Method for image frame acquisition in fundus cameras and related products

Abstract

The application discloses a method and related product for image frame collection in a fundus camera. The method comprises: acquiring a receiving time of a current image frame collected by the fundus camera; determining a starting exposure time for next image frame collection based on the receiving time; and enabling a flash at the starting exposure time so as to realize synchronous execution of flash and exposure of the next image frame. With the scheme of the application, accurate synchronization of image frame and flash can be realized without additional hardware cost.

Description

Technical Field

[0001] This application generally relates to the field of fundus camera technology. More specifically, this application relates to a method, apparatus, and computer-readable storage medium for acquiring image frames in a fundus camera. Furthermore, this application also relates to a fundus camera. Background Technology

[0002] The key steps in capturing fundus images using a fundus camera involve flashing white light for an extremely short time (e.g., milliseconds) using an illumination component (e.g., a flash), then directing this white light through an optical system to illuminate the fundus. The reflected light from the fundus is then used to expose and image the image on a photosensitive element (e.g., a complementary metal-oxide-semiconductor, "CMOS"). During image acquisition, ensuring clear and adequately exposed fundus images requires careful control of flash intensity and duration. When the exposure intensity is too high and the flash duration is too long, the prolonged exposure to the eye can negatively impact the shooting experience and stimulate pupil constriction, hindering the entry of white light into the fundus and affecting the image quality. In some cases, it can even lead to complete image failure. Therefore, controlling the flash duration and intensity to be as short as possible while maintaining image quality is a crucial parameter for fundus cameras.

[0003] Currently, there are several common methods for capturing high-quality fundus images: hardware frame synchronization with a high-performance CMOS sensor, hardware frame synchronization with a standard CMOS sensor, and extending the flash duration when a hardware frame synchronization signal is unavailable. However, with hardware frame synchronization and a high-performance CMOS sensor, some CMOS or system-on-a-chip (SoC) platforms lack frame synchronization signals, significantly increasing hardware costs. The hardware frame synchronization with a standard CMOS sensor suffers from insufficient light sensitivity. With a hardware frame synchronization signal, increased flash brightness is necessary to achieve good fundus image quality. This results in a stronger overall flash intensity, making the strong light stimulation more noticeable to the human eye. Furthermore, extending the flash duration allows for full CMOS exposure, but this also leads to stronger light stimulation perceived by the human eye. Under strong light stimulation, the human eye experiences poor sensory comfort, with significant pupil constriction, increasing the probability of poor fundus image quality and thus affecting the performance and quality of the fundus camera. Meanwhile, the high brightness and long duration of the flashes place higher demands on the peak power of the hardware system, which further increases the hardware cost and affects the system stability and performance in battery-powered portable fundus cameras.

[0004] In view of this, there is an urgent need to provide a solution for image frame acquisition in fundus cameras that can achieve precise synchronization of image frames and flash without increasing hardware costs, so as to reduce flash duration and obtain high-quality fundus images. Summary of the Invention

[0005] In order to at least solve one or more of the technical problems mentioned above, this application proposes a scheme for image frame acquisition in a fundus camera in several aspects.

[0006] In a first aspect, this application provides a method for acquiring image frames in a fundus camera, comprising: obtaining the reception time of a current image frame acquired by the fundus camera; determining a start exposure time for acquiring the next image frame based on the reception time; and activating a flash at the start exposure time to achieve synchronous execution of flash and exposure for the next image frame.

[0007] In one embodiment, the fundus camera includes an image sensor, wherein acquiring the reception time of the current image frame acquired by the fundus camera includes: using an interrupt operation to acquire in real time the reception time of the current image frame received from the image sensor.

[0008] In another embodiment, the fundus camera includes a hardware processor, the hardware processor including a camera serial interface module, wherein obtaining the reception time of the current image frame acquired by the fundus camera includes: using the interrupt operation at the camera serial interface module to record the time when the current image frame arrives at the camera serial interface module, as the reception time of the current image frame.

[0009] In another embodiment, the fundus camera includes a flash component for flash illumination, wherein determining the start exposure time for acquiring the next image frame based on the receiving time includes: determining the start exposure time for acquiring the next image frame according to an image frame output time constant, an activation duration of the flash component, and the receiving time, wherein the output time constant is the time span from when the image sensor of the fundus camera starts acquiring an image frame to when the hardware processor of the fundus camera receives the image frame, and the activation duration is the time span from when the flash component is turned on to when the illumination requirement is met.

[0010] In another embodiment, determining the start exposure time for acquiring the next image frame based on the image frame output time constant, the flash component activation duration, and the receiving time includes: performing a summation operation on the receiving time and the output time constant to obtain a summation result; subtracting the activation duration from the summation result to obtain the start exposure time for acquiring the next image frame.

[0011] In yet another embodiment, the method further includes: adjusting the illumination duration of the flash component based on the resolution of the image sensor of the fundus camera, the exposure value parameter, and the frame output time constant, so that the illumination duration is less than the frame output time constant.

[0012] In yet another embodiment, the method further includes adjusting the brightness value of the flash component and the gain value of the image sensor to maximize the use of the energy of the lighting component.

[0013] In a second aspect, this application also provides an apparatus for acquiring image frames in a fundus camera, comprising: a processor; and a memory storing program instructions for acquiring image frames in a fundus camera, wherein when the program instructions are executed by the processor, the various embodiments of the first aspect described above are implemented.

[0014] In a third aspect, this application also provides a computer-readable storage medium that stores program instructions for acquiring image frames in a fundus camera, which, when executed by a processor, implement the method and its various embodiments described in the first aspect.

[0015] In a fourth aspect, this application also provides a fundus camera, comprising: a flash assembly for flash illumination during the acquisition of fundus camera image frames; an image sensor for exposure and acquisition of the fundus camera image frames; and a hardware processor connected to the flash assembly and the image sensor and configured to control the flash assembly and the image sensor to implement the method in the first aspect and several embodiments thereof.

[0016] Using the image frame acquisition scheme for fundus cameras provided above, this embodiment determines the start exposure time for the next image frame acquisition based on the reception time of the current image frame. This allows for synchronized execution of flash and exposure for the next image frame when the flash is activated at the start exposure time. Based on this, precise synchronization of image frames and flash can be achieved without additional hardware costs. Furthermore, this embodiment utilizes interrupt operations at the camera's serial interface module to obtain the reception time of the current image frame, thereby improving the time accuracy of the current image frame reception time and ensuring precise synchronization between the image frame and flash.

[0017] Furthermore, this embodiment adjusts the illumination duration of the flash component by adjusting the image sensor resolution, exposure parameters, and frame output time constant, ensuring the illumination duration is less than the frame output time constant. This approach not only minimizes the flash duration but also effectively utilizes the full minimum flash duration, resulting in high-quality fundus images. Additionally, this embodiment adjusts the brightness of the flash component and the gain of the image sensor to maximize the use of the illumination component's energy. This reduces the perceived flash intensity and improves the user's sensory experience during shooting. Attached Figure Description

[0018] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0019] Figure 1 This is an exemplary flowchart illustrating a method for acquiring image frames in a fundus camera according to an embodiment of this application;

[0020] Figure 2 This is an exemplary schematic diagram showing an overall image frame acquisition in a fundus camera according to an embodiment of this application;

[0021] Figure 3 This is an exemplary schematic diagram illustrating multi-frame image data acquired from fundus images according to an embodiment of this application;

[0022] Figure 4 This is an exemplary schematic diagram showing fundus images acquired at different brightness values ​​of the flash assembly according to an embodiment of this application;

[0023] Figure 5 This is an exemplary schematic diagram showing fundus images acquired at different gain values ​​of an image sensor according to an embodiment of this application;

[0024] Figure 6 This is an exemplary schematic diagram showing a fundus image after adjusting the brightness value of the flash assembly and the gain value of the image sensor according to an embodiment of this application;

[0025] Figure 7 This is an exemplary structural block diagram illustrating a fundus camera according to an embodiment of this application; and

[0026] Figure 8 This is an exemplary structural block diagram illustrating an apparatus for acquiring image frames in a fundus camera according to an embodiment of this application. Detailed Implementation

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the embodiments described in this specification are only some embodiments provided by this application for the purpose of facilitating a clear understanding of the solutions and complying with legal requirements, and are not all embodiments that can be implemented in this application. Based on the embodiments disclosed in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Figure 1 This is an exemplary flowchart illustrating a method 100 for acquiring image frames in a fundus camera according to an embodiment of this application. Figure 1 As shown, in step S110, the reception time of the current image frame acquired by the fundus camera is obtained. In one embodiment, the fundus camera may include an image sensor, and thus obtaining the reception time of the current image frame acquired by the fundus camera may include using an interrupt operation to obtain the reception time of the current image frame received from the image sensor in real time. In one implementation scenario, the aforementioned image sensor may be, for example, a complementary metal-oxide-semiconductor (CMOS) semiconductor. In one embodiment, the aforementioned fundus camera may also include a hardware processor, and the hardware processor may include a camera serial interface module. Further, when obtaining the reception time of the current image frame acquired by the fundus camera, the time when the current image frame arrives at the camera serial interface module can be recorded using an interrupt operation at the camera serial interface module as the reception time of the current image frame. In one implementation scenario, the aforementioned hardware processor may be, for example, a system-on-a-chip (SoC), and the aforementioned camera serial interface module may be, for example, a "csic" interface module.

[0029] It is understood that in practical applications, a single image frame acquired by a fundus camera is acquired when the CMOS exposure begins, then transmitted to the SoC via, for example, a MIPI bus, and finally output by the SoC to the application program (“app”) through its memory. This app can be, for example, software for image display and editing. In the aforementioned image acquisition and transmission process, the acquisition of image frame data from the start of CMOS exposure followed by transmission to the SoC via, for example, a MIPI bus, constitutes hardware data transmission. The transmission time for each image frame during this process is uniform, or equal. However, when the image frame data is transmitted to the app, the output time between different image frames can vary due to the influence of software system scheduling. Therefore, as an exemplary implementation, this application proposes to record the arrival time of the current image frame at the camera serial interface module (e.g., a CSIC interface module) using an interrupt operation at the camera serial interface module, as the reception time of the current image frame. Through this interrupt setting, the solution of this application can improve the accuracy of the reception time of the current image frame, thereby obtaining the most accurate synchronization time between the image frame and the flash.

[0030] After obtaining the reception time of the current image frame, in step S120, the start exposure time for acquiring the next image frame is determined based on the reception time. In one embodiment, the fundus camera may further include a flash component for flash illumination, thereby determining the start exposure time for acquiring the next image frame based on the image frame output time constant, the flash component activation duration, and the reception time. In one implementation scenario, the aforementioned output time constant is the time span from when the fundus camera's image sensor begins acquiring image frames to when the fundus camera's hardware processor receives the image frames. Specifically, the aforementioned output time constant is the time span from when the fundus camera's image sensor begins acquiring (sensing) the first pixel in each image frame data until the fundus camera's hardware processor receives the last pixel, which also includes bus transmission time. That is, the aforementioned output time constant is equal to the sum of the fundus camera's image sensor's light-sensing time, bus transmission time, and the time when the hardware processor reads out (or receives) the image frame data. In another implementation scenario, the aforementioned activation duration is the time span from when the flash component is turned on to when the illumination requirement is met.

[0031] Further, a summation operation is performed on the receiving time and the frame output time constant to obtain the summation result. Then, the activation duration is subtracted from the summation result to obtain the start exposure time for the next image frame acquisition. As an example, assuming the aforementioned frame output time constant is denoted as T, the receiving time of the current image frame is denoted as t, the activation duration of the flash component is denoted as Rt, and the start exposure time for the next image frame acquisition is denoted as t', then the start exposure time for the next image frame acquisition is denoted as t' = t + T - Rt. Based on the aforementioned start exposure time, in step S130, the flash is activated at the start exposure time to achieve synchronous execution of the flash and exposure for the next image frame. That is, when the illumination flash of the fundus camera is synchronized, the embodiment of this application illuminates the illumination flash based on the start exposure time t' of the next image frame acquisition determined by the receiving time t, thereby achieving precise synchronization between the illumination flash and the image frame.

[0032] As described above, this application embodiment obtains the precise reception time of the current image frame by utilizing interrupt operations at the camera's serial interface module without increasing hardware costs. Then, based on the reception time, the start exposure time for acquiring the next image frame is determined to obtain the most precise synchronization time between the image frame and the flash, thereby achieving precise synchronization between the image frame and the flash. Using the solution of this application, the synchronization error between the image frame and the flash can be less than 1 millisecond ("ms"). For example, for a CMOS system with a frame rate of 30 frames per second ("fps"), the error rate can be less than 3%, thus providing technical support for reducing flash duration.

[0033] As described in the background section above, achieving high-quality fundus image capture under high-performance flash illumination requires a high-performance CMOS sensor and corresponding frame synchronization hardware design. Generally, a high-performance CMOS sensor significantly increases the hardware cost, and hardware frame synchronization also requires a separate design. For some CMOS sensors that do not support hardware frame synchronization, a high-end CMOS sensor with hardware frame synchronization capabilities must be selected, further increasing hardware costs. Furthermore, in solutions lacking hardware frame synchronization, obtaining high-quality fundus images and a good human visual experience necessitates a redesign of the hardware, significantly increasing overall costs. In addition, higher flash brightness and longer flash duration place higher demands on the peak power of the hardware system, further increasing hardware costs and affecting system stability and performance in battery-powered portable fundus cameras. In this embodiment, an effect almost equivalent to hardware frame synchronization is achieved through software, thereby significantly reducing the hardware cost of the fundus camera.

[0034] Figure 2 This is an exemplary overall schematic diagram illustrating image frame acquisition in a fundus camera according to an embodiment of this application. Figure 2As shown, the fundus camera in this embodiment may include a CMOS 210 and a SoC 220. The SoC 220 may include a CSIC 221 interface module and a driver module 222. As described above, a frame of image data acquired by the fundus camera is first acquired via the CMOS 210 when exposure begins, and then transmitted to the SoC 220 via, for example, a MIPI 230 bus. In the SoC 220, the image frame data is first received via the CSIC 221, and then output to the app 240 via, for example, the driver module 222. After all image frames are acquired, a complete fundus image can be obtained. In one implementation scenario, when the CSIC 221 receives an image frame, it can interrupt the operation to record the time t when the current image frame arrives at the camera serial interface module, and use this time t as the reception time of the current image frame. Furthermore, based on the frame output time constant T, the reception time t of the current image frame, and the activation duration Rt of the flash component, the start exposure time t' = t + T - Rt for the acquisition of the next image frame can be determined to achieve precise synchronization between the illumination flash and the image frame.

[0035] Under the premise of precise synchronization between the illumination flash and the image frame, a specific image frame data can be accurately acquired, and the flash illumination can be activated at the moment the specified image frame data begins exposure. Furthermore, when the previous image frame data is received, the next image frame data has already begun exposure (e.g., ...). Figure 3 (As shown). In this case, due to the synchronization of the illumination flash and the image frame, the full flash duration can be ensured to obtain a high-quality image.

[0036] Figure 3 This is an exemplary schematic diagram illustrating multiple frames of image data acquired from fundus images according to an embodiment of this application. For example... Figure 3 The example illustrates six image frames, namely image frame data I1 to image frame data I6. With a fixed resolution and exposure parameters (e.g., frame rate) for the fundus camera, the output duration of each image frame is T. As mentioned earlier, the next image frame has already begun exposure while the previous frame is being received. Taking image frame data I1 and image frame data I2 as examples, assuming image frame data I1 is received at point A and image frame data I2 is exposed at point B, the synchronization of the illumination flash and the image frames ensures the acquisition of the complete flash duration (or illumination duration) to obtain a high-quality image.

[0037] It is understood that, under the fixed resolution and frame rate of the fundus camera, the frame output duration T of each image frame is constant. Therefore, in this embodiment, the illumination duration of the flash component can be adjusted according to the resolution of the fundus camera's image sensor, exposure parameters, and the frame output time constant, so that the illumination duration is less than the frame output time constant. Based on this, the amount of illumination light entering the human eye can be reduced, the stimulation to the human eye can be decreased, and the sensory experience of the subject can be improved. Furthermore, as described above... Figure 3 For example, assuming the illumination duration is denoted as L, in this embodiment of the application, the illumination duration L can be minimized based on the resolution of the image sensor of the fundus camera, the exposure value parameter, and the frame output time constant, so that L < T.

[0038] In some embodiments, since the quality of each image frame data is related to the exposure (photosensitive) time of the pixel and the illumination duration, a shorter illumination duration may result in lower brightness of some pixels, leading to poorer quality of the final fundus image. Therefore, by reducing the illumination duration L, the illumination duration can be controlled to be no less than the acquisition time of coms.

[0039] In one embodiment, the brightness value of the flash component and the gain value of the image sensor can be adjusted to maximize the use of the illumination component's energy. Based on this, the fundus camera can achieve high-performance flash illumination with soft exposure (e.g., a reduction in illumination flash energy of approximately 80%), greatly reducing the flash intensity perceived by the human eye and further enhancing the sensory experience of shooting.

[0040] It's important to understand that when the flash duration of the flash unit and the exposure time of the CMOS are fixed, the larger the brightness value B of the flash unit, the brighter the fundus image acquired by the CMOS (e.g., Figure 4 As shown), the lower the noise in the fundus image, the stronger the light stimulus perceived by the human eye. The larger the gain G of the Coms, the brighter the fundus image acquired by the Coms (e.g., ...). Figure 5 As shown in the figure, the greater the noise in the fundus image, the stronger the light stimulation perceived by the human eye.

[0041] Figure 4 This is an exemplary schematic diagram showing fundus images acquired at different brightness values ​​of the flash assembly according to an embodiment of this application. Figure 4 The image shows fundus images corresponding to luminance values ​​of 10, 20, 40, and 60 for the flash assembly, from left to right. It can be seen from the image that the fundus image is brightest when the luminance value of the flash assembly is 60.

[0042] Figure 5 This is an exemplary schematic diagram illustrating fundus images acquired at different gain values ​​of an image sensor according to an embodiment of this application. Figure 5 The image shows fundus images with image sensor gains of 64, 256, 384, and 512, from left to right. It can be seen from the image that the fundus image is brightest when the image sensor gain is 512.

[0043] Therefore, to minimize the light stimulation perceived by the human eye and the noise in the acquired fundus images, embodiments of this application balance the parameter values ​​of the brightness value B of the flash component and the gain value G of the image sensor to maximize the use of the illumination component's energy, thereby minimizing the light stimulation perceived by the human eye and obtaining high-quality fundus images. For example, Figure 6 The fundus image shown is after adjusting the brightness value of the flash assembly and the gain value of the image sensor, and this fundus image is relative to the above. Figure 4 and Figure 5 The fundus images shown have good quality.

[0044] In one embodiment, this application also provides a fundus camera, which may include a flash assembly, an image sensor, and a hardware processor, such as... Figure 7 As shown in the figure.

[0045] Specifically Figure 7 This is an exemplary structural block diagram illustrating a fundus camera 700 according to an embodiment of this application. Figure 7 As shown, the fundus camera 700 may include a flash assembly 710, an image sensor 720, and a hardware processor 730. In one embodiment, the aforementioned flash assembly can be used for flash illumination during fundus camera image frame acquisition. The aforementioned image sensor 720 can be used for exposure and acquisition of fundus camera image frames, wherein the image sensor 720 may be, for example, a CMOS. In one implementation scenario, the aforementioned hardware processor 730 can be connected to the flash assembly and the image sensor, and configured to control the flash assembly and the image sensor to achieve the combination of the above... Figures 1-6 The method described is for acquiring image frames in a fundus camera. As an example, the aforementioned hardware processor can be a SoC.

[0046] Figure 8 This is an exemplary structural block diagram illustrating a device 800 for acquiring image frames in a fundus camera according to an embodiment of this application. It will be understood that the device implementing the solution of this application can be a single device (e.g., a computing device) or a multifunctional device including various peripheral devices.

[0047] like Figure 8As shown, the device of this application may include a central processing unit (“CPU”) 811, which may be a general-purpose CPU, a special-purpose CPU, or other information processing and program execution unit. Furthermore, the device 800 may also include a mass storage device 812 and a read-only memory (“ROM”) 813. The mass storage device 812 may be configured to store various types of data, including the reception time of the current image frame, the start exposure time of the next image frame acquisition, algorithm data, intermediate results, and various programs required to run the device 800. The ROM 813 may be configured to store power-on self-test (POST) data for the device 800, initialization of various functional modules in the system, drivers for the system's basic input / output, and data and instructions required to boot the operating system.

[0048] Optionally, device 800 may also include other hardware platforms or components, such as the tensor processing unit (“TPU”) 814, graphics processing unit (“GPU”) 815, field-programmable gate array (“FPGA”) 816, and machine learning unit (“MLU”) 817 shown. It is understood that although various hardware platforms or components are shown in device 800, they are merely exemplary and not limiting, and those skilled in the art can add or remove appropriate hardware as needed. For example, device 800 may implement the method for image frame acquisition in a fundus camera of this application by including only a CPU, associated storage devices, and interface devices.

[0049] In some embodiments, to facilitate data transmission and interaction with external networks, the device 800 of this application further includes a communication interface 818, through which it can connect to a local area network / wireless local area network (“LAN / WLAN”) 805, and further through the LAN / WLAN to connect to a local server 806 or to the Internet (“Internet”) 807. Alternatively or additionally, the device 800 of this application can also directly connect to the Internet or cellular network based on wireless communication technology, such as 3G (“3G”), 4G (“4G”), or 5G (“5G”) wireless communication technology, via the communication interface 818. In some application scenarios, the device 800 of this application can also access the server 808 and database 809 of an external network as needed to obtain various known algorithms, data, and modules, and can remotely store various data, such as data or instructions for presenting, for example, the reception time of the current image frame, the start exposure time of the next image frame acquisition, and fundus images.

[0050] Peripherals of device 800 may include a display device 802, an input device 803, and a data transmission interface 804. In one embodiment, the display device 802 may include, for example, one or more speakers and / or one or more visual displays, configured to provide voice prompts and / or display images and videos of the captured image frames of this application. The input device 803 may include, for example, a keyboard, mouse, microphone, gesture capture camera, or other input buttons or controls, configured to receive audio data input and / or user commands. The data transmission interface 804 may include, for example, a serial interface, parallel interface, or Universal Serial Bus interface (“USB”), Small Computer System Interface (“SCSI”), Serial ATA, FireWire (“FireWire”), PCI Express, and High Definition Multimedia Interface (“HDMI”), configured for data transmission and interaction with other devices or systems. According to the scheme of this application, the data transmission interface 804 can receive the time when the current image frame arrives at the camera serial interface module, recorded by the camera serial interface module, and transmit to device 800 data or results including the reception time of the current image frame or various other types of data or results.

[0051] The CPU 811, mass storage 812, ROM 813, TPU 814, GPU 815, FPGA 816, MLU 817, and communication interface 818 of the device 800 of this application can be interconnected via bus 819, and can interact with peripheral devices through this bus. In one embodiment, the CPU 811 can control other hardware components in the device 800 and its peripheral devices through this bus 819.

[0052] The above combination Figure 8 This application describes a device for acquiring image frames from a fundus camera that can be used to perform the functions described herein. It should be understood that the device structure or architecture described here is merely exemplary, and the implementation methods and entities described herein are not limited thereto, but can be modified without departing from the spirit of this application.

[0053] Based on the foregoing description in conjunction with the accompanying drawings, those skilled in the art will understand that the embodiments of this application can also be implemented by a software program. Therefore, this application also provides a computer program product. This computer program product can be used to implement the embodiments of this application in conjunction with the accompanying drawings. Figures 1-6 The method described is for acquiring image frames in a fundus camera.

[0054] It should be noted that although the operations of the method of this application are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. On the contrary, the steps depicted in the flowchart can be performed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0055] It should be understood that when the terms "first," "second," "third," and "fourth," etc., are used in the claims, specification, and drawings of this application, they are used only to distinguish different objects and not to describe a specific order. The terms "comprising" and "including" as used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

[0056] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0057] Although the embodiments of this application are described above, the content is merely an example adopted for the purpose of facilitating understanding of this application and is not intended to limit the scope and application scenarios of this application. Any person skilled in the art described in this application may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application, but the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A method for acquiring image frames in a fundus camera, characterized in that, include: Obtain the reception time of the current image frame acquired by the fundus camera; The start exposure time for acquiring the next image frame is determined based on the received time; as well as The flash is activated at the start of exposure to synchronize the flash and exposure in the next image frame. The fundus camera includes a flash assembly for flash illumination, wherein determining the start exposure time for acquiring the next image frame based on the reception time includes: The start exposure time for acquiring the next image frame is determined based on the image frame output time constant, the flash component activation duration, and the receiving time. The frame output time constant is the time span from when the image sensor of the fundus camera starts acquiring image frames to when the hardware processor of the fundus camera receives the image frames, and the activation duration is the time span from when the flash component is turned on to when the illumination requirement is met. The determination of the start exposure time for acquiring the next image frame, based on the image frame output time constant, the flash component activation duration, and the receiving time, includes: Perform a summation operation on the received time and the frame output time constant to obtain the summation result; Subtract the activation duration from the summation result to obtain the start exposure time for the next image frame acquisition.

2. The method according to claim 1, characterized in that, The fundus camera includes an image sensor, wherein acquiring the reception time of the current image frame captured by the fundus camera includes: The interrupt operation is used to obtain the reception time of the current image frame received from the image sensor in real time.

3. The method according to claim 2, characterized in that, The fundus camera includes a hardware processor, which includes a camera serial interface module. The acquisition of the reception time of the current image frame captured by the fundus camera includes: The interrupt operation at the camera serial interface module is used to record the time when the current image frame arrives at the camera serial interface module, which is used as the reception time of the current image frame.

4. The method according to claim 1, characterized in that, include: The illumination duration of the flash assembly is adjusted based on the resolution, exposure parameters, and frame output time constant of the image sensor of the fundus camera, so that the illumination duration is less than the frame output time constant.

5. The method according to claim 4, characterized in that, Also includes: The brightness value of the flash assembly and the gain value of the image sensor are adjusted to maximize the use of the flash assembly's energy.

6. A device for acquiring image frames in a fundus camera, characterized in that, include: processor; as well as A memory that stores program instructions for acquiring image frames in a fundus camera, which, when executed by the processor, implement the method according to any one of claims 1-5.

7. A computer-readable storage medium storing program instructions for acquiring image frames in a fundus camera, which, when executed by a processor, implement the method according to any one of claims 1-5.

8. A fundus camera, comprising: Flash assembly, used for flash illumination during the acquisition of image frames by a fundus camera; An image sensor for exposing and acquiring image frames from the fundus camera; as well as A hardware processor connected to the flash assembly and the image sensor, and configured to control the flash assembly and the image sensor to implement the method according to any one of claims 1-5.

Images