CN111556224B - Multi-camera synchronous calibration method, device and system - Google Patents
Multi-camera synchronous calibration method, device and system Download PDFInfo
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- CN111556224B CN111556224B CN202010428647.XA CN202010428647A CN111556224B CN 111556224 B CN111556224 B CN 111556224B CN 202010428647 A CN202010428647 A CN 202010428647A CN 111556224 B CN111556224 B CN 111556224B
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Abstract
The embodiment of the invention provides a multi-camera synchronous calibration method, a multi-camera synchronous calibration device and a multi-camera synchronous calibration system, wherein the multi-camera synchronous calibration device comprises a processor, a synchronous trigger module, a digital tube timing module and a storage module, wherein the processor is used for respectively determining the synchronous signal sending time corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set; the processor is further used for sending a first synchronization signal to the synchronization triggering module according to the synchronization signal sending time in the synchronization signal sending time set and starting the digital tube timing module to start timing, wherein the first synchronization signal is used for indicating the synchronization triggering module to send multi-channel pulse signals at different times obtained by timing of the digital tube timing module so as to achieve the purpose that the plurality of cameras finish shooting pictures at the same time. By adopting the scheme, the time delay error between the cameras is reduced, and the synchronism between the multiple cameras is ensured.
Description
Technical Field
The embodiment of the invention relates to the technical field of camera calibration, in particular to a multi-camera synchronous calibration method, device and system.
Background
With the development of scientific technology, the use of multiple cameras for capturing image data is involved in many application fields (such as the field of aerial photogrammetry, the field of vehicle-mounted mobile photogrammetry and the field of real-time monitoring of industrial automation production processes).
When a plurality of cameras are used for acquiring image data, each camera can shoot according to the received pulse trigger signal after receiving the pulse trigger signal. After shooting is finished, a plurality of photos are obtained, and the obtained photos are sent to a remote server to be stored for subsequent use. In the field of multi-camera application, the requirement on synchronism of photo shooting is high, and generally the requirement is limited to be below millisecond level.
However, due to individual differences among the cameras, the time taken by each camera from the time when the pulse trigger signal is received to the time when the picture is taken is different, and a certain delay error exists, so that the synchronism among the multiple cameras is influenced.
Disclosure of Invention
The embodiment of the invention provides a multi-camera synchronous calibration method, device and system, which ensure the synchronism among multiple cameras.
In a first aspect, an embodiment of the present invention provides a multi-camera synchronization calibration apparatus, including: the device comprises a processor, a synchronous trigger module, a digital tube timing module and a storage module, wherein a plurality of lengths to be calibrated are stored in the storage module, each length to be calibrated corresponds to one camera to be calibrated, the number of the digital tube timing modules is multiple, each camera corresponds to one digital tube timing module,
the processor is connected with the digital tube timing module corresponding to each camera;
the processor is connected with the storage module and the synchronous trigger module, and the synchronous trigger module is externally connected with a plurality of cameras to be calibrated;
the processor is used for respectively determining the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set;
the processor is further configured to send a first synchronization signal to the synchronization trigger module according to a synchronization signal sending time in the synchronization signal sending time set, and start the digital tube timing module to start timing, where the first synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals at different times obtained by timing with the digital tube timing module, so that multiple cameras complete shooting pictures at the same time.
Optionally, the method further includes: the processor is further configured to send a second synchronization signal to the synchronization trigger module, where the second synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals to the multiple cameras at the same time, so that the multiple cameras start shooting at the same time, and at a time when the multiple cameras start shooting at the same time, start the digital tube timing modules corresponding to the multiple cameras to start timing, so as to obtain multiple first times; the second synchronization signal is further used for indicating a digital tube timing module corresponding to each camera to stop timing when shooting of the camera is completed, and a plurality of second moments are obtained; the processor is used for determining the time length to be calibrated of each camera according to the first time and the second time corresponding to each camera, and storing the time length to be calibrated in the storage module.
Optionally, the method further includes: the processor is further configured to send a second synchronization signal to the synchronization trigger module every preset duration to obtain multiple groups of first time and second time corresponding to each camera; sending a plurality of groups of first moments and second moments corresponding to each camera to a server, so that the server determines a plurality of initial time lengths to be calibrated corresponding to each camera according to the plurality of groups of first moments and second moments corresponding to each camera, and calculates an average value according to the plurality of initial time lengths to be calibrated to obtain the time length to be calibrated corresponding to each camera; the processor is further configured to receive the time length to be calibrated corresponding to each camera returned by the server, and store the time length to be calibrated in the storage module.
Optionally, the method further includes: the processor is used for switching off a Global Positioning System (GPS) signal of the synchronous trigger module to a real-time clock (RTC) for timing, and sending a third synchronous signal by the RTC, wherein the third synchronous signal is used for indicating the synchronous trigger module to send a multi-path pulse signal so as to enable a plurality of cameras after calibration to finish shooting photos; the processor is also used for determining the delay error of each path of pulse triggered by the synchronous trigger module according to the pulse output time of each path of pulse and the photo shooting completion time; the processor is further configured to store the delay error of each path of pulse triggered by the synchronous trigger module into the storage module.
Optionally, the method further includes: the processor is used for sending a third synchronous signal to the synchronous trigger module every other preset time length to obtain a plurality of groups of pulse output time and photo shooting completion time corresponding to each path of pulse; the processor is further configured to send a plurality of groups of pulse output times and photo shooting completion times corresponding to each pulse to a server, so that the server determines a plurality of initial delay errors of the synchronous trigger module according to the plurality of groups of pulse output times and the photo shooting completion times corresponding to each pulse, and calculates an average value according to the plurality of initial delay errors to obtain a delay error of each pulse corresponding to the synchronous trigger module; the processor is further configured to receive a delay error of each path of pulse corresponding to the synchronous trigger module returned by the server, and store the delay error in the storage module.
Optionally, the synchronous trigger module is one or more of a GPS signal generator, a function signal generator, encoder pulses, stepper motor pulses, a PPS signal pulse generator, or a PLC pulse generator.
In a second aspect, an embodiment of the present invention provides a multi-camera synchronization system, including: the device comprises a plurality of cameras, a storage module, a processor, a digital tube timing module and a synchronous trigger module, wherein the storage module stores a plurality of to-be-calibrated durations, each to-be-calibrated duration corresponds to one camera to be calibrated, the number of digital tube timing modules is multiple, each camera corresponds to one digital tube timing module, and the processor is connected with the digital tube timing module corresponding to each camera; the processor is connected with the storage module, the processor is also connected with the synchronous trigger module, and the synchronous trigger module is connected with a plurality of cameras to be calibrated; the processor is used for respectively determining the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set; the processor is further configured to send a first synchronization signal to the synchronization trigger module according to a synchronization signal sending time in the synchronization signal sending time set, and start the digital tube timing module to start timing, where the first synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals at different times obtained by timing with the digital tube timing module, so that multiple cameras complete shooting pictures at the same time.
Optionally, the system further includes a server, where the server is configured to receive multiple sets of first time and second time corresponding to each camera, determine multiple initial time durations to be calibrated corresponding to each camera according to the multiple sets of first time and second time corresponding to each camera, and calculate an average value according to the multiple initial time durations to be calibrated to obtain the time duration to be calibrated corresponding to each camera; the server is further configured to return the to-be-calibrated duration corresponding to each camera to the processor, so that the processor stores the to-be-calibrated duration corresponding to each camera in the storage module.
In a third aspect, an embodiment of the present invention provides a multi-camera synchronous calibration method, which is applied to a multi-camera synchronous calibration device, where the device includes a processor, a synchronous trigger module, a plurality of digital tube timing modules, one digital tube timing module corresponding to each camera, a storage module, and a digital tube timing module corresponding to each camera, where the processor is connected to the digital tube timing module corresponding to each camera, the processor is connected to the storage module, the processor is connected to the synchronous trigger module, and the synchronous trigger module is externally connected to a plurality of cameras, and includes: the processor respectively determines the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set; the processor also sends a first synchronization signal to the synchronization triggering module according to the synchronization signal sending time in the synchronization signal sending time set, and starts the digital tube timing module to start timing, wherein the first synchronization signal is used for indicating the synchronization triggering module to send multi-path pulse signals at different times obtained by timing according to the digital tube timing module, so that the plurality of cameras finish shooting pictures at the same time.
Optionally, the method further includes: the processor sends a second synchronous signal to the synchronous trigger module, wherein the second synchronous signal is used for indicating the synchronous trigger module to send a plurality of paths of pulse signals to the plurality of cameras simultaneously so that the plurality of cameras start shooting simultaneously, and at the moment when the plurality of cameras start shooting simultaneously, the digital tube timing modules corresponding to the plurality of cameras are started to start timing to obtain a plurality of first moments; the second synchronous signal indicates that the digital tube timing modules corresponding to the cameras stop timing when the shooting of the cameras is finished, so that a plurality of second moments are obtained; and the processor determines the time length to be calibrated of each camera according to the first time and the second time.
After the scheme is adopted, the processor can determine the sending time of a pulse signal according to the determined time length to be calibrated of each camera, start the timer to time, and then respectively and sequentially trigger the synchronous trigger modules according to the determined sending time of the pulse signal, so that the synchronous trigger modules respectively send the pulse signals to the cameras corresponding to the time length to be calibrated at different times obtained by the timing of the timer, finally, the multi-path cameras finish shooting at the same time, the time delay error among the cameras is reduced, and the synchronism among the multi-cameras is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a multi-camera synchronous calibration device according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a process of completing shooting by a camera according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an application of a camera calibration process provided in an embodiment of the present specification;
fig. 4 is a flowchart illustrating steps of a multi-camera synchronization calibration method provided in an embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In the prior art, the moment when the camera performs photographing after receiving the trigger pulse is the default moment when the camera completes one frame of image, however, in practical application, the camera uses a mechanical shutter to complete the photographing of the image, and a certain delay error exists between the moment when the camera performs photographing after receiving the trigger pulse and the moment when the camera completes one frame of image, which affects the synchronism among the multiple cameras.
In addition, it is also described in the prior art that the line frequency for modifying the line scanning camera is used for realizing the synchronous control, but the types of the cameras may be various, the working principle of each camera is different, the applicability of the improvement simply performed on one type of camera is not strong, and when the cameras needing the synchronous control have a plurality of types, the configuration process is complicated, errors are easy to occur, the accuracy of the synchronous control is reduced, the scheme of the application does not need to be directed to a certain type of camera, the scheme can be applied to the cameras of various types, the configuration process is simple, and the accuracy of the synchronous control is improved.
Fig. 1 is a schematic structural diagram of a multi-camera synchronous calibration apparatus provided in an embodiment of the present invention, as shown in fig. 1, including: the calibration device comprises a processor 101, a synchronous trigger module 102, a digital tube timing module 105 and a storage module 103, wherein a plurality of to-be-calibrated durations are stored in the storage module 103, each to-be-calibrated duration corresponds to a camera 104 to be calibrated one by one, the number of the digital tube timing modules 105 is multiple, each camera 104 corresponds to one digital tube timing module 105, and the processor 101 is connected with the digital tube timing module 105 corresponding to each camera 104.
The processor 101 is connected to the storage module 103, the processor 101 is further connected to the synchronization triggering module 102, and the synchronization triggering module 102 is externally connected to a plurality of cameras 104.
The processor 101 is configured to determine, according to the to-be-calibrated duration stored in the storage module 103, the synchronization signal sending time corresponding to each camera 104, so as to obtain a synchronization signal sending time set.
The processor 101 is further configured to send a first synchronization signal to the synchronization trigger module 102 according to a synchronization signal sending time in the synchronization signal sending time set, and start the vial timing module 105 to start timing, where the first synchronization signal is used to instruct the synchronization trigger module 102 to send multiple pulse signals at different times obtained by timing according to the vial timing module 105, so that the multiple cameras 104 complete shooting photos at the same time.
Specifically, as shown in fig. 2, a schematic diagram of a process of completing shooting by a camera according to an embodiment of the present invention specifically includes three processes, where the camera starts shooting and completes shooting after receiving a pulse signal and responding to the pulse signal, and the three processes correspond to three times, i.e., T1, T2, and T3, respectively. The time taken for each camera to complete shooting by the camera after receiving the pulse signal is different due to individual differences between the cameras. I.e., the duration of time taken from T3 to T1 is different. For cameras of the same model, the error of the time length used by each camera from the time when the pulse signal is received to the time when the camera finishes shooting is within an acceptable range. For cameras of different brands or different models, the error ratio between the used time lengths of each camera from the time when each camera receives the pulse signal to the time when the camera finishes shooting is larger, and the requirement of scenes with higher requirements on the synchronism of the cameras cannot be met. Therefore, the test needs to be performed according to a plurality of groups of cameras with different models, and the time length to be calibrated of each group of cameras is determined. Wherein the time length to be calibrated is determined according to the time length from the pulse trigger received by each camera to the time length from the time when the camera shutter finishes shooting.
The storage module may be a memory provided in the processor, or may be a separately deployed memory. The processor may be a CPLD processor.
For example, in a specific example, as shown in table 1, after receiving the trigger pulse signal sent by the synchronous trigger module 102, the camera performs photographing at a time T1, and completes photographing of one frame of image at a time T3. Taking three groups of cameras, i.e., a camera 1, a camera 2 and a camera 3 as an example, each camera is tested three times respectively, and the average photographing time of each camera is determined. In order to obtain more accurate Δ t, more sets of camera shooting data may be sampled. And then determining the average shooting time length of each camera according to the multiple groups of camera shooting data. I.e. the shooting duration of the camera can be defaulted.
For camera 1, Δ t1 obtained is 0.9s, which indicates that the camera needs 0.9s from the time when the trigger signal is received to the time when the photographing is completed. Similarly, Δ t2 of camera 2 is 1.07s, and Δ t3 of camera 3 is 0.96 s. Therefore, the time period to be calibrated for the camera to perform photographing has already been determined. Specifically, the time length to be calibrated of the camera 1 is delayed by 0.1s, the time length to be calibrated of the camera 2 is advanced by 0.07s, and the time length to be calibrated of the camera 3 is delayed by 0.04 s.
Based on Δ t1 being 0.9s, processor 101 feeds back 0.1s to sync trigger module 102 so that sync trigger module 102 can issue sync pulse signal 1 with a delay of 0.1s at 1 s. That is, T1 is 1.1s to trigger camera 1 to take a picture, and camera 1 finishes taking a picture at the time T3 is 1.1s +0.9s is 2 s.
Similarly, based on Δ t2 being 1.07s, processor 101 feeds back 0.07s to sync trigger module 102 so that sync trigger module 102 can issue sync pulse signal 2 0.07s earlier at 1 s. That is, T1 is 0.93s to trigger camera 2 to take a picture, and camera 2 finishes taking a picture at the time T3 is 0.93s +1.07s is 2 s.
Similarly, based on Δ t3 being 0.96s, processor 101 feeds back 0.04s to synchronization trigger module 102, so that synchronization trigger module 102 may issue synchronization trigger module 103 with a delay of 0.04s at 1 s. That is, T1 is 1.04s to trigger the camera 3 to take a picture, and the camera 3 finishes taking a picture at the time T3 is 0.96s +1.04s is 2 s. Through the above operations, the photographing of the camera 1, the camera 2 and the camera 3 which are originally completed at different times is completed at the same time.
The above example is only 3 cameras, and the process of achieving the synchronization of photographing for a plurality of groups of cameras is the same as the above principle.
TABLE 1
After the scheme is adopted, the processor can determine the pulse signal sending time according to the determined time length to be calibrated of each camera, and then sequentially trigger the synchronous trigger modules respectively according to the determined pulse signal sending time, so that the synchronous trigger modules respectively send pulse signals to the cameras corresponding to the time length to be calibrated at different times, and finally, the multi-path cameras finish shooting at the same time, the delay error among the cameras is reduced, and the synchronism among the multiple cameras is ensured.
The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.
In a specific embodiment, the apparatus may further include:
the processor 101 is further configured to send a second synchronization signal to the synchronization triggering module 102, where the second synchronization signal is used to instruct the synchronization triggering module 102 to send multiple pulse signals to the multiple cameras 104 at the same time, so that the multiple cameras 104 start shooting at the same time, and at a time when the multiple cameras 104 start shooting at the same time, start the digital tube timing modules 105 corresponding to the multiple cameras 104 to start timing, so as to obtain multiple first times.
The second synchronization signal is further configured to instruct the digital tube timing module 105 corresponding to each camera 104 to stop timing when the shooting by the camera 104 is completed, so as to obtain a plurality of second moments.
The processor 101 is configured to determine a time length to be calibrated of each camera 104 according to the first time and the second time corresponding to each camera 104, and store the time length to be calibrated in the storage module.
Specifically, in the process of determining the time length to be calibrated of each camera, the time length used by the camera 104 from the time when the pulse is received to the time when the camera shutter completes shooting needs to be recorded by the digital tube timing module 105. The length of time to be calibrated corresponding to each camera 104 is then determined according to the length of time that each camera 104 takes to complete shooting of the camera shutter after receiving the pulse trigger. The nixie tube timing module 105 may be a nixie tube timer.
As shown in fig. 3, an application diagram of a camera calibration process provided in the embodiment of the present disclosure is provided, in this example, three groups of cameras are taken as an example, and a digital tube timing module, which may be a digital tube timer, is correspondingly allocated to each camera. The synchronization triggering module 102 outputs a pulse according to a second synchronization signal sent by the processor 101, and records a pulse output time T1, the pulse is divided into three paths and input to the 3 cameras and the corresponding three digital tube timers, and the 3 cameras and the corresponding three digital tube timers receive the pulse signal at the same time. The nixie tube timer starts timing, wherein the nixie tube timer can be timed and displayed with an accuracy of 0.00001 s. After receiving the pulse signal, the 3 cameras start the shutter to take a picture, finish taking a picture, and record the current photographing time T3 through image data. For the trigger time T1 and the photographing completion time T3 of each camera, the difference Δ T may be determined as T3-T1, and Δ T may be defaulted to the self-delay error of the camera. And further determining the time length to be calibrated of each camera according to the self-delay error of each camera.
In addition, the processor is further configured to send a second synchronization signal to the synchronization trigger module every preset duration to obtain multiple sets of first time and second time corresponding to each camera;
sending a plurality of groups of first moments and second moments corresponding to each camera to a server, so that the server determines a plurality of initial time lengths to be calibrated corresponding to each camera according to the plurality of groups of first moments and second moments corresponding to each camera, and calculates an average value according to the plurality of initial time lengths to be calibrated to obtain the time length to be calibrated corresponding to each camera;
the processor is further configured to receive the time length to be calibrated corresponding to each camera returned by the server, and store the time length to be calibrated in the storage module.
Specifically, in order to improve the accuracy of the time length to be calibrated, multiple sets of tests may be performed on each camera. The processor sends a second synchronization signal to the synchronization triggering module every other preset time length to obtain multiple groups of first time and second time, namely multiple groups of T1 and T3, corresponding to each camera, and sends acquired data to the server, and the server determines an average value of self-delay errors of each camera according to the multiple groups of T1 and T3, and further determines the time length to be calibrated of each camera according to the average value of the self-delay errors of each camera. Wherein, the error of the time length to be calibrated can be 0-0.00002 s. In this example, the error of the time period to be calibrated is 0.00001 s. The preset duration may be set to 1-3 s. The photos corresponding to the multiple groups of T1 and T3 can also be transmitted to the server together with the T1 and the T3.
In addition, the pictures taken by each camera and the corresponding sets of T1 and T3 may be transmitted to the server through a web portal or USB. Wherein, the USB may be USB 3.0.
In the prior art, on the premise of acquiring the synchronous frame period of each sensor, a brief scheme of how to synchronize each sensor is realized is not described in detail, and how to acquire the frame period is not described, and how to acquire specific parameters and analyze and process signals is not described.
In one embodiment, the synchronization triggering module may be one or more of a GPS signal generator, a function signal generator, an encoder pulse, a stepper motor pulse, a PPS signal pulse generator, or a PLC pulse generator. The synchronous trigger modules can accurately give out multiple trigger pulses, and the multiple trigger pulses are completely synchronous in time.
In addition, in a specific example, the GPS synchronous trigger which can be based on the ARM-CPLD is composed of an ARM-CPLD module and an RTC module. The basic working principle is as follows: when the GPS signal is normal, the synchronous trigger receives the PPS signal of the GPS receiver, reads the GPS information and calibrates the RTC clock on the board to judge whether the trigger condition is met, and when the preset trigger condition is met, the synchronous trigger signals are correspondingly output in sequence according to the time length to be calibrated, so that a plurality of cameras finish the shooting of photos at the same time.
In addition, in a specific embodiment, the method further comprises the following steps:
the processor is configured to send a third synchronization signal by an RTC (Real-Time Clock) when a GPS (Global Positioning System) signal of the synchronization trigger module is switched off and the RTC is switched to the RTC, where the third synchronization signal is used to instruct the synchronization trigger module to send a multi-path pulse signal, so that a plurality of calibrated cameras complete shooting of photos.
The processor is also used for determining the delay error of each path of pulse triggered by the synchronous trigger module according to the pulse output time of each path of pulse and the photo shooting completion time.
The processor is further configured to store the delay error of each path of pulse triggered by the synchronous trigger module into the storage module.
In addition, the method can further comprise the following steps:
the processor is used for sending a third synchronous signal to the synchronous trigger module every other preset time length to obtain a plurality of groups of pulse output time and photo shooting completion time corresponding to each path of pulse.
The processor is further used for sending the multiple groups of pulse output time and the photo shooting completion time corresponding to each path of pulse to the server, so that the server determines multiple initial delay errors of the synchronous trigger module according to the multiple groups of pulse output time and the photo shooting completion time corresponding to each path of pulse, calculates an average value according to the multiple initial delay errors, and obtains the delay error of each path of pulse corresponding to the synchronous trigger module.
The processor is further configured to receive a delay error of each path of pulse corresponding to the synchronous trigger module returned by the server, and store the delay error in the storage module.
Specifically, the self-delay of the camera can be corrected, and the self-generated pulse delay depending on the RTC mode can be corrected. For example, when the GPS signal is unlocked and the synchronizer cannot receive the PPS signal of the GPS receiver, the synchronizer is switched to the RTC mode, the CPLD counter and the RTC module on the board continue to output the extended time service pulse and the serial port time information, and an error is generated by a timing system generated by the RTC completely. The calibration and correction of the system depend on the pulse delay generated by the RTC mode, and the calibration and correction must be carried out on the premise that the self-delay calibration of the camera is finished. When a GPS signal exists in the system, a plurality of data samples are collected in an operation mode, the image data samples do not have delay errors, the GPS signal is cut off in the collection process, the system is switched to RTC timing, the pulse time T1 output by each path of pulse has the delay errors, the time error delta T can be obtained by checking the corresponding photo of the corresponding pulse time, the time error delta T is T3-T1, the average value of the delta T is calculated through the collected data samples, and the delay errors of the pulses generated by the RTC timing are obtained. The delay error is written into the storage module, and when the system is switched from the GPS time tick to the RTC time tick, the RTC delay compensation value stored in the storage module is called, so that the synchronization precision requirement between each camera is ensured when the cameras shoot.
In the prior art, only the technical scheme suitable for calibrating the imaging time precision of all optical remote sensing cameras based on GPS hardware pulse per second signals is disclosed, the application range is narrow, the method is not limited by the GPS signals, the triggering can be realized by pulse signals, and powerful guarantee is provided for realizing synchronous control.
In addition, the synchronous calibration device can be deployed in a camera, and a synchronous camera is obtained. The method specifically comprises the following steps: the device comprises a camera, a storage module, a processor and a synchronous trigger module, wherein the storage module is used for storing the time length to be calibrated of the camera, the storage module is connected with the processor, the processor is connected with the synchronous trigger module, and the synchronous trigger module is connected with the camera.
The processor is used for determining the synchronous signal sending time corresponding to the camera according to the time length to be calibrated stored in the storage module.
The processor is further configured to send a first synchronization signal to the synchronization trigger module according to the sending time of the synchronization signal, where the first synchronization signal is used to instruct the synchronization trigger module to send a pulse signal according to the to-be-calibrated duration. When the camera is used for shooting with other cameras, the shooting of photos can be completed simultaneously.
In addition, a multi-camera synchronization system can be formed according to a plurality of synchronous cameras, and specifically, the multi-camera synchronization system can include: the device comprises a plurality of cameras, a storage module, a processor, a digital tube timing module and a synchronous trigger module, wherein each time length to be calibrated corresponds to one of the cameras to be calibrated, the digital tube timing modules are multiple, each camera corresponds to one digital tube timing module, and the processor is connected with each digital tube timing module corresponding to the camera.
The processor is connected with the storage module, the processor is also connected with the synchronous trigger module, and the synchronous trigger module is connected with a plurality of cameras to be calibrated;
the processor is used for respectively determining the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set;
the processor is further configured to send a first synchronization signal to the synchronization trigger module according to a synchronization signal sending time in the synchronization signal sending time set, and start the digital tube timing module to start timing, where the first synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals at different times obtained by timing with the digital tube timing module, so that multiple cameras complete shooting pictures at the same time.
The multi-camera synchronization system can be applied to the field with higher requirements on the synchronization of multi-picture shooting, and the pictures at multiple angles or multiple directions can be shot simultaneously. In addition, the shot pictures are sent to the service terminal for storage. When the photos are needed to be used subsequently, the photos can be directly obtained from the service terminal, so that the storage time length and the safety of the photos are increased, and the convenience of obtaining the photos is improved.
In one embodiment, a server is also included,
the server is used for receiving the multiple groups of first time and second time corresponding to each camera, determining multiple initial time lengths to be calibrated corresponding to each camera according to the multiple groups of first time and second time corresponding to each camera, and calculating an average value according to the multiple initial time lengths to be calibrated to obtain the time length to be calibrated corresponding to each camera.
The server is further configured to return the to-be-calibrated duration corresponding to each camera to the processor, so that the processor stores the to-be-calibrated duration corresponding to each camera in the storage module.
The server is used for receiving the multiple groups of first time and second time corresponding to each camera through a network port or a USB.
The embodiment of the specification also provides a method corresponding to the device, which is used for realizing the photographing synchronism among the multiple cameras.
As shown in fig. 4, a flowchart of steps of a multi-camera synchronous calibration method provided in an embodiment of this specification may be applied to a multi-camera synchronous calibration device, where the device includes a processor, a synchronous trigger module, a vial timing module and a storage module, where the vial timing module is multiple, each camera corresponds to one vial timing module, the processor is connected to the vial timing module corresponding to each camera, the processor is connected to the synchronous trigger module, and the synchronous trigger module is externally connected to multiple cameras, where the method specifically includes:
s401, the processor respectively determines the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module, and a synchronous signal sending time set is obtained.
S402, the processor further sends a first synchronization signal to the synchronization trigger module according to the synchronization signal sending time in the synchronization signal sending time set, and starts the digital tube timing module to start timing, wherein the first synchronization signal is used for indicating the synchronization trigger module to send multi-channel pulse signals at different times obtained by timing of the digital tube timing module, so that the plurality of cameras finish shooting pictures at the same time.
After the scheme is adopted, the processor can determine the pulse signal sending time according to the determined time length to be calibrated of each camera, and then sequentially trigger the synchronous trigger modules respectively according to the determined pulse signal sending time, so that the synchronous trigger modules respectively send pulse signals to the cameras corresponding to the time length to be calibrated at different times, and finally, the multi-path cameras finish shooting at the same time, the delay error among the cameras is reduced, and the synchronism among the multiple cameras is ensured.
In a specific embodiment, the method further comprises:
the processor sends a second synchronous signal to the synchronous trigger module, the second synchronous signal is used for indicating the synchronous trigger module to send multi-channel pulse signals to the plurality of cameras simultaneously so that the plurality of cameras start shooting simultaneously, and at the moment when the plurality of cameras start shooting simultaneously, the digital tube timing modules corresponding to the plurality of cameras are started to start timing to obtain a plurality of first moments.
And the second synchronous signal indicates that the digital tube timing modules corresponding to the plurality of cameras stop timing when the shooting of the cameras is finished, so that a plurality of second moments are obtained.
And the processor determines the time length to be calibrated of each camera according to the first time and the second time.
The method can realize that a plurality of cameras synchronously complete the shooting of the photos according to the time length to be calibrated of each camera, and can meet the accuracy requirement of synchronism among the cameras. Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A multi-camera synchronous calibration device, comprising: the device comprises a processor, a synchronous trigger module, a digital tube timing module and a storage module, wherein a plurality of to-be-calibrated durations are stored in the storage module, each to-be-calibrated duration corresponds to a camera to be calibrated one by one, the number of the digital tube timing modules is multiple, and each camera corresponds to one digital tube timing module, wherein the to-be-calibrated duration is determined according to the duration from the time when each camera receives pulse trigger to the time when a camera shutter finishes shooting;
the processor is connected with the digital tube timing module corresponding to each camera;
the processor is connected with the storage module and the synchronous trigger module, and the synchronous trigger module is externally connected with a plurality of cameras to be calibrated;
the processor is used for respectively determining the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set;
the processor is further configured to send a first synchronization signal to the synchronization trigger module according to a synchronization signal sending time in the synchronization signal sending time set, and start the digital tube timing module to start timing, where the first synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals at different times obtained by timing with the digital tube timing module, so that multiple cameras complete shooting pictures at the same time.
2. The apparatus of claim 1, further comprising:
the processor is further configured to send a second synchronization signal to the synchronization trigger module, where the second synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals to the multiple cameras at the same time, so that the multiple cameras start shooting at the same time, and at a time when the multiple cameras start shooting at the same time, start the digital tube timing modules corresponding to the multiple cameras to start timing, so as to obtain multiple first times;
the second synchronization signal is further used for indicating a digital tube timing module corresponding to each camera to stop timing when shooting of the camera is completed, and a plurality of second moments are obtained;
the processor is used for determining the time length to be calibrated of each camera according to the first time and the second time corresponding to each camera, and storing the time length to be calibrated in the storage module.
3. The apparatus of claim 2, further comprising:
the processor is further configured to send a second synchronization signal to the synchronization trigger module every preset duration to obtain multiple groups of first time and second time corresponding to each camera;
sending a plurality of groups of first moments and second moments corresponding to each camera to a server, so that the server determines a plurality of initial time lengths to be calibrated corresponding to each camera according to the plurality of groups of first moments and second moments corresponding to each camera, and calculates an average value according to the plurality of initial time lengths to be calibrated to obtain the time length to be calibrated corresponding to each camera;
the processor is further configured to receive the time length to be calibrated corresponding to each camera returned by the server, and store the time length to be calibrated in the storage module.
4. The apparatus of claim 1, further comprising:
the processor is used for switching off a Global Positioning System (GPS) signal of the synchronous trigger module and switching to a real-time clock (RTC) for timing, and the RTC sends a third synchronous signal, wherein the third synchronous signal is used for indicating the synchronous trigger module to send a plurality of paths of pulse signals so that a plurality of cameras after calibration are finished complete the shooting of photos; the processor is also used for determining the delay error of each path of pulse triggered by the synchronous trigger module according to the pulse output time of each path of pulse and the photo shooting completion time;
the processor is further configured to store the delay error of each path of pulse triggered by the synchronous trigger module into the storage module.
5. The apparatus of claim 4, further comprising:
the processor is used for sending a third synchronous signal to the synchronous trigger module every other preset time length to obtain a plurality of groups of pulse output time and photo shooting completion time corresponding to each path of pulse;
the processor is further configured to send a plurality of groups of pulse output times and photo shooting completion times corresponding to each pulse to a server, so that the server determines a plurality of initial delay errors of the synchronous trigger module according to the plurality of groups of pulse output times and the photo shooting completion times corresponding to each pulse, and calculates an average value according to the plurality of initial delay errors to obtain a delay error of each pulse corresponding to the synchronous trigger module;
the processor is further configured to receive a delay error of each path of pulse corresponding to the synchronous trigger module returned by the server, and store the delay error in the storage module.
6. The apparatus of claim 1, wherein the synchronization trigger module is one or more of a GPS signal generator, a function signal generator, an encoder pulse, a stepper motor pulse, a PPS signal pulse generator, or a PLC pulse generator.
7. A multi-camera synchronization system, comprising: the device comprises a plurality of cameras, a storage module, a processor, a digital tube timing module and a synchronous trigger module, wherein the storage module stores a plurality of to-be-calibrated durations, each to-be-calibrated duration corresponds to one to each camera to be calibrated, the number of the digital tube timing modules is multiple, each camera corresponds to one digital tube timing module, and the to-be-calibrated duration is determined according to the duration from the time when each camera receives pulse trigger to the time when the camera shutter completes shooting;
the processor is connected with the digital tube timing module corresponding to each camera;
the processor is connected with the storage module, the processor is also connected with the synchronous trigger module, and the synchronous trigger module is connected with a plurality of cameras to be calibrated;
the processor is used for respectively determining the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set;
the processor is further configured to send a first synchronization signal to the synchronization trigger module according to a synchronization signal sending time in the synchronization signal sending time set, and start the digital tube timing module to start timing, where the first synchronization signal is used to instruct the synchronization trigger module to send multiple pulse signals at different times obtained by timing with the digital tube timing module, so that multiple cameras complete shooting pictures at the same time.
8. The system of claim 7, further comprising a server,
the server is used for receiving multiple groups of first time and second time corresponding to each camera, determining multiple initial time lengths to be calibrated corresponding to each camera according to the multiple groups of first time and second time corresponding to each camera, and calculating an average value according to the multiple initial time lengths to be calibrated to obtain the time length to be calibrated corresponding to each camera;
the server is further configured to return the to-be-calibrated duration corresponding to each camera to the processor, so that the processor stores the to-be-calibrated duration corresponding to each camera in the storage module.
9. The multi-camera synchronous calibration method is applied to a multi-camera synchronous calibration device, the device comprises a processor, a synchronous trigger module, a digital tube timing module and a storage module, the number of the digital tube timing modules is multiple, each camera corresponds to one digital tube timing module, the processor is connected with the digital tube timing module corresponding to each camera, the processor is connected with the storage module, the processor is connected with the synchronous trigger module, and the synchronous trigger module is externally connected with a plurality of cameras, and the method comprises the following steps:
the processor respectively determines the sending time of the synchronous signal corresponding to each camera according to the time length to be calibrated stored in the storage module to obtain a synchronous signal sending time set; the time length to be calibrated is determined according to the time length from the time when each camera receives the pulse trigger to the time when the camera shutter finishes shooting;
the processor also sends a first synchronization signal to the synchronization triggering module according to the synchronization signal sending time in the synchronization signal sending time set, and starts the digital tube timing module to start timing, wherein the first synchronization signal is used for indicating the synchronization triggering module to send multi-path pulse signals at different times obtained by timing according to the digital tube timing module, so that the plurality of cameras finish shooting pictures at the same time.
10. The method of claim 9, further comprising:
the processor sends a second synchronous signal to the synchronous trigger module, wherein the second synchronous signal is used for indicating the synchronous trigger module to send a plurality of paths of pulse signals to the plurality of cameras simultaneously so that the plurality of cameras start shooting simultaneously, and at the moment when the plurality of cameras start shooting simultaneously, the digital tube timing modules corresponding to the plurality of cameras are started to start timing to obtain a plurality of first moments;
the second synchronous signal indicates that the digital tube timing modules corresponding to the cameras stop timing when the shooting of the cameras is finished, so that a plurality of second moments are obtained;
and the processor determines the time length to be calibrated of each camera according to the first time and the second time.
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| CN112461042B (en) * | 2020-11-19 | 2022-10-18 | 福建卓航特种设备有限公司 | Synchronous percussion performance correction device and correction method |
| EP4272424A4 (en) * | 2021-02-01 | 2024-03-06 | Huawei Technologies Co., Ltd. | A system for wireless synchronized capturing, and a smart device |
| CN113285579B (en) * | 2021-05-28 | 2022-05-03 | 普源精电科技股份有限公司 | Synchronization method of multichannel signals, power supply module, electronic equipment and power supply equipment |
| CN113824889B (en) * | 2021-11-24 | 2022-03-11 | 山东信通电子股份有限公司 | Method and equipment for monitoring hidden danger of power transmission line |
| CN114785326B (en) * | 2022-06-20 | 2023-02-24 | 成都理工大学 | Synchronous triggering system of electricity experiment data recording equipment |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104503306A (en) * | 2014-11-26 | 2015-04-08 | 北京航空航天大学 | Multi-camera synchronous triggering device and control method |
| CN104764442A (en) * | 2015-04-15 | 2015-07-08 | 中测新图(北京)遥感技术有限责任公司 | Method and device for determining exposure time of aerial photogrammetric camera in light-small unmanned aerial vehicle |
| CN107168163A (en) * | 2017-05-27 | 2017-09-15 | 西安工业大学 | A kind of submicrosecond Multi-path synchronous triggering device and its triggering method |
| CN107277389A (en) * | 2017-08-09 | 2017-10-20 | 山东科技大学 | Digital Photogrammetric System polyphaser dynamic synchronization exposure circuit and method based on FPGA |
| CN107991654A (en) * | 2016-10-27 | 2018-05-04 | 北京遥感设备研究所 | A kind of method for weather radar servo-information and intermediate-freuqncy signal synchronous acquisition |
| CN111757018A (en) * | 2020-06-22 | 2020-10-09 | 季华实验室 | Camera group synchronous exposure control method and system, computer readable storage medium and camera group control system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10104284B2 (en) * | 2014-09-19 | 2018-10-16 | Huawei Technologies Co., Ltd. | Method and apparatus for determining photographing delay time, and photographing device |
-
2020
- 2020-05-20 CN CN202010428647.XA patent/CN111556224B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104503306A (en) * | 2014-11-26 | 2015-04-08 | 北京航空航天大学 | Multi-camera synchronous triggering device and control method |
| CN104764442A (en) * | 2015-04-15 | 2015-07-08 | 中测新图(北京)遥感技术有限责任公司 | Method and device for determining exposure time of aerial photogrammetric camera in light-small unmanned aerial vehicle |
| CN107991654A (en) * | 2016-10-27 | 2018-05-04 | 北京遥感设备研究所 | A kind of method for weather radar servo-information and intermediate-freuqncy signal synchronous acquisition |
| CN107168163A (en) * | 2017-05-27 | 2017-09-15 | 西安工业大学 | A kind of submicrosecond Multi-path synchronous triggering device and its triggering method |
| CN107277389A (en) * | 2017-08-09 | 2017-10-20 | 山东科技大学 | Digital Photogrammetric System polyphaser dynamic synchronization exposure circuit and method based on FPGA |
| CN111757018A (en) * | 2020-06-22 | 2020-10-09 | 季华实验室 | Camera group synchronous exposure control method and system, computer readable storage medium and camera group control system |
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