Multi-camera time synchronization method, device and equipment and storage medium

Abstract

The invention relates to the technical field of multi-camera systems, and discloses a multi-camera time synchronization method, device and equipment and a storage medium, and the method comprises the steps: setting the refresh rate of screen display content and the frequency of a screen PWM modulation wave, the frequency of the PWM modulation wave being less than or equal to half of the refresh rate of the screen display content; controlling a plurality of cameras to shoot the dynamic screen, and selecting a group of photos which are shot by different cameras and have the same screen display content; taking one camera as a reference camera, and taking the position of one dark fringe in a picture shot by the reference camera as a reference position; comparing dark fringe positions in photos shot by other cameras with the reference position to obtain a pixel difference set of each camera; and adjusting the time of the camera to be synchronous with the time of the reference camera according to the pixel difference set of each camera. According to the invention, photo pixels are converted into time statistics by using dark fringes generated by a screen during PWM dimming, the alignment precision is high, and the investment cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-camera systems, and in particular to a multi-camera time synchronization method, device, equipment and storage medium. Background Art

[0002] When collecting image data, in order to improve data collection efficiency, multiple cameras are usually used to shoot simultaneously. However, different cameras have different exposure and shooting times, so certain measures need to be taken to unify the time standards of different cameras.

[0003] At present, network timing, hardware synchronization signals and event synchronization methods are commonly used to unify the time of multiple cameras. For some specific occasions, it is difficult to use hardware synchronization solutions (network timing and hardware synchronization signals), and only event synchronization methods can be used for time synchronization. When performing camera time synchronization, the conventional approach adopts the solution of "high-frequency events in reality + short exposure of cameras". When multiple cameras with short exposure capture the same high-frequency event, it is considered that this moment is the same time base for multiple cameras, and the accuracy is the inverse of the frequency. The higher the event frequency, the more accurate the synchronization time accuracy. However, it is difficult to create high-frequency events in reality. For example, high-frequency displays are expensive and the frequency is still not high enough, or special hardware equipment is required. While the production cost is high, the synchronization accuracy is still low. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problems of complexity and high cost of the multi-camera time synchronization method in the prior art, thereby providing a multi-camera time synchronization method, device, equipment and storage medium.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a multi-camera time synchronization method, comprising: setting a refresh rate of screen display content and a frequency of a screen PWM modulation wave, wherein the frequency of the PWM modulation wave is less than or equal to half of the refresh rate of the screen display content; controlling multiple cameras to capture a dynamic screen, and selecting a group of photos with the same screen display content captured by different cameras; using one of the cameras as a reference camera, and using a position of a dark line in the photos captured by the reference camera as a reference position; comparing the dark line positions in the photos captured by other cameras with the reference position to obtain a pixel difference set of each camera; and adjusting the time of each camera to synchronize with the time of the reference camera according to the pixel difference set of the camera.

[0007] The multi-camera time synchronization method provided by the present invention converts the photo pixels into time statistics by judging the position of the dark stripes generated when PWM adjusts the screen brightness and combining with the low-frequency synchronization events, so that the time of each camera is synchronized with the time of the reference camera. The synchronization accuracy between multiple cameras can reach an alignment accuracy of 0.1 milliseconds. The synchronization method is simple, and the synchronization method uses the side effect of screen flickering caused by the bright and dark stripes in the PWM brightness adjustment to measure the time. There is no need to use a high refresh rate screen additionally, and there is no need to customize the hardware equipment, so the investment cost is low.

[0008] In an optional implementation, the process of setting the refresh rate of the screen display content and the frequency of the screen PWM modulation wave includes: setting the screen background to white.

[0009] In the multi-camera time synchronization method provided by the present invention, the screen background is mainly white, the stripes generated by PWM can be clearly identified, and the interpretation error can be reduced.

[0010] In an optional implementation, the process of controlling multiple cameras to shoot a dynamic screen includes: controlling the multiple cameras to maintain the same short exposure parameters to perform high-speed continuous shooting of the screen.

[0011] The multi-camera time synchronization method provided by the present invention can enable multiple cameras to accurately capture the same screen display content through high-speed continuous shooting, thereby reducing errors in the subsequent time synchronization process and shortening the time of the entire synchronization process.

[0012] In an optional embodiment, the process of using one of the cameras as a reference camera and using the position of one of the dark lines in the photo taken by the reference camera as the reference position includes: selecting one of the multiple dark lines in the photo taken by the reference camera as the reference dark line; and recording the reference position of the reference dark line using a ruler on the screen.

[0013] The multi-camera time synchronization method provided by the present invention has a built-in ruler on the screen. When the camera shoots the screen display content, the dark lines generated by PWM and the ruler are displayed on the photo, which is convenient for reading the exact position of each dark line through the photo, convenient for converting pixel statistics into time statistics, and convenient for time conversion in subsequent steps.

[0014] In an optional embodiment, the position of dark lines in photos taken by other cameras is compared with the reference position to obtain the pixel difference set of each camera, including: recording the positions of all dark lines in each photo through a ruler on the screen; calculating the difference between the position of each dark line in each photo and the reference position, and taking all the differences in each photo as the pixel difference set of the camera corresponding to the photo.

[0015] In an optional embodiment, the process of adjusting the time of each camera to synchronize with the time of a reference camera according to the pixel difference set of each camera includes: respectively obtaining the pixel differences that meet preset conditions in the pixel difference set of each camera as the pixel adjustment values ​​of the corresponding camera; calculating the time adjustment value of each camera according to the refresh rate of the screen display content, the wavelength of the PWM modulation wave and the pixel adjustment value of each camera; and adjusting the time of the corresponding camera to be synchronized with the time of the reference camera based on the time adjustment value of each camera.

[0016] The multi-camera time synchronization method provided by the present invention can calculate the number of pixel differences corresponding to each photo by comparing the dark patterns in the photos taken by each camera with the reference position, and screen out the minimum pixel difference in each set as the time adjustment value of the camera corresponding to the photo, so as to quickly and accurately realize the conversion between pixels and time and reduce the calculation complexity.

[0017] In an optional implementation, the time adjustment value Δt of each camera i The calculation formula is:

[0018]

[0019] Where N is the refresh rate of the screen display content, w is the wavelength of the PWM modulation wave, the unit is pixel, Δw i is the pixel adjustment value of the i-th camera, Δt i The unit is seconds.

[0020] In a second aspect, the present invention provides a multi-camera time synchronization device, comprising: an initialization module, used to set the refresh rate of screen display content and the frequency of the screen PWM modulation wave, the frequency of the PWM modulation wave is less than or equal to half of the refresh rate of the screen display content; an acquisition module, used to control multiple cameras to shoot a dynamic screen, and select a group of photos with the same screen display content taken by different cameras; a reference module, used to use one of the cameras as a reference camera, and use one of the dark line positions in the photos taken by the reference camera as the reference position; a comparison module, used to compare the dark line positions in the photos taken by other cameras with the reference position, and obtain a pixel difference set of each camera; an adjustment module, used to adjust the time of each camera to synchronize with the time of the reference camera according to the pixel difference set of each camera.

[0021] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the multi-camera time synchronization method of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0022] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the multi-camera time synchronization method of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 is a flowchart of a multi-camera time synchronization method according to an embodiment of the present invention;

[0025] Figure 2 is a waveform diagram of a PWM modulation wave according to an embodiment of the present invention;

[0026] Figure 3 is another flowchart of a multi-camera time synchronization method according to an embodiment of the present invention;

[0027] Figure 4 is a screen display image captured simultaneously by different cameras according to an embodiment of the present invention;

[0028] Figure 5 is another flowchart of a multi-camera time synchronization method according to an embodiment of the present invention;

[0029] Figure 6 is another flowchart of a multi-camera time synchronization method according to an embodiment of the present invention;

[0030] Figure 7 is a structural block diagram of a multi-camera time synchronization device according to an embodiment of the present invention;

[0031] Figure 8 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0034] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] This embodiment provides a multi-camera time synchronization method, such as Figure 1 As shown, including:

[0036] Step S1: setting the refresh rate of the screen display content and the frequency of the screen PWM modulation wave, the frequency of the PWM modulation wave is less than or equal to half of the refresh rate of the screen display content.

[0037] like Figure 2 As shown, since the three-color light effects of independent control have different rates of change with voltage, changing the screen input voltage in order to adjust the screen brightness will cause the screen to display color cast. Therefore, when the screen adjusts the brightness, it is usually used to input 5V and 0V at intervals to reduce the overall brightness. The time proportion of 5V and 0V is the duty cycle. Due to the visual persistence effect, people usually do not perceive the flickering, but feel that the screen is darkening as a whole. When using a camera with short exposure and high speed continuous shooting, due to the propagation of PWM signals, pixels at different positions of the screen will periodically appear "high-low-high-low" voltages. When a high voltage passes through a certain screen position, this position becomes brighter. In the next time period, this position passes through a low voltage again, and this position becomes darker. When viewed continuously, it is the alternation of bright and dark stripes, that is, it is clear that the light and dark stripes are moving.

[0038] For example, the movement of light and dark stripes will form different phases, and these phases can be accurate to the pixel level. For example, a 240Hz square wave and a 2K pixel phase resolution, the screen has about 5 stripes, and each stripe has 400 pixels. This means that 100 pixels move in 1ms, and each pixel corresponds to 1 / 100ms. The theoretical time resolution is 1 / 100ms, which is much higher than the 2ms accuracy of a 500Hz refresh rate display.

[0039] Specifically, the refresh rate of the screen display content is set to N, and the screen refreshes the display content every 1 / N second; the frequency of the screen PWM modulation wave is set to M, and M≤N / 2 is ensured; the total width of adjacent bright and dark lines generated by the PWM modulation wave on the screen is one cycle, and the PWM modulation wave is set to move one cycle every 1 / M second.

[0040] Step S2: Control multiple cameras to shoot dynamic screens, and select a group of photos with the same screen display content shot by different cameras.

[0041] Specifically, after controlling a plurality of cameras to be synchronized to shoot the dynamic screen, a group of photos having the same screen display content shot by different cameras are sorted out.

[0042] Step S3: One of the cameras is used as a reference camera, and the position of one of the dark lines in the photo taken by the reference camera is used as the reference position.

[0043] Step S4: Compare the dark pattern positions in the photos taken by other cameras with the reference positions to obtain a pixel difference set of each camera.

[0044] Specifically, after a camera is selected as a reference camera, a dark line position in a photo taken by the camera is used as a reference position, and is compared with the dark line positions in photos taken by other cameras to obtain a pixel difference set for each camera.

[0045] Step S5: adjusting the time of each camera to synchronize with the time of the reference camera according to the pixel difference set of the camera.

[0046] Specifically, the pixel difference set of each camera is converted into a time parameter corresponding to the camera, and the time of each camera is adjusted according to the time parameter, so that the time of each camera is synchronized with the time of the reference camera.

[0047] The multi-camera time synchronization method provided in this embodiment converts the photo pixels into time statistics by judging the position of the dark lines generated when PWM adjusts the screen brightness and combining low-frequency synchronization events, so that the time of each camera is synchronized with the reference camera time. The synchronization accuracy between multiple cameras can reach an alignment accuracy of 0.1 milliseconds. The synchronization method is simple and uses the side effect of PWM brightness adjustment to measure time. There is no need to use a high refresh rate screen or customize hardware equipment, and the investment cost is low.

[0048] In some optional implementations, the process of setting the refresh rate of the screen display content and the frequency of the screen PWM modulation wave includes: setting the screen background to white.

[0049] It should be noted that the screen background may also be other colors that can form an obvious color difference with the dark pattern of the PWM modulation wave.

[0050] In some optional implementations, the process of controlling multiple cameras to shoot a dynamic screen includes: controlling the multiple cameras to maintain the same short exposure parameters to perform high-speed continuous shooting of the screen.

[0051] Specifically, a plurality of cameras to be synchronized are controlled to shoot the dynamic screen with the same short exposure parameters to reduce the error between different cameras.

[0052] In some optional embodiments, such as Figure 3 Figure 2 As shown, the process of using one of the cameras as a reference camera and using the position of one of the dark lines in the photo taken by the reference camera as the reference position includes:

[0053] Step S31: selecting one of the multiple dark lines in the photo taken by the reference camera as a reference dark line.

[0054] Step S32: Record the reference position of the reference dark pattern using the ruler on the screen.

[0055] For example, Figure 4 As shown, when camera A and camera B simultaneously capture the number 4, these two photos are regarded as a group of photos taken by different cameras with the same screen display content, and camera A is taken as the reference camera, and the second dark pattern a in the photo taken by camera A is taken as the reference dark pattern. The reference position of the reference dark pattern is read as w1 through the ruler on the screen; the total width of adjacent dark patterns and light patterns of the PWM modulated wave is a wavelength, and the wavelength of the PWM modulated wave read as w through the ruler.

[0056] In some optional embodiments, such as Figure 5 As shown, the process of comparing the dark pattern positions in the photos taken by other cameras with the reference positions to obtain the pixel difference set of each camera includes:

[0057] Step S41: Record the positions of all dark lines in each photo using the ruler on the screen.

[0058] Step S42: Calculate the difference between the position of each dark pattern in each photo and the reference position respectively, and use all the differences in each photo as the pixel difference set of the camera corresponding to the photo.

[0059] For example, Figure 4 As shown, after reading through the ruler that the position of each dark line in the photo taken by camera B is 0, w2, w3 and w4 respectively, the position of each dark line in the photo taken by camera B is subtracted from the reference position w1 to obtain the pixel difference Δw1, Δw2, Δw3, and Δw4 corresponding to each dark line, and Δw1, Δw2, Δw3, and Δw4 are used as the pixel difference set of camera B.

[0060] In some optional implementations, the process of adjusting the time of each camera to be synchronized with the time of the reference camera according to the pixel difference set of each camera is as follows: Figure 6 As shown, including:

[0061] Step S51: respectively obtaining pixel differences that meet preset conditions in the pixel difference set of each camera as pixel adjustment values ​​of the corresponding camera.

[0062] Specifically, since the screen refreshes the displayed content every 1 / N second, the frequency of the screen PWM modulation wave is set to M, and M≤N / 2. Then, within every 1 / N second, the dark pattern value of the PWM modulation wave can only move a distance less than half of its own wavelength. Therefore, the pixel difference less than half a wavelength in each camera pixel difference set is selected as the pixel adjustment value of the corresponding camera.

[0063] For example, Figure 4 As shown, all pixel differences in the pixel difference set of camera B are compared with half of the PWM modulation wave length w, among which only Δw2 is less than w / 2, and Δw2 is used as the pixel adjustment value Δw of camera B. B .

[0064] Step S52: Calculate the time adjustment value of each camera according to the refresh rate of the screen display content, the wavelength of the PWM modulation wave and the pixel adjustment value of each camera.

[0065] Specifically, the time adjustment value Δt of each camera is i The calculation formula is:

[0066]

[0067] Where N is the refresh rate of the screen display content, w is the wavelength of the PWM modulation wave, the unit is pixel, Δw i is the pixel adjustment value of the i-th camera, Δt i The unit is seconds.

[0068] For example, Figure 4 As shown in the figure, assuming that the dark stripes of the PWM modulation wave move from the left side of the screen to the right side of the screen, it can be determined that within 1 / N seconds, the movement of the black stripes is less than half a wavelength w, and thus it can be determined that the time of camera B is earlier than the time of camera A, and the time difference (i.e., time adjustment value) Δt B for:

[0069]

[0070] Step S53: adjusting the time of each camera to be synchronized with the time of the reference camera based on the time adjustment value of each camera.

[0071] For example, Figure 4 As shown in the figure, if camera A records its own time as T1 and camera B records its own shooting time as T2, then Δt should be added to the time T2 of camera B itself. BAfter that, the time of camera B is synchronized to the time of camera A.

[0072] In this embodiment, a multi-camera time synchronization device is also provided, which is used to implement the above embodiment and any optional implementation mode, and the descriptions that have been made will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0073] This embodiment provides a multi-camera time synchronization device, such as Figure 7 As shown, including:

[0074] The initialization module 801 is used to set the refresh rate of the screen display content and the frequency of the screen PWM modulation wave. The frequency of the PWM modulation wave is less than or equal to half of the refresh rate of the screen display content.

[0075] The acquisition module 802 is used to control multiple cameras to shoot dynamic screens, and select a group of photos with the same screen display content shot by different cameras.

[0076] The reference module 803 is used to use one of the cameras as a reference camera and use the position of a dark line in the photo taken by the reference camera as a reference position.

[0077] The comparison module 804 is used to compare the dark pattern positions in the photos taken by other cameras with the reference positions to obtain a pixel difference set of each camera.

[0078] The adjustment module 805 is used to adjust the time synchronization of each camera with the time synchronization of the reference camera according to the pixel difference set of each camera.

[0079] The hardware-based logic mapping device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0080] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0081] The embodiment of the present invention also provides a computer device having the above Figure 7 The multi-camera time synchronization device shown.

[0082] like Figure 8As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 8 A processor 10 is taken as an example.

[0083] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0084] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0085] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the use of a computer device based on the presentation of a small program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0086] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0087] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0088] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0089] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0090] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A multi-camera time synchronization method, characterized in that: include: Setting the refresh rate of the screen display content and the frequency of the screen PWM modulation wave, wherein the frequency of the PWM modulation wave is less than or equal to half of the refresh rate of the screen display content; Control multiple cameras to shoot dynamic screens, and select a group of photos taken by different cameras with the same screen display content; One of the cameras is used as a reference camera, and a dark line position in a photo taken by the reference camera is used as a reference position; Compare the dark pattern positions in the photos taken by other cameras with the reference positions to obtain a pixel difference set of each camera; The time of each camera is adjusted to be synchronized with the time of the reference camera according to the pixel difference set of the camera.

2. The multi-camera time synchronization method according to claim 1, characterized in that: The process of setting the refresh rate of the screen display content and the frequency of the screen PWM modulation wave includes: Set the screen background to white.

3. The multi-camera time synchronization method according to claim 2, characterized in that: The process of controlling multiple cameras to shoot dynamic screens includes: The multiple cameras are controlled to maintain the same short exposure parameter to perform high-speed continuous shooting of the screen.

4. The multi-camera time synchronization method according to claim 3, characterized in that: The process of using one of the cameras as a reference camera and using a dark line position in a photo taken by the reference camera as a reference position includes: Selecting one of the plurality of dark lines in the photo taken by the reference camera as a reference dark line; The reference position of the reference dark pattern is recorded by the ruler on the screen.

5. The multi-camera time synchronization method according to claim 4, characterized in that: The process of comparing the dark pattern positions in the photos taken by other cameras with the reference positions to obtain the pixel difference set of each camera includes: Use the ruler on the screen to record the location of all dark patterns in each photo; The difference between the position of each dark pattern in each photo and the reference position is calculated respectively, and all the difference values ​​in each photo are used as the pixel difference set of the camera corresponding to the photo.

6. The multi-camera time synchronization method according to claim 5, characterized in that: The process of adjusting the time of each camera to be synchronized with the time of the reference camera according to the pixel difference set of each camera includes: Respectively obtain the pixel differences that meet the preset conditions in the pixel difference set of each camera as the pixel adjustment value of the corresponding camera; Calculate the time adjustment value of each camera according to the refresh rate of the screen display content, the wavelength of the PWM modulation wave and the pixel adjustment value of each camera; Based on the time adjustment value of each camera, the time of the corresponding camera is adjusted to be synchronized with the time of the reference camera.

7. The multi-camera time synchronization method according to claim 6, characterized in that: The time adjustment value Δt of each camera i The calculation formula is: Where N is the refresh rate of the screen display content, w is the wavelength of the PWM modulation wave, Δw i Pixel adjustment value for the i-th camera.

8. A multi-camera time synchronization device, characterized in that: include: An initialization module, used to set the refresh rate of the screen display content and the frequency of the screen PWM modulation wave, wherein the frequency of the PWM modulation wave is less than or equal to half of the refresh rate of the screen display content; An acquisition module is used to control multiple cameras to shoot dynamic screens and select a group of photos with the same screen display content shot by different cameras; A reference module, used to use one of the cameras as a reference camera and use a dark line position in a photo taken by the reference camera as a reference position; A comparison module, used to compare the dark pattern position in the photos taken by other cameras with the reference position to obtain a pixel difference set of each camera; The adjustment module is used to adjust the time of each camera to synchronize with the time of the reference camera according to the pixel difference set of the camera.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the multi-camera time synchronization method according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the multi-camera time synchronization method according to any one of claims 1 to 7.

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