A time-controlled non-contact deformation measurement method, device, computer equipment, and medium

Abstract

This invention provides a time-controlled, non-contact deformation measurement method, apparatus, computer equipment, and medium, relating to the field of optical experimental mechanics. The method includes the following steps: determining the time-series control parameters, intrinsic and extrinsic parameters, and coordinate transformation matrix of an industrial camera; acquiring a sequence of images of the surface of the object under test based on a trigger signal and triggering a light source to provide illumination to generate a first data stream; controlling an event camera to output a second data stream showing the pixel brightness changes on the surface of the object under test; parsing the second data stream and dynamically controlling the image acquisition of the industrial camera according to instantaneous motion state parameters; performing digital image correlation matching and 3D reconstruction to obtain a high spatial resolution deformation field of the object under test at the sampling time; performing event-driven 3D reconstruction to generate a 3D deformation measurement result. This scheme resolves the contradiction between clear imaging of high-speed moving objects and long-term continuous acquisition by combining short exposure and long interval time-series control parameters.

Description

Technical Field

[0001] This invention relates to the field of optical experimental mechanics technology, and in particular to a time-controlled non-contact deformation measurement method, device, computer equipment, and medium. Background Technology

[0002] Vehicles used in aerospace, aviation, and marine industries possess numerous high-speed moving components, such as the high-speed rotating disks, rotor blades, and propellers in engines. These high-speed moving components endure enormous centrifugal loads during operation; for example, the rotating disk experiences radial and axial shear forces. The structural integrity of these components is crucial for ensuring the safe operation of the vehicle. Therefore, accurately assessing the performance of high-speed moving components is essential for the safe operation of aircraft and other vehicles. Currently, deformation measurement of moving components is mainly achieved through two methods: contact and non-contact methods.

[0003] Contact deformation measurement methods measure the deformation of high-speed moving parts by attaching strain gauges to the surface of the component. However, when the strain gauges are attached to areas with large centrifugal loads, the adhesive may not have sufficient shear strength, causing the strain gauges to fall off. High noise during high-speed rotation leads to unstable strain signal transmission. Based on the contact deformation measurement method, only the deformation at local points can be measured, making it difficult to achieve full-field deformation measurement of high-speed moving parts.

[0004] Non-contact deformation measurement methods acquire images of the moving part's surface and perform correlation matching to achieve deformation measurement. However, current ordinary industrial cameras struggle to capture clear images of the surface of high-speed moving parts, leading to deformation measurement failures. While high-frame-rate cameras can obtain clear images of the surface of high-speed moving parts, their data transmission rate limits deformation measurement to a very short time. Therefore, existing non-contact deformation measurement systems are insufficient to meet the requirements for continuous deformation measurement of high-speed moving parts over extended periods.

[0005] In summary, there is currently a lack of suitable measurement systems and methods for the full-field three-dimensional deformation of high-speed rotating components, and further research is still needed. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a time-controlled non-contact deformation measurement method to solve the technical problem of the lack of an effective method for measuring the full-field three-dimensional deformation of high-speed rotating components in the prior art. The method includes:

[0007] Determine the timing control parameters of the industrial camera, obtain the intrinsic and extrinsic parameters of the industrial camera, and obtain the coordinate system transformation matrix between the industrial camera and the event camera. The timing control parameters include the single exposure time t and the exposure interval T between two adjacent exposures.

[0008] A trigger signal is generated according to the timing control parameters. Based on the trigger signal, the industrial camera is controlled to acquire a sequence of images of the surface of the object under test. During each exposure, the light source is synchronously triggered to provide illumination, generating a first data stream. The event camera is controlled to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner, generating a second data stream. The first data stream and the second data stream are aligned with a unified time axis.

[0009] The second data stream is parsed in real time, the instantaneous motion state parameters of the object under test are calculated, the timing control parameters are dynamically adjusted according to the instantaneous motion state parameters, and the acquisition of sequential images of the industrial camera is controlled based on the adjusted timing control parameters.

[0010] Based on the intrinsic and extrinsic parameters, digital image correlation matching and 3D reconstruction are performed on the first data stream to obtain the high spatial resolution deformation field of the object under test at the sampling time. Based on the second data stream and the coordinate system transformation matrix, event-driven 3D reconstruction is performed to obtain the high temporal resolution motion profile of the object under test during the interval between two adjacent exposures. The high temporal resolution motion profile is fused into the spatial coordinate system of the high spatial resolution deformation field by interpolation registration to generate a 3D deformation measurement result.

[0011] This invention also provides a time-controlled non-contact deformation measurement device to solve the technical problem of lacking an effective method for measuring the full-field three-dimensional deformation of high-speed rotating components in the prior art. The device includes:

[0012] The parameter acquisition and determination module is used to determine the timing control parameters of the industrial camera, acquire the intrinsic and extrinsic parameters of the industrial camera, and acquire the coordinate system transformation matrix between the industrial camera and the event camera. The timing control parameters include the single exposure time t and the exposure interval T between two adjacent exposures.

[0013] The data acquisition module is used to generate a trigger signal according to the timing control parameters, control the industrial camera to acquire a sequence of images of the surface of the object under test based on the trigger signal, and synchronously trigger the light source to provide illumination during each exposure to generate a first data stream, control the event camera to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner to generate a second data stream, and align the first data stream and the second data stream with a unified time axis.

[0014] The parsing and adjustment module is used to parse the second data stream in real time, calculate the instantaneous motion state parameters of the object under test, dynamically adjust the timing control parameters according to the instantaneous motion state parameters, and control the acquisition of the sequence images of the industrial camera based on the adjusted timing control parameters.

[0015] The measurement result generation module is used to perform digital image correlation matching and 3D reconstruction on the first data stream based on the intrinsic and extrinsic parameters to obtain the high spatial resolution deformation field of the object under test at the sampling time. Based on the second data stream and the coordinate system transformation matrix, event-driven 3D reconstruction is performed to obtain the high temporal resolution motion contour of the object under test during the interval between two adjacent exposures. The high temporal resolution motion contour is fused into the spatial coordinate system of the high spatial resolution deformation field by interpolation registration method to generate 3D deformation measurement results.

[0016] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-mentioned time-controlled non-contact deformation measurement method, thereby solving the technical problem of lacking an effective method for measuring the full-field three-dimensional deformation of high-speed rotating components in the prior art.

[0017] This invention also provides a computer-readable storage medium storing a computer program that performs any of the above-described time-controlled non-contact deformation measurement methods, in order to solve the technical problem of lacking an effective method for measuring the full-field three-dimensional deformation of high-speed rotating components in the prior art.

[0018] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least:

[0019] By designing timing control parameters that combine short exposures with long intervals, the contradiction between clear imaging of high-speed moving objects and long-term continuous acquisition was resolved. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a time-controlled non-contact deformation measurement method provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of timing signal acquisition and control provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the timing control for the transitional measurement of the wheel acceleration provided in an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of fatigue test timing control provided in an embodiment of the present invention;

[0025] Figure 5 This is a structural block diagram of a computer device provided in an embodiment of the present invention;

[0026] Figure 6 This is a structural block diagram of a time-controlled non-contact deformation measurement device provided in an embodiment of the present invention. Detailed Implementation

[0027] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0028] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In this embodiment of the invention, a time-controllable non-contact deformation measurement method is provided, such as... Figure 1 As shown, the method includes:

[0030] Step S101: Determine the timing control parameters of the industrial camera, obtain the intrinsic and extrinsic parameters of the industrial camera, and obtain the coordinate system transformation matrix between the industrial camera and the event camera. The timing control parameters include the single exposure time t and the exposure interval T between two adjacent exposures.

[0031] Step S102: Generate a trigger signal according to the timing control parameters, control the industrial camera to acquire a sequence of images of the surface of the object under test based on the trigger signal, and synchronously trigger the light source to provide illumination during each exposure to generate a first data stream. Control the event camera to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner to generate a second data stream, and align the first data stream and the second data stream with a unified time axis.

[0032] Step S103: Analyze the second data stream in real time, calculate the instantaneous motion state parameters of the object under test, dynamically adjust the timing control parameters according to the instantaneous motion state parameters, and control the acquisition of the sequence images of the industrial camera based on the adjusted timing control parameters;

[0033] Step S104: Based on the intrinsic and extrinsic parameters, perform digital image correlation matching and 3D reconstruction on the first data stream to obtain the high spatial resolution deformation field of the object under test at the sampling time. Based on the second data stream and the coordinate system transformation matrix, perform event-driven 3D reconstruction to obtain the high temporal resolution motion profile of the object under test during two adjacent exposure intervals. Through interpolation registration, fuse the high temporal resolution motion profile into the spatial coordinate system of the high spatial resolution deformation field to generate a 3D deformation measurement result.

[0034] In practice, the timing control parameters of the industrial camera are determined through the following steps:

[0035] A first time threshold t1 is determined based on the motion speed and measurement accuracy requirements, where the first time threshold t1 is used to ensure image clarity, t1=(ε×R) / v, where v is the maximum motion speed of the measured object, R is the image pixel resolution, and ε is the maximum allowable image motion blur pixel value; a second time threshold t2 is determined based on the amount of single-frame image data, the number of cameras, and the data transmission bandwidth, where the second time threshold t2 is used to determine the upper limit of the data transmission bandwidth, t2=(D×N) / M, where D is the amount of single-frame image data, N is the number of cameras, and M is the upper limit of the data transmission bandwidth; a single exposure time t is determined such that the single exposure time t is less than or equal to the first time threshold t1; an exposure interval time T between two adjacent exposures is determined such that the exposure interval time T is greater than or equal to the second time threshold t2; the single exposure time t and the exposure interval time T are used as timing control parameters.

[0036] In specific implementation, the following steps are used to generate a trigger signal based on the timing control parameters, control the industrial camera to acquire a sequence of images of the surface of the object under test based on the trigger signal, and synchronously trigger the light source to provide illumination during each exposure to generate a first data stream. The event camera is then controlled to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner to generate a second data stream. Finally, the first data stream and the second data stream are aligned along a unified time axis.

[0037] Based on the single exposure time t and the exposure interval time T in the timing control parameters, a trigger signal with the single exposure time t and the exposure interval time T is generated; the trigger signal is sent to the industrial camera to control the industrial camera to acquire a sequence of images of the surface of the object under test according to the timing control parameters; during each exposure, a synchronous trigger signal is sent to the light source to control the light source to provide illumination within the exposure time, and the acquired sequence of images is used as the first data stream; the event camera is initialized, a contrast threshold for brightness change is set, and a continuous acquisition mode is started; the brightness change of the surface of the object under test is monitored pixel by pixel in real time through the event camera; when the brightness change of any pixel exceeds the contrast threshold, an original event containing the current timestamp, pixel coordinates, and polarity of the brightness change direction is generated; the original events are arranged in chronological order and output as asynchronous event stream data as the second data stream; the acquisition time of each frame of the first data stream is matched with the timestamp of each event in the second data stream to establish a unified time axis correspondence, so that the first data stream and the second data stream are aligned with a unified time axis.

[0038] In specific implementation, the second data stream is parsed in real time through the following steps: the instantaneous motion state parameters of the object under test are calculated; the timing control parameters are dynamically adjusted based on the instantaneous motion state parameters; and the acquisition of sequential images from the industrial camera is controlled based on the adjusted timing control parameters.

[0039] The system receives the second data stream in real time, performs accumulation and clustering processing on the second data stream, and extracts the event density, event change rate, and spatial distribution features of event clusters within each time window. The spatial distribution features include the centroid coordinates, contour edges, spatial span, and timestamp distribution of events within the cluster. Based on the event density and event change rate, the system calculates the instantaneous translational velocity or instantaneous translational acceleration of the measured object. Based on the spatial distribution features of the event clusters, the system calculates the instantaneous rotational angular velocity, instantaneous local strain rate, or instantaneous vibration mode of the measured object. At least one of the instantaneous translational velocity, instantaneous translational acceleration, instantaneous rotational angular velocity, instantaneous local strain rate, and instantaneous vibration mode is used as the... The instantaneous motion state parameters are described; the instantaneous motion state parameters are compared with a preset dynamic threshold, and when the instantaneous motion state parameters exceed the dynamic threshold, it is determined that a critical transient event has occurred; an interval time threshold is set according to the type of the critical transient event, the minimum trigger interval limit of the industrial camera, and the upper limit of the data transmission bandwidth; based on the determination result of the critical transient event, the exposure interval time T in the timing control parameters is dynamically adjusted, and during the duration of the critical transient event, the exposure interval time T is shortened to the interval time threshold; an updated trigger signal is generated based on the adjusted exposure interval time T, and the industrial camera is controlled to perform image acquisition according to the shortened exposure interval time based on the updated trigger signal.

[0040] In specific implementation, the following steps are used to dynamically adjust the exposure interval time T in the timing control parameters based on the determination result of the critical transient event, and to shorten the exposure interval time T to the interval time threshold during the duration of the critical transient event:

[0041] When the instantaneous motion state parameter exceeds the dynamic threshold, the trigger mode of the industrial camera is switched from the equal-interval timed trigger mode to the event trigger mode. In the event trigger mode, the interval between two adjacent exposures of the industrial camera is dynamically set to the interval time threshold. The second data stream is analyzed in real time, and specific event types are identified. When the specific event type is identified, the trigger signal is immediately generated. The trigger signal controls the industrial camera to perform image acquisition, and the interval between two adjacent exposures is less than or equal to the interval time threshold. The specific event types include the number of events accumulated per unit time exceeding a first event density threshold, the time interval between adjacent events being less than a first time interval threshold, and the analyzed instantaneous velocity exceeding a first velocity threshold. The instantaneous motion state parameter is continuously monitored. When the instantaneous motion state parameter falls below the preset dynamic threshold, the key transient event is determined to have ended. The trigger mode of the industrial camera is switched back to the equal-interval timed trigger mode, and the interval between two adjacent exposures is restored to the exposure interval time T.

[0042] In specific implementation, the following steps are used to perform digital image correlation matching and three-dimensional reconstruction on the first data stream based on the intrinsic and extrinsic parameters, so as to obtain the high spatial resolution deformation field of the measured object at the sampling time:

[0043] Each frame of the sequence image in the first data stream is divided into multiple overlapping or adjacent computational sub-regions according to a preset sub-region size and sub-region step size. Based on stereo image pairs acquired by different industrial cameras at the same sampling time, stereo matching is performed on the stereo image pairs using a zero-mean normalized cross-correlation algorithm to determine the corresponding points of the same physical point on the surface of the object under test in the images from different cameras, thus obtaining stereo matching point pairs. Between sequence images acquired by the same industrial camera at different sampling times, temporal matching is performed using a zero-mean normalized cross-correlation algorithm to determine the pre-deformation... In the subsequent image, corresponding points of the same physical point on the surface of the object under test are obtained to form time-series matching point pairs. Based on the intrinsic and extrinsic parameters, the three-dimensional matching point pairs are reconstructed using triangulation to obtain full-field three-dimensional point cloud data of the surface of the object under test at each sampling time. The time-series matching point pairs are used to establish the point correspondence between different sampling times. The full-field three-dimensional point cloud data is interpolated and differentially calculated to obtain the full-field displacement field of the surface of the object under test. The full-field displacement field is numerically differentiated to obtain the full-field strain field, which is used as the high spatial resolution deformation field.

[0044] In specific implementation, the following steps are used to achieve event-driven 3D reconstruction based on the second data stream and the coordinate system transformation matrix, so as to obtain the high temporal resolution motion profile of the object under test during the interval between two adjacent exposures:

[0045] Within the exposure interval T between two adjacent exposures, the second data stream is accumulated according to a preset time window to generate an event frame image. The grayscale value of each pixel in the event frame image is the number of events or the event polarity integral that occurred at the current pixel coordinate position within the time window. Feature matching is performed on the event frame images generated by different event cameras or the event frame images generated by the same event camera in different time windows to determine the correspondence between corresponding points in the event frame images. Based on the coordinate system transformation matrix and the correspondence between corresponding points, the corresponding points matched in the event frame images are reconstructed in three dimensions to obtain the three-dimensional motion trajectory contour of the surface of the object under test during the two adjacent exposure intervals, and the three-dimensional motion trajectory contour is used as the high temporal resolution motion contour.

[0046] In this embodiment of the invention, a time-controlled non-contact deformation measurement method is provided, which is described in detail using the deformation measurement of a turntable with a radius of 0.5m that is accelerated from a stationary state to a rotation speed of 20,000 rpm as an example.

[0047] Step 1: Determine the timing control parameters of the industrial camera.

[0048] First, two key parameters are calculated: the single exposure time t of the camera and the exposure interval T between two adjacent exposures. The timing signal acquisition and control diagram is shown below. Figure 2 As shown.

[0049] In this embodiment, the linear velocity of the turntable edge is measured to be 523.5 m / s. A megapixel (1280×1024) resolution camera is used to photograph a turntable with a diameter of 1 m, resulting in an image pixel resolution of 1 mm. A first time threshold t1 is determined based on the motion speed and measurement accuracy requirements. t1 is used to ensure image clarity, and is calculated as t1 = (ε×R) / v, where v is the maximum motion speed of the measured object, R is the image pixel resolution, and ε is the maximum allowable image motion blur pixel value. Setting ε to 0.1 pixels, t1 = (0.1×1 mm) / 523.5 m / s ≈ 0.19 μs. The single exposure time t is determined to be less than or equal to the first time threshold t1. In this embodiment, the single exposure time t is set to 100 ns, resulting in a turntable edge displacement of approximately 0.05 mm within the exposure time, corresponding to an image size of 0.05 pixels. This ensures that the camera captures a clear image of the high-speed rotation of the turntable within the exposure time.

[0050] In this embodiment, the time it takes for the turntable to reach 20,000 rpm from a stationary state is set to 10 minutes. To measure the surface deformation of the turntable throughout the entire process of increasing the rotational speed, the exposure interval T between two adjacent exposures needs to be determined. A second time threshold t2 is determined based on the amount of image data per frame, the number of cameras, and the data transmission bandwidth. Here, t2 is used to determine the upper limit of the data transmission bandwidth: t2 = (D × N) / M, where D is the amount of image data per frame, N is the number of cameras, and M is the upper limit of the data transmission bandwidth. In this embodiment, the camera image bit depth is set to 12, so the megapixel image space size is approximately 14 MB. Using two industrial cameras, D = 14 MB, N = 2. Using a USB 3.0 interface with a transmission rate of approximately 400 MB / s, t2 = (14 × 2) / 400 = 0.07 s. The exposure interval T between two adjacent exposures is determined to be greater than or equal to the second time threshold t2. In this embodiment, the sequence sampling interval T is set to 1 s, which is much greater than 0.07 s, ensuring that the proposed camera measurement system can achieve deformation measurement throughout the entire high-speed movement of the turntable. After setting the above parameters, the schematic diagram of the timing control for the transition state measurement of the wheel acceleration is as follows: Figure 3 As shown.

[0051] In some embodiments, the two parameters, namely the single exposure time t and the exposure interval T between two adjacent exposures, can be designed according to experimental requirements. The design result depends on the size and speed of the high-speed moving object, the camera resolution, and the required deformation measurement accuracy. For example, if the experimental objective is only to record the deformation state of the object as it moves from low speed to high speed, the need for deformation measurement during high-speed motion is more urgent. In this case, the exposure interval T between two adjacent exposures during low-speed motion can be designed to be larger, such as 5s, while the exposure interval T between two adjacent exposures during high-speed motion can be designed to be smaller, such as 0.2s.

[0052] This design is also applicable to non-contact deformation measurement tests in other scenarios, such as calculating the single exposure time t and the exposure interval T between two adjacent exposures in the measurement system proposed in this invention, combined with fatigue testing. If the expected fatigue failure cycle count is 10... 6The observation area is 10mm × 20mm. The loading frequency of the fatigue testing machine is set to 50Hz, meaning one loading cycle is 20ms, and the fatigue duration is expected to be 5.6 hours. The single exposure time t of a conventional industrial camera is approximately 20μs, which meets the dynamic image acquisition requirements of the fatigue test. Therefore, a common industrial camera is selected as the acquisition device, and the single exposure time t is set to 20μs. The exposure interval T between two adjacent exposures is set to 10s, meaning approximately 2000 data points will be collected throughout the fatigue test, meeting the experimental observation requirements. If the selected camera has a resolution of one megapixel (1280 × 1024), then one pixel is 20μm. Both parameters ensure long-term, high-precision surface image measurement of the component. The fatigue test timing control diagram is shown below. Figure 4 As shown.

[0053] Step 2: Obtain the internal and external parameters of the industrial camera.

[0054] The two industrial cameras were calibrated. In this embodiment, Zhang Zhengyou's calibration method was used to calibrate the intrinsic and extrinsic parameters of the camera system. The first step was to collect calibration data. A checkerboard calibration board was placed in front of the two camera measurement systems. Each time the checkerboard changed position or orientation, the industrial camera simultaneously captured and stored images of the checkerboard. To ensure the accuracy of the camera calibration results, at least 10 sets of images from different positions on the checkerboard should be collected. The second step was to process the calibration data. Using the checkerboard images collected by the system, combined with Zhang Zhengyou's calibration method, the intrinsic and extrinsic parameters of the camera were calibrated through processes such as corner detection, initialization of camera parameters, and nonlinear optimization of camera intrinsic and extrinsic parameters. The intrinsic parameters of the calibrated camera included the camera principal point coordinates u0 and v0, and the equivalent focal length f. x f And distortion coefficients k1, k2, etc., and extrinsic parameters including rotation matrix R and translation vector T.

[0055] Step 3: Obtain the coordinate system transformation matrix between the industrial camera and the event camera.

[0056] In this embodiment, based on the completed industrial camera calibration, a joint calibration of the event camera and the industrial camera is further performed. A checkerboard calibration board is placed within the common field of view of both the industrial camera and the event camera, and both cameras simultaneously acquire checkerboard images. The industrial camera acquires a clear checkerboard image, while the event camera outputs event stream data including edge brightness changes as the checkerboard moves. The event stream data is accumulated over a time window to generate event frame images. The corner coordinates in the industrial camera image and the corresponding corner coordinates in the event frame image are extracted. The rotation matrix and translation vector between the event camera coordinate system and the industrial camera coordinate system are solved using the PnP algorithm to obtain the coordinate system transformation matrix. This coordinate system transformation matrix is ​​used to subsequently unify the 3D point cloud reconstructed by the event camera into the world coordinate system of the industrial camera.

[0057] Step 4: Generate a trigger signal based on the timing control parameters to control the industrial camera to acquire a sequence of images and generate the first data stream.

[0058] Set up a deformation measurement system. The measurement system includes the test piece to be measured, an industrial camera and lens assembly, a light source, an event camera, a timing control module, and a computer. The industrial camera and lens assembly includes two industrial cameras, positioned in front of the high-speed moving object with a field of view angle of 30°-60°, ensuring clear imaging of the camera system during the experiment.

[0059] Based on the single exposure time t=100ns and exposure interval time T=1s in the timing control parameters determined in step 1, a trigger signal with these values ​​is generated. This trigger signal is sent to the industrial camera, which then acquires a sequence of images of the surface of the object under test according to the timing control parameters. During each exposure, a synchronous trigger signal is sent to the light source to control the light source to provide illumination within the exposure time. In this embodiment, a laser light source with better supplementary lighting effect is used. The rising edge of the control signal is later than the rising edge of the camera's single trigger signal, and the falling edge is earlier than the falling edge of the camera's single trigger signal. This allows the light source to flash during each single imaging exposure of the camera, ensuring clear imaging. The acquired sequence of images is then used as the first data stream.

[0060] Step 5: Control the event camera to output event stream data and generate a second data stream.

[0061] In this embodiment, while the industrial camera acquires a sequence of images, an event camera is controlled to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner. First, the event camera is initialized, a contrast threshold for brightness changes is set, and continuous acquisition mode is initiated. The event camera monitors the brightness changes on the surface of the object under test pixel by pixel in real time. When the brightness change of any pixel exceeds the contrast threshold, a raw event is immediately generated. This raw event includes the current timestamp, the coordinates of the pixel, and the directional polarity of the brightness change. The raw events are arranged in chronological order and continuously output as an asynchronous event stream data, serving as the second data stream.

[0062] Step 6: Align the first data stream and the second data stream along the same timeline.

[0063] The acquisition time of each frame in the first data stream is matched with the timestamp of each event in the second data stream to establish a unified timeline correspondence, so that the first data stream and the second data stream are aligned according to a unified timeline.

[0064] Step 7: Analyze the second data stream in real time and calculate the instantaneous motion state parameters of the object under test.

[0065] The system receives a second data stream in real time, performs accumulation and clustering processing on the second data stream, and extracts the event density, event change rate, and spatial distribution characteristics of event clusters within each time window. The spatial distribution characteristics include the centroid coordinates, contour edges, spatial span, and timestamp distribution of events within the cluster.

[0066] Based on the event density and the rate of change of the events, the instantaneous translational velocity or instantaneous translational acceleration of the measured object can be calculated. For example, the instantaneous translational velocity can be calculated from the displacement of the center of mass of the event cluster per unit time, and the instantaneous translational acceleration can be calculated from the rate of change of the event change rate.

[0067] Based on the spatial distribution characteristics of event clusters, the instantaneous rotational angular velocity, instantaneous local strain rate, or instantaneous vibration mode of the measured object is calculated. For example, the instantaneous rotational angular velocity is calculated from the centroid displacement trajectory of the event cluster within adjacent time windows; the instantaneous local strain rate is calculated from the contour edge changes and spatial span changes of the event cluster, where contour edge changes characterize the tensile or compressive deformation of the measured object's surface, and spatial span changes characterize the degree of expansion or contraction of the measured object's surface region; and the instantaneous vibration frequency and instantaneous vibration amplitude are calculated from the timestamp distribution of events within the event cluster, serving as the instantaneous vibration mode.

[0068] At least one of the instantaneous translational velocity, instantaneous translational acceleration, instantaneous rotational angular velocity, instantaneous local strain rate, and instantaneous vibration mode is used as the instantaneous motion state parameter.

[0069] Step 8: Dynamically adjust the timing control parameters based on the instantaneous motion state parameters to control the image acquisition of the industrial camera.

[0070] The instantaneous motion state parameters are compared with preset dynamic thresholds. When the instantaneous motion state parameters exceed the dynamic thresholds, it is determined that a critical transient event has occurred. In this embodiment, the preset dynamic thresholds include velocity thresholds, acceleration thresholds, angular velocity thresholds, strain rate thresholds, and vibration amplitude thresholds. The specific values ​​are preset based on the material properties of the object under test, the test target requirements, and historical test data.

[0071] The interval time threshold is set based on the type of critical transient event, the minimum trigger interval limit of the industrial camera, and the upper limit of the data transmission bandwidth. For example, when an instantaneous speed exceeds the speed threshold, a smaller interval time threshold is set according to the degree of speed exceedance; when the minimum trigger interval of the industrial camera is 100μs and the minimum interval corresponding to the upper limit of the data transmission bandwidth is 0.07s, the interval time threshold is the larger of the two values.

[0072] Based on the determination of the critical transient event, the exposure interval T in the timing control parameters is dynamically adjusted. During the duration of the critical transient event, the exposure interval T is shortened to the interval time threshold. Specifically, this includes: when the instantaneous motion state parameter exceeds the dynamic threshold, the trigger mode of the industrial camera is switched from the equal-interval timed trigger mode to the event trigger mode. In the event trigger mode, the interval between two adjacent exposures of the industrial camera is dynamically set to the interval time threshold; the second data stream is analyzed in real time, and specific event types are identified. When a specific event type is identified, a trigger signal is immediately generated. The trigger signal controls the industrial camera to perform image acquisition, and the interval between two adjacent exposures is less than or equal to the interval time threshold. Specific event types include the number of events accumulated per unit time exceeding the first event density threshold, the time interval between adjacent events being less than the first time interval threshold, and the analyzed instantaneous velocity exceeding the first velocity threshold; the instantaneous motion state parameter is continuously monitored. When the instantaneous motion state parameter falls back below the preset dynamic threshold, the critical transient event is determined to have ended, the trigger mode of the industrial camera is switched back to the equal-interval timed trigger mode, and the interval between two adjacent exposures is restored to the initial exposure interval T=1s.

[0073] An updated trigger signal is generated based on the adjusted exposure interval T. The industrial camera is then controlled to acquire images according to the shortened exposure interval, thereby capturing the detailed deformation process of the object under test at a higher sampling frequency during critical transient events.

[0074] Step 9: Perform digital image correlation matching and 3D reconstruction on the first data stream based on intrinsic and extrinsic parameters to obtain a high spatial resolution deformation field.

[0075] The system processes and analyzes the first data stream acquired to calculate the deformation of the turntable surface. In this embodiment, the Digital Image Correlation (DIC) algorithm is used to process the acquired turntable surface image to achieve the final deformation calculation. The calculation process is as follows:

[0076] Step 9.1: Divide each frame sequence image in the first data stream into multiple overlapping or adjacent computational sub-regions according to the preset sub-region size and sub-region step size.

[0077] Step 9.2: Based on stereo image pairs acquired by different industrial cameras at the same sampling time, stereo matching is performed on the stereo image pairs using the zero-mean normalized cross-correlation algorithm to determine the corresponding points in the different camera images that correspond to the same physical point on the surface of the object being measured, thus obtaining stereo matching point pairs.

[0078] Step 9.3: Between sequential images acquired at different sampling times by the same industrial camera, time-series matching is performed using the zero-mean normalized cross-correlation algorithm to determine the corresponding points of the same physical point on the surface of the object under test in the images before and after deformation, thus obtaining time-series matching point pairs.

[0079] Step 9.4: Based on the intrinsic and extrinsic parameters of the industrial camera, use triangulation to perform three-dimensional reconstruction of the stereo matching point pairs to obtain the full-field three-dimensional point cloud data of the surface of the object under test at each sampling time.

[0080] Step 9.5: Establish the point correspondence between different sampling times using time-series matching point pairs, perform interpolation and difference calculation on the full-field three-dimensional point cloud data to obtain the full-field displacement field of the surface of the measured object, perform numerical differentiation calculation on the full-field displacement field to obtain the full-field strain field, and use it as a high spatial resolution deformation field.

[0081] Step 10: Perform event-driven 3D reconstruction based on the second data stream and coordinate system transformation matrix to obtain a high temporal resolution motion profile.

[0082] Within the exposure interval T between two consecutive exposures, the second data stream is accumulated according to a preset time window to generate an event frame image. The grayscale value of each pixel in the event frame image is the number of events occurring at the current pixel coordinate position within that time window, or the event polarity integral. The width of the time window is dynamically adjusted based on the motion speed of the object being measured and the desired temporal resolution; when the instantaneous motion state parameters increase, the width of the time window decreases; when the instantaneous motion state parameters decrease, the width of the time window increases.

[0083] Feature matching is performed on event frame images generated by different event cameras or event frame images generated by the same event camera in different time windows to determine the correspondence of corresponding points between event frame images.

[0084] Based on the coordinate system transformation matrix and the correspondence of corresponding points, the corresponding points matched in the event frame image are reconstructed in three dimensions to obtain the three-dimensional motion trajectory contour of the surface of the object under test during the interval between two adjacent exposures, and the three-dimensional motion trajectory contour is used as the high temporal resolution motion contour.

[0085] Step 11: Data fusion to generate three-dimensional deformation measurement results.

[0086] The high temporal resolution motion profile is fused into the spatial coordinate system of the high spatial resolution deformation field using interpolation registration. Specifically, using the high spatial resolution deformation field as a spatial reference, the high temporal resolution motion profile is interpolated and registered to the same spatial coordinate system, generating a final 3D deformation measurement result that combines high spatial and temporal resolution. This fused result includes both high-precision full-field deformation information at the sampling time of the industrial camera and high temporal resolution motion details during the sampling interval, fully presenting the deformation evolution of the measured object throughout the entire experiment.

[0087] Thus, the surface deformation measurement of the turntable was completed during the entire process of gradually increasing the speed from a stationary state to 20,000 rpm.

[0088] In this embodiment, a computer device is provided, such as... Figure 5 As shown, it includes a memory 501, a processor 502, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described time-controlled non-contact deformation measurement method.

[0089] Specifically, the computer device can be a computer terminal, a server, or a similar computing device.

[0090] In this embodiment, a computer-readable storage medium is provided, which stores a computer program that performs any of the time-controlled non-contact deformation measurement methods described above.

[0091] Specifically, computer-readable storage media include both permanent and non-permanent, removable and non-removable media, which can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer-readable storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media do not include transient media, such as modulated data signals and carrier waves.

[0092] Based on the same inventive concept, this invention also provides a time-controlled non-contact deformation measurement device, as described in the following embodiments. Since the principle of the time-controlled non-contact deformation measurement device is similar to that of the time-controlled non-contact deformation measurement method, the implementation of the time-controlled non-contact deformation measurement device can refer to the implementation of the time-controlled non-contact deformation measurement method, and will not be repeated. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0093] Figure 6 This is a structural block diagram of a time-controlled non-contact deformation measuring device according to an embodiment of the present invention, such as... Figure 6 As shown, it includes: a parameter acquisition and determination module 601, a data acquisition module 602, an analysis and adjustment module 603, and a measurement result generation module 604. The structure is described below.

[0094] The parameter acquisition and determination module 601 is used to determine the timing control parameters of the industrial camera, acquire the intrinsic and extrinsic parameters of the industrial camera, and acquire the coordinate system transformation matrix between the industrial camera and the event camera. The timing control parameters include the single exposure time t and the exposure interval T between two adjacent exposures.

[0095] The data acquisition module 602 is used to generate a trigger signal according to the timing control parameters, control the industrial camera to acquire a sequence of images of the surface of the object under test based on the trigger signal, and synchronously trigger the light source to provide illumination during each exposure to generate a first data stream, control the event camera to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner to generate a second data stream, and align the first data stream and the second data stream with a unified time axis.

[0096] The parsing and adjustment module 603 is used to parse the second data stream in real time, calculate the instantaneous motion state parameters of the object under test, dynamically adjust the timing control parameters according to the instantaneous motion state parameters, and control the acquisition of the sequence images of the industrial camera based on the adjusted timing control parameters.

[0097] The measurement result generation module 604 is used to perform digital image correlation matching and three-dimensional reconstruction on the first data stream based on the intrinsic and extrinsic parameters to obtain the high spatial resolution deformation field of the object under test at the sampling time. Based on the second data stream and the coordinate system transformation matrix, event-driven three-dimensional reconstruction is performed to obtain the high temporal resolution motion contour of the object under test during two adjacent exposure intervals. The high temporal resolution motion contour is fused into the spatial coordinate system of the high spatial resolution deformation field by interpolation registration method to generate a three-dimensional deformation measurement result.

[0098] In one embodiment, the module for obtaining and determining parameters includes:

[0099] The first time threshold unit is calculated to determine the first time threshold t1 based on the motion speed and measurement accuracy requirements. The first time threshold t1 is used to ensure image clarity. t1 = (ε × R) / v, where v is the maximum motion speed of the measured object, R is the image pixel resolution, and ε is the maximum allowable image motion blur pixel value.

[0100] The second time threshold unit is calculated to determine the second time threshold t2 based on the amount of single-frame image data, the number of cameras, and the data transmission bandwidth. The second time threshold t2 is used to determine the upper limit of the data transmission bandwidth, t2=(D×N) / M, where D is the amount of single-frame image data, N is the number of cameras, and M is the upper limit of the data transmission bandwidth.

[0101] A single exposure time unit is determined to determine the single exposure time t, such that the single exposure time t is less than or equal to a first time threshold t1;

[0102] An exposure interval time unit is defined to determine the exposure interval time T between two adjacent exposures, such that the exposure interval time T is greater than or equal to a second time threshold t2;

[0103] A timing control parameter determination unit is used to use the single exposure time t and the exposure interval time T as timing control parameters.

[0104] In one embodiment, the data acquisition module includes:

[0105] A trigger signal generation unit is used to generate a trigger signal having the single exposure time t and the exposure interval time T in the timing control parameters.

[0106] A first data stream generation unit is used to send the trigger signal to the industrial camera, control the industrial camera to acquire a sequence of images of the surface of the object under test according to the timing control parameters, send a synchronization trigger signal to the light source during each exposure, control the light source to provide illumination within the exposure time, and use the acquired sequence of images as the first data stream.

[0107] Start the event camera unit to initialize the event camera, set the contrast threshold for brightness changes, and start the continuous acquisition mode;

[0108] A raw event unit is generated to monitor the brightness change of the surface of the object under test in real time, pixel by pixel, through the event camera. When the brightness change of any pixel exceeds the contrast threshold, a raw event containing the current timestamp, pixel coordinates and the polarity of the brightness change direction is generated.

[0109] A second data stream unit is generated to arrange the original events in chronological order and output them as asynchronous event stream data as the second data stream;

[0110] The timeline alignment unit is used to match the acquisition time of each frame of image in the first data stream with the timestamp of each event in the second data stream, establish a unified timeline correspondence, and align the first data stream and the second data stream according to a unified timeline.

[0111] In one embodiment, the parsing adjustment module includes:

[0112] The feature extraction unit is used to receive the second data stream in real time, perform accumulation and clustering processing on the second data stream, and extract the event density, event change rate and spatial distribution features of event clusters within each time window. The spatial distribution features include the centroid coordinates, contour edges, spatial span and timestamp distribution of events within the cluster.

[0113] The first parameter calculation unit is used to calculate the instantaneous translational velocity or instantaneous translational acceleration of the measured object based on the event density and the event change rate.

[0114] The second parameter calculation unit is used to calculate the instantaneous rotational angular velocity, instantaneous local strain rate, or instantaneous vibration mode of the measured object based on the spatial distribution characteristics of the event cluster.

[0115] The instantaneous motion state parameter acquisition unit is used to take at least one of the instantaneous translational velocity, instantaneous translational acceleration, instantaneous rotational angular velocity, instantaneous local strain rate and instantaneous vibration mode as the instantaneous motion state parameter;

[0116] The transient event determination unit is used to compare the instantaneous motion state parameters with a preset dynamic threshold. When the instantaneous motion state parameters exceed the dynamic threshold, it is determined that a critical transient event has occurred.

[0117] An interval time threshold unit is set to set an interval time threshold based on the type of the key transient event, the minimum trigger interval limit of the industrial camera, and the upper limit of the data transmission bandwidth.

[0118] The dynamic adjustment unit is used to dynamically adjust the exposure interval time T in the timing control parameters according to the determination result of the key transient event, and shorten the exposure interval time T to the interval time threshold during the duration of the key transient event.

[0119] The parameter application unit is used to generate an updated trigger signal based on the adjusted exposure interval time T, and to control the industrial camera to perform image acquisition according to the shortened exposure interval time based on the updated trigger signal.

[0120] In one embodiment, the dynamic adjustment unit is further configured to: switch the triggering mode of the industrial camera from an equal-interval timed triggering mode to an event-triggered mode when the instantaneous motion state parameter exceeds the dynamic threshold; dynamically set the interval between two adjacent exposures of the industrial camera to the interval time threshold in the event-triggered mode; parse the second data stream in real time and identify specific event types; immediately generate the trigger signal when the specific event type is identified; control the industrial camera to perform image acquisition through the trigger signal, and ensure that the interval between two adjacent exposures is less than or equal to the interval time threshold; wherein the specific event types include the number of events accumulated per unit time exceeding a first event density threshold, the time interval between adjacent events being less than a first time interval threshold, and the parsed instantaneous velocity exceeding a first velocity threshold; continuously monitor the instantaneous motion state parameter; determine that the key transient event has ended when the instantaneous motion state parameter falls below the preset dynamic threshold; switch the triggering mode of the industrial camera back to the equal-interval timed triggering mode; and restore the interval between two adjacent exposures to the exposure interval time T.

[0121] In one embodiment, the module for generating measurement results includes:

[0122] The step size division unit is used to divide each frame sequence image in the first data stream into multiple overlapping or adjacent computational sub-regions according to a preset sub-region size and sub-region step size.

[0123] A stereo matching point pair generation unit is used to perform stereo matching on stereo image pairs acquired by different industrial cameras at the same sampling time using a zero-mean normalized cross-correlation algorithm to determine the corresponding points in different camera images that correspond to the same physical point on the surface of the object under test, thereby obtaining stereo matching point pairs.

[0124] The point-to-point matching unit is used to perform temporal matching between sequential images acquired at different sampling times by the same industrial camera, using a zero-mean normalized cross-correlation algorithm, to determine the corresponding points of the same physical point on the surface of the object under test in the images before and after deformation, and to obtain temporal matching point pairs.

[0125] The three-dimensional reconstruction unit is used to perform three-dimensional reconstruction of the stereo matching point pair based on the intrinsic and extrinsic parameters using triangulation methods, so as to obtain the full-field three-dimensional point cloud data of the surface of the object under test at each sampling time.

[0126] The deformation field calculation unit is used to establish the point correspondence between different sampling times using the time-series matching point pairs, perform interpolation and difference calculation on the full-field three-dimensional point cloud data to obtain the full-field displacement field of the surface of the object under test, perform numerical differentiation calculation on the full-field displacement field to obtain the full-field strain field, and use it as the high spatial resolution deformation field.

[0127] In one embodiment, the module for generating measurement results further includes:

[0128] An event frame image generation unit is used to accumulate the second data stream within the exposure interval T between two adjacent exposures according to a preset time window to generate an event frame image, wherein the grayscale value of each pixel in the event frame image is the number of events occurring at the current pixel coordinate position within the time window or the event polarity integral.

[0129] A correspondence construction unit is used to perform feature matching on the event frame images generated by different event cameras or the event frame images generated by the same event camera in different time windows, and to determine the correspondence between the corresponding points of the event frame images.

[0130] The motion contour unit is extracted and used to perform three-dimensional reconstruction on the matched corresponding points in the event frame image based on the coordinate system transformation matrix and the correspondence of the corresponding points, so as to obtain the three-dimensional motion trajectory contour of the surface of the object under test during the two adjacent exposure intervals, and the three-dimensional motion trajectory contour is used as the high temporal resolution motion contour.

[0131] The embodiments of the present invention achieve the following technical effects:

[0132] By designing timing control parameters that combine short exposures with long intervals, the contradiction between clear imaging of high-speed moving objects and long-term continuous acquisition was resolved. By introducing an event camera for asynchronous event stream acquisition, real-time monitoring of microscopic changes on the object surface during the sampling interval was achieved. Through adaptive triggering adjustment based on event stream data, the sampling frequency was automatically increased when key transient events occurred, capturing complete deformation details without increasing the overall data volume. Through dual-channel data fusion, deformation measurement results with both high spatial and temporal resolution were generated, providing more comprehensive data support for the structural integrity assessment of high-speed moving components.

[0133] Obviously, those skilled in the art should understand that the modules or steps of the above-described embodiments of the present invention can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the embodiments of the present invention are not limited to any particular hardware and software combination.

[0134] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A time-controlled non-contact deformation measurement method, characterized in that, include: Determine the timing control parameters of the industrial camera, obtain the intrinsic and extrinsic parameters of the industrial camera, and obtain the coordinate system transformation matrix between the industrial camera and the event camera. The timing control parameters include the single exposure time t and the exposure interval T between two adjacent exposures. Determine the timing control parameters of the industrial camera, including: A first time threshold t1 is determined based on the motion speed and measurement accuracy requirements, where the first time threshold t1 is used to ensure image clarity, t1 = (ε × R) / v, where v is the maximum motion speed of the measured object, R is the image pixel resolution, and ε is the maximum allowable image motion blur pixel value. A second time threshold t2 is determined based on the amount of image data per frame, the number of cameras, and the data transmission bandwidth, where the second time threshold t2 is used to determine the upper limit of the data transmission bandwidth, t2 = (D × N) / M, where D is the amount of image data per frame, N is the number of cameras, and M is the upper limit of the data transmission bandwidth. A single exposure time t is determined such that the single exposure time t is less than or equal to the first time threshold t1. An exposure interval time T between two adjacent exposures is determined such that the exposure interval time T is greater than or equal to the second time threshold t2. The single exposure time t and the exposure interval time T are used as timing control parameters. A trigger signal is generated according to the timing control parameters. Based on the trigger signal, the industrial camera is controlled to acquire a sequence of images of the surface of the object under test. During each exposure, the light source is synchronously triggered to provide illumination, generating a first data stream. The event camera is controlled to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner, generating a second data stream. The first data stream and the second data stream are aligned with a unified time axis. The second data stream is parsed in real time, the instantaneous motion state parameters of the object under test are calculated, the timing control parameters are dynamically adjusted according to the instantaneous motion state parameters, and the acquisition of sequential images of the industrial camera is controlled based on the adjusted timing control parameters. Based on the intrinsic and extrinsic parameters, digital image correlation matching and 3D reconstruction are performed on the first data stream to obtain the high spatial resolution deformation field of the object under test at the sampling time. Based on the second data stream and the coordinate system transformation matrix, event-driven 3D reconstruction is performed to obtain the high temporal resolution motion profile of the object under test during the interval between two adjacent exposures. The high temporal resolution motion profile is fused into the spatial coordinate system of the high spatial resolution deformation field by interpolation registration to generate a 3D deformation measurement result.

2. The time-controllable non-contact deformation measurement method as described in claim 1, characterized in that, A trigger signal is generated according to the timing control parameters. Based on the trigger signal, the industrial camera is controlled to acquire a sequence of images of the surface of the object under test. During each exposure, a light source is synchronously triggered to provide illumination, generating a first data stream. The event camera is controlled to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner, generating a second data stream. The first data stream and the second data stream are aligned along a unified time axis, including: Based on the single exposure time t and the exposure interval time T in the timing control parameters, a trigger signal with the single exposure time t and the exposure interval time T is generated; The trigger signal is sent to the industrial camera to control the industrial camera to acquire a sequence of images of the surface of the object under test according to the timing control parameters. During each exposure, a synchronous trigger signal is sent to the light source to control the light source to provide illumination within the exposure time, and the acquired sequence of images is used as the first data stream. Initialize the event camera, set the contrast threshold for brightness changes, and start the continuous acquisition mode; The event camera monitors the brightness changes of the surface of the object under test in real time, pixel by pixel. When the brightness change of any pixel exceeds the contrast threshold, an original event containing the current timestamp, pixel coordinates and the polarity of the brightness change direction is generated. The original events are arranged in chronological order and output as asynchronous event stream data, serving as the second data stream; The acquisition time of each frame in the first data stream is matched with the timestamp of each event in the second data stream to establish a unified timeline correspondence, so that the first data stream and the second data stream are aligned according to a unified timeline.

3. The time-controlled non-contact deformation measurement method as described in claim 1, characterized in that, The process includes real-time parsing of the second data stream, calculation of the instantaneous motion state parameters of the object under test, dynamic adjustment of the timing control parameters based on the instantaneous motion state parameters, and control of the acquisition of sequential images from the industrial camera based on the adjusted timing control parameters. The second data stream is received in real time, and the second data stream is accumulated and clustered to extract the event density, event change rate and spatial distribution features of event clusters within each time window. The spatial distribution features include the centroid coordinates, contour edges, spatial span and timestamp distribution of events within the cluster. The instantaneous translational velocity or instantaneous translational acceleration of the measured object is calculated based on the event density and the event change rate. Based on the spatial distribution characteristics of the event cluster, the instantaneous rotational angular velocity, instantaneous local strain rate, or instantaneous vibration mode of the measured object are calculated. The instantaneous translational velocity, instantaneous translational acceleration, instantaneous rotational angular velocity, instantaneous local strain rate, and instantaneous vibration mode are used as the instantaneous motion state parameters; The instantaneous motion state parameters are compared with a preset dynamic threshold. When the instantaneous motion state parameters exceed the dynamic threshold, it is determined that a critical transient event has occurred. The interval time threshold is set according to the type of the key transient event, the minimum trigger interval limit of the industrial camera, and the upper limit of the data transmission bandwidth; Based on the determination result of the critical transient event, the exposure interval time T in the timing control parameters is dynamically adjusted, and during the duration of the critical transient event, the exposure interval time T is shortened to the interval time threshold. An updated trigger signal is generated based on the adjusted exposure interval T, and the industrial camera is controlled to acquire images according to the shortened exposure interval based on the updated trigger signal.

4. The time-controllable non-contact deformation measurement method as described in claim 3, characterized in that, Based on the determination result of the critical transient event, the exposure interval time T in the timing control parameters is dynamically adjusted. During the duration of the critical transient event, the exposure interval time T is shortened to the interval time threshold, including: When the instantaneous motion state parameter exceeds the dynamic threshold, the triggering mode of the industrial camera is switched from the equal interval timed triggering mode to the event triggering mode. In the event triggering mode, the interval between two adjacent exposures of the industrial camera is dynamically set to the interval time threshold. The second data stream is parsed in real time, and specific event types are identified. When the specific event type is identified, the trigger signal is generated immediately. The trigger signal controls the industrial camera to perform image acquisition, and the interval between two adjacent exposures is less than or equal to the interval time threshold. The specific event type includes the number of events accumulated per unit time exceeding a first event density threshold, the time interval between adjacent events being less than a first time interval threshold, and the parsed instantaneous velocity exceeding a first velocity threshold. The instantaneous motion state parameters are continuously monitored. When the instantaneous motion state parameters fall below the preset dynamic threshold, the key transient event is determined to have ended. The trigger mode of the industrial camera is switched back to the equal-interval timed trigger mode, and the interval between two adjacent exposures is restored to the exposure interval time T.

5. The time-controllable non-contact deformation measurement method as described in claim 1, characterized in that, Based on the intrinsic and extrinsic parameters, digital image correlation matching and 3D reconstruction are performed on the first data stream to obtain the high spatial resolution deformation field of the measured object at the sampling time, including: Each frame sequence image in the first data stream is divided into multiple overlapping or adjacent computational sub-regions according to a preset sub-region size and sub-region step size; Based on stereo image pairs acquired by different industrial cameras at the same sampling time, stereo matching is performed on the stereo image pairs using a zero-mean normalized cross-correlation algorithm to determine the corresponding points in the different camera images that correspond to the same physical point on the surface of the object being measured, thus obtaining stereo matching point pairs. Between sequential images acquired at different sampling times by the same industrial camera, time-series matching is performed using a zero-mean normalized cross-correlation algorithm to determine the corresponding points of the same physical point on the surface of the object under test in the images before and after deformation, thus obtaining time-series matching point pairs. Based on the aforementioned intrinsic and extrinsic parameters, the three-dimensional matching point pairs are reconstructed using triangulation methods to obtain full-field three-dimensional point cloud data of the surface of the object under test at each sampling time. By using the time-series matching point pairs to establish the point correspondence between different sampling times, interpolation and difference calculations are performed on the full-field three-dimensional point cloud data to obtain the full-field displacement field of the surface of the object under test. The full-field displacement field is numerically differentiated to obtain the full-field strain field, which is then used as the high spatial resolution deformation field.

6. The time-controllable non-contact deformation measurement method as described in claim 1, characterized in that, Event-driven 3D reconstruction is performed based on the second data stream and the coordinate system transformation matrix to obtain the high temporal resolution motion profile of the object under test during the interval between two adjacent exposures, including: Within the exposure interval T between two adjacent exposures, the second data stream is accumulated according to a preset time window to generate an event frame image, wherein the grayscale value of each pixel in the event frame image is the number of events occurring at the current pixel coordinate position within the time window or the event polarity integral. Feature matching is performed on the event frame images generated by different event cameras or the event frame images generated by the same event camera in different time windows to determine the correspondence of corresponding points between the event frame images; Based on the coordinate system transformation matrix and the correspondence of the corresponding points, the corresponding points matched in the event frame image are reconstructed in three dimensions to obtain the three-dimensional motion trajectory contour of the surface of the object under test during the two adjacent exposure intervals, and the three-dimensional motion trajectory contour is used as the high temporal resolution motion contour.

7. A time-controlled non-contact deformation measuring device, said measuring device being used to perform the measuring method of claim 1, characterized in that, include: The parameter acquisition and determination module is used to determine the timing control parameters of the industrial camera, acquire the intrinsic and extrinsic parameters of the industrial camera, and acquire the coordinate system transformation matrix between the industrial camera and the event camera. The timing control parameters include the single exposure time t and the exposure interval T between two adjacent exposures. The module for obtaining and determining parameters includes: The first time threshold unit is calculated to determine the first time threshold t1 based on the motion speed and measurement accuracy requirements. The first time threshold t1 is used to ensure image clarity. t1 = (ε × R) / v, where v is the maximum motion speed of the measured object, R is the image pixel resolution, and ε is the maximum allowable image motion blur pixel value. The second time threshold unit is calculated to determine the second time threshold t2 based on the amount of single-frame image data, the number of cameras, and the data transmission bandwidth. The second time threshold t2 is used to determine the upper limit of the data transmission bandwidth, t2=(D×N) / M, where D is the amount of single-frame image data, N is the number of cameras, and M is the upper limit of the data transmission bandwidth. A single exposure time unit is determined to determine the single exposure time t, such that the single exposure time t is less than or equal to a first time threshold t1; An exposure interval time unit is defined to determine the exposure interval time T between two adjacent exposures, such that the exposure interval time T is greater than or equal to a second time threshold t2. A timing control parameter determination unit is used to use the single exposure time t and the exposure interval time T as timing control parameters; The data acquisition module is used to generate a trigger signal according to the timing control parameters, control the industrial camera to acquire a sequence of images of the surface of the object under test based on the trigger signal, and synchronously trigger the light source to provide illumination during each exposure to generate a first data stream, control the event camera to continuously output event stream data of pixel brightness changes on the surface of the object under test in an asynchronous manner to generate a second data stream, and align the first data stream and the second data stream with a unified time axis. The parsing and adjustment module is used to parse the second data stream in real time, calculate the instantaneous motion state parameters of the object under test, dynamically adjust the timing control parameters according to the instantaneous motion state parameters, and control the acquisition of the sequence images of the industrial camera based on the adjusted timing control parameters. The measurement result generation module is used to perform digital image correlation matching and 3D reconstruction on the first data stream based on the intrinsic and extrinsic parameters to obtain the high spatial resolution deformation field of the object under test at the sampling time. Based on the second data stream and the coordinate system transformation matrix, event-driven 3D reconstruction is performed to obtain the high temporal resolution motion contour of the object under test during the interval between two adjacent exposures. The high temporal resolution motion contour is fused into the spatial coordinate system of the high spatial resolution deformation field by interpolation registration method to generate 3D deformation measurement results.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the time-controlled non-contact deformation measurement method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that performs a time-controlled non-contact deformation measurement method according to any one of claims 1 to 6.

Images