A method and system for determining a fly-by trigger point

Abstract

The present application relates to the technical field of flying shutter trigger point, and particularly relates to a flying shutter trigger point determination method and system, which comprises the following steps: acquiring a system trigger delay time and a camera exposure time, the trigger delay time being a time from a trigger signal being sent to the camera receiving the trigger signal; determining a target imaging position of the flying shutter; collecting instantaneous motion state parameters of a motion axis at the same time when the trigger signal is sent, including a current axis position, instantaneous speed and acceleration; calculating a position offset of an actual imaging position of the flying shutter relative to a trigger signal sending position according to the instantaneous motion state parameters, the trigger delay time and the camera exposure time through a kinematics model; and determining a corresponding target trigger point position according to the target imaging position and the position offset. The present application collects instantaneous motion state parameters of a motion axis at a trigger time, calculates a position offset of flying shutter imaging to determine a target trigger point position, and is suitable for application scenarios without fixed trigger points and variable speed operation.

Description

Technical Field

[0001] This invention relates to the field of aerial photography trigger point technology, and in particular to a method and system for determining the trigger point of aerial photography. Background Technology

[0002] In the field of industrial vision inspection and positioning, "flying camera" refers to an imaging method where the camera, controlled by a trigger signal, completes exposure and image acquisition during the relative motion between the imaging camera and the object under test. This allows for image acquisition without interrupting the motion process, significantly improving production inspection efficiency and is widely used in industrial scenarios such as tape inspection, high-speed mounting, and die-cutting positioning. The flying camera trigger point refers to the physical position corresponding to the axis of motion of the object under test at the moment the trigger signal is issued. Due to the inherent hardware delays in trigger signal transmission, camera response, and exposure, there is a deviation between the physical position of the object under test and the trigger point when the camera actually images the image. This deviation increases with increasing motion speed, directly affecting the positional accuracy of the image in high-precision positioning scenarios.

[0003] Currently, the commonly used method for calibrating drone position deviation is the static comparison calibration method. This method involves pre-selecting a fixed shooting position, acquiring static reference images and dynamic images of the same location, comparing pixel differences of the same feature and converting them into physical position deviations, which are then used as fixed compensation parameters to correct the trigger position. This method relies on fixed shooting points for calibration and is only suitable for scenarios where the shooting position is fixed and the movement speed is constant. For scenarios where the shooting position is dynamically generated, there are no fixed trigger points, or the motion axis moves at varying speeds, dynamic deviation calibration and compensation cannot be achieved, significantly limiting its application scope and making it difficult to guarantee the positioning accuracy of drone imaging.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] In view of at least one of the above technical problems, the present invention provides a method and system for determining the trigger point of a drone, which adopts real-time acquisition of the instantaneous motion state of the motion axis and combines it with a kinematic model to calculate the imaging position offset, so as to determine the trigger point of the drone in dynamic scenes.

[0006] This invention provides a method for determining the trigger point of a flying camera, comprising the following steps: The system trigger delay time t0 and the camera exposure time t1 are obtained, wherein the trigger delay time t0 is the time from when the trigger signal is sent to when the camera receives the trigger signal; Determine the target imaging position (pt) for aerial photography; At the same time as the trigger signal is issued, the instantaneous motion state parameters of the motion axis are collected, including the current axis position p1, instantaneous velocity v1, and acceleration a1; Based on the instantaneous motion state parameters, combined with the trigger delay time t0 and the camera exposure time t1, the position offset of the actual imaging position pa of the aerial photography relative to the position where the trigger signal was emitted is calculated using a kinematic model. Based on the target imaging position pt and the position offset, the corresponding target trigger point p is determined.

[0007] Furthermore, the instantaneous motion state parameters of the motion axis are collected, including: Set an initial trigger point p0, and control the motion axis to emit a trigger signal when it passes the initial trigger point. At the same time as the trigger signal is emitted, the instantaneous motion state parameters of the motion axis are collected synchronously.

[0008] Further, the calculation of the position offset using a kinematic model includes: Based on the positional distance between the axis position p1 and the initial trigger point p0, and combined with the instantaneous velocity v1 and the acceleration a1, the instantaneous velocity v0 and acceleration a0 of the initial trigger point p0 are calculated. Based on the uniformly accelerated linear motion displacement model, and combined with the total duration corresponding to the trigger delay time t0 and the exposure time t1, the position offset is calculated.

[0009] Further, the instantaneous velocity v0 and acceleration a0 of the initial trigger point p0 are calculated, including: The instantaneous speed ; It is approximately assumed that the acceleration a0 at the initial trigger point p0 is equal to the collected acceleration a1.

[0010] Further, the position offset is calculated, including: Position offset .

[0011] Further, determine the corresponding target trigger point p, including: Using the target imaging position pt as a reference, the position coordinates of the target trigger point p are obtained by offsetting the position offset by the distance in the opposite direction of the movement of the object being measured.

[0012] Furthermore, the instantaneous motion state parameters of the acquired motion axis include: The motion axis is driven and controlled by a motion controller. At the same time as the trigger signal is output, the current axis position p1, instantaneous velocity v1 and acceleration a1 of the motion axis are captured from the motion controller through hardware synchronous latching.

[0013] Furthermore, the method is applied to a dual-camera RFID tape detection system, wherein the motion axis is a rotating mechanism that drives the tape, and the object being measured is an RFID tape with equally spaced antenna patterns on its surface, including: The distance between the center points of the field of view of the positioning camera and the detection camera in the direction of the conveyor belt movement is pre-calibrated; Control the rotation mechanism to make any antenna pattern on the material strip enter the field of view of the positioning camera, control the positioning camera to statically capture images, and identify the center point coordinates of the antenna pattern through template matching; By combining the field-of-view distance between the positioning camera and the detection camera with the fixed distance between the material strip antenna patterns, the target imaging position where the current antenna pattern moves to the center of the field of view of the detection camera, and the initial trigger point corresponding to the next antenna pattern are calculated. Based on the positional relationship between the target imaging position and the initial trigger point, select either static image acquisition mode or aerial image acquisition mode; if aerial image acquisition mode is selected, then apply the method for determining the aerial trigger point to calculate the final trigger point and control the detection camera to complete aerial imaging. Repeat the above steps until the detection stops.

[0014] This invention also provides a system for determining the trigger point of aerial photography, including a motion axis, an imaging camera, and a control processing module: The motion axis is used to drive the object under test to make incremental motion along the axial direction; The imaging camera is used to take photographs; The control processing module is configured to perform the following steps: The system trigger delay time t0 and the camera exposure time t1 are obtained, wherein the trigger delay time t0 is the time from when the trigger signal is sent to when the camera receives the trigger signal; Determine the target imaging position (pt) for aerial photography; While outputting the trigger signal to the imaging camera, the instantaneous motion state parameters of the motion axis are acquired, including the current axis position p1, instantaneous velocity v1, and acceleration a1. Based on the instantaneous motion state parameters, combined with the trigger delay time t0 and the camera exposure time t1, the position offset of the actual imaging position pa of the aerial photography relative to the position where the trigger signal was emitted is calculated using a kinematic model. Based on the target imaging position pt and the position offset, the corresponding target trigger point p is determined.

[0015] Furthermore, the control processing module collects the instantaneous motion state parameters of the motion axis and is configured as follows: An initial trigger point p0 is set, and the motion axis is controlled to move along the axial direction. When the motion axis passes the initial trigger point p0, the trigger signal is output to the imaging camera, and the instantaneous motion state parameters of the motion axis are collected simultaneously with the output of the trigger signal.

[0016] The technical solution of this invention can achieve the following technical effects: This invention eliminates the need for static comparison calibration based on fixed image capture points. By acquiring the instantaneous position, velocity, and acceleration parameters of the motion axis, combined with the system trigger delay and camera exposure parameters, the offset of the flying image position can be calculated, and the target trigger point can be derived in reverse. It is adaptable to application scenarios without fixed trigger points and where the image capture position is dynamically generated. It can also effectively handle conditions where the motion axis operates at varying speeds, broadening the applicability of flying image trigger calibration technology and improving the positioning accuracy of flying image imaging under dynamic conditions.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a logical schematic diagram of the method for determining the trigger point of the flying camera in an embodiment of the present invention; Figure 2 This is a logic diagram illustrating the acquisition of instantaneous motion state parameters of the motion axis in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the logic of calculating the position offset using a kinematic model in an embodiment of the present invention. Figure 4 This is a logical diagram illustrating the determination of the corresponding target trigger point p in an embodiment of the present invention; Figure 5 This is a logic diagram illustrating the application of the determination method to a dual-camera RFID tape detection system in an embodiment of the present invention. Figure 6 This is a schematic diagram of the structure of the dual-camera RFID tape detection system in an embodiment of the present invention.

[0020] Reference numerals: 1. Positioning camera; 2. Detection camera; 3. Material belt; 4. Rotating mechanism. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] This invention provides a method such as Figures 1 to 5 The method for determining the trigger point of the flying camera, as shown, includes the following steps: Obtain the system trigger delay time t0 and the camera exposure time t1. The trigger delay time t0 is the time from when the trigger signal is sent to when the camera receives the trigger signal. Determine the target imaging position (pt) for aerial photography; At the same time as the trigger signal is issued, the instantaneous motion state parameters of the motion axis are collected, including the current axis position p1, instantaneous velocity v1, and acceleration a1; Based on the instantaneous motion state parameters, combined with the trigger delay time t0 and the camera exposure time t1, the position offset of the actual imaging position pa of the flying camera relative to the position where the trigger signal was emitted is calculated through the kinematic model; Based on the target imaging position pt and the position offset, determine the corresponding target trigger point p.

[0024] The working principle of this invention is as follows: This system is applied to industrial vision-based aerial imaging systems where the measured object is driven by a motion axis to perform continuous incremental motion. The measured object can be various types of objects to be inspected, such as material strips or workpiece carriers with serialized surface features. First, the system's trigger delay time t0 and the camera's exposure time t1 are pre-acquired. The trigger delay time t0 is the hardware transmission and response delay from the trigger signal output from the control terminal to the signal received by the camera's trigger port. This delay time t0 can be obtained by measuring the time difference between the trigger output signal and the camera received signal using an oscilloscope. The exposure time t1 is directly read from and stored in the camera's imaging configuration parameters as a fixed base parameter for subsequent offset calculations. Second, the target imaging position pt is determined. The target imaging position pt is the physical coordinate corresponding to the point where the target feature of the measured object is expected to fall exactly at a specified position in the camera's imaging field of view. This can be either a pre-calibrated fixed inspection station coordinate or a position coordinate dynamically calculated based on the inspection results of previous positioning processes, adapting to different production inspection needs such as fixed-point inspection and dynamic-point inspection. Then, a trigger signal is sent to the camera... At the same time, the instantaneous motion state parameters of the motion axis are synchronously acquired, including at least the current axis position p1, instantaneous running speed v1, and instantaneous acceleration a1. Then, based on the acquired instantaneous motion state parameters, combined with the pre-acquired trigger delay time t0 and camera exposure time t1, the position offset of the actual imaging position pa of the flying camera relative to the trigger signal emission position is calculated through the kinematic model. Finally, based on the determined target imaging position pt and the calculated position offset, the corresponding target trigger point p is derived in reverse. When the motion axis moves to the target trigger point p, a trigger signal is emitted. During the trigger delay and exposure process, the object under test continues to move along the motion direction by the corresponding position offset distance, so that the actual imaging position pa of the camera coincides exactly with the target imaging position pt, thereby achieving accurate determination of the flying camera trigger point.

[0025] In some embodiments of the present invention, such as Figure 2 As shown, the instantaneous motion state parameters of the motion axis are collected, including: Set the initial trigger point p0, and control the motion axis to issue a trigger signal when it passes the initial trigger point. At the same time as the trigger signal is issued, the instantaneous motion state parameters of the motion axis are collected synchronously.

[0026] An initial trigger point p0 is preset. This initial trigger point p0 is not a fixed work position that has been pre-calibrated, but rather a temporary reference point selected only for acquiring the motion state at the trigger moment and supporting the subsequent position offset calculation. It can be flexibly selected according to the approximate position range of the target imaging position pt, and can also be dynamically adjusted according to the target position under different detection conditions, without being limited to a fixed physical coordinate. The motion axis is controlled to drive the measured object to make continuous incremental movements along the preset motion direction of the axis. When the motion axis moves to pass through the initial trigger point p0, the system immediately sends a trigger signal to the camera. At the same time as the trigger signal is sent, the instantaneous motion state parameters of the motion axis are synchronously acquired, including the current axis position p1, instantaneous velocity v1, and acceleration a1. By selecting the initial trigger point p0 as the position reference for the trigger action, and coordinating the synchronous execution of the trigger signal output and parameter acquisition, it is possible to ensure that the acquired motion state parameters and the trigger action are highly correlated in time, reflecting the actual motion conditions at the trigger moment.

[0027] In some embodiments of the present invention, such as Figure 3 As shown, the position offset is calculated using a kinematic model, including: Based on the positional distance between axis position p1 and initial trigger point p0, combined with instantaneous velocity v1 and acceleration a1, the instantaneous velocity v0 and acceleration a0 of the initial trigger point p0 are calculated. Based on the uniformly accelerated linear motion displacement model, and combined with the total duration corresponding to the trigger delay time t0 and the exposure time t1, the position offset is calculated.

[0028] Based on the positional distance between the current axis position p1 and the initial trigger point p0 obtained through synchronous acquisition, and combined with the instantaneous velocity v1 and acceleration a1 obtained through synchronous acquisition, the instantaneous velocity v0 corresponding to the initial trigger point p0 is calculated according to the velocity-displacement correspondence of uniformly accelerated linear motion. On this basis, based on the displacement calculation model of uniformly accelerated linear motion, and combined with the effective total imaging time corresponding to the trigger delay time t0 and the camera exposure time t1, the displacement of the measured object along the motion direction during the time period from the issuance of the trigger signal to the completion of effective imaging is calculated using the calculated instantaneous velocity v0 and acceleration a0. This displacement is the position offset of the actual imaging position pa of the aerial photography relative to the initial trigger point p0.

[0029] In some embodiments of the present invention, the instantaneous velocity v0 and acceleration a0 of the initial trigger point p0 are calculated, including: instantaneous speed ; In this context, it is approximately assumed that the acceleration a0 at the initial trigger point p0 is equal to the collected acceleration a1.

[0030] The instantaneous velocity v0 is calculated based on the velocity-displacement relationship of uniformly accelerated linear motion. As for the acceleration parameter, since the synchronization error between the trigger signal output and the acquisition of motion state parameters is extremely small, and the physical position distance between the two is extremely short, the acceleration of the motion axis will hardly produce observable changes within this tiny motion range. Therefore, it is approximately assumed that the acceleration a0 at the initial trigger point p0 is equal to the acquired acceleration a1. No additional point-by-point conversion of acceleration is required. This ensures that the calculation accuracy of the motion parameters at the trigger moment meets the requirements of high-precision aerial photography positioning, while also effectively simplifying the calculation process and reducing the computational load of the control system.

[0031] In some embodiments of the present invention, the position offset is calculated, including: Position offset .

[0032] In some embodiments of the present invention, such as Figure 4 As shown, the corresponding target trigger point p is determined, including: Using the target imaging position pt as a reference, the position coordinates of the target trigger point p are obtained by offsetting the position offset by offset in the opposite direction of the movement of the object being measured.

[0033] Using the predetermined target imaging position pt as the alignment reference for the final imaging, the physical position coordinates of the target trigger point p are calculated by offsetting a distance equal to the position offset in the opposite direction of the movement of the object under test. When the motion axis drives the object under test to the target trigger point p, the system issues a trigger signal. Within the total time corresponding to the trigger delay and exposure, the object under test will continuously move a displacement equal to the position offset in the positive direction of movement, so that the target feature of the object under test is exactly aligned with the target imaging position pt to complete the imaging. This ensures that the actual imaging position of the aerial photography coincides precisely with the preset target imaging position. By deriving the offset in reverse, the precise trigger position can be obtained intuitively and efficiently, adapting to various aerial photography detection scenarios where target positions are dynamically generated.

[0034] In some embodiments of the present invention, the instantaneous motion state parameters of the motion axis are collected, including: The motion axis is driven and controlled by the motion controller. At the same time as the trigger signal is output, the current axis position p1, instantaneous velocity v1 and acceleration a1 of the motion axis are captured from the motion controller through hardware synchronous latching.

[0035] The motion axis is driven and controlled by a motion controller, which is the core unit for motion execution and status feedback of the motion axis. It can acquire and store position, velocity, and acceleration status data of the motion axis in real time. Simultaneously with outputting a trigger signal to the camera, the motion control system's hardware synchronous latching mechanism directly retrieves the current axis position p1, instantaneous velocity v1, and acceleration a1 from the real-time status register inside the motion controller. Compared to software polling, hardware synchronous latching is a hardware-level synchronous triggering and data capture method, unaffected by system software scheduling delays. It can control the time difference between the trigger signal output and data acquisition to the microsecond level, maximizing the correspondence between the acquired motion state parameters and the actual motion conditions at the trigger moment. This effectively avoids parameter errors introduced by sampling time deviations, providing a reliable data foundation for the accurate calculation of the subsequent position offset.

[0036] In some embodiments of the present invention, such as Figure 5 and Figure 6 As shown, the method is applied to a dual-camera RFID tape detection system. The motion axis is a rotating mechanism 4 that drives the tape 3 to move. The object being measured is an RFID tape 3 with equally spaced antenna patterns on its surface, including: The distance between the center points of the fields of view of the positioning camera 1 and the detection camera 2 in the direction of the material belt 3 is pre-calibrated; Control the rotation mechanism 4 to run, so that any antenna pattern on the material belt 3 enters the field of view of the positioning camera 1, control the positioning camera 1 to statically capture images, and identify the center point coordinates of the antenna pattern through template matching. By combining the field-of-view distance between positioning camera 1 and detection camera 2 with the fixed spacing of the antenna pattern of material strip 3, the target imaging position where the current antenna pattern moves to the center of the field of view of detection camera 2, and the initial trigger point corresponding to the next antenna pattern are calculated. Based on the positional relationship between the target imaging position and the initial trigger point, select either the static imaging mode or the aerial imaging mode; if the aerial imaging mode is selected, the final trigger point is calculated using the method for determining the aerial trigger point, and the detection camera 2 is controlled to complete the aerial imaging. Repeat the above steps until the detection stops.

[0037] First, system parameter calibration and basic configuration are completed in advance. A calibration strip 3 with standard spacing marks is used to calibrate the field-of-view spacing between the positioning camera 1 and the detection camera 2. The rotating mechanism 4 is controlled to move the calibration strip 3 step by step, aligning the calibration features sequentially with the center of the field of view of the positioning camera 1 and the center of the field of view of the detection camera 2. The position coordinates of the rotating mechanism 4 are recorded in both alignment states. The difference between the two coordinates is stored in the motion controller as the field-of-view spacing between the center points of the two cameras along the movement direction of the strip 3. Simultaneously, the system's trigger delay time and the camera's exposure time are measured in advance for use in calculating the shooting position. The basic parameters are set; after calibration, the continuous detection process is started, and the rotating mechanism 4 is controlled to run stably in a clockwise direction, driving the RFID material belt 3 to make continuous incremental movements along the conveying direction. When any antenna pattern on the material belt 3 moves into the field of view of the positioning camera 1, the positioning camera 1 is controlled to perform static image acquisition. The acquired static image is processed by a preset template matching algorithm to identify the coordinate position of the center point of the antenna pattern in the image, thereby obtaining the actual physical position reference of the antenna pattern. Then, the system combines the pre-calibrated field of view distance between the two cameras and the antenna on the RFID material belt 3. The system calculates the target imaging position when the current antenna pattern moves to the center of the field of view of the detection camera 2, based on the fixed design spacing of the pattern. Simultaneously, it preliminarily calculates the initial trigger point for the next antenna pattern based on the current operating status of the conveyor belt 3. Next, the system automatically selects the corresponding image acquisition mode based on the positional relationship between the target imaging position and the initial trigger point, combined with the current operating speed of the conveyor belt 3 and the detection requirements. When the conveyor belt 3 is in a low-speed debugging or accuracy calibration stage, the static image acquisition mode is selected. After controlling the rotating mechanism 4 to precisely move the antenna pattern to the target imaging position, the detection camera 2 is controlled to complete the static image acquisition. When the material strip 3 is in a normal continuous high-speed production inspection state, the flying image acquisition mode is selected to improve the overall inspection efficiency. If the flying image acquisition mode is selected, the flying trigger point determination method in the aforementioned embodiment is used to calculate the final accurate trigger point, so that the actual imaging position of the inspection camera 2 falls precisely at the target imaging position, and the flying image imaging inspection of a single antenna pattern is completed. The system repeatedly executes the above steps of static positioning image acquisition, target position and trigger point calculation, image acquisition mode selection and imaging inspection, and inspects all antenna patterns on the material strip 3 one by one until the entire roll of material strip 3 is inspected or the system receives a stop operation command.

[0038] Based on the same inventive concept as the method for determining the trigger point of a flying camera in the foregoing embodiments, the present invention also provides a system for determining the trigger point of a flying camera, including a motion axis, an imaging camera, and a control processing module: The motion axis is used to drive the object being measured to make incremental movements along the axial direction; Imaging cameras are used to take photographs; The control processing module is configured to perform the following steps: Obtain the system trigger delay time t0 and the camera exposure time t1. The trigger delay time t0 is the time from when the trigger signal is sent to when the camera receives the trigger signal. Determine the target imaging position (pt) for aerial photography; While outputting a trigger signal to the imaging camera, the instantaneous motion state parameters of the motion axis are acquired, including the current axis position p1, instantaneous velocity v1, and acceleration a1. Based on the instantaneous motion state parameters, combined with the trigger delay time t0 and the camera exposure time t1, the position offset of the actual imaging position pa of the flying camera relative to the position where the trigger signal was emitted is calculated through the kinematic model; Based on the target imaging position pt and the position offset, determine the corresponding target trigger point p.

[0039] The above-described determination system in this invention can effectively realize the method and system for determining the trigger point of the flying camera, and the technical effects it can achieve are as described in the above embodiments, which will not be repeated here.

[0040] In some embodiments of the present invention, the control processing module collects instantaneous motion state parameters of the motion axis and is configured as follows: Set the initial trigger point p0, control the motion axis to move along the axial direction, and output a trigger signal to the imaging camera when the motion axis passes the initial trigger point p0. At the same time as the trigger signal is output, the instantaneous motion state parameters of the motion axis are collected simultaneously.

[0041] Similarly, the above-mentioned optimization schemes for the system can also respectively achieve the optimization effects corresponding to the methods in the embodiments, which will not be repeated here.

[0042] Although this application has been described in conjunction with specific features and embodiments, it is apparent that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and accompanying drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application is intended to include such modifications and modifications.

Claims

1. A method for determining the trigger point of a flying camera, characterized in that, Includes the following steps: The system trigger delay time t0 and the camera exposure time t1 are obtained, wherein the trigger delay time t0 is the time from when the trigger signal is sent to when the camera receives the trigger signal; Determine the target imaging position (pt) for aerial photography; At the same time as the trigger signal is issued, the instantaneous motion state parameters of the motion axis are collected, including the current axis position p1, instantaneous velocity v1, and acceleration a1; Based on the instantaneous motion state parameters, combined with the trigger delay time t0 and the camera exposure time t1, the position offset of the actual imaging position pa of the aerial photography relative to the position where the trigger signal was emitted is calculated using a kinematic model. Based on the target imaging position pt and the position offset, the corresponding target trigger point p is determined.

2. The method for determining the trigger point of the flying camera according to claim 1, characterized in that, The instantaneous motion state parameters of the motion axis are collected, including: Set an initial trigger point p0, and control the motion axis to emit a trigger signal when it passes the initial trigger point. At the same time as the trigger signal is emitted, the instantaneous motion state parameters of the motion axis are collected synchronously.

3. The method for determining the trigger point of the flying camera according to claim 2, characterized in that, The calculation of the position offset using a kinematic model includes: Based on the positional distance between the axis position p1 and the initial trigger point p0, and combined with the instantaneous velocity v1 and the acceleration a1, the instantaneous velocity v0 and acceleration a0 of the initial trigger point p0 are calculated. Based on the uniformly accelerated linear motion displacement model, and combined with the total duration corresponding to the trigger delay time t0 and the exposure time t1, the position offset is calculated.

4. The method for determining the trigger point of the flying camera according to claim 3, characterized in that, The instantaneous velocity v0 and acceleration a0 of the initial trigger point p0 are calculated, including: The instantaneous speed ; It is approximately assumed that the acceleration a0 at the initial trigger point p0 is equal to the collected acceleration a1.

5. The method for determining the trigger point of the flying camera according to claim 4, characterized in that, The position offset is calculated as follows: Position offset .

6. The method for determining the trigger point of the flying camera according to claim 1, characterized in that, Determine the corresponding target trigger point p, including: Using the target imaging position pt as a reference, the position coordinates of the target trigger point p are obtained by offsetting the position offset by the distance in the opposite direction of the movement of the object being measured.

7. The method for determining the trigger point of the flying camera according to claim 1, characterized in that, The instantaneous motion state parameters of the acquired motion axis include: The motion axis is driven and controlled by a motion controller. At the same time as the trigger signal is output, the current axis position p1, instantaneous velocity v1 and acceleration a1 of the motion axis are captured from the motion controller through hardware synchronous latching.

8. The method for determining the trigger point of the flying camera according to claim 1, characterized in that, The method is applied to a dual-camera RFID tape detection system, wherein the motion axis is a rotating mechanism that drives the tape, and the object being measured is an RFID tape with equally spaced antenna patterns on its surface, including: The distance between the center points of the field of view of the positioning camera and the detection camera in the direction of the conveyor belt movement is pre-calibrated; Control the rotation mechanism to make any antenna pattern on the material strip enter the field of view of the positioning camera, control the positioning camera to statically capture images, and identify the center point coordinates of the antenna pattern through template matching; By combining the field-of-view distance between the positioning camera and the detection camera with the fixed distance between the material strip antenna patterns, the target imaging position where the current antenna pattern moves to the center of the field of view of the detection camera, and the initial trigger point corresponding to the next antenna pattern are calculated. Based on the positional relationship between the target imaging position and the initial trigger point, select either static image acquisition mode or aerial image acquisition mode; if aerial image acquisition mode is selected, then apply the method for determining the aerial trigger point to calculate the final trigger point and control the detection camera to complete aerial imaging. Repeat the above steps until the detection stops.

9. A system for determining the trigger point of a flying camera, characterized in that, The determination method as described in any one of claims 1 to 8 includes a motion axis, an imaging camera, and a control processing module. The motion axis is used to drive the object under test to make incremental motion along the axial direction; The imaging camera is used to take photographs; The control processing module is configured to perform the following steps: The system trigger delay time t0 and the camera exposure time t1 are obtained, wherein the trigger delay time t0 is the time from when the trigger signal is sent to when the camera receives the trigger signal; Determine the target imaging position (pt) for aerial photography; While outputting the trigger signal to the imaging camera, the instantaneous motion state parameters of the motion axis are acquired, including the current axis position p1, instantaneous velocity v1, and acceleration a1. Based on the instantaneous motion state parameters, combined with the trigger delay time t0 and the camera exposure time t1, the position offset of the actual imaging position pa of the aerial photography relative to the position where the trigger signal was emitted is calculated using a kinematic model. Based on the target imaging position pt and the position offset, the corresponding target trigger point p is determined.

10. The system for determining the trigger point of a drone according to claim 9, characterized in that, The control processing module collects the instantaneous motion state parameters of the motion axis and is configured as follows: An initial trigger point p0 is set, and the motion axis is controlled to move along the axial direction. When the motion axis passes the initial trigger point p0, the trigger signal is output to the imaging camera, and the instantaneous motion state parameters of the motion axis are collected simultaneously with the output of the trigger signal.

Images