB 3.0 interface. The image processing program performs the following operations: It calculates the phase map from the fringe distortion of the image using a phase-shifting method or Gray code decoding algorithm. Based on the principle of triangulation and combined with calibration parameters, it converts the phase map into a depth map. The depth map is then back-projected into three-dimensional space to generate point cloud data containing spatial coordinates. The point cloud is then meshed (e.g., Poisson reconstruction) to generate a triangular mesh model; simultaneously, a frame of a clear two-dimensional image is selected as a texture map and mapped onto the three-dimensional model.

[0045] The final generated 3D visualization model includes geometric structure and surface texture. The system saves it as a common format file, specifically including PLY / OBJ files and PNG / JPG files. These files can be directly opened by third-party 3D processing software such as MeshLab, CloudCompare, and Blender, facilitating subsequent biometric extraction or editing.

[0046] Figure 3This is an example image of a palm print collected and processed in this embodiment.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A non-contact three-dimensional palmprint acquisition device based on structured light, comprising a support assembly, a structured light projection device, an image acquisition device, a trigger unit, a light supplementing device, and a control and processing unit; characterized in that the support assembly is used to mount each device, and the optical axes of the structured light projection device and the image acquisition device are configured to intersect at an image acquisition area; the structured light projection device, the image acquisition device, and the trigger unit are respectively in communication connection with the control and processing unit; the trigger unit is used to detect a target signal in the image acquisition area and send a trigger instruction to the control and processing unit, and the control and processing unit is configured to control the structured light projection device to project a structured light pattern according to the trigger instruction; the trigger output end of the structured light projection device is electrically connected with the trigger input end of the image acquisition device, and is configured to synchronously trigger the image acquisition device to perform image acquisition when the structured light pattern is projected.

2. The apparatus of claim 1, wherein, the structured light projection device is a DLP projector, and the image acquisition device is an industrial camera; the DLP projector is configured to project a sinusoidal fringe pattern or a Gray code pattern to the image acquisition area; and the industrial camera is configured to perform exposure acquisition when receiving a rising edge of the synchronous trigger signal.

3. The apparatus of claim 1, wherein, the trigger unit comprises a microcontroller and a sensing sensor; the sensing sensor is used to detect whether a palm enters the image acquisition area and transmit a detection signal to the microcontroller; and the microcontroller is connected with the control and processing unit through serial communication.

4. The apparatus of claim 3, wherein, the microcontroller adopts an ESP32C3 single-chip microcomputer; the trigger unit further comprises a USB serial line, the ESP32C3 single-chip microcomputer is connected with the control and processing unit through the USB serial line, and is configured to obtain a +5V working voltage from the control and processing unit through the USB serial line and send a trigger signal to the control and processing unit through the USB serial line.

5. The apparatus of claim 1, wherein, the support assembly comprises a fixed support and an angle adjusting mechanism; the angle adjusting mechanism is connected with the structured light projection device and the image acquisition device, and is used to adjust the pitch angles of the two devices, so that the optical axes of the structured light projection device and the image acquisition device are on the same plane and intersect at the position of the trigger unit.

6. The apparatus of claim 1, wherein, the light supplementing device is an anti-flickering light source, is mounted on the support assembly, and has a central optical axis perpendicular to the bottom plane of the device, and is used to provide a uniform illumination environment.

7. The apparatus of claim 1, wherein, the specific way of communication connection is: the structured light projection device is connected with the control and processing unit through a USB interface; the image acquisition device is connected with the control and processing unit through a USB interface; the trigger unit is connected with the control and processing unit through a USB-to-serial line.

8. The apparatus of claim 1, wherein, the control and processing unit is configured with an image processing module, and the image processing module is used to perform the following steps: receive a set of two-dimensional images with structured light fringes and a two-dimensional image without fringes collected by the image acquisition device; perform phase unwrapping on the two-dimensional images to calculate a depth map and generate point cloud data; and perform three-dimensional reconstruction on the point cloud data to obtain a three-dimensional palmprint. The three-dimensional model file containing texture information and mesh data is generated by three-dimensional reconstruction and texture mapping based on point cloud data and two-dimensional images without stripes.

9. The apparatus of claim 1, wherein, The lens of the structured light projection device is inconsistent with the lens specification of the image acquisition device, and the depth of field range of both covers the image acquisition area.

10. A non-contact three-dimensional palmprint acquisition method based on structured light, characterized in that, The method uses the device of claim 1, comprising the following steps: The triggering unit monitors the image acquisition area, and sends a triggering instruction to the control and processing unit when detecting a target object signal; The control and processing unit responds to the triggering instruction, and controls the structured light projection device to project a preset structured light pattern sequence to the image acquisition area; The structured light projection device sends a synchronization triggering signal to the image acquisition device through the triggering output end when projecting each frame of pattern; The image acquisition device performs exposure when receiving the synchronization triggering signal, captures a two-dimensional image with structured light stripes projected on the target object surface, and transmits image data to the control and processing unit; The control and processing unit acquires a two-dimensional image sequence, calculates phase information and depth information by using a structured light three-dimensional reconstruction algorithm, and generates point cloud data; A three-dimensional mesh model is constructed based on the point cloud data, and the texture of the two-dimensional image is mapped to the three-dimensional mesh model to generate a visual three-dimensional palm print model.

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