Image collection method, apparatus and device, and storage medium and program product

Abstract

The present application relates to the technical field of image collection. Disclosed are an image collection method, apparatus and device, and a storage medium and a program product. The method is applied to an image collection device, wherein the image collection device comprises a fill light lamp, a master camera, a slave camera and a controller. The method comprises: a controller sending a first exposure control signal to a master camera; when the first exposure control signal is received, the master camera performing exposure periodically; when single exposure is completed, the master camera sending a frame synchronization signal to a slave camera; when the frame synchronization signal is received, the slave camera performing exposure; on the basis of exposure moments of the master camera and the slave camera, the controller controlling a fill light lamp to fill light periodically, wherein a fill light time period of the fill light lamp covers exposure time periods of the master camera and the slave camera; and the master camera and the slave camera transmitting collected image data to the controller.

Description

Image acquisition method, device, equipment, storage medium and program product

[0001] This application claims priority to Chinese patent application No. 202410134106.4, filed on January 30, 2024, entitled “Image Acquisition Method, Device, Equipment, Storage Medium and Program Product”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The embodiments of the present application relate to the field of image acquisition technology, and in particular to an image acquisition method, apparatus, device, storage medium, and program product. Background Art

[0003] Nowadays, there are more and more ways to authenticate an identity, including authentication through image acquisition and image feature comparison, such as palm print recognition and face recognition.

[0004] In the related art, during the image acquisition process, it is usually necessary to simultaneously use at least two cameras to respectively acquire identity authentication images, and then fuse the image features of the images acquired by the at least two cameras, so as to perform identity authentication using the fused image features.

[0005] However, in the identity authentication image acquisition solution provided by the related art, at least two cameras are independently controlled by the main control chip and are exposed simultaneously under the control of the main control chip, resulting in high instantaneous power consumption of the image acquisition device, which easily causes the device to overheat.

[0006] Summary of the Invention

[0007] The present application provides an image acquisition method, apparatus, device, storage medium, and program product. The technical solutions are as follows:

[0008] On the one hand, an embodiment of the present application provides an image acquisition method, which is performed by an image acquisition device, wherein the image acquisition device includes a fill light, a main camera, a slave camera, and a controller;

[0009] The method comprises:

[0010] The controller sends a first exposure control signal to the main camera;

[0011] Upon receiving the first exposure control signal, the main camera performs periodic exposure;

[0012] When a single exposure is completed, the master camera sends a synchronization signal to the slave camera;

[0013] When the synchronization signal is received, the slave camera is exposed;

[0014] The controller controls the fill light to periodically fill light based on the exposure moments of the main camera and the slave camera, and the fill light period of the fill light covers the exposure periods of the main camera and the slave camera;

[0015] The main camera and the slave camera transmit the collected image data to the controller.

[0016] On the other hand, an embodiment of the present application provides an image acquisition device, comprising:

[0017] A control module, configured to send a first exposure control signal to the main camera module;

[0018] The main camera module is configured to perform periodic exposure upon receiving the first exposure control signal;

[0019] The master camera module is further configured to send a synchronization signal to the slave camera module upon completion of a single exposure;

[0020] The slave camera module is configured to expose the image when receiving the synchronization signal;

[0021] The control module is further configured to control the fill light to periodically fill in light based on the exposure moments of the main camera module and the slave camera module, wherein the fill light period of the fill light covers the exposure period of the main camera module and the slave camera module;

[0022] The main camera module is further configured to transmit the collected image data to the control module;

[0023] The slave camera module is also used to transmit the collected image data to the control module.

[0024] Light on timer Light off timer On the other hand, an embodiment of the present application provides an image acquisition device, which includes a fill light, a main camera, a slave camera, a controller and a memory, wherein the memory stores at least one segment of computer instructions, and the at least one segment of program is loaded and executed by the controller to implement the image acquisition method as described in the above aspects.

[0025] On the other hand, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores at least one computer instruction, and the at least one program is loaded and executed by a controller to implement the image acquisition method as described in the above aspects.

[0026] On the other hand, an embodiment of the present application provides a computer program product or a computer program. The computer program product includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The controller of the image acquisition device reads the computer instructions from the computer-readable storage medium, and the controller executes the computer instructions to implement the image acquisition method as described in the above aspects.

[0027] In an embodiment of the present application, the image acquisition device includes at least two cameras, including a master camera and a slave camera, and the master camera has the function of sending a frame synchronization signal to the slave camera. During the image acquisition process, the controller only needs to control the master camera to start periodic exposure by sending an exposure control signal. The master camera can send a frame synchronization signal to the slave camera after each exposure is completed to instruct the slave camera to expose, so that the master camera and the slave camera are cross-exposed, which can avoid the problem of instantaneous excessive power consumption caused by the simultaneous exposure of the master camera and the slave camera; and after the single exposure of the master camera is completed, the frame synchronization signal is sent to the slave camera, which can enable the slave camera and the master camera to maintain the same frame rate for periodic exposure. In addition, the controller will also control the fill light to perform periodic fill light, and ensure that the fill light period of the fill light covers the exposure period of the master and slave cameras, that is, the fill light remains on during the exposure period of the master and slave cameras, thereby avoiding the problem of underexposure and improving the image acquisition quality of the image acquisition device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 shows a schematic diagram of a main control chip independently controlling two cameras;

[0029] FIG2 is a schematic diagram showing a control process under a camera control scheme;

[0030] FIG3 shows a schematic diagram of a control process under another camera control scheme;

[0031] FIG4 shows a timing diagram of the exposure process of two cameras;

[0032] FIG5 shows a timing diagram of an exposure and fill light process;

[0033] FIG6 shows a schematic diagram of a palmprint recognition device provided by an exemplary embodiment of the present application;

[0034] FIG7 shows a flow chart of an image acquisition method provided by an exemplary embodiment of the present application;

[0035] FIG8 shows a schematic diagram of an image acquisition device provided by an exemplary embodiment of the present application;

[0036] FIG9 shows a timing diagram of camera exposure provided by an exemplary embodiment of the present application;

[0037] FIG10 shows a schematic diagram of an image acquisition device including two slave cameras provided by an exemplary embodiment of the present application;

[0038] FIG11 is a schematic diagram showing an image acquisition device including two slave cameras provided by another exemplary embodiment of the present application;

[0039] FIG12 is a schematic diagram showing a fill light period and an exposure period provided by an exemplary embodiment of the present application;

[0040] FIG13 shows a timing diagram of fill light filling and camera exposure provided by an exemplary embodiment of the present application;

[0041] FIG14 shows a timing diagram of the fill light filling and camera exposure process provided by another exemplary embodiment of the present application;

[0042] FIG15 shows a schematic structural diagram of an image acquisition device provided by an exemplary embodiment of the present application;

[0043] FIG16 is a schematic diagram showing a controller structure provided by an exemplary embodiment of the present application;

[0044] FIG17 shows a timing diagram of a fill light process performed by a master fill light and a slave fill light according to an exemplary embodiment of the present application;

[0045] FIG18 shows a schematic diagram of an image acquisition device provided by an exemplary embodiment of the present application;

[0046] FIG19 shows a structural diagram of an image acquisition device provided by an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0048] When performing identity authentication, user identity feature images are often collected as samples, such as fingerprint images, facial images, and palm print images, and features are extracted from the collected images to obtain identity image features. During the identity authentication process, the image features collected and extracted in real time are compared with the previously saved identity image features to determine whether the identity authentication has been passed. In addition, to ensure that the acquired image features are more comprehensive, multiple cameras may be used simultaneously for image acquisition to obtain image features from different aspects or regions. For example, when performing facial identity recognition, an infrared camera can be used to capture infrared images for liveness detection to ensure that the object of facial recognition is alive, and an RGB camera can be used to capture RGB images at the same time, so that facial features can be compared using the RGB images to achieve facial identity recognition.

[0049] When using multiple cameras for image acquisition, related technologies propose the following two camera exposure control schemes.

[0050] In the first related technical solution, the identity verification device independently controls two cameras. For illustration, please refer to Figure 1, which shows a schematic diagram of a main control chip independently controlling two cameras. The figure includes a main control chip 101, camera A 102, and camera B 103. Main control chip 101 is independently connected to cameras A 102 and B 103, respectively, and independently controlled.

[0051] The main control chip 101 includes an IIC (Inter-Integrated Circuit) controller (or I2C controller), which is used to send an initialization signal (II2 signal) to camera A102 or camera B103, which may include a timing signal and exposure duration, etc. The main control chip 101 is connected to camera A102 and camera B103 respectively through GPIO (General Propose Input Output), which is used to send a reset signal and an enable signal to camera A102 and camera B103. The main control chip 101 also includes a MIPI (Mobile Industry Processor Interface) controller, which is used to send a master clock signal (mclk signal) to camera A102 and camera B103 respectively, and to receive image data collected by camera A102 and camera B103. The main control chip 101 also includes a clock, which is used to send MIPI clock signals to camera A102 and camera B103 respectively. The master clock signal is used to drive the internal clock of camera A102. The master clock signal determines the working speed of the camera, and the MIPI clock signal refers to the clock signal of the MIPI interface, which is a clock signal used to control the synchronous transmission of image data.

[0052] 2 , which shows a schematic diagram of a camera control solution. The solution includes a main control chip 201, a first camera 202, and a second camera 203. The main control chip 201 controls the first camera 202 and the second camera 203, respectively, and is used to send initialization signals and main clock signals to the first camera 202 and the second camera 203, respectively.

[0053] To improve image acquisition quality in low-light environments, the first camera 202 and the second camera 203 send a strobe signal to the main control chip 201, instructing the main control chip 201 to control the fill light for fill illumination. During camera exposure, the strobe signal is at a high level. Accordingly, the main control chip 210 controls the fill light for fill illumination when the strobe signal is at a high level.

[0054] After a single camera exposure, the first camera 202 and the second camera 203 will send the collected image data to the main control chip 201. During the above process, the camera is in Continue mode, and the main control chip 201 independently controls the first camera 202 and the second camera 203. All kinds of signals are sent to the first camera and the second camera respectively by the main control signal.

[0055] In the second related technical solution, the main control chip of the identity authentication device is connected to camera A and camera B respectively through a PWM (Pulse Width Modulation) interface or a GPIO interface, and the synchronous control of camera A and camera B is realized through the FSYNC (Frame SYNC) signal.

[0056] Schematically, please refer to Figure 3, which shows a schematic diagram of a camera control solution of the present application. Among them, the main control chip 301 sends initialization information and a master clock signal to the first camera 302 and the second camera 303. In addition, both cameras send strobe signals and image data to the main control chip. The main control chip 301 sends frame synchronization signals to the first camera 302 and the second camera 303 respectively through the PWM interface or the GPIO interface, thereby realizing synchronous control of the first camera 302 and the second camera 303. In the above process, the camera is in Master-Slave mode, and the external host realizes synchronous control through PWM or GPIO.

[0057] In the first related technical solution, two cameras are controlled separately by a main control chip, enabling continuous exposure. Refer to Figure 4, which shows the exposure timing diagram for the two cameras. The image sensors of the cameras expose at the end of a single frame. During the exposure process, the strobe signal remains high, and the image sensors send a frame synchronization signal at the end of the exposure.

[0058] In response to detecting a rising edge in the frame synchronization signal, the image sensor sends a single frame of captured image data to the main control chip, corresponding to a low MIPI readout signal. After the image data transmission is completed, the MIPI readout signal goes high, halting image data transmission. In the figure, the exposure times of cameras A and B overlap. Since both cameras are operating simultaneously, the average and peak power consumption are high, resulting in higher overall power consumption and a high risk of device overheating.

[0059] Please refer to Table 1, which shows the comparison of the advantages and disadvantages of the above-mentioned related technical solution 1 and related technical solution 2.

[0060] Table 1

[0061] In the first related technical solution, the main control chip independently controls the two cameras, which is relatively simple to implement and suitable for continuous shooting. However, since the two cameras need to be exposed simultaneously, the peak power consumption of the device is high during simultaneous exposure.

[0062] In the second related technical solution, the time difference between the exposure of the first camera and the second camera can be pre-set to avoid high power consumption caused by the simultaneous exposure of the two cameras. However, the main control chip controls the camera exposure through FSIN (frame synchronization signal), so the PWM drive and the camera drive need to be implemented synchronously, which is relatively complex. And the synchronization control needs to rely on a high-precision clock to ensure that the time difference between the main control chip sending the FSIN signal to the two cameras meets the set time difference. In addition, since system scheduling is required to control the camera exposure through PWM, in addition to the set time difference, there will be a delay in system scheduling, so it cannot be guaranteed that the time difference between the exposure of the two cameras meets the set time difference.

[0063] Therefore, to simultaneously address the problems of the aforementioned related technical solutions 1 and 2, namely, achieving precise synchronous control while reducing peak power consumption, an embodiment of the present application provides an image acquisition method that controls exposure of the master camera only through a controller, and then controls exposure of the slave camera using a frame synchronization signal emitted by the master camera. This method ensures that the exposure times of the master and slave cameras are staggered, thus reducing peak power consumption. Furthermore, the method does not rely on a high-precision clock and can guarantee the time difference between the exposures of the master and slave cameras. Since system scheduling is not required, no additional delay is generated.

[0064] On the other hand, the quality of the image collected by the camera will affect the result of identity authentication. For example, if the camera is underexposed, the quality of the collected image will be low, resulting in inaccurate identity authentication results.

[0065] Figure 5 shows an exposure and fill light timing diagram. A high level for the fill light indicates it's on, a low level indicates it's off, and a high level for the strobe signal indicates the camera is exposing. In the first frame, the fill light is off during the camera exposure period, resulting in an ineffective exposure. In the third frame, the fill light turns on and then off during the exposure period, causing underexposure and, consequently, poor image quality.

[0066] Therefore, the solution provided in the embodiment of the present application can align the fill light period with the exposure period, thereby reducing power consumption as much as possible while avoiding the problems of invalid exposure and underexposure.

[0067] The image acquisition method provided in the embodiments of the present application can be applied to at least the following scenarios.

[0068] 1. Palmprint recognition scenario.

[0069] In a palmprint recognition scenario, a palmprint recognition device is required to capture the user's palmprints. Please refer to Figure 6, which shows a schematic diagram of a palmprint recognition device provided by an exemplary embodiment of the present application. In the figure, the palmprint recognition device 610 includes a first camera 611, a second camera 612, a fill light 613, an infrared emitting component 614 (such as an infrared LED), and a controller (not shown in the figure). The first camera 611 and the second camera 612 include an RGB (Red-Green-Blue) camera and an infrared camera, with the first camera 611 serving as the main camera. The infrared emitting component 614 is used to emit infrared light. The infrared light emitted by the infrared emitting component 614 is reflected on the surface of an object, and the reflected infrared light is received by the infrared camera, thereby obtaining infrared image data. During the palmprint recognition process, the infrared camera can obtain the vein pattern of the palm as an identity feature for palmprint recognition. The RGB camera is used to capture the RGB image of the palm.

[0070] Among them, the infrared emitting component 614 emits infrared light that is invisible to the human eye, which serves as fill light in the exposure process of the infrared camera; the visible light emitted by the fill light 613 serves as fill light in the exposure process of the RGB camera.

[0071] During palmprint recognition, the controller sends a first exposure control signal to the first camera 611, controlling it to perform periodic exposures. After the first camera 611 completes a single exposure, it sends a frame synchronization signal to the second camera 612, controlling it to perform further exposures. Furthermore, during the exposure period, the controller controls the fill light 613 to provide fill light, and the first and second cameras 611, 612, transmit the captured palmprint image data to the controller.

[0072] 2. Face recognition scenario.

[0073] In face recognition scenarios, a face recognition device is required to capture a user's facial image. The face recognition device includes a controller and at least two cameras. This embodiment uses a face recognition device comprising a first camera and a second camera as an example, with the first camera being the master camera and the second camera being the slave camera. Optionally, the first camera and the second camera can be an infrared camera and an RGB camera, respectively, or can be RGB cameras that capture images of different facial parts or facial regions.

[0074] Correspondingly, the face recognition device is also provided with a fill light. Optionally, the face recognition device can be provided with multiple fill lights, and different fill lights are used to fill light for the exposure process of different cameras. Specifically, when the cameras are of the same type, the different fill lights can be of the same type, for example, multiple fill lights are all white light fill lights (visible light) for filling light for RGB cameras; when the cameras are of different types, the different fill lights can be of different types, for example, the fill lights can include an infrared emission component for filling light for an IR camera, and a white light fill light for filling light for an RGB camera.

[0075] During facial image acquisition, the controller in the facial recognition device sends a first exposure signal to the first camera, controlling periodic exposure. The first camera then sends a frame synchronization signal to the second camera, controlling exposure. The controller controls the fill light to periodically fill in the image based on the exposure periods of the two cameras, preventing underexposure. Both the first and second cameras transmit the captured facial image data to the controller, which then compares facial features to generate facial recognition results.

[0076] In addition, the solution provided in the embodiments of the present application can also be applied to other identity authentication scenarios, or to multi-camera image acquisition devices that require image acquisition. The embodiments of the present application only use the above two application scenarios as examples to illustrate the camera exposure control and fill light control methods in the image acquisition device.

[0077] It should be noted that the information (including but not limited to user palm print images, user facial images, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions.

[0078] Before collecting the user's relevant data and during the process of collecting the user's relevant data, this application can display a prompt interface, pop-up window or output voice prompt information. The prompt interface, pop-up window or voice prompt information is used to remind the user that his or her relevant data is currently being collected, so that this application only starts to execute the relevant steps of obtaining the user's relevant data after obtaining the user's confirmation operation on the prompt interface or pop-up window. Otherwise (that is, when the user's confirmation operation on the prompt interface or pop-up window is not obtained), the relevant steps of obtaining the user's relevant data are terminated, that is, the user's relevant data is not obtained.

[0079] Please refer to Figure 7, which shows a flow chart of an image acquisition method provided by an exemplary embodiment of the present application. The method is used in an image acquisition device, which includes a fill light, a main camera, a slave camera, and a controller. The method includes the following steps.

[0080] Step 701: The controller sends a first exposure control signal to the main camera.

[0081] The first exposure control signal is a control signal that instructs the camera to perform exposure. In some embodiments, when an object to be identified is identified, the controller sends the first exposure control signal to the main camera.

[0082] In the embodiment of the present application, the master camera refers to the camera among the multiple cameras that directly receives the exposure control signal sent by the controller. In addition, the master camera can control the exposure of the slave cameras in the master-slave mode.

[0083] For example, when the image acquisition device includes an IR camera and an RGB camera, the IR camera is the master camera and the RGB camera is the slave camera, or the RGB camera is the master camera and the IR camera is the slave camera.

[0084] For another example, when the image acquisition device includes a first RGB camera and a second RGB camera, the first RGB camera is the master camera and the second RGB camera is the slave camera, or the second RGB camera is the master camera and the first RGB camera is the slave camera.

[0085] In some embodiments, before sending the first exposure control signal to the main camera, the controller also sends an initialization signal, a reset signal, a main clock signal, etc. to the main camera to ensure the availability of the exposure function of the main camera.

[0086] In addition to controlling the camera for exposure, the main controller can also control the fill light for fill lighting, or perform image data processing on the image data returned by the camera, etc. For example, when the image acquisition device is a palmprint recognition device, the controller sends a first exposure control signal to the main camera to control the main camera to expose. After the main camera is exposed and sends the captured palmprint image to the controller, the controller extracts palmprint features from the received palmprint image to determine the palmprint features to be identified, and compares them with pre-stored palmprint features to obtain a palmprint recognition result.

[0087] Optionally, the end of a single exposure of the main camera is regarded as the end of a frame, and then the camera sends the image data collected in the previous frame to the controller.

[0088] Optionally, the main camera includes a main image sensor, the controller sends a first exposure control signal to the main image sensor, and the main image sensor performs exposure upon receiving the first exposure control signal.

[0089] Step 702: Upon receiving the first exposure control signal, the main camera performs periodic exposure.

[0090] The main camera performs periodic exposures at a preset frequency, with each exposure lasting the same length of time. Exposure refers to the amount of light hitting the camera sensor, which determines the brightness of the image.

[0091] In an illustrative example, the main camera is exposed at a frequency of 25 fps, and each exposure duration is 5 ms.

[0092] Optionally, the controller sends the exposure duration and exposure frequency to the main camera. During the subsequent process in which the controller controls the main camera to perform exposure, the exposure duration and exposure frequency do not change.

[0093] Optionally, the controller sends the modified exposure duration and exposure frequency to the main camera in response to the user's modification operation. The exposure duration and exposure frequency do not change until the user's modification operation is received again.

[0094] Optionally, the controller sends an exposure frequency to the main camera while sending the first exposure signal to the main camera. Upon receiving the exposure frequency and the first exposure signal, the main camera performs periodic exposure according to the received exposure frequency.

[0095] In some embodiments, the frame rate of the image output by the main camera is related to the frequency of exposure of the main camera. The main camera can capture one frame of image each time it is exposed. Therefore, the higher the exposure frequency of the camera, the greater the output frame rate of the image.

[0096] Step 703: When a single exposure is completed, the master camera sends a frame synchronization signal to the slave camera.

[0097] Different from the related art, in which the controller sends a frame synchronization signal to each camera to instruct each camera to perform exposure, in the embodiment of the present application, each time the main camera completes an exposure, it sends a frame synchronization signal to the slave camera.

[0098] In some embodiments, the master camera and the slave camera are connected via a specific signal interface (pin) for transmitting frame synchronization signals. Furthermore, in operation, the master camera and the slave camera are in a master-slave mode. In this master-slave mode, the slave camera receives the frame synchronization signal transmitted by the master camera via the specific signal pin and performs exposure based on the frame synchronization signal sent by the master camera.

[0099] In a possible implementation, the frame synchronization signal is a high-level signal, that is, after the master camera completes a single round of exposure, the signal pin used for transmitting the frame synchronization signal to the slave camera is set to a high level.

[0100] Step 704: Expose from the camera when a frame synchronization signal is received.

[0101] When a frame synchronization signal is received, the camera performs an exposure.

[0102] Since the main camera sends a frame synchronization signal to the slave camera when completing a single exposure, the frequency of the frame synchronization signal received by the slave camera is consistent with the exposure frequency of the main camera. Therefore, the exposure frequency of the slave camera is consistent with that of the main camera, and the frame rate of the image captured by the slave camera is consistent with that of the main camera.

[0103] For example, the exposure frequency of the main camera is 25fps, that is, the main camera captures 25 frames of images in one second, and then the main camera performs 25 exposures in one second. After each exposure, a frame synchronization signal is sent to the slave camera, that is, the frame synchronization signal is sent 25 times in one second, so that the slave camera also performs 25 exposures in one second, and the frame rate is also 25fps.

[0104] Exposure is performed when the slave camera receives the frame synchronization signal from the master camera. This allows the slave camera and the master camera to stagger their exposure times, preventing excessive peak power consumption from overheating the image acquisition device. Furthermore, the controller maintains a stable exposure time difference between the master and slave cameras without the need for a high-precision clock.

[0105] In a possible implementation, when the frame synchronization signal is a high-level signal, exposure is performed when the camera detects a high-level signal through a specific signal pin.

[0106] Step 705 : The controller controls the fill light to periodically fill light based on the exposure moments of the master camera and the slave camera, and the fill light period of the fill light covers the exposure period of the master camera and the slave camera.

[0107] The fill light period of the fill light refers to the period when the fill light is on. For example, for an infrared emitting component, the fill light period is the period when the infrared emitting component emits infrared rays, and for a visible light fill light, the fill light period is the period when the visible light fill light is on.

[0108] The exposure period refers to the period during which the camera's image sensor is in an exposed state.

[0109] During the camera's exposure period, the fill light needs to be on to illuminate the subject. Therefore, the controller controls the fill light to periodically illuminate the subject based on the camera's exposure timing. The fill light's exposure frequency matches the camera's exposure frequency.

[0110] Furthermore, to prevent the fill light from brightening and then dimming, or dimming and then brightening, which could cause underexposure of the camera, the fill light's fill period should overlap with the camera's exposure period. "Overlapping the camera's exposure period" means that the exposure period falls within the fill light period, meaning that the fill light's fill period is greater than or equal to the camera's exposure period.

[0111] For example, if the fill light's fill duration is 3ms and the camera's exposure duration is 5ms, even if the fill light starts filling in the moment the camera starts exposing, it will be off in the last 2ms of the camera's exposure, resulting in underexposure. Therefore, the fill light's fill duration should be longer than the camera's exposure duration, for example, 6ms.

[0112] Step 706: The master camera and the slave camera transmit the collected image data to the controller.

[0113] After a single exposure of the main camera and the slave camera, one frame of image acquisition is completed, and the image data acquired in the previous frame is sent to the controller.

[0114] Optionally, after receiving the image data, the controller processes the image data to obtain image features for subsequent operations. For example, in a face recognition device, the controller extracts facial features based on the received image data to obtain facial features to be recognized, and then compares the facial features with pre-stored facial features to obtain a facial recognition result.

[0115] In summary, in the embodiment of the present application, the image acquisition device includes at least two cameras, including a master camera and a slave camera, and the master camera has the function of sending a frame synchronization signal to the slave camera. During the image acquisition process, the controller only needs to control the master camera to start periodic exposure by sending an exposure control signal. The master camera can send a frame synchronization signal to the slave camera after each exposure is completed to instruct the slave camera to expose, so that the master camera and the slave camera are cross-exposed, which can avoid the problem of instantaneous excessive power consumption caused by the simultaneous exposure of the master camera and the slave camera; and, after the single exposure of the master camera is completed, the frame synchronization signal is sent to the slave camera, which can enable the slave camera and the master camera to maintain the same frame rate for periodic exposure. In addition, the controller will also control the fill light to perform periodic fill light, and ensure that the fill light period of the fill light covers the exposure period of the master and slave cameras, that is, the fill light remains on during the exposure period of the master and slave cameras, thereby avoiding the problem of underexposure and improving the image acquisition quality of the image acquisition device.

[0116] In this embodiment of the present application, the controller only sends the first exposure control signal to the master camera to control the master camera's exposure. The slave camera is controlled by the frame synchronization signal sent by the master camera. Therefore, the frame synchronization interface of the master camera is connected to the frame synchronization interface of the slave camera, and the frame synchronization interface of the master camera is configured as an output state, and the frame synchronization interface of the slave camera is configured as an input state.

[0117] In some embodiments, when the frame synchronization interface of the main camera is configured as an output state, the main camera can only send signals to the outside through the interface, and cannot receive signals through the interface. When the frame synchronization interface of the slave camera is configured as an input state, the camera can only receive signals through the interface, and cannot send signals to the outside through the interface.

[0118] When a single exposure is completed, the master camera sends a frame synchronization signal to the slave camera via the frame synchronization interface. Correspondingly, the slave camera performs exposure in response to the frame synchronization signal received by the frame synchronization interface.

[0119] Optionally, a master-slave synchronization control relationship is formed between the master camera and the slave camera, wherein the master camera controls the exposure of the slave camera.

[0120] Schematically, please refer to Figure 8, which shows a schematic diagram of an image acquisition device provided by an exemplary embodiment of the present application. The image acquisition device includes a controller 801, a main camera 802, and a slave camera 803. The controller 801 sends an initialization signal and a master clock signal to the main camera 802 and the slave camera 803, respectively. In addition, as the main camera 802 and the slave camera 803 are exposed, the main camera 802 and the slave camera 803 respectively send a strobe signal to the controller 801, instructing the controller 801 to control the fill light for fill light. After exposure, the main camera 802 and the slave camera 803 respectively send the collected image data to the controller 801.

[0121] The master camera 802 and the slave camera 803 are connected via a frame synchronization interface (FSYNC). The frame synchronization interface of the master camera 802 is configured as an output state, while the frame synchronization interface of the slave camera 803 is configured as an input state. The controller 801 sends a first exposure control signal to the master camera 802 via the IIC interface. The master camera 802 then performs periodic exposure. After completing a single exposure cycle, the master camera 802 sends a frame synchronization signal to the slave camera 803 via the frame synchronization interface to control the exposure of the slave camera 803.

[0122] In the above embodiment, a single master camera and a single slave camera are used as an example. In some possible scenarios, when the image acquisition device is provided with n slave cameras (n ≥ 2), the first to n-1th slave cameras are configured with multiple frame synchronization interfaces, and the nth slave camera is configured with one or more frame synchronization interfaces.

[0123] The first frame synchronization interface of the first slave camera is connected to the frame synchronization interface of the master camera, and the second frame synchronization interface of the i-th slave camera is connected to the first frame synchronization interface of the (i+1)-th slave camera, where i ≥ 1 and i < n. Furthermore, the first frame synchronization interface of each slave camera is configured as an input state, and the second frame synchronization interface of each slave camera is configured as an output state.

[0124] After the i-th slave camera completes a single exposure, it sends a frame synchronization signal to the first frame synchronization interface of the i+1-th slave camera through the second frame synchronization interface. After the i+1-th slave camera receives the frame synchronization signal, it performs exposure.

[0125] In this way, when the image acquisition device is set up with three or more cameras, the exposure periods of each camera are staggered to avoid power consumption spikes caused by simultaneous exposure.

[0126] When the camera is exposing, a strobe signal can be used to instruct the controller to provide fill light. In one possible embodiment, the strobe signal is in a high-level state during the camera exposure process, and in a low-level state during the period when the camera is not exposing. Therefore, when the main camera completes a single exposure, the strobe signal will switch from a high level to a low level in a short period of time, that is, a falling edge is generated. Optionally, when a falling edge of the strobe signal is detected, the main camera sends a frame synchronization signal to the slave camera via the frame synchronization interface.

[0127] Among them, the strobe signal can also be used to instruct the fill light to perform fill light, and since the strobe signal switches to a low level when the exposure of the main camera ends, the falling edge of the signal corresponds to the end of exposure.

[0128] Please refer to Figure 9, which shows a timing diagram of camera exposure provided by an exemplary embodiment of the present application, including a timing diagram of master camera exposure and a timing diagram of slave camera exposure.

[0129] During the master camera's exposure, the first strobe signal remains high. At the end of exposure, the first strobe signal switches to a low state, generating a falling edge. Upon detecting the falling edge of the first strobe signal, the master camera sends a frame synchronization signal to the slave camera. Upon receiving the frame synchronization signal from the slave camera, exposure begins. During the slave camera's exposure period, the second strobe signal remains high.

[0130] When the slave camera finishes exposing, the second strobe signal switches to a low level. Upon detecting a falling edge in the second strobe signal, the corresponding frame synchronization signal of the slave camera switches to a high level. Furthermore, the master camera and the slave camera send the captured image data to the controller in response to the rising edge of the frame synchronization signal. The corresponding MIPI readout signal switches to a low level. After the image data transmission is completed, the MIPI readout signal is switched back to a high level. In the figure, both the master camera and the slave camera send the captured image data to the controller after each exposure.

[0131] In one possible implementation, there are multiple cameras in the image acquisition device, and there is a master camera and at least two slave cameras among the multiple cameras. There may be two connection methods for the frame synchronization interface between the master camera and the slave cameras. The following takes the example of three cameras in the image acquisition device to illustrate the connection method of the frame synchronization interface.

[0132] Method 1: The frame synchronization interfaces of the slave cameras are connected to the frame synchronization interface of the master camera.

[0133] The master camera's frame synchronization interface is configured as an output, and each slave camera's frame synchronization interface is configured as an input. When the master camera completes a single exposure, it sends a frame synchronization signal to each slave camera via the frame synchronization interface. This allows the master camera's exposure period to be staggered with that of each slave camera, reducing peak power consumption to a certain extent.

[0134] Please refer to Figure 10, which shows a schematic diagram of an image acquisition device including two slave cameras provided by an exemplary embodiment of the present application. The device includes a controller 1001, a master camera 1002, a first slave camera 1003, and a second slave camera 1004. The controller 1001 sends initialization signals and a master clock signal to each of the multiple cameras, and each camera sends a strobe signal and collected image data to the controller 1101. When controlling the camera to perform exposure, the controller 1001 sends a first exposure control signal to the master camera 1002. After the master camera 1002 completes a single exposure, the controller 1001 sends a frame synchronization signal to the first slave camera 1003 and the second slave camera 1004, respectively, to control the first slave camera 1003 and the second slave camera 1004 to perform exposure.

[0135] Method 2: When the slave camera supports serving as both a receiver and a transmitter of a frame synchronization signal, the frame synchronization interfaces of multiple slave cameras are connected in sequence.

[0136] Optionally, there are two frame synchronization interfaces in the first slave camera, one of which is configured as an input state and connected to the master camera, and the other is configured as an output state and connected to the second slave camera. Optionally, when the master camera completes a single exposure, the master camera sends a frame synchronization signal to the first slave camera through the frame synchronization interface, and the first slave camera performs exposure after receiving the frame synchronization signal. When the first slave camera completes a single exposure, the first slave camera sends a frame synchronization signal to the second slave camera through the frame synchronization interface to control the second slave camera to perform exposure.

[0137] This connection method allows multiple cameras to be exposed in sequence, thus avoiding excessive peak power consumption and causing device heating.

[0138] Please refer to Figure 11, which shows a schematic diagram of an image acquisition device including two slave cameras provided by another exemplary embodiment of the present application. It includes a controller 1101, a master camera 1102, a first slave camera 1103, and a second slave camera 1104. The controller 1101 sends a first exposure control signal to the master camera 1102. After the master camera 1102 completes a single exposure, it sends a frame synchronization signal to the first slave camera 1103 to control the first slave camera 1103 to perform exposure. When the first slave camera 1103 completes a single exposure, it sends a frame synchronization signal to the second slave camera 1104 to control the second slave camera 1104 to perform exposure. In addition, the controller 1101 is connected to the IIC interface and GPIO interface between each camera to realize the transmission of other control signals and image data.

[0139] In an embodiment of the present application, the main camera sends a frame synchronization signal to the slave camera through the frame synchronization interface to control the exposure of the slave camera, which can ensure that the exposure frame rate of the slave camera is consistent with that of the main camera, and perform staggered exposure to avoid high peak power consumption.

[0140] Furthermore, in the case where multiple slave cameras are set up, by configuring the two frame synchronization interfaces of the slave cameras as input state and output state respectively, the current slave camera can trigger the next slave camera to expose by sending a frame synchronization signal to the next slave camera after completing a single round of exposure, thereby achieving staggered exposure periods of multiple slave cameras and avoiding power consumption spikes caused by simultaneous exposure.

[0141] In one possible implementation, in order to avoid high power consumption caused by continuous exposure of the camera, the controller may identify the subject to be photographed within the shooting range, and control the camera to expose if the subject to be photographed is identified.

[0142] When it is recognized that there is an object to be photographed within the shooting range, the controller sends a first exposure control signal to the main camera.

[0143] When it is recognized that there is an object to be photographed within the shooting range, it indicates that the image acquisition device currently needs to shoot. Therefore, the controller sends a first exposure control signal to the main camera, and the main camera sends a frame synchronization signal to the slave camera to control the exposure of the slave camera.

[0144] For example, in a palmprint recognition scenario, the image acquisition device is also the palmprint recognition device, which is typically fixed in a certain location for identity verification. Therefore, when no object is currently being verified, it is desirable for the camera in the palmprint recognition device not to perform exposure. Therefore, upon detecting a user or a hand within the shooting range, the controller sends a first exposure control signal to the master camera. After the master camera completes a single exposure, it then sends a frame synchronization signal to the slave camera to control exposure.

[0145] After the palmprint recognition device begins periodic exposure, the subject to be photographed may leave the shooting range. Therefore, if the controller recognizes that the subject to be photographed has left the shooting range, it sends a second exposure control signal to the main camera. This second exposure control signal is used to control the main camera to stop periodic exposure. Upon receiving the second exposure control signal, the main camera stops periodic exposure.

[0146] Since the master camera stops periodic exposure, it will no longer send frame synchronization signals to the slave camera, so the slave camera will no longer expose. This can avoid the camera still exposing after the object to be photographed leaves the shooting range, which will generate more power consumption and waste device processing resources.

[0147] For example, in a palm print recognition scenario, after the user performs palm print recognition and the palm is away from the device at a certain distance, there is no need for continuous exposure. Therefore, after detecting that the palm has left the shooting range, the controller sends a second exposure control signal to the main camera, so that the main camera stops periodic exposure, and then stops exposure from the camera.

[0148] Optionally, the image capture device includes a sensor detector that can emit infrared signals or microwave signals to sense whether the object to be photographed is within the shooting range. In addition, other methods can also be used to identify whether the object to be photographed is within the shooting range. This embodiment does not limit the specific method for identifying the object to be photographed within the shooting range.

[0149] In an embodiment of the present application, by identifying whether there is an object to be photographed within the shooting range, the controller determines whether to send an exposure control signal to the main camera, thereby avoiding the camera still performing periodic exposure when there is no object to be photographed within the current shooting range, thereby avoiding waste of power consumption.

[0150] The strobe signal sent by the camera can indicate whether the camera is currently exposed. Optionally, when the strobe signal is at a high level, the camera is in an exposed state, and when the strobe signal is at a low level, the camera is not exposed. Therefore, the controller can control the fill light to provide fill light based on the state of the received strobe signal, so that the fill light's fill phase overlaps the exposure phase of each camera.

[0151] First, the controller receives stroboscopic signals sent by the main camera and the slave camera, and the stroboscopic signals are used to instruct fill light.

[0152] The controller can detect four states of the strobe signal: high level, low level, rising edge, and falling edge. When the strobe signal is high, the camera is in the exposure state; when the strobe signal is low, the camera is not exposed. When the camera starts exposure, the strobe signal switches from low level to high level, generating a rising edge of the strobe signal; when the camera stops exposure, the strobe signal switches from high level to low level, generating a falling edge of the strobe signal.

[0153] In one possible implementation, the controller controls the fill light to periodically fill light based on a stroboscopic signal state, wherein the stroboscopic signal state includes a rising edge and a falling edge, wherein the rising edge corresponds to the start of exposure and the falling edge corresponds to the end of exposure.

[0154] Optionally, when the controller detects a target strobe signal state of the strobe signal, the controller controls the fill light to periodically fill in the light, wherein the target strobe signal state can be a rising edge of the signal and a falling edge of the signal.

[0155] Since the fill light is needed to provide fill light during the exposure period, in order to avoid the high power consumption caused by the fill light being always on, the exposure start time and exposure end time can be used as the basis for controlling the fill light to turn on and off, that is, the rising edge and falling edge of the strobe signal can be used as the basis for controlling the fill light to turn on and off.

[0156] In one possible implementation, the controller is configured with different control strategies for different strobe signal states. For example, if a falling edge of the strobe signal is detected, indicating the end of exposure, the controller may control the fill light to turn off; whereas if a rising edge of the strobe signal is detected, indicating the beginning of exposure, the controller may control the fill light to turn on.

[0157] Therefore, the controller controls the fill light to periodically fill light through the timer group based on the control strategy corresponding to the target stroboscopic signal state, so that the fill light period covers the exposure period.

[0158] 12 shows a schematic diagram of the fill light period and exposure period provided by an exemplary embodiment of the present application. When the strobe signal is at a high level and the camera is exposed, the fill light period (at a high level) completely covers the camera exposure period, ensuring that the fill light is on throughout the entire exposure period.

[0159] The timer group includes a light-on timer and a light-off timer. The controller controls the fill light to perform periodic fill light according to the timing status of different timers in the timer group.

[0160] The on timer is used to control the timing of the fill light to start filling light, that is, when the on timer reaches the timer length, the controller controls the fill light to turn on. The off timer is used to control the timing of the fill light to stop filling light, that is, when the off timer reaches the timer length, the controller controls the fill light to turn off.

[0161] In one possible implementation, when the controller receives strobe signals from different cameras, it controls the fill light to periodically fill in the light based on the same timer group. The timer is set with a timer duration. After the timer is activated, the timer begins counting. When the timer duration reaches the timer duration, the controller controls the fill light according to the control strategy corresponding to the timer.

[0162] When the fill light is controlled by a timer for periodic fill light, the timing durations of the light-on timer and the light-off timer need to be set to ensure that the fill light is in the on state during the exposure period.

[0163] Optionally, the lights-on timer corresponds to the first timer duration, and the lights-off timer corresponds to the second timer duration. If the fill light is on during the lights-off timer, the fill light's on-time must be greater than or equal to the camera's exposure duration. Therefore, the second timer duration must be greater than or equal to the camera's single exposure duration.

[0164] On the other hand, since the light-on timer and the light-off timer are used alternately, while ensuring that the light-on time is greater than the exposure time, it is also necessary to ensure that the frame time is an integer multiple of the sum of the first timer time and the second timer time, so as to ensure that multiple cameras can complete the exposure within the same single frame time.

[0165] For example, if the frame rate of a camera (master or slave) is 25fps, the frame duration is 40ms. Assuming the exposure duration is 5ms, since the second timer duration should be greater than or equal to the single exposure duration of the camera, the second timer duration can be set to 6ms. In addition, the frame duration needs to be an integer multiple of the sum of the first timer duration and the second timer duration, so the first timer duration can be 4ms.

[0166] Optionally, the controller controls the fill light to periodically fill light through the timer group, and there may be the following two situations.

[0167] 1. Control the fill light periodically based on the falling edge of the signal.

[0168] In one possible implementation, upon detecting a falling edge of the signal, the controller activates a light-on timer in the timer group and controls the fill light to turn off. Subsequently, when the light-on timer reaches a first timer duration, the controller activates a light-off timer in the timer group and controls the fill light to turn on. Furthermore, when the light-off timer reaches a second timer duration, the controller activates a light-on timer in the timer group and controls the fill light to turn off. Activating a timer means triggering a timer to start timing.

[0169] Detecting a falling edge of the signal indicates that the current camera exposure has ended, and the fill light is not needed at this time. In this case, the fill light is controlled to turn off when a falling edge of the signal is detected. At the same time, the light-on timer in the timer group needs to be activated, and the fill light remains off during the timing of the light-on timer. When the timing duration of the light-on timer reaches the preset first timer duration, the controller controls the fill light to turn on and activates the light-off timer. During the timing of the light-off timer, the fill light remains on, and then if the timing duration of the light-off timer reaches the preset second timer duration, the fill light needs to be controlled to turn off. Thus, by alternately activating the light-on timer and the light-off timer in the timer group, the fill light period can cover the camera exposure period.

[0170] Optionally, when a falling edge is detected, the controller triggers an interrupt and activates the timer group to start timing. The controller needs to configure the light-on timer and light-off timer in advance, for example, by setting the light-on timer and light-off timer through the ktimer_set() function, and can initialize the timer through the hrtimer_init() function.

[0171] In some embodiments, when the exposure duration of the camera and the image output frame rate are adjustable, the controller can dynamically configure the timer durations of the light-on timer and the light-off timer according to the real-time exposure duration and the real-time image output frame rate of the camera to ensure that the timer duration of the light-off timer is greater than or equal to the real-time exposure duration, and the single frame duration (the inverse of the image output frame rate) is an integer multiple of the sum of the timer durations of the light-off timer and the light-on timer.

[0172] Optionally, when a falling edge of the strobe signal is detected, the controller triggers an interrupt and calls a preset light-on timer and light-off timer in the interrupt function.

[0173] When a falling edge is detected, an interrupt is triggered and the interrupt function is executed. The controller first turns off the fill light and activates the light-on timer for timing. When the light-on timer reaches the first timer duration, the controller turns on the fill light and activates the light-off timer. When the light-off timer reaches the second timer duration, the controller turns off the fill light and activates the light-on timer for timing.

[0174] Schematically, please refer to Figure 13, which shows a timing diagram of the fill light filling and camera exposure process provided by an exemplary embodiment of the present application. In the figure, when the falling edge of the strobe signal is detected, the controller controls the fill light to turn off and activates the light timer in the timer group. After the light timer is activated, the timing starts. During the timing process, the fill light is in the off state (low level). When the first timer duration is reached, the fill light is controlled to turn on and the light off timer is activated. During the timing of the light off timer, the fill light in the corresponding figure is in the on state (high level). When the second timer duration is reached, the controller activates the light timer in the timer group and controls the fill light to turn off. The light on timer and the light off timer alternately time to control the fill light to light up periodically. When the strobe signal switches to a high level (that is, the camera starts to expose), the fill light remains on until the falling edge of the strobe signal is detected again.

[0175] For example, when the camera's image output frame rate is 25fps (frame duration is 40ms) and the exposure duration is 4ms, the first timer duration of the light-on timer is set to 4ms, and the second timer duration of the light-off timer is set to 6ms. When a falling edge of the signal is detected, the controller activates the light-on timer in the timer group and controls the fill light to turn off. The light-on timer is first counted, and when the first timer duration is reached, the fill light is controlled to turn on, and the light-off timer is activated. The sum of the first timer duration and the second timer duration is 10ms. In one frame, the light-on timer and the light-off timer are activated 4 times respectively. The exposure period is the last period in one frame. Then, when the light-off timer is activated for the last time, the fill light is controlled to turn on, which ensures that the fill light is on during the exposure period.

[0176] 2. Control the fill light periodically based on the rising and falling edges of the signal.

[0177] In one possible implementation, when a rising edge of the signal is detected, the controller activates the off timer in the timer group and controls the fill light to turn on. Subsequently, when the off timer reaches the second timer duration, the controller activates the on timer in the timer group and controls the fill light to turn off. Similarly, when the on timer reaches the first timer duration, the controller activates the off timer in the timer group and controls the fill light to turn on.

[0178] Detecting the rising edge of the signal indicates that the current camera has started to expose, and a fill light is needed at this time. In this case, the fill light is controlled to turn on when the rising edge of the signal is detected. Therefore, it is also necessary to activate the lights-off timer in the timer group, and the fill light remains on during the timing of the lights-off timer. When the timing duration of the lights-off timer reaches the preset second timer duration, the controller controls the fill light to turn off and activates the lights-on timer. During the timing of the lights-on timer, the fill light remains off, and then when the timing duration of the lights-on timer reaches the preset first timer duration, it is necessary to control the fill light to turn on. Thus, by alternately activating the lights-off timer and the lights-on timer in the timer group, the fill light can be turned on during the period when the camera is exposing.

[0179] Optionally, upon detecting a rising edge of the signal, the controller triggers an interrupt and activates the timer group to start timing. The controller needs to configure the light-on timer, light-off timer, and interrupt function in advance. The specific configuration process can refer to the configuration process shown in the above embodiment and is not described in detail in this embodiment.

[0180] Schematically, please refer to Figure 14, which shows a timing diagram of the fill light filling and camera exposure process provided by another exemplary embodiment of the present application. In the figure, when the rising edge of the strobe signal is detected, the controller controls the fill light to turn on and activates the light-off timer in the timer group. After the light-off timer is activated, the timing starts. During the timing process, the fill light is in the on state (high level). When the second timer duration is reached, the fill light is controlled to turn off and the light-on timer is activated. During the timing process of the light-on timer, the fill light in the corresponding figure is in the off state (low level). When the first timer duration is reached, the controller reactivates the light-off timer in the timer group and controls the fill light to turn on. The light-on timer and the light-off timer alternate timing to control the fill light to light up periodically. When the strobe signal switches to a high level, the fill light remains on until the rising edge of the strobe signal is detected again.

[0181] For example, when the camera's image output frame rate is 25fps (frame duration is 40ms) and the exposure duration is 4ms, the first timer duration of the light-on timer is set to 4ms, and the second timer duration of the light-off timer is set to 6ms. When a rising edge of the signal is detected, the controller activates the light-off timer in the timer group and controls the fill light to turn on, thereby ensuring that the fill light is on during the exposure period. The light-off timer is first timed, and when the second timer duration is reached, the fill light is controlled to turn off, and the light-on timer is activated. The sum of the first timer duration and the second timer duration is 10ms. Between the detection of two adjacent signal rising edges, the light-on timer and the light-off timer are activated 4 times respectively, and the fill light is turned on when a rising edge of the signal is detected, and the light-off timer is activated, thereby ensuring that the fill light is on during the exposure period.

[0182] In one possible implementation, the light-on timer and the light-off timer are alternately timed. Since the controller will call functions and other factors in the process of executing the control strategy, the light-on timer and the light-off timer may alternately time for a period of time, which may cause the timer timing to be inaccurate, and cause the fill light period and the exposure period to offset. Therefore, when the falling edge and the rising edge of the signal are detected, the controller resets the light-on timer and the light-off timer to avoid deviation between the fill light period and the exposure period.

[0183] Optionally, the timer resets the light-on timer before activating the light-on timer each time, and resets the light-off timer before activating the light-off timer each time, which can also ensure the accuracy of the timer timing.

[0184] In a possible implementation, different fill lights are provided in the image acquisition device for providing fill light during exposure periods of different cameras.

[0185] Schematically, please refer to FIG15 , which shows a schematic diagram of the structure of an image acquisition device provided by an exemplary embodiment of the present application. It includes an infrared light-emitting diode 1501, an RGB light guide ring 1502, an IR camera 1503, an RGB camera 1504, and a fill light 1505. The infrared light-emitting diode 1501 is used to emit infrared light so that the IR camera 1503 can obtain infrared image data based on the infrared reflection, that is, it is used to fill light for the IR camera 1503. The RGB light guide ring 1502 is used to control the amount of light received by the image sensor when the RGB camera 1504 is shooting. It includes multiple fill lights, and the fill light 1505 is used to fill light for the RGB camera 1504.

[0186] Both the master camera and the slave camera send strobe signals to the controller, and the controller receives the first strobe signal sent by the master camera, or receives the second strobe signal sent by the slave camera.

[0187] Because different fill lights are independently controlled, the controller controls the master fill light corresponding to the primary camera to periodically fill light based on the strobe signal state of the first strobe signal. The controller controls the slave fill light corresponding to the slave camera to periodically fill light based on the strobe signal state of the second strobe signal, where the slave fill light is different from the master fill light.

[0188] The fill lights corresponding to different cameras are controlled separately by the controller based on their respective strobe signals, which can meet the exposure requirements of the two cameras.

[0189] For illustration, please refer to Figure 16, which shows a schematic diagram of the controller structure provided by an exemplary embodiment of the present application. The controller includes a camera control component 1601 and a fill light alignment component 1602. The camera control component 1601 is used to control the main camera to perform periodic exposure, and the fill light alignment component 1602 is used to control the fill light periods of the fill lights corresponding to multiple cameras to align with the exposure periods of the corresponding cameras.

[0190] The following describes a process in which the controller controls the fill light to perform periodic fill light based on the falling edges of the first strobe signal and the second strobe signal.

[0191] During image acquisition, the controller sends a first exposure control signal to the master camera to control the master camera to perform periodic exposure. When the master camera completes a single exposure, the controller detects the falling edge of the first strobe signal and controls the fill light corresponding to the master camera to perform periodic fill light. Furthermore, upon detecting the falling edge of the first strobe signal, the master camera sends a frame synchronization signal to the slave camera. Upon receiving the frame synchronization signal, the slave camera begins exposure. When the slave camera finishes exposure, the controller detects the falling edge of the second strobe signal and controls the slave fill light corresponding to the slave camera to perform periodic fill light.

[0192] For illustration, please refer to Figure 17, which shows a timing diagram of the main fill light and the slave fill light provided by an exemplary embodiment of the present application. Upon detecting the falling edge of the first strobe signal corresponding to the main camera, the controller controls the main fill light to periodically fill in the light; upon detecting the falling edge of the second strobe signal corresponding to the slave camera, the controller controls the slave fill light to periodically fill in the light. The main fill light's fill period is aligned with the main camera's exposure period, and the slave fill light's fill period is aligned with the slave camera's exposure period.

[0193] In an embodiment of the present application, the controller controls the fill light to perform periodic fill light through a timer group according to the detected stroboscopic signal state, and can ensure that the fill light time of the fill light is aligned with the exposure time of the camera by setting appropriate timing duration and control strategy.

[0194] In addition, different cameras correspond to different fill lights. The controller controls the fill lights separately to ensure that the exposure time of the main camera and the slave camera can be aligned with the fill light time, avoiding underexposure or invalid exposure.

[0195] In a possible implementation, upon receiving the first exposure control signal, the main camera performs periodic exposure based on an exposure frequency and a single exposure duration, where the exposure frequency is configured by the controller.

[0196] Optionally, the controller sends the exposure frequency to the main camera simultaneously when sending the initialization signal to the main camera. Alternatively, the controller sends the exposure frequency to the main camera before sending the first exposure control signal to the main camera each time.

[0197] In another possible embodiment, when an image acquisition device captures an image of a subject, the subject may remain within the camera's shooting range for a short period of time. Consequently, the image captured during this short period may be of poor quality, such as being blurry or obscured by the subject, making it difficult to use for subsequent processing. For example, in a palmprint recognition scenario, a user may not keep their palm within the camera's shooting range. Therefore, the poor quality of the image captured during this short period may result in inaccurate palmprint recognition, leading to a low palmprint recognition success rate.

[0198] In one possible embodiment, the controller determines at least one of the image output frame rate and exposure time of the camera based on historical image acquisition quality; configures the camera based on at least one of the image output frame rate and exposure time, and configures the timer duration of the light-on timer and the light-off timer in the timer group based on at least one of the image output frame rate and exposure time.

[0199] To acquire more high-quality images in a shorter time, the camera's frame rate (i.e., exposure frequency) can be increased if the number of valid images captured by the camera falls below a threshold. A valid image is one whose clarity exceeds the threshold. Increasing the camera's exposure frequency allows the image acquisition device to capture more images per unit time, enabling the controller to select high-quality images from the larger number of captured images for subsequent processing.

[0200] The adjusted camera exposure frequency is sent to the camera through the controller. After receiving the adjusted exposure frequency and the first exposure control signal, the camera configures the exposure frequency according to the adjusted exposure frequency and performs periodic exposure.

[0201] For example, in a palmprint recognition scenario, if a small number of valid images are captured during a palmprint recognition process, the camera's frame rate (i.e., the camera's exposure frequency) is increased. This allows the image acquisition device to capture more palmprint images during the palmprint recognition process, allowing the controller to select higher-quality images from these images for further palmprint feature comparison. In a palmprint recognition scenario, a valid image is one that can be used for palmprint recognition, meaning it contains a relatively comprehensive set of palmprint features.

[0202] Optionally, in order to obtain more high-quality images in a shorter time, when the number of valid images in the images captured by the camera is lower than the number threshold, the exposure time of the camera can be increased, thereby shortening the time it takes the camera to obtain a single-frame image, so that more images can be captured in a unit time.

[0203] Similarly, after adjusting the camera's exposure frequency, in order to ensure that the fill light can provide fill light during the camera's exposure phase, that is, to ensure that the fill light's fill light period overlaps the camera's exposure period, the controller needs to adjust the first timer duration corresponding to the light-on timer and the second timer duration corresponding to the light-off timer according to the adjusted frame rate and camera exposure duration.

[0204] In an embodiment of the present application, the frame rate of the camera is configured by a controller, and when the quality of multiple captured images is poor, the controller can dynamically adjust the exposure frame rate and exposure duration of the camera, and configure a timer group in a targeted manner, which is conducive to subsequently capturing more images within the same duration, thereby obtaining higher quality images.

[0205] Please refer to FIG18 , which shows a schematic diagram of an image acquisition device provided by an exemplary embodiment of the present application. The device includes:

[0206] The control module 1801 is configured to send a first exposure control signal to the main camera module 1802;

[0207] The main camera module 1802 is configured to perform periodic exposure upon receiving the first exposure control signal;

[0208] The master camera module 1802 is further configured to send a frame synchronization signal to the slave camera module 1803 upon completion of a single exposure;

[0209] The slave camera module 1803 is configured to expose the image when receiving the frame synchronization signal;

[0210] The control module 1801 is further configured to control the fill light to periodically fill in light based on the exposure moments of the main camera module 1802 and the slave camera module 1803, where the fill light period covers the exposure periods of the main camera module 1802 and the slave camera module 1803;

[0211] The main camera module 1802 is also used to transmit the collected image data to the control module 1801;

[0212] The slave camera module 1803 is also used to transmit the collected image data to the control module 1801 .

[0213] Optionally, the control module 1801 is configured to:

[0214] receiving stroboscopic signals sent by the master camera module 1802 and the slave camera module 1803, wherein the stroboscopic signals are used to indicate fill light, and the fill light timing indicated by the stroboscopic signals matches the exposure timing;

[0215] Based on the stroboscopic signal state of the stroboscopic signal, the fill light is controlled to periodically fill light, the stroboscopic signal state includes a signal rising edge and a signal falling edge, the signal rising edge corresponds to the exposure start time, and the signal falling edge corresponds to the exposure end time.

[0216] Optionally, the control module 1801 is configured to:

[0217] Based on the control strategy corresponding to the stroboscopic signal state, the fill light is controlled to periodically fill light through a timer group, and the timer group includes a light-on timer and a light-off timer.

[0218] Optionally, the control module 1801 is configured to:

[0219] When a falling edge of the signal is detected, the light-on timer in the timer group is activated, and the fill light is controlled to be turned off;

[0220] When the light-on timer reaches the first timer duration, activating the light-off timer in the timer group and controlling the fill light to turn on;

[0221] When the light-off timer reaches the second timer duration, the light-on timer in the timer group is activated, and the fill light is controlled to be turned off.

[0222] Optionally, the control module 1801 is configured to:

[0223] When a rising edge of the signal is detected, the light-off timer in the timer group is activated, and the fill light is controlled to turn on;

[0224] When the light-off timer reaches the second timer duration, activating the light-on timer in the timer group and controlling the fill light to turn off;

[0225] When the light-on timer reaches the first timer duration, the light-off timer in the timer group is activated, and the fill light is controlled to turn on.

[0226] Optionally, the second timer duration is greater than or equal to the single exposure duration of the main camera module 1802 and the slave camera module 1803, and the frame duration is an integer multiple of the sum of the first timer duration and the second timer duration.

[0227] Optionally, the control module 1801 is further configured to:

[0228] When the falling edge of the signal and the rising edge of the signal are detected, the lighting timer and the lighting off timer are reset.

[0229] Optionally, the control module 1801 is configured to:

[0230] receiving a first stroboscopic signal sent by the master camera module 1802 or receiving a second stroboscopic signal sent by the slave camera module 1803;

[0231] Based on the stroboscopic signal state of the first stroboscopic signal, controlling the main fill light corresponding to the main camera module 1802 to periodically fill light;

[0232] Based on the stroboscopic signal state of the second stroboscopic signal, the slave fill light corresponding to the slave camera module 1803 is controlled to periodically fill light, and the slave fill light is different from the master fill light.

[0233] Optionally, the frame synchronization interface of the master camera module 1802 is connected to the frame synchronization interface of the slave camera module 1803, and the frame synchronization interface of the master camera module 1802 is configured as an output state, and the frame synchronization interface of the slave camera module 1803 is configured as an input state;

[0234] The master camera module 1802 is configured to send the frame synchronization signal to the slave camera module 1803 via a frame synchronization interface when a single exposure is completed.

[0235] Optionally, the main camera module 1802 is configured to:

[0236] When a falling edge of a stroboscopic signal is detected, the frame synchronization signal is sent to the slave camera module 1803 via the frame synchronization interface. The stroboscopic signal is used to indicate fill light, and the falling edge of the signal corresponds to the end of exposure.

[0237] Optionally, the main camera module 1802 is configured to:

[0238] When the first exposure control signal is received, periodic exposure is performed based on an exposure frequency and a single exposure duration, where the exposure frequency is configured by the control module 1801 .

[0239] Optionally, the control module 1801 is configured to:

[0240] When it is recognized that there is an object to be photographed within the shooting range, the first exposure control signal is sent to the main camera module 1802;

[0241] When it is recognized that the subject to be photographed leaves the photographing range, a second exposure control signal is sent to the main camera module 1802;

[0242] The main camera module 1802 is configured to stop periodic exposure when receiving the second exposure control signal.

[0243] It should be noted that the apparatus provided in the above embodiments is merely exemplified by the division of the above functional modules. In actual applications, the above functions can be distributed among different functional modules as needed, that is, the internal structure of the apparatus can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments are based on the same concept. The implementation process is detailed in the method embodiments and will not be repeated here.

[0244] Please refer to Figure 19, which shows a structural diagram of an image acquisition device 1900 provided by an exemplary embodiment of the present application. The image acquisition device can be a palm print recognition device, a face recognition device, or other device with image acquisition function.

[0245] Typically, the image acquisition device 1900 includes a controller 1901 and a memory 1902 .

[0246] The controller 1901 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The controller 1901 may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), and programmable logic array (PLA). The controller 1901 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a central processing unit (CPU); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the controller 1901 may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the controller 1901 may also include an artificial intelligence (AI) processor, which is used to process computing operations related to machine learning.

[0247] Memory 1902 may include one or more computer-readable storage media, which may be tangible and non-transitory. Memory 1902 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in memory 1902 is used to store at least one instruction, which is executed by controller 1901 to implement the image acquisition method provided in the embodiments of the present application.

[0248] In some embodiments, the terminal 1900 may optionally further include: a peripheral device interface 1905 and peripheral devices, wherein the peripheral devices include a main camera 1903 and a slave camera 1904 .

[0249] The main camera 1903 and the slave camera 1904 are used to capture the image to be captured within the shooting range and send the captured image data to the controller. The main camera 1903 performs exposure based on the exposure control signal sent by the controller 1901, while the slave camera 1904 performs exposure based on the frame synchronization signal sent by the main camera 1903.

[0250] The peripheral device interface 1905 can be used to connect at least one peripheral device related to input / output (I / O) to the controller 1901 and the memory 1902. In some embodiments, the controller 1901, the memory 1902, and the peripheral device interface 1905 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the controller 1901, the memory 1902, and the peripheral device interface 1905 can be implemented on separate chips or circuit boards, which is not limited in this embodiment.

[0251] Those skilled in the art will understand that the structure shown in FIG19 does not constitute a limitation on the terminal 1900 , and may include more or fewer components than shown in the figure, or combine certain components, or adopt a different component arrangement.

[0252] An embodiment of the present application further provides a computer-readable storage medium, which stores at least one section of computer instructions. The at least one section of the program is loaded and executed by a controller to implement the image acquisition method described in the above embodiments.

[0253] According to one aspect of the present application, a computer program product is provided, comprising computer instructions stored in a computer-readable storage medium. A controller of an image acquisition device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the terminal to perform the image acquisition method provided in various optional implementations of the above aspects.

[0254] Those skilled in the art will appreciate that in one or more of the above examples, the functions described in the embodiments of the present application can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable storage medium or transmitted as one or more instructions or codes on a computer-readable storage medium. Computer-readable storage media include computer storage media and communication media, wherein communication media include any media that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0255] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An image acquisition method, the method being performed by an image acquisition device, the image acquisition device comprising a fill light, a main camera, a slave camera, and a controller; The method comprises: The controller sends a first exposure control signal to the main camera; Upon receiving the first exposure control signal, the main camera performs periodic exposure; When a single exposure is completed, the master camera sends a frame synchronization signal to the slave camera; When the frame synchronization signal is received, the slave camera is exposed; The controller controls the fill light to periodically fill light based on the exposure moments of the main camera and the slave camera, and the fill light period of the fill light covers the exposure periods of the main camera and the slave camera; The main camera and the slave camera transmit the collected image data to the controller.

2. The method according to claim 1, wherein The controller controls the fill light to periodically fill light based on the exposure moments of the master camera and the slave camera, including: The controller receives a stroboscopic signal sent by the master camera and the slave camera, wherein the stroboscopic signal is used to indicate fill light, and the fill light moment indicated by the stroboscopic signal matches the exposure moment; Based on the stroboscopic signal state of the stroboscopic signal, the controller controls the fill light to periodically fill light, and the stroboscopic signal state includes a signal rising edge and a signal falling edge, the signal rising edge corresponds to the exposure start time, and the signal falling edge corresponds to the exposure end time.

3. The method according to claim 2, wherein: In the case of the stroboscopic signal state based on the stroboscopic signal, the controller controls the fill light to periodically fill light, including: The controller controls the fill light to periodically fill light through a timer group based on a control strategy corresponding to the stroboscopic signal state, and the timer group includes a light-on timer and a light-off timer.

4. The method according to claim 3, wherein: The controller controls the fill light to periodically fill light through a timer group based on a control strategy corresponding to the stroboscopic signal state, including: When a falling edge of the signal is detected, the controller activates the light-on timer in the timer group and controls the fill light to be turned off; When the light-on timer reaches the first timer duration, the controller activates the light-off timer in the timer group and controls the fill light to turn on; When the light-off timer reaches the second timer duration, the controller activates the light-on timer in the timer group and controls the fill light to turn off.

5. The method according to claim 3, wherein: The controller controls the fill light to periodically fill light through a timer group based on a control strategy corresponding to the stroboscopic signal state, including: When a rising edge of the signal is detected, the controller activates the light-off timer in the timer group and controls the fill light to turn on; When the light-off timer reaches the second timer duration, the controller activates the light-on timer in the timer group and controls the fill light to turn off; When the light-on timer reaches the first timer duration, the controller activates the light-off timer in the timer group and controls the fill light to turn on.

6. The method according to claim 4 or 5, wherein: The duration of the second timer is greater than or equal to a single exposure duration of the master camera and the slave camera, and a frame duration is an integer multiple of a sum of a duration of the first timer and a duration of the second timer.

7. The method according to any one of claims 3 to 6, wherein: The method further comprises: When the falling edge of the signal and the rising edge of the signal are detected, the controller resets the light-on timer and the light-off timer.

8. The method according to any one of claims 2 to 7, wherein: The controller receives the stroboscopic signals sent by the master camera and the slave camera, including: The controller receives a first stroboscopic signal sent by the master camera, or receives a second stroboscopic signal sent by the slave camera; The controller controls the fill light to periodically fill light based on the stroboscopic signal state of the stroboscopic signal, comprising: Based on the stroboscopic signal state of the first stroboscopic signal, the controller controls the main fill light corresponding to the main camera to periodically fill light; Based on the stroboscopic signal state of the second stroboscopic signal, the controller controls the slave fill light corresponding to the slave camera to periodically fill light, and the slave fill light is different from the master fill light.

9. The method according to any one of claims 1 to 8, wherein: The frame synchronization interface of the master camera is connected to the frame synchronization interface of the slave camera, and the frame synchronization interface of the master camera is configured as an output state, and the frame synchronization interface of the slave camera is configured as an input state; When a single exposure is completed, the master camera sends a frame synchronization signal to the slave camera, including: When a single exposure is completed, the master camera sends the frame synchronization signal to the slave camera through the frame synchronization interface.

10. The method according to claim 9, wherein: When a single exposure is completed, the master camera sends the frame synchronization signal to the slave camera through the frame synchronization interface, including: When a falling edge of the stroboscopic signal is detected, the master camera sends the frame synchronization signal to the slave camera through the frame synchronization interface. The stroboscopic signal is used to indicate fill light, and the falling edge of the signal corresponds to the end time of exposure.

11. The method according to any one of claims 1 to 10, wherein: The periodic exposure of the main camera upon receiving the first exposure control signal includes: When the first exposure control signal is received, the main camera periodically exposes based on an exposure frequency and a single exposure duration, where the exposure frequency is configured by the controller.

12. The method according to any one of claims 1 to 11, characterized in that: The controller sends a first exposure control signal to the main camera, including: When it is recognized that there is an object to be photographed within the shooting range, the controller sends the first exposure control signal to the main camera; The method further comprises: When it is recognized that the subject to be photographed leaves the photographing range, the controller sends a second exposure control signal to the main camera; When the second exposure control signal is received, the main camera stops periodic exposure.

13. An image acquisition device, comprising: A control module, configured to send a first exposure control signal to the main camera module; The main camera module is configured to perform periodic exposure upon receiving the first exposure control signal; The master camera module is further configured to send a frame synchronization signal to the slave camera module upon completion of a single exposure; The slave camera module is configured to expose the image when receiving the frame synchronization signal; The control module is further configured to control the fill light to periodically fill in light based on the exposure moments of the main camera module and the slave camera module, wherein the fill light period of the fill light covers the exposure period of the main camera module and the slave camera module; The main camera module is further used to transmit the collected image data to the control module; The slave camera module is also used to transmit the collected image data to the control module.

14. The device according to claim 13, wherein The control module is used to: receiving stroboscopic signals sent by the master camera module and the slave camera module, wherein the stroboscopic signals are used to indicate fill light, and the fill light timing indicated by the stroboscopic signals matches the exposure timing; Based on the stroboscopic signal state of the stroboscopic signal, the fill light is controlled to periodically fill light, the stroboscopic signal state includes a signal rising edge and a signal falling edge, the signal rising edge corresponds to the exposure start time, and the signal falling edge corresponds to the exposure end time.

15. The device according to claim 14, wherein The control module is used to: Based on the control strategy corresponding to the stroboscopic signal state, the fill light is controlled to periodically fill light through a timer group, and the timer group includes a light-on timer and a light-off timer.

16. The device according to claim 14, wherein The control module is used to: When a falling edge of the signal is detected, the light-on timer in the timer group is activated, and the fill light is controlled to be turned off; when the light-on timer reaches a first timer duration, the light-off timer in the timer group is activated, and the fill light is controlled to be turned on; when the light-off timer reaches a second timer duration, the light-on timer in the timer group is activated, and the fill light is controlled to be turned off; or, When the rising edge of the signal is detected, the light-off timer in the timer group is activated and the fill light is controlled to turn on; when the light-off timer reaches the second timer duration, the controller activates the light-on timer in the timer group and controls the fill light to turn off; when the light-on timer reaches the first timer duration, the controller activates the light-off timer in the timer group and controls the fill light to turn on.

17. The device according to claim 16, wherein The duration of the second timer is greater than or equal to a single exposure duration of the master camera and the slave camera, and a frame duration is an integer multiple of a sum of a duration of the first timer and a duration of the second timer.

18. An image acquisition device, comprising a fill light, a main camera, a slave camera, a controller, and a memory, wherein the memory stores at least one segment of computer instructions, and the at least one segment of computer instructions is loaded and executed by the controller to implement the image acquisition method according to any one of claims 1 to 12.

19. A computer-readable storage medium, wherein at least one computer instruction is stored in the computer-readable storage medium, and the at least one computer instruction is loaded and executed by a controller to implement the image acquisition method according to any one of claims 1 to 12.

20. A computer program product, comprising computer instructions, wherein the computer instructions are stored in a computer-readable storage medium, a controller of an image acquisition device reads the computer instructions from the computer-readable storage medium, and the controller executes the computer instructions to implement the image acquisition method according to any one of claims 1 to 12.

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