A method and system for dynamic delay calibration of flash units based on Bluetooth in photographic equipment

Abstract

This application provides a method and system for dynamic delay calibration of flash units based on Bluetooth in a photographic device, belonging to the field of wireless communication technology. The method determines the distance dataset between the photographic device and each flash unit using a wireless signal strength detection method, thus identifying signal delay differences between flash units at different spatial locations. Simultaneously, it adjusts the initial signal attenuation coefficient to correct signal delay in response to environmental interference noise, achieving dynamic adjustment to complex and changing communication environments. The adjusted signal delay is used to determine a global synchronization reference time point, which is then used to automatically generate personalized trigger times for each flash unit, achieving dynamic compensation for the delay of each flash unit while ensuring that all flash units trigger accurately at the same time without manual intervention. If any flash unit fails to receive a control command, it retransmits the control command through a backup channel, improving the stability and anti-interference capability of multi-flash wireless network collaboration.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, specifically to a method and system for dynamic delay calibration of flash units based on Bluetooth in photographic equipment. Background Technology

[0002] Currently, in the field of photography, synchronized flash control is a crucial element in ensuring image quality, especially in multi-flash collaboration, where its accuracy directly impacts the quality of the final image. Existing wireless signal-based flash control methods often overlook the complexity and dynamic changes in the communication environment between flash units, making them difficult to adapt to different scenarios in practical use. Particularly in multi-flash collaboration, the instability of wireless signal transmission and the diverse positioning of flash units often cause deviations in flash trigger timing, resulting in uneven brightness or misaligned shadows in the image, affecting the consistency of the final result.

[0003] The information provided in the background section of this application is only for enhancing the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] In view of this, this application provides a method and system for dynamic delay calibration of flash units based on Bluetooth of a photography device, which can realize synchronous triggering of multiple flash units.

[0005] In a first aspect, embodiments of this application provide a method for dynamic delay calibration of flash units based on Bluetooth in a photographic device. The method includes: acquiring the position coordinates of the photographic device and the position coordinates of each flash unit, and determining a distance dataset between the position coordinates of each flash unit and the position coordinates of the photographic device using a wireless signal strength detection method; determining the signal propagation time of each flash unit based on the distance dataset, and determining the signal delay value of each flash unit based on the signal propagation time; acquiring the signal strength and channel occupancy rate of a current noise signal; if the signal strength exceeds a preset noise signal strength threshold, adjusting an initial signal attenuation coefficient based on the current noise signal strength; and adjusting the initial signal attenuation coefficient based on the adjusted signal attenuation rate. The initial signal attenuation coefficient and the channel occupancy rate are used to adjust the signal delay value, and the global synchronization reference time point of the flash is determined based on the adjusted signal delay value. The trigger time offset of each flash is determined based on the global synchronization reference time point, and the trigger time of each flash is determined based on the trigger time offset. The control command of each flash is determined based on the trigger time, and the control command is sent to each flash to output an acknowledgment signal for each flash. If at least one flash fails to output the acknowledgment signal, the current flash is marked as an abnormal flash, and the control command is resent to the abnormal flash using a backup channel.

[0006] Secondly, embodiments of this application provide a dynamic delay calibration system for flash units based on Bluetooth of a photographic device. This system includes: a first acquisition module, a first determination module, a second acquisition module, an adjustment module, a second determination module, a third determination module, and a transmission module. The first acquisition module is used to acquire the position coordinates of the photographic device and the position coordinates of each flash unit, and to determine a distance dataset between the position coordinates of each flash unit and the position coordinates of the photographic device using a wireless signal strength detection method. The first determination module is used to determine the signal propagation time of each flash unit based on the distance dataset, and to determine the signal delay value of each flash unit based on the signal propagation time. The second acquisition module is used to acquire the signal strength and channel occupancy rate of the current noise signal; if the signal strength exceeds a preset noise signal strength threshold, it adjusts the initial signal attenuation coefficient based on the current noise signal strength. The adjustment module is used to adjust the initial signal attenuation coefficient and the channel occupancy rate based on the adjusted initial signal attenuation coefficient. The system comprises: a first module for adjusting the signal delay value and determining the global synchronization reference time point of the flash lamps based on the adjusted signal delay value; a second module for determining the trigger time offset of each flash lamp based on the global synchronization reference time point and determining the trigger time of each flash lamp based on the trigger time offset; a third module for determining the control command of each flash lamp based on the trigger time and sending the control command to each flash lamp to output an acknowledgment signal for each flash lamp; and a sending module for marking the current flash lamp as an abnormal flash lamp and resending the control command to the abnormal flash lamp using a backup channel if at least one flash lamp fails to output the acknowledgment signal.

[0007] This application provides a method and system for dynamic delay calibration of flash units based on Bluetooth in a photographic device. The method determines the distance dataset between the photographic device and each flash unit using a wireless signal strength detection method, thus identifying signal delay differences between flash units at different spatial locations. Simultaneously, it adjusts the initial signal attenuation coefficient to correct signal delay in response to environmental interference noise, achieving dynamic adjustment to complex and changing communication environments. The adjusted signal delay is used to determine a global synchronization reference time point, which is then used to automatically generate personalized trigger times for each flash unit, achieving dynamic compensation for the delay of each flash unit. Furthermore, without manual intervention, it ensures that all flash units trigger accurately at the same time, significantly improving the synchronization accuracy and image quality of multi-flash collaborative shooting. If a flash unit fails to receive a control command, it retransmits the control command through a backup channel, avoiding flash triggering anomalies caused by main channel transmission failures or lost control commands, thus improving the stability and anti-interference capability of multi-flash wireless network collaboration. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a flowchart illustrating an exemplary embodiment of the present application of a method for dynamic delay calibration of a flash based on Bluetooth of a photographic device.

[0010] Figure 2 This is a flowchart illustrating a method for dynamic delay calibration of a camera flash based on Bluetooth, provided in another exemplary embodiment of this application.

[0011] Figure 3 This is a flowchart illustrating a method for dynamic delay calibration of a camera flash based on Bluetooth, provided in another exemplary embodiment of this application.

[0012] Figure 4 This is a flowchart illustrating a method for dynamic delay calibration of a camera flash based on Bluetooth, provided in another exemplary embodiment of this application.

[0013] Figure 5 This is a flowchart illustrating a method for dynamic delay calibration of a camera flash based on Bluetooth, provided in another exemplary embodiment of this application.

[0014] Figure 6 This is a flowchart illustrating a method for dynamic delay calibration of a camera flash based on Bluetooth, provided in another exemplary embodiment of this application.

[0015] Figure 7 This is a flowchart illustrating a method for dynamic delay calibration of a camera flash based on Bluetooth, provided in another exemplary embodiment of this application. Detailed Implementation

[0016] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this application will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this application.

[0017] The terms “a,” “one,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and that other elements / components / etc. may exist in addition to those listed. The terms “first” and “second” are used only as markers and are not a limitation on the number of objects.

[0018] Currently, in the field of photography, synchronized flash control is a crucial element in ensuring image quality, especially in multi-flash collaboration, where its accuracy directly impacts the quality of the final image. Existing wireless signal-based flash control methods often overlook the complexity and dynamic changes in the communication environment between flash units, making them difficult to adapt to different scenarios in practical use. Particularly in multi-flash collaboration, the instability of wireless signal transmission and the diverse positioning of flash units often cause deviations in flash trigger timing, resulting in uneven brightness or misaligned shadows in the image, affecting the consistency of the final result.

[0019] Specifically, due to the varying propagation times of wireless signals at different distances and in different environments, flash units located in different positions receive inconsistent trigger timing commands, leading to flash synchronization issues. Furthermore, this synchronization discrepancy is exacerbated by the physical spatial distribution of flash units, especially in three-dimensional space, where the complexity of wireless signal propagation paths makes relying solely on fixed parameters ineffective. For example, in a large photography studio, flash units close to the camera may respond almost instantly, while distant flash units may trigger with a delay due to longer signal propagation times, ultimately resulting in uneven brightness or misaligned shadows in the image.

[0020] Therefore, how to dynamically adapt to the communication delay differences in different spatial locations in a multi-flash system and achieve precise triggering of all flashes at the same time has become a technical problem that needs to be solved to improve photographic effects.

[0021] This application provides a method for dynamic delay calibration of a flash unit based on Bluetooth in a photographic device, such as... Figure 1 The illustrated method is a dynamic delay calibration method for a camera's flash based on Bluetooth. This method may include the following steps:

[0022] Step S110: Obtain the position coordinates of the camera equipment and each flash unit respectively, and use the wireless signal strength detection method to determine the distance dataset between the position coordinates of each flash unit and the position coordinates of the camera equipment;

[0023] Step S120: Determine the signal propagation time of each flash unit based on the distance dataset, and determine the signal delay value of each flash unit based on the signal propagation time;

[0024] Step S130: Obtain the signal strength and channel occupancy rate of the current noise signal. If the signal strength exceeds the preset noise signal strength threshold, adjust the initial signal attenuation coefficient according to the current noise signal strength.

[0025] Step S140: Adjust the signal delay value according to the adjusted initial signal attenuation coefficient and channel occupancy rate, and determine the global synchronization reference time point of the flash lamp according to the adjusted signal delay value;

[0026] Step S150: Determine the trigger time offset of each flash unit based on the global synchronization reference time point, and determine the trigger time of each flash unit based on the trigger time offset;

[0027] Step S160: Determine the control command for each flash based on the trigger time, and send the control command to each flash to output an acknowledgment signal for each flash.

[0028] Step S170: If at least one flash unit fails to output a confirmation signal, mark the current flash unit as an abnormal flash unit and resend the control command to the abnormal flash unit using the backup channel.

[0029] According to the Bluetooth-based flash dynamic delay calibration method for photographic equipment provided in this application, this method can determine the distance dataset between the photographic equipment and each flash unit by using a wireless signal strength detection method, and determine the signal delay difference of flash units at different locations from a spatial dimension. Simultaneously, it adjusts the initial signal attenuation coefficient to correct signal delay in response to environmental interference noise, achieving dynamic adjustment to complex and changing communication environments. The adjusted signal delay is used to determine the global synchronization reference time point, based on which personalized trigger times are automatically generated for each flash unit, achieving dynamic compensation for the delay of each flash unit. Furthermore, it ensures that all flash units trigger accurately at the same time without manual intervention, significantly improving the synchronization accuracy and image quality of multi-flash collaborative shooting. If a flash unit fails to receive a control command, the control command is retransmitted through a backup channel, avoiding flash triggering abnormalities caused by main channel transmission failure or loss of control commands, thus improving the stability and anti-interference capability of multi-flash wireless network collaboration.

[0030] The following is a detailed description of each step in the flash dynamic delay calibration method based on Bluetooth of a photographic device provided in the embodiments of this application:

[0031] In one embodiment of this application, step S110 involves acquiring the position coordinates of the camera device and the position coordinates of each flash unit, and using a wireless signal strength detection method to determine the distance dataset between the position coordinates of each flash unit and the position coordinates of the camera device. The step also includes the following steps: Figure 2 As shown, the specific content is as follows:

[0032] Step S210: Determine the spatial distribution model between the flash units and the photographic equipment based on the position coordinates of the photographic equipment and the position coordinates of each flash unit;

[0033] Step S220: Based on the spatial distribution model, the signal strength distribution data of the signals emitted by each flash lamp is determined by the wireless signal strength detection method;

[0034] Step S230: Obtain the path loss index of the Bluetooth signal from each flash to the camera device, and determine the distance dataset between the position coordinates of each flash and the position coordinates of the camera device based on the path loss index and signal strength distribution data.

[0035] Specifically, the system database of the photographic equipment can be accessed via an interface to extract the unique device identifier and corresponding 3D position coordinates of each flash unit in the flash unit registration list. These 3D position coordinates can be collected and stored using a GPS module and an altitude sensor. Simultaneously, the position coordinates of the photographic equipment are set as the origin of a Cartesian coordinate system, serving as the reference point for the spatial distribution model. The coordinates of the photographic equipment and each flash unit are mapped to this Cartesian coordinate system to form a complete spatial distribution model of the flash units and the photographic equipment. Next, based on the constructed spatial distribution model, corresponding signal detection parameters are set for the Bluetooth RF module of the photographic equipment (e.g., the detection frequency band is the commonly used 2.4GHz for Bluetooth, and the sampling frequency is 10 times / second). The RSSI values ​​of the Bluetooth broadcast signals emitted by each flash unit are collected in real time using the built-in Bluetooth RF module and Received Signal Strength Indicator (RSSI) detection unit of the photographic equipment. The processed RSSI values ​​are then compared with the unique device identifier and spatial position coordinates of the corresponding flash unit to form signal strength distribution data for the signals emitted by each flash unit. Furthermore, the path loss index of the Bluetooth signal can be matched and determined from a preset environmental parameter library. For example, the path loss exponent is 2 in unobstructed free space scenarios, 2.5~3 in slightly occluded indoor scenarios, and 3~4 in heavily occluded outdoor scenarios. The path loss model is then used as the distance calculation formula, which is as follows:

[0036]

[0037] Where d is the distance (in meters) between the position coordinates of the flash and the position coordinates of the camera, P0 is the Bluetooth signal strength at a reference distance of 1 meter, RSSI is the signal strength value of each flash, and n is the path loss index. The path loss index and signal strength distribution data can be substituted into the formula to calculate the relative distance between each flash and the camera, thus forming a distance dataset.

[0038] For example, the position coordinates of the camera equipment are set to the origin (0,0,0) meters of a three-dimensional Cartesian coordinate system. The position coordinates of flash A (10.5,20.3,5.0) meters, flash B (15.2,18.7,4.8) meters, and flash C (8.3,22.1,4.5) meters are extracted from the preset device registration list. If the current scene is an indoor studio, the signal transmission from the three flashes to the camera equipment follows a straight path without obvious obstacles. Therefore, the coordinates and transmission path characteristics of each flash, along with the origin coordinates of the camera equipment, are mapped to this three-dimensional coordinate system, constructing a spatial distribution model between the flashes and the camera equipment. Next, based on this spatial distribution model, the detection frequency band of the Bluetooth RF module of the photography equipment was set to 2.4GHz, and the sampling frequency was set to 10 times / second. Received Signal Strength Indication (RSSI) values ​​of the Bluetooth signals emitted by the three flashes were collected, yielding RSSI values ​​of -65dBm for flash A, -70dBm for flash B, and -62dBm for flash C. Considering the environmental characteristics of the current indoor photography studio, the path loss index n = 2.5 was determined for the Bluetooth signal from each flash to the photography equipment, and the Bluetooth signal strength P0 = -40dBm was set at a reference distance of 1 meter. Substituting the determined path loss index and the above signal strength distribution data into the path loss model formula, the distances between flash A and the photography equipment were calculated to be 10.0 meters, 15.8 meters, and 7.6 meters, respectively.

[0039] In one embodiment of this application, in step S120, the signal propagation time of each flash unit is determined based on the distance dataset. Specifically, the ambient temperature data and propagation medium, such as medium type and refractive index, of the current shooting scene can be collected using the temperature and humidity sensor and environmental detection module built into the photography equipment. For example, Bluetooth signals are electromagnetic waves, and the propagation medium is air. Then, the signal propagation time corresponding to each flash unit can be calculated using the formula: signal propagation time = distance / signal propagation speed. For example, the distance between flash unit A and the photography equipment is 10.71 meters, and the distance between flash unit B and the photography equipment is 13.43 meters. Simultaneously, the built-in sensor of the photography equipment detects that the current shooting scene is an indoor photography studio, the Bluetooth signal propagation medium is dry air, and the ambient temperature is 25 degrees Celsius. Therefore, the signal propagation speed in the current environment is 2.997 × 10⁻⁶. 8 m / s. Then, according to the formula for signal propagation time, the signal propagation time of each flash was calculated. The signal propagation time of flash A was: 10.71 / 2.997 × 10⁻⁶ m / s. 8 ≈3.573×10 -8 The signal propagation time of flash B is: 13.43 / 2.997 × 10 seconds. 8≈4.481×10 -8 Second.

[0040] In one embodiment of this application, step S120, determining the signal delay value of each flash based on the signal propagation time, further includes the following steps: obtaining the inherent signal delay value of the Bluetooth signal, adding the signal propagation time to the inherent signal delay value of the Bluetooth signal, and using the sum as the signal delay value of each flash. Specifically, the inherent signal delay value of the Bluetooth signal refers to the fixed delay value caused by hardware characteristics and Bluetooth communication protocol layer rules throughout the entire process of the Bluetooth signal being generated and emitted from the Bluetooth communication module of the photographic device, sent to the Bluetooth communication module of the flash for reception, demodulation, protocol parsing, and recognition as a valid signal. Next, the signal propagation time is arithmetically added to the extracted inherent signal delay value of the Bluetooth signal; the result is the signal delay value corresponding to each flash, thus ensuring the authenticity and accuracy of the signal delay value. For example, the extracted inherent signal delay value of the Bluetooth signal is 1.2 × 10⁻⁶. -7 Seconds. The signal propagation time of flash A is 3.573 × 10⁻⁶ seconds. -8 The signal propagation time of flash B is 4.450 × 10 seconds. -8 Seconds. Therefore, the signal delay value of flash A is: 3.573 × 10. -8 Seconds + 1.2 × 10 -7 Seconds = 1.5573 × 10 -7 Seconds; the signal delay value of flash B is: 4.450 × 10 -8 Seconds + 1.2 × 10 -7 Seconds = 1.6450 × 10 -7 Second.

[0041] In one embodiment of this application, step S130 involves obtaining the signal strength and channel occupancy rate of the current noise signal. If the signal strength exceeds a preset noise signal strength threshold, the initial signal attenuation coefficient is adjusted based on the current noise signal strength. The method also includes the following steps: Figure 3 As shown, the specific content is as follows:

[0042] Step S310: Based on the current noise signal strength, determine the difference between the current noise signal strength and the preset noise signal strength threshold;

[0043] Step S320: Obtain the initial signal attenuation coefficient and adjust the initial signal attenuation coefficient according to the difference between the noise signal intensity and the preset noise signal intensity threshold.

[0044] Specifically, the environmental parameters of the 2.4GHz Bluetooth communication band can be collected in real time using the built-in radio frequency detection module and wireless noise sensor of the camera equipment. The noise signal strength is measured in dBm, and channel occupancy is collected as a percentage. Channel occupancy data can be detected in real time using Bluetooth band carrier sensing technology, calculating the percentage of time the Bluetooth channel is occupied by other devices per unit of time as the current channel occupancy data. Instantaneous extreme value removal processing can be performed on the collected noise data to eliminate abnormal values ​​caused by sudden environmental interference. The average of multiple consecutive valid values ​​is taken as the current noise signal strength, ensuring data authenticity and stability. Subsequently, a preset noise signal strength threshold is obtained from the camera equipment's system parameter library. The preset noise signal strength threshold can be set according to different Bluetooth models and the actual Bluetooth signal transmission requirements of the shooting scenario (such as studio or outdoor shooting), ensuring the critical noise strength for normal transmission of Bluetooth control commands. If the current noise signal strength exceeds the preset noise signal strength threshold, it is determined that the noise strength exceeds the standard, and the initial signal attenuation coefficient is adjusted; if the current noise signal strength does not exceed the preset noise signal strength threshold, it is determined that the noise environment meets the requirements, and the initial signal attenuation coefficient remains unchanged.

[0045] Furthermore, the initial signal attenuation coefficient of the Bluetooth signal can be obtained from the system parameter library of the camera device. Its physical value range is 0-1 (1 represents no signal attenuation, and 0 represents complete signal attenuation). Subsequently, the initial signal attenuation coefficient is dynamically adjusted using a linear adjustment formula, which is: Adjusted initial signal attenuation coefficient = Initial signal attenuation coefficient × (1 + Difference between noise signal strength and preset noise signal strength threshold / Absolute value of preset noise signal strength threshold).

[0046] For example, the preset noise signal strength threshold is -80dBm, and the initial signal attenuation coefficient is 0.8. The built-in RF detection module of the camera can perform real-time noise signal strength acquisition in the Bluetooth 2.4GHz operating band. After 10 consecutive acquisitions and removal of instantaneous extreme values, the effective average value of the current noise signal strength is obtained as -75dBm. The difference between the current noise signal strength and the preset noise signal strength threshold is calculated to be 5dBm, and the absolute value of the preset noise signal strength threshold is 80dBm. Substituting these parameters into the linear adjustment formula, the adjusted initial signal attenuation coefficient is calculated to be 0.85. The reasonableness of this adjustment result within the 0-1 value range can be verified; if it falls within a reasonable range, it is considered a valid result. Finally, the new signal attenuation coefficient of 0.85 can be stored in the camera's system parameter library for later retrieval in conjunction with channel occupancy rate adjustments to the initial time delay estimate.

[0047] In one embodiment of this application, step S140, which adjusts the signal delay value based on the adjusted initial signal attenuation coefficient and channel occupancy rate, further includes the following steps: Figure 4 As shown, the specific content is as follows:

[0048] Step S410: Calculate the change between the adjusted initial signal attenuation coefficient and the initial signal attenuation coefficient, and determine the correction coefficient based on the change and the channel occupancy rate;

[0049] Step S420: Adjust the signal delay value according to the correction factor.

[0050] Specifically, the change in signal attenuation coefficient due to excessive noise and channel occupancy, two core environmental factors affecting Bluetooth signal transmission delay, can be quantified and fused to generate a unified correction coefficient. Therefore, the correction coefficient = (1 + the change between the initial signal attenuation coefficient and the initial signal attenuation coefficient) × (1 + channel occupancy / 100%), and the adjusted signal delay value = signal delay value × correction coefficient. For example, if the initial signal attenuation coefficient is set to 0.8, the adjusted initial signal attenuation coefficient is 0.85, the channel occupancy is 60%, and the current Bluetooth signal delay is 10 milliseconds, the change in the current signal attenuation coefficient = 0.85 - 0.8 = 0.05. Substituting the change and channel occupancy into the correction coefficient calculation formula, we get the correction coefficient = (1 + 0.05) × (1 + 0.6) = 1.68. Then, multiplying the signal delay value of 10 milliseconds by the correction coefficient 1.68, we get the adjusted signal delay value: 10 × 1.68 = 16.8 milliseconds.

[0051] In one embodiment of this application, step S140, which determines the global synchronization reference time point of the flash lamp based on the adjusted signal delay value, further includes the following steps: Figure 5 As shown, the specific content is as follows:

[0052] Step S510: Sort the adjusted signal delay values ​​in order from minimum to maximum to generate a delay sequence, and use the minimum signal delay value in the delay sequence as the synchronization reference time point;

[0053] Step S520: Obtain the timestamp of the flash corresponding to the synchronization reference time point and the timestamps of the other flashes respectively. Use the timestamp of the flash corresponding to the synchronization reference time point as the global synchronization reference time point, and adjust the timestamps of the other flashes according to the global synchronization reference time point.

[0054] Specifically, the adjusted signal delay values ​​for all flashes can be obtained from the photographic equipment, along with a unique device identifier for each flash. Then, a lightweight sorting algorithm adapted to the computing power of IoT chips, such as bubble sort or simple selection sort, is used. This algorithm is logically simple, highly real-time, and involves no complex non-linear calculations, meeting the real-time synchronization requirements of the photographic equipment. All adjusted signal delay values ​​are sorted in ascending order from minimum to maximum, generating a delay sequence containing the device ID, adjusted signal delay value, and sequence position. The minimum signal delay value is extracted from the generated delay sequence and used as the synchronization reference time point. The flash device identifier corresponding to this minimum value is recorded and stored in the system's temporary cache. The flash corresponding to this minimum signal delay value is least affected by wireless interference and signal transmission distance, exhibiting optimal Bluetooth signal transmission delay. Using this as the synchronization reference time point reduces errors in subsequent multi-flash synchronization and improves overall synchronization accuracy.

[0055] Furthermore, the timestamp of the flash corresponding to the synchronization reference time point is obtained, along with the corresponding timestamps of all other flashes. These timestamps are real-time records of the time each flash's Bluetooth module receives the signal from the photographic device, measured in milliseconds. The timestamp of the flash corresponding to the synchronization reference time point is then directly set as the global synchronization reference time point, which is the time at which all flashes finally achieve synchronized triggering. Next, the difference between the adjusted signal delay value of each of the other flashes and the synchronization reference time point is calculated. This difference represents the quantified amount of time that the other flashes need to trigger earlier due to transmission delay differences. The calculation formula is: Timestamp Adjustment Difference = Flash Adjusted Signal Delay Value - Synchronization Reference Time Point. Finally, the original timestamp of each of the other flashes is subtracted from the corresponding timestamp adjustment difference to achieve precise adjustment of the flash timestamps, aligning all flash timestamps with the global synchronization reference time point.

[0056] For example, the adjusted signal delay values ​​of flash A, flash B, and flash C after environmental compensation are 2.5 ms, 3.8 ms, and 1.2 ms, respectively. These adjusted signal delay values ​​are sorted in ascending order from minimum to maximum, generating a delay sequence: {Flash C: 1.2 ms, Flash A: 2.5 ms, Flash B: 3.8 ms}. The minimum signal delay value of 1.2 ms in this delay sequence can be extracted as the synchronization reference time point, and the flash corresponding to this value is recorded as flash C. Subsequently, the timestamps of flash C (999.8 ms), flash A (1000.0 ms), and flash B (1001.5 ms) corresponding to the synchronization reference time point are obtained respectively. The timestamp of flash C (999.8 ms) is directly set as the global synchronization reference time point. Next, calculate the difference between the adjusted signal delay values ​​of flash A and flash B and the synchronization reference time point. The difference for flash A is 2.5 ms - 1.2 ms = 1.3 ms, and the difference for flash B is 3.8 ms - 1.2 ms = 2.6 ms. Then, subtract the corresponding difference from the timestamps of flash A and flash B respectively to obtain the initial adjusted timestamp of flash A as 998.7 ms and the initial adjusted timestamp of flash B as 998.9 ms.

[0057] In the above method, under wireless networking scenarios, by using a delay sequence and selecting the minimum delay value as the synchronization reference time point, the flash unit least affected by environmental interference and signal transmission distance is accurately selected as the synchronization reference, reducing the error of multi-flash synchronization and improving synchronization accuracy. Furthermore, lightweight algorithms such as bubble sort are used to adapt to the computing power of the IoT chip in the photographic equipment, ensuring the real-time and automated nature of the sorting process. By setting the timestamp of the flash unit corresponding to the synchronization reference time point as the global synchronization reference time point, a unified time reference is provided for the synchronization of multiple flash units, further ensuring that the alignment accuracy between all flash unit timestamps and the global synchronization reference time point meets the actual needs of multi-flash collaborative shooting.

[0058] In one embodiment of this application, step S150, which determines the trigger time offset of each flash based on the global synchronization reference time point, further includes the following step: subtracting the global synchronization reference time point from the adjusted signal delay value, and using the result of the subtraction as the trigger time offset of each flash. Specifically, the global synchronization reference time point is the unified time target for all flashes to achieve synchronized flashing. The adjusted signal delay value corresponding to each flash is the delay data after noise and channel occupancy compensation, which can truly reflect the actual Bluetooth signal transmission delay of each flash. Next, the time when the photographic device sends the trigger control command to the flash is advanced to the trigger time offset time before the global synchronization reference time point. After receiving the trigger command, the flash completes signal transmission, parsing, and response after adjusting its own signal delay value, and finally flashes precisely at the global synchronization reference time point, thus achieving compensation and cancellation for the transmission delay of each flash.

[0059] For example, if the global synchronization reference time is 1002.0 milliseconds, and the adjusted signal delay values ​​for each flash are: {Flash A: 2.5 milliseconds, Flash B: 3.8 milliseconds, Flash C: 1.2 milliseconds}, then the trigger time offset for Flash A = 1002.0 milliseconds - 2.5 milliseconds = 999.5 milliseconds; the trigger time offset for Flash B = 1002.0 milliseconds - 3.8 milliseconds = 998.2 milliseconds; and the trigger time offset for Flash C = 1002.0 milliseconds - 1.2 milliseconds = 1000.8 milliseconds.

[0060] In one embodiment of this application, step S150, which determines the trigger time of each flash lamp based on the trigger time offset, further includes the following steps: Figure 6 As shown, the specific content is as follows:

[0061] Step S610: Obtain the initial trigger time of each flash unit;

[0062] Step S620: Subtract the initial trigger time from the trigger time offset to determine the trigger time of each flash unit;

[0063] Step S630: If the deviation between the trigger time and the global synchronization reference time exceeds the preset deviation threshold, the trigger time of each flash is adjusted using the weighted average method.

[0064] Specifically, the synchronization accuracy of trigger time can be improved through deviation threshold verification. Trigger times exceeding the threshold are adjusted using a weighted average method to ensure that the deviation of all flash trigger times from the global synchronization reference time point meets the accuracy requirements of multi-flash collaborative shooting. The preset deviation threshold is set based on the synchronization requirements of multi-flash collaborative shooting to avoid uneven brightness and misaligned shadows in the captured image, while also considering the wireless transmission accuracy of the Bluetooth 2.4GHz band. The preset deviation threshold also needs to be dynamically adapted according to the flash usage scenario, taking into account the degree of environmental interference, the number of flashes, and the spatial distribution distance. For example, the preset deviation threshold can be increased for multiple Bluetooth devices coexisting and long-distance transmission. Conversely, it can be decreased for enclosed studios and unobstructed short-distance transmission. The calculated deviation value is compared with the preset deviation threshold. If the deviation value does not exceed the preset deviation threshold, the trigger time is directly used as the final trigger time for that flash; if the deviation value exceeds the preset deviation threshold, a weighted average method is used to adjust the initial trigger time. The global synchronization reference time point is given a high weight, and the trigger time is given a low weight. The formula for the weighted average method is: Adjusted trigger time = Global synchronization reference time point × Weight corresponding to the global synchronization reference time point + Trigger time × Weight corresponding to the trigger time.

[0065] For example, the preset deviation threshold is set to 0.3 milliseconds, the weight corresponding to the global synchronization reference time point is 0.9, the weight corresponding to the trigger time is 0.1, and the global synchronization reference time point is 1002.0 milliseconds. The initial trigger times of flash X, flash Y, and flash Z are obtained as 1003.0 milliseconds, 1002.5 milliseconds, and 1004.0 milliseconds respectively. The trigger time offsets for flash X, Y, and Z are 3.4 milliseconds, 1.8 milliseconds, and 4.2 milliseconds. The calculated trigger times are: 1003.0 - 3.4 = 999.6 milliseconds; 1002.5 - 1.8 = 1000.7 milliseconds; and 1004.0 - 4.2 = 999.8 milliseconds. The deviation between the trigger time of each flash and the global synchronization reference time is calculated using the formula. The deviation for flash X is |999.6 - 1002.0| = 2.4 milliseconds, for flash Y it is |1000.7 - 1002.0| = 1.3 milliseconds, and for flash Z it is |999.8 - 1002.0| = 2.2 milliseconds. All three deviations exceed the preset deviation threshold of 0.3 milliseconds. Therefore, according to the weighted average algorithm, the adjusted trigger time for flash X is: 1002.0 × 0.9 + 999.6 × 0.1 = 1001.76 milliseconds; the adjusted trigger time for flash Y is: 1002.0 × 0.9 + 1000.7 × 0.1 = 1001.87 milliseconds; and the adjusted trigger time for flash Z is: 1002.0 × 0.9 + 999.8 × 0.1 = 1001.78 milliseconds. The deviation values ​​for flash X, Y, and Z were recalculated to be 0.24 milliseconds, 0.13 milliseconds, and 0.22 milliseconds, respectively. It can be seen that none of these values ​​exceed the preset deviation threshold, thus confirming that the accuracy requirements are met.

[0066] In one embodiment of this application, in steps S160-S170, the control command for each flash is determined based on the trigger time, and the control command is sent to each flash to output an acknowledgment signal for each flash. If at least one flash fails to output an acknowledgment signal, the current flash is marked as an abnormal flash, and the control command is resent to the abnormal flash using a backup channel. Specifically, a standardized control command adapted for Bluetooth communication can be generated based on the unique device identifier of each flash and the final trigger time. Subsequently, the photographic device distributes the encapsulated control command to all flashes in batches via the Bluetooth wireless broadcast channel.

[0067] Furthermore, after receiving the control command, the Bluetooth communication module of each flash unit verifies the check code. If the verification is successful, it is determined that the command transmission is error-free, and then a confirmation signal is sent back to the photography equipment. This signal includes the flash unit's unique device identifier and the command reception timestamp. If the verification fails, the transmission is abandoned. The confirmation signals of each flash unit are received and counted in real time within the preset feedback timeout period.

[0068] Furthermore, if no acknowledgment signal is received from a particular flash unit within the preset feedback timeout period, the flash unit is deemed to have failed to receive the command, and its unique device identifier is marked as an abnormal flash unit. Subsequently, a pre-stored Bluetooth backup communication channel is retrieved, and the control command transmission method is switched from the main channel's broadcast mode to a point-to-point directional transmission mode. A standardized control command, identical to the original command, is sent separately to the abnormal flash unit's device identifier. Directional transmission improves the success rate of command reception for abnormal flash units and avoids signal dispersion issues associated with broadcasting from the main channel. After the abnormal flash unit's Bluetooth communication module receives the retransmission command from the backup channel, the verification process is repeated. Upon successful verification, an acknowledgment signal is immediately sent back to the camera device. Upon receiving this signal, the camera device corrects the status of the corresponding abnormal flash unit to "received." If no acknowledgment signal is received after multiple retransmissions, the flash unit's device status is marked as faulty and logged for subsequent manual troubleshooting, ensuring that the synchronous triggering of other normal flash units is not affected.

[0069] In one embodiment of this application, after retransmitting the control command to the faulty flashlight using a backup channel in step S170, the following steps are also included: Figure 7 As shown, the specific content is as follows:

[0070] Step S710: Obtain the transmission delay of the backup channel and the historical feedback delay of the backup channel, and based on the transmission delay and historical feedback delay of the backup channel, use the Kalman filter method to determine the predicted value of the trigger time error of the abnormal flash lamp.

[0071] Step S720: Update the trigger time corresponding to the abnormal flash according to the trigger time error prediction value, and update the control command of each flash according to the updated trigger time corresponding to the abnormal flash;

[0072] Step S730: If all flash units output a confirmation signal, then the synchronization triggering mechanism is activated so that all flash units execute the trigger command at the same time.

[0073] Specifically, the transmission delay of the backup channel can be acquired in real time through a Bluetooth radio frequency detection module, and the continuously acquired values ​​are averaged to eliminate instantaneous signal fluctuation errors. Then, the historical feedback delay of the backup channel is obtained from the system database. These two values ​​are used as observed and predicted values, respectively, and substituted into the Kalman filter algorithm for iterative calculation. Finally, a predicted value for the abnormal flash trigger time error, which quantifies the deviation caused by the backup channel transmission characteristics, is obtained. The trigger time of this flash is updated based on the predicted trigger time error value, and the control commands for all flashes are updated synchronously. The trigger time of normal flashes remains unchanged, while only the trigger time of abnormal flashes is updated. This ensures the consistency and integrity of the control command format, improves the efficiency of control command updates, and ensures that the trigger time of abnormal flashes is aligned with the global synchronization reference time point. When all flashes are in the received state and the confirmation signal from the abnormal flash contains a CRC32 (Cyclic Redundancy Check) verification message indicating a new control command has passed, the synchronization triggering mechanism based on the global synchronization reference time is immediately initiated. A synchronization triggering command containing a precise timestamp is sent to all flashes, enabling all flashes to complete time calibration based on their updated trigger times and execute the triggering command at the same time. If there are still flashes in the statistics table that have not output a confirmation signal, the system will repeat the process of retransmitting through the backup channel, Kalman filtering error prediction, and updating the trigger time and control command until all flashes have completed the confirmation reception, ensuring that no device is missed.

[0074] For example, with a global synchronization reference time of 1002.0 milliseconds, the trigger times of flash A, flash B, flash C, and flash D are 1001.728 milliseconds, 1001.91 milliseconds, 1001.704 milliseconds, and 1001.85 milliseconds, respectively. The backup channel is Bluetooth channel 38 in the 2.4GHz band. Flash D is an abnormal flash. The real-time transmission delay of the backup channel 38 was continuously collected five times using the Bluetooth RF detection module, yielding values ​​of 0.7 milliseconds, 0.8 milliseconds, 0.9 milliseconds, 0.8 milliseconds, and 0.8 milliseconds, respectively. The average value was taken to obtain a backup channel transmission delay of 0.8 milliseconds. The historical feedback delay of the backup channel is 0.6 milliseconds. These two values ​​are used as the observed value and the state prediction value, respectively, and substituted into the Kalman filter method for iterative calculation, resulting in a predicted trigger time error of 0.2 milliseconds for the abnormal flash D. Next, the trigger time of flash D is reduced by 0.2 milliseconds from 1001.85 milliseconds to obtain its updated trigger time of 1001.65 milliseconds. Then, the control commands for all flashes are updated synchronously. The trigger times of flashes A, B, and C remain unchanged; only the trigger time parameter of flash D is updated. The new command still encapsulates the device's unique identifier, device response rate, and CRC32 cyclic redundancy check code according to the Bluetooth 2.4GHz communication protocol. Finally, the updated control command is resent to flash D through backup channel 38. After completing the CRC32 check, flash D sends back a confirmation signal containing its own device identifier and receiving timestamp to the photographic equipment. After confirming that flashes A, B, C, and D have all output confirmation signals, a synchronous triggering mechanism with 1002.0 milliseconds as the core time point is immediately initiated. Synchronous triggering commands containing precise timestamps are issued to all flashes. All flashes complete time calibration based on their corresponding trigger times, and finally execute the trigger command at the same moment at the global synchronization reference time of 1002.0 milliseconds, achieving high-precision synchronous flashing of multiple flashes.

[0075] This application also provides a flash dynamic delay calibration system based on Bluetooth of a photographic device. The system may include a first acquisition module, a first determination module, a second acquisition module, an adjustment module, a second determination module, a third determination module, and a transmission module. The first acquisition module is used to acquire the position coordinates of the photographic device and the position coordinates of each flash, and uses a wireless signal strength detection method to determine the distance dataset between the position coordinates of each flash and the position coordinates of the photographic device. The first determination module is used to determine the signal propagation time of each flash based on the distance dataset, and determine the signal delay value of each flash based on the signal propagation time. The second acquisition module is used to acquire the signal strength and channel occupancy rate of the current noise signal; if the signal strength exceeds a preset noise signal strength threshold, it adjusts the initial signal attenuation coefficient based on the current noise signal strength. The adjustment module is used to adjust the initial signal attenuation coefficient based on the adjusted initial signal attenuation coefficient. The system comprises three modules: a first module for adjusting the signal delay value based on the number of flashes and channel occupancy, and a second module for determining the trigger time offset of each flash based on the global synchronization reference time, and a third module for determining the control command of each flash based on the trigger time and sending the control command to each flash to output an acknowledgment signal for each flash; and a fourth module for marking the current flash as an abnormal flash and resending the control command to the abnormal flash using a backup channel if at least one flash fails to output an acknowledgment signal.

[0076] It should be noted that the embodiments of the flash dynamic delay calibration system based on Bluetooth of photographic equipment provided in this application can be used to execute the processing flow of the embodiments of the flash dynamic delay calibration method based on Bluetooth of photographic equipment in the above embodiments. Its functions will not be repeated here, but can be referred to the detailed description of the above method embodiments.

[0077] This application also provides an electronic device, which includes one or more processors and memory resources represented by a memory for storing instructions executable by the processor, such as application programs. The application programs stored in the memory may include one or more modules, each corresponding to a set of instructions. Furthermore, the processor is configured to execute instructions to perform the aforementioned flash dynamic delay calibration method based on Bluetooth of a photographic device.

[0078] The electronic device may also include a power supply component configured to perform power management of the electronic device, a wired or wireless network interface configured to connect the electronic device to a network, and an input / output (I / O) interface. The electronic device can be operated based on operating devices stored in memory, such as Windows Server™, Mac OS X™, Unix™, Linux™, FreeBSD™, or similar.

[0079] In one embodiment, a computer device, which may be a server, is also provided. The computer device includes a processor, memory, input / output interfaces (I / O), and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is connected to the system bus via the I / O interfaces. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the computer device stores data. The I / O interfaces of the computer device are used for exchanging information between the processor and external devices. The communication interface of the computer device is used for communicating with external terminals via a network connection. When the computer program is executed by the processor, it implements a dynamic time-delay calibration method for a camera's flash based on Bluetooth.

[0080] In one embodiment, a computer device is provided, which may be a terminal. The computer device includes a processor, memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface of the computer device is used for exchanging information between the processor and external devices. The communication interface of the computer device is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for dynamic time-delay calibration of a flash unit based on Bluetooth in a photographic device. The display unit of the computer device is used to form a visually visible image and may be a display screen, a projection device, or a virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0081] This application also provides a non-transitory computer-readable storage medium, which, when the instructions in the storage medium are executed by the processor of the electronic device, enables the electronic device to perform a dynamic delay calibration method for a camera device's flash based on Bluetooth.

[0082] This application may take the form of a computer program product implemented on one or more storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing program code. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to: phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0083] It should be noted that although the steps of the Bluetooth-based flash dynamic delay calibration method for photographic devices in this application are described in a specific order in the accompanying drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps, such as omitting certain steps, combining multiple steps into one step, and / or breaking down one step into multiple steps, should all be considered part of this application.

[0084] It should be understood that this application is not limited to the detailed structure and arrangement of the module in the Bluetooth-based flash dynamic delay calibration system for photographic equipment proposed in this specification. This application can have other implementations and can be implemented and executed in various ways. The foregoing variations and modifications fall within the scope of this application. It should be understood that the application and definition of this application extend to all alternative combinations of two or more individual features mentioned or apparent in the text and / or drawings. All these different combinations constitute multiple alternative aspects of this application.

Claims

1. A method for dynamic delay calibration of a flash unit based on Bluetooth in a photographic device, characterized in that, include: The position coordinates of the camera device and each flash unit are obtained respectively, and the distance data between the position coordinates of each flash unit and the position coordinates of the camera device is determined by the wireless signal strength detection method. The signal propagation time of each flash is determined based on the distance dataset, and the signal delay value of each flash is determined based on the signal propagation time. The signal strength and channel occupancy rate of the current noise signal are obtained. If the signal strength exceeds a preset noise signal strength threshold, the initial signal attenuation coefficient is adjusted according to the current noise signal strength. The signal delay value is adjusted based on the adjusted initial signal attenuation coefficient and the channel occupancy rate, and the global synchronization reference time point of the flash is determined based on the adjusted signal delay value. The trigger time offset of each flash is determined based on the global synchronization reference time point, and the trigger time of each flash is determined based on the trigger time offset. The control command for each of the flashes is determined based on the trigger time, and the control command is sent to each of the flashes to output an acknowledgment signal for each of the flashes; If at least one of the flashlights fails to output the confirmation signal, the current flashlight is marked as an abnormal flashlight, and the control command is resent to the abnormal flashlight using a backup channel.

2. The method for dynamic delay calibration of flash based on Bluetooth of photographic equipment according to claim 1, characterized in that, The distance dataset determined using the wireless signal strength detection method to determine the position coordinates of each flash unit and the position coordinates of the photographic device includes: A spatial distribution model between the flash units and the photographic equipment is determined based on the position coordinates of the photographic equipment and the position coordinates of each flash unit. Based on the spatial distribution model, the signal strength distribution data of the signals emitted by each of the flashlights are determined by the wireless signal strength detection method. The path loss index of the Bluetooth signal from each of the flashes to the camera device is obtained, and the distance dataset between the position coordinates of each flash and the position coordinates of the camera device is determined based on the path loss index and the signal strength distribution data.

3. The method for dynamic delay calibration of flash based on Bluetooth of photographic equipment according to claim 2, characterized in that, Determining the signal delay value of each flash lamp based on the signal propagation time includes: Obtain the inherent signal delay value of the Bluetooth signal, add the signal propagation time to the inherent signal delay value of the Bluetooth signal, and use the sum as the signal delay value of each flash.

4. The method for dynamic delay calibration of flash based on Bluetooth of a photographic device according to claim 1, characterized in that, The step of adjusting the initial signal attenuation coefficient according to the current noise signal strength includes: Based on the current noise signal strength, determine the difference between the current noise signal strength and the preset noise signal strength threshold; Obtain the initial signal attenuation coefficient, and adjust the initial signal attenuation coefficient according to the difference between the noise signal intensity and the preset noise signal intensity threshold.

5. The method for dynamic delay calibration of flash based on Bluetooth of a photographic device according to claim 1, characterized in that, The step of adjusting the signal delay value based on the adjusted initial signal attenuation coefficient and the channel occupancy rate includes: Calculate the change between the adjusted initial signal attenuation coefficient and the initial signal attenuation coefficient, and determine the correction coefficient based on the change and the channel occupancy rate; The signal delay value is adjusted according to the correction factor.

6. The method for dynamic delay calibration of flash based on Bluetooth of a photographic device according to claim 1, characterized in that, Determining the global synchronization reference time point of the flash based on the adjusted signal delay value includes: The adjusted signal delay values ​​are sorted in order from minimum to maximum to generate a delay sequence, and the minimum signal delay value in the delay sequence is used as the synchronization reference time point. The timestamps of the flash corresponding to the synchronization reference time point and the timestamps of the other flashes are obtained respectively. The timestamp of the flash corresponding to the synchronization reference time point is used as the global synchronization reference time point, and the timestamps of the other flashes are adjusted according to the global synchronization reference time point.

7. The method for dynamic delay calibration of flash based on Bluetooth of photographic equipment according to claim 1, characterized in that, The step of determining the trigger time offset of each flash lamp based on the global synchronization reference time point includes: The global synchronization reference time point is subtracted from the adjusted signal delay value, and the result of the subtraction is used as the trigger time offset of each flash lamp.

8. The method for dynamic delay calibration of flash based on Bluetooth of a photographic device according to claim 1, characterized in that, Determining the trigger time of each flash based on the trigger time offset includes: Obtain the initial trigger time of each of the aforementioned flashlights; The trigger time of each flash is determined based on the trigger time offset and the initial trigger time; If the deviation between the trigger time and the global synchronization reference time exceeds a preset deviation threshold, the trigger time of each flash lamp is adjusted using a weighted average method.

9. The method for dynamic delay calibration of flash based on Bluetooth of a photographic device according to claim 1, characterized in that, After retransmitting the control command to the malfunctioning flashlight using a backup channel, the method further includes: The transmission delay of the backup channel and the historical feedback delay of the backup channel are obtained, and based on the transmission delay of the backup channel and the historical feedback delay, the Kalman filter method is used to determine the predicted trigger time error value of the abnormal flash lamp. The trigger time corresponding to the abnormal flash is updated according to the predicted trigger time error value, and the control command of each flash is updated according to the updated trigger time corresponding to the abnormal flash. If all the flash units output the confirmation signal, a synchronization triggering mechanism is activated so that all the flash units execute the trigger command at the same time.

10. A dynamic delay calibration system for flash units based on Bluetooth in photographic equipment, characterized in that, include: The first acquisition module is used to acquire the position coordinates of the camera device and the position coordinates of each flash, and to determine the distance dataset between the position coordinates of each flash and the position coordinates of the camera device using a wireless signal strength detection method. The first determining module is used to determine the signal propagation time of each of the flash lamps based on the distance dataset, and to determine the signal delay value of each of the flash lamps based on the signal propagation time; The second acquisition module is used to acquire the signal strength and channel occupancy rate of the current noise signal. If the signal strength exceeds a preset noise signal strength threshold, the initial signal attenuation coefficient is adjusted according to the current noise signal strength. The adjustment module is used to adjust the signal delay value according to the adjusted initial signal attenuation coefficient and the channel occupancy rate, and to determine the global synchronization reference time point of the flash lamp according to the adjusted signal delay value; The second determining module is used to determine the trigger time offset of each of the flash lamps based on the global synchronization reference time point, and to determine the trigger time of each of the flash lamps based on the trigger time offset. The third determining module is used to determine the control command of each of the flash lamps according to the trigger time, and send the control command to each of the flash lamps to output the confirmation reception signal of each of the flash lamps; The transmitting module is configured to mark the current flash as an abnormal flash if at least one of the flashes fails to output the confirmation signal, and to retransmit the control command to the abnormal flash using a backup channel.

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