Line-scan imaging cooperative control method and device under high-speed continuous relative motion condition

Abstract

The application discloses a line-scan imaging cooperative control method and device under high-speed continuous relative motion, and belongs to the technical field of machine vision and image acquisition. The method acquires the relative motion speed in real time during the imaging process by presetting the axial space sampling interval threshold and the single-row space image motion threshold, cooperatively controls the trigger row frequency and the single-row exposure integration time, makes the axial space sampling interval and the single-row space image motion satisfy the constraint condition, and applies the consistency constraint to avoid exposure overlap. The device comprises a speed acquisition module, a parameter setting module, a trigger row frequency control module, an exposure integration time control module, a constraint control module and an imaging execution module. The application guarantees the space sampling sufficiency along the relative motion direction and the single-row imaging definition under the premise of not reducing the operation efficiency, effectively suppresses the missing scan and the motion blur, the control logic is intuitive and clear, the applicability is strong, and the engineering implementation is facilitated.

Description

Technical Field

[0001] This invention relates to the field of high-speed motion imaging and precision detection and control technology, specifically a method and device for coordinated control of line scan imaging under high-speed continuous relative motion conditions. Background Technology

[0002] Line scan imaging systems acquire image information of the surface of the object being measured by sampling line by line. They offer advantages such as high resolution, stable imaging, and controllable data volume, and are widely used in industrial inspection, track inspection, mobile measurement, and online inspection. In these applications, there is usually relative motion between the line scan imaging system and the object being measured, and the image quality largely depends on the relative speed of this motion. Trigger line frequency and single-line exposure points time Reasonable setting of imaging parameters, etc.

[0003] Under conditions of low relative speed or intermittent motion, existing technologies typically achieve satisfactory imaging results using fixed trigger frequency and fixed exposure integration time. However, when the imaging system and the object under test are in a state of high-speed and continuous relative motion, especially when there are speed fluctuations or when both image sharpness and sampling integrity need to be considered, the coupling relationship between imaging parameters is significantly enhanced. Simply using fixed parameters or adjusting only a single parameter is insufficient to simultaneously meet the requirements of sufficient spatial sampling and image sharpness.

[0004] Specifically, the following technical problems exist under conditions of high-speed continuous relative motion:

[0005] First, trigger line frequency Directly determines the axial spatial sampling interval of adjacent scan lines in the direction of relative motion. Their relationship is .when When the setting is too low Enlarging the image can easily lead to missed areas in the measured region, affecting the integrity of the image; while When the setting is too high, although it can be reduced However, this will place higher demands on data transmission and processing capabilities, and may also limit exposure time, thus affecting image brightness.

[0006] Second, single-line exposure time. Directly affects spatial image shift caused by relative motion during single-line exposure. Their relationship is .when When the setting is too long, significant spatial image shift will occur during single-line imaging, causing stretching or blurring of fine features and reducing image resolution; while While a short time can reduce image shift, it will also reduce image brightness and affect the signal-to-noise ratio.

[0007] Third, in continuous trigger acquisition mode, and These are not independent parameters. The improvement will shorten the time interval between two adjacent triggers (trigger cycle). ),and If not By implementing coordination constraints, the following may occur: This can cause exposure overlap or imaging timing conflicts, leading to imaging failure. Therefore, in high-speed, continuous relative motion scenes, triggering line frequency... Exposure points time There are significant temporal consistency constraints between them.

[0008] In existing technologies, some solutions improve high-speed imaging by increasing line frequency, shortening exposure time, or limiting relative motion speed. For example, the solution disclosed in Chinese patent document CN106289106A can emit a trigger signal based on the object's speed to achieve trigger acquisition at a fixed distance. However, although this method achieves speed-based trigger control, it does not treat the axial spatial sampling interval and single-line spatial image shift as explicit physical constraints for coordinated control, nor does it address high-speed continuous motion scenarios. and The coupling relationship provides a temporal consistency constraint mechanism, but it is difficult to guarantee the stability of imaging quality when the speed changes significantly.

[0009] For example, the solution disclosed in Chinese patent document CN203365701U mainly solves the problem of image distortion correction, but does not involve a coordinated control strategy of dynamically adjusting the trigger line frequency and exposure integration time according to the motion speed, nor does it clarify the constraints on the axial spatial sampling interval and single-line spatial image shift.

[0010] For example, the solution disclosed in Chinese patent document CN104503306B is mainly aimed at intermittent triggering scenarios. It controls the shooting interval according to the preset overlap requirements, without considering the impact of spatial image shift on the image clarity during single-line exposure under high-speed continuous motion conditions of line scanning imaging. It also does not coordinate the constraints on the trigger line frequency and exposure integration time to avoid timing conflicts. Therefore, it is difficult to directly apply to the high-speed continuous imaging control of line scanning imaging systems.

[0011] Furthermore, existing line scan imaging systems generally employ a fixed trigger frequency coupled with an encoder, using encoder pulse signals to control the camera to continuously acquire images at a preset line frequency. This method yields good results under ideal conditions where the object moves at a uniform speed and its velocity is known. However, in practical applications, when the speed fluctuates or when balancing sampling density and image sharpness is required, the fixed-parameter approach struggles to adapt to dynamically changing conditions. Some solutions reduce motion blur by simply shortening the exposure time, but without simultaneously adjusting the trigger line frequency to ensure a reasonable sampling interval. This can lead to excessively large spacing between adjacent scan lines during high-speed motion, resulting in missed scans and affecting image integrity.

[0012] Therefore, there is an urgent need in this field for a universal collaborative control scheme: based on the minimum resolvable spatial scale of the target to be detected, the axial spatial sampling interval of adjacent scan lines is determined. Spatial image shift during single-line exposure As a definite physical constraint (e.g.) , ), and in meeting the imaging timing consistency constraint ( Under the premise of triggering line frequency Exposure points time By implementing systematic coordinated control, stable, clear, and complete line scan imaging results can be obtained under conditions of high-speed continuous relative motion. Summary of the Invention

[0013] This invention relates to a method and apparatus for coordinated control of line scanning imaging under high-speed continuous relative motion conditions, particularly addressing how to optimize the control parameters of a line scanning imaging system in high-speed moving environments to ensure imaging quality and sampling accuracy.

[0014] A collaborative control method for line scan imaging under high-speed continuous relative motion conditions includes the following steps:

[0015] A) Pre-set the maximum permissible axial spatial sampling interval threshold along the direction of relative motion between the line scan imaging system and the object under test. And the allowed single-line spatial image shift threshold ;

[0016] B) Acquire the relative motion velocity between the line scan imaging system and the object under test during the imaging process. ;

[0017] C) Based on the relative motion velocity With the maximum allowable axial space sampling interval threshold The trigger line frequency of the control line scanning imaging system The axial spatial sampling interval of adjacent scan lines in the direction of relative motion is increased. satisfy and ;

[0018] D) Based on the relative motion velocity With the single-row spatial image shift threshold The single-line exposure integration time of the control line scan imaging system This causes the spatial image generated during a single-line exposure along the direction of relative motion to shift... satisfy and ;

[0019] E) Control the trigger line frequency With the single-line exposure integration time The relationship between the single-line exposure integration time and the time between the two lines makes the single-line exposure integration time... Not exceeding the adjacent trigger interval, that is: ;

[0020] F) Based on the aforementioned trigger line frequency With the single-line exposure integration time It outputs trigger control signals and exposure control parameters to drive the line scan imaging system to perform line scan imaging acquisition.

[0021] Furthermore, the target step size for axial spatial sampling is preset. The Not greater than The expected sampling interval;

[0022] Triggering line frequency in step C) according to Confirmed, among which It is a rounding function;

[0023] The single-line exposure integration time mentioned in step D) according to Confirmed, among which This is a function that takes the minimum value.

[0024] Furthermore, the velocity estimate obtained by filtering and / or fusing multiple sensors on the measured velocity is used as the relative motion velocity. The relative motion velocity is updated according to a preset update cycle. This is used for subsequent calculations and updating of the trigger line frequency. With single-line exposure time ...

[0025] Furthermore, it also includes:

[0026] Real-time monitoring of the relative motion velocity The system monitors the speed fluctuations, generating a uniform motion alert signal when the speed fluctuations exceed a first preset threshold; and / or monitors the deviation of the line scan imaging system from the preset motion trajectory in real time, generating a trajectory adjustment alert signal when the deviation exceeds a second preset threshold.

[0027] Furthermore, it also includes:

[0028] Based on the relative motion speed Motion control commands are generated based on a preset motion trajectory. These commands are used to control the motion drive device of the line scan imaging system to adjust the motion speed and / or direction of the line scan imaging system.

[0029] A coordinated control device for line scanning imaging under high-speed continuous relative motion conditions includes:

[0030] The velocity acquisition module is used to acquire the relative velocity between the line scan imaging system and the object under test during the imaging process. ;

[0031] The parameter setting module is used to set the maximum allowable axial space sampling interval threshold. And the allowed single-line spatial image shift threshold ;

[0032] Trigger the line frequency control module to control the relative motion speed. and the maximum allowable axial space sampling interval threshold Control trigger line frequency This allows for the axial spatial sampling interval between adjacent scan lines in the direction of relative motion. satisfy and ;

[0033] The exposure integration time control module is used to control the relative motion speed. and the single-line spatial image shift threshold Controlling single-line exposure integration time This causes the spatial image generated along the direction of relative motion during single-line exposure integration to shift... satisfy and ;

[0034] The constraint control module is used to control the trigger line frequency. and the single-line exposure integration time The relationship makes ;

[0035] The imaging execution module is used to determine the trigger line frequency. and the single-line exposure integration time It outputs trigger control signals and exposure control parameters to drive the line scan imaging system to perform line scan imaging acquisition.

[0036] Furthermore, the speed acquisition module includes one or a combination of an encoder, an odometer, and an inertial measurement unit.

[0037] Furthermore, the trigger line frequency control module is configured according to... Determine the trigger line frequency, where The target sampling step size is a preset axial space and is no greater than 1. The expected sampling interval is It is a rounding function;

[0038] The single-line exposure integral time control module is according to Determine the single-line exposure integral time, where This is a function that takes the minimum value.

[0039] Furthermore, it also includes:

[0040] The motion monitoring module is used to monitor the relative motion speed in real time. The system monitors the speed fluctuations, generating a uniform motion alert signal when the speed fluctuations exceed a first preset threshold; and / or monitors the deviation of the line scan imaging system from the preset motion trajectory in real time, generating a trajectory adjustment alert signal when the deviation exceeds a second preset threshold.

[0041] Furthermore, it also includes:

[0042] Motion control module, used for based on the relative motion speed Motion control commands are generated based on a preset motion trajectory. These commands are used to control the motion drive device of the line scan imaging system to adjust the motion speed and / or direction of the line scan imaging system.

[0043] Compared with existing technologies, the present invention introduces an axial spatial sampling interval threshold. With single-line spatial image shift threshold Based on this, the trigger line frequency and single-line exposure integration time are subject to coordinated constraints, enabling the line scan imaging system to maintain stable imaging timing and controllable imaging quality even under high-speed, continuous relative motion conditions. Without significantly reducing the relative motion speed or sacrificing operational efficiency, this invention ensures sufficient axial spatial sampling along the relative motion direction, avoiding missed scans caused by excessive spacing between adjacent scan lines. Furthermore, it effectively limits spatial image shift during single-line exposure, thereby suppressing motion blur and improving the discriminability of fine target features. Because this invention uses clearly defined physical quantities and their constraints as the control basis, and the parameter calculation and control logic are intuitive and clear, it is applicable to different speed conditions and various types of line scan imaging systems, thus possessing good versatility and facilitating engineering implementation and widespread application. Attached Figure Description

[0044] Figure 1 This is a schematic diagram illustrating the system and variable definitions for line scan imaging under conditions of high-speed continuous relative motion.

[0045] Figure 2 This is a flowchart of the line scan imaging collaborative control method under high-speed continuous relative motion conditions according to the present invention.

[0046] Figure 3 This is a diagram showing the coordinated control relationship between the trigger line frequency and the exposure integration time as a function of speed in this invention.

[0047] Figure 4 This is a block diagram of the linear scanning imaging collaborative control device under high-speed continuous relative motion conditions according to the present invention.

[0048] Figure 5 This is a schematic diagram illustrating the deviation between the preset motion trajectory and the actual motion trajectory in an embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1: A Cooperative Control Method for Line Scan Imaging under High-Speed ​​Continuous Relative Motion Conditions

[0051] like Figures 1 to 3 As shown, this embodiment provides a collaborative control method for line scanning imaging under high-speed continuous relative motion conditions, applicable to imaging scenarios where there is high-speed, continuous relative motion between the line scanning imaging system and the object under test. Figure 1Display system and variable definitions, Figure 2 Demonstration method and process, Figure 3 This demonstrates the coordinated control relationship between trigger line frequency and exposure integration time as speed changes.

[0052] For ease of understanding, combined with Figure 1 Explanation of key variables:

[0053] The relative velocity between the line scan imaging system and the object being measured, expressed in units such as m / s;

[0054] In some implementations, the measured velocity may be filtered and / or fused from multiple sensors to obtain a more stable velocity estimate. This is used to improve control stability.

[0055] Line scan imaging system trigger frequency (line trigger frequency), unit such as Hz (line / s);

[0056] Single-line exposure integration time, in units such as s or μs;

[0057] : The axial spatial sampling interval between adjacent scan lines in the direction of relative motion; its relationship with , The relationship is: ;

[0058] Spatial image shift generated along the direction of relative motion during single-line exposure; and its relationship with , The relationship is: ;

[0059] : Maximum permissible axial spatial sampling interval threshold;

[0060] Allowable single-line spatial image shift threshold;

[0061] : Axial spatial sampling target step size (desired sampling interval), satisfying ;

[0062] The method in this embodiment includes the following steps:

[0063] Step A): Threshold parameter setting

[0064] Before imaging begins, the following threshold parameters are preset based on the minimum resolvable spatial scale of the target to be detected and the imaging accuracy requirements:

[0065] (1) Maximum allowable axial spatial sampling interval threshold This is used to limit the maximum spatial interval between two adjacent scan lines in the relative motion direction, in order to avoid missed scans.

[0066] (2) Allowable single-line spatial image shift threshold It is used to limit the upper limit of spatial image shift caused by relative motion during a single-line exposure, in order to suppress motion blur.

[0067] like Figure 1 As shown, and Corresponding to axial sampling intervals and single-line space image shift The constraint threshold. The above threshold can be configured according to engineering requirements (e.g., (It can be set to no more than 1 mm), and the present invention does not limit its specific value.

[0068] Furthermore, the target step size for axial spatial sampling can be preset. Its satisfaction This is used for precise control of subsequent trigger line frequency and allows for sufficient margin.

[0069] Step B): Obtaining relative motion velocity

[0070] During the imaging process, the relative velocity between the line scan imaging system and the object under test is acquired in real time. .

[0071] The The speed can be obtained through an encoder, odometer, inertial measurement unit (IMU), or a combination thereof. In some implementations, the measured speed can be filtered and / or fused using multiple sensors to obtain a more stable speed estimate. The filtering / fusion methods can include moving average filtering, Kalman filtering, low-pass filtering, etc., and this invention is not limited to these.

[0072] Step C): Triggering coordinated control of line frequency

[0073] like Figure 2 and Figure 3 As shown, to ensure sufficient axial spatial sampling, this embodiment is based on relative motion velocity. With the maximum allowable axial space sampling interval threshold Trigger line frequency of line scanning imaging system Control is performed to adjust the axial spatial sampling interval between adjacent scan lines. satisfy:

[0074] ,and

[0075] In one specific implementation, the sampling target step size can be preset according to the axial space. ( Determine the trigger line frequency :

[0076]

[0077] in, This represents the floor function, used to convert continuously calculated line frequencies into discrete line frequency values ​​that can be set by the imaging system, thereby ensuring that the actual sampling interval does not exceed the threshold. .like Figure 3 As shown, trigger line frequency With speed Approximately linear growth.

[0078] Step D): Coordinated control of exposure integration time

[0079] like Figure 2 As shown, to suppress spatial image shift during single-line exposure, this embodiment is based on relative motion speed. With single-line spatial image shift threshold Single-line exposure integral time Control is performed to shift the spatial image generated during a single-line exposure. satisfy:

[0080] ,and

[0081] like Figure 3 As shown, the image shift constraint gives the upper limit of the exposure time. It decreases as speed increases (inverse proportional relationship).

[0082] Step E): Exposure timing constraint control

[0083] To avoid exposure time exceeding the time interval between two adjacent triggers, which would cause exposure windows to overlap (see...). Figure 3 ), for exposure integral time With trigger line frequency Apply consistency constraints:

[0084]

[0085] In one specific implementation, single-line exposure integration time It can be determined in the following way:

[0086]

[0087] in, To find the minimum value of the function. Through the above method, It simultaneously satisfies image shift constraints and trigger timing constraints, avoiding overlapping exposures and motion blur under high-speed conditions.

[0088] like Figure 3 As shown, trigger cycle It decreases as speed increases (inversely proportional relationship). Actual exposure integral time Take two constraints and The smaller value in the range forms the envelope: in the low-speed region (operating point 1). Mainly affected by the triggering cycle Restriction: In high-speed areas (operating point 3). Mainly constrained by image shift Limitation; the medium-speed region (operating point 2) is a transition zone. This reflects the principle of coordinated control between trigger line frequency and exposure integration time.

[0089] Step F): Output control signal to drive imaging acquisition.

[0090] According to the trigger line frequency With the single-line exposure integration time It outputs trigger control signals and exposure control parameters to drive the line scan imaging system to perform line scan imaging acquisition. The trigger control signal is based on the trigger line frequency. Generate periodic trigger pulses (trigger period) Exposure control parameters should include at least the single-line exposure integration time. It also allows for the selection of imaging parameters, including gain and aperture.

[0091] In one embodiment, when the relative motion speed (When changes occur, the trigger line frequency can be recalculated and updated according to a preset update cycle (e.g., 5 ms to 100 ms). Exposure points time This aims to achieve a balance between real-time performance and system stability. The update cycle can be adjusted according to the frequency of speed changes and system response requirements; this invention does not impose any limitations on it.

[0092] Application Scenarios and Numerical Examples

[0093] In a specific application scenario, the mobile detection platform moves continuously along the axial direction of the water conveyance tunnel. The platform is equipped with multiple line-scanning cameras (which can be arrays) and linear near-infrared active illumination components to collect grayscale information reflected from the tunnel inner wall line by line. It can also form a two-dimensional unfolded image covering the entire or near-the entire cross-section through circumferential stitching, which can be used for the identification and treatment of defects such as cracks and leaks.

[0094] To illustrate triggering line frequency With single-line exposure time The collaborative computing process can be configured as follows:

[0095] = 0.5 mm, = 0.4 mm (satisfies) ), = 0.8 mm.

[0096] Example 1: When =3 m / s (3000 mm / s)

[0097] line / s

[0098] μs, μs

[0099] μs

[0100] verify:

[0101]

[0102]

[0103] and

[0104] Example 2: =1.5 m / s (1500 mm / s)

[0105] line / s

[0106] μs, μs

[0107] μs

[0108] verify:

[0109]

[0110]

[0111]

[0112] Similarly satisfied , , .

[0113] When the speed changes, the speed is updated according to a preset update cycle. and accordingly and This ensures that the above constraints are continuously satisfied.

[0114] The two examples above correspond to Figure 3 Operating points in different speed ranges:

[0115] Example 1 ( =3 m / s) is close to the high-speed region, =133.3 μs is mainly affected by the trigger period limit;

[0116] Example 2 ( =1.5 m / s) is in the low to medium speed range. =266.7 μs is also limited by the trigger period.

[0117] When the speed increases further (such as...) >5 m / s), will enter Figure 3 The high-speed area shown at this time The main constraint will be image shift. The limitation is that the exposure time needs to be significantly shortened to suppress motion blur.

[0118] To enhance feasibility, in a preferred embodiment, the following constraints or processing strategies are further provided:

[0119] (1) When If the value is too small or close to 0, a minimum speed can be set. ,when Use default imaging parameters or pause updates to avoid Calculation errors may result in unreasonable exposure times;

[0120] (2) Trigger line frequency Exposure points time Subject to the limitations allowed by the camera hardware (e.g.) , When the calculation result exceeds the limit, a saturation limit is applied, and an alarm or prompt message can be output.

[0121] (3) Ensure , , , , The units are consistent (e.g.) When using m / s, , Use m to match the threshold; or use mm to match.

[0122] In typical application scenarios, the value ranges of each parameter are shown in the following examples (for illustrative purposes only and not constituting a limitation):

[0123] Minimum speed This value can be set to 0.05–0.2 m / s, for example, 0.1 m / s. When the speed is below this value, the system is considered to be stationary or in a very low-speed state, in which case the default parameters can be used or dynamic updates can be paused.

[0124] Trigger line frequency range :

[0125] - : Depends on the camera's minimum line frequency capability, typically 100–500 Hz;

[0126] - It depends on the camera's maximum line frequency capability and data transmission bandwidth, with a typical value of 20 to 200 kHz.

[0127] For high-speed linear scan cameras It can reach 100 kHz or higher.

[0128] Exposure points time range :

[0129] - : Depends on the camera's minimum exposure time capability, typically 1–10 μs;

[0130] - It depends on the camera's maximum exposure time capability, typically ranging from 10 ms to 1 s.

[0131] In high-speed motion scenarios, actual use Typically, it falls within the range of 10–500 μs.

[0132] Update cycle Typical values ​​are 10–100 ms, for example, 50 ms. The choice of update cycle needs to be balanced between real-time responsiveness and system stability.

[0133] - An update cycle that is too short (e.g., <5 ms) may cause parameters to change frequently, affecting imaging stability;

[0134] - An excessively long update cycle (e.g., >200 ms) may cause a lag in response to speed changes.

[0135] The above parameter ranges may be adjusted depending on the specific application scenario, camera model, and motion characteristics.

[0136] Controller implementation process and parameter calculation example (preferred implementation method)

[0137] In a preferred embodiment, the cooperative control method is implemented by a controller, and its control logic can be executed according to the following process:

[0138] S1) Initialization: Read and load threshold parameters , and optional target step size Update cycle Minimum speed and line frequency and exposure upper and lower limits , .

[0139] S2) Speed ​​Acquisition: Collects speed measurements and can filter the measured speeds; the relative motion speed used for control calculations is denoted as... When using filtering For the velocity estimation after filtering, before filtering was applied... To measure the speed.

[0140] S3) Boundary determination: If Then execute the low-speed strategy and return to S2;

[0141] S4) Trigger line frequency calculation: based on Calculate the trigger line frequency

[0142]

[0143] And obtain by performing hardware saturation limit

[0144]

[0145] in This indicates that the parameter is limited to a given upper and lower limit range.

[0146] S5) Exposure integration time calculation: Calculate the upper limit of exposure given by the image shift constraint and the upper limit of exposure given by the timing constraint respectively:

[0147] ,

[0148] The smaller of the two values ​​is taken as the theoretical exposure time:

[0149]

[0150] Further hardware saturation limiting yields:

[0151]

[0152] S6) Output and Execution: Output trigger pulse (period) ) and exposure parameters ( (and execute it cyclically according to the update cycle).

[0153] in This indicates that the parameter saturation is limited to a given range. The above process is an exemplary description and does not constitute a limitation on the implementation method.

[0154] Activity monitoring and alerts (optional implementation)

[0155] like Figure 5 As shown, in some embodiments, the method further includes a motion state monitoring step:

[0156] (1) Real-time monitoring of the relative motion velocity Fluctuation: When the speed fluctuation exceeds the preset threshold, a uniform motion reminder signal is generated;

[0157] (2) Real-time monitoring of the deviation of the line scan imaging system from the preset motion trajectory. When the deviation exceeds the preset threshold, a trajectory adjustment reminder signal is generated.

[0158] Among these, speed fluctuations and deviations can be calculated using commonly used indicators in this field; for example, speed fluctuations can be calculated using... express( (For moving average speed), the degree of deviation can be used express( Denotes the Euclidean norm. For actual trajectory points The projection / closest point on the preset trajectory), but the present invention is not limited thereto. The reminder signal can be sent to the operator through a display screen, indicator light or sound, so as to adjust the movement status in a timely manner.

[0159] Motion control (optional implementation)

[0160] like Figure 5 As shown, in some embodiments, the method further includes a motion control step: based on the relative motion velocity Generate motion control commands based on preset motion trajectories The motion control command is used to control the motion drive device of the line scanning imaging system to adjust the motion speed and / or direction of the line scanning imaging system, thereby achieving closed-loop control. Optionally, the motion control can be initiated or strengthened when the aforementioned reminder signal is generated, but the basis for motion control remains the relative motion speed. With the preset motion trajectory.

[0161] In one alternative implementation, motion control uses a control cycle. Execute, will the first The speed value for each control cycle is denoted as... (in For the (Constructing the velocity error based on the value of the discrete control period) And a discrete PID controller is used to generate the speed adjustment, for example:

[0162]

[0163] in , , These are the proportional, integral, and differential coefficients, respectively.

[0164] It should be noted that the aforementioned motion monitoring and motion control are optional functions. Their purpose is to improve motion status and indirectly enhance imaging stability, without changing the trigger line frequency. Exposure points time The collaborative constraint relationship and its calculation method.

[0165] Through the above steps, this embodiment achieves coordinated control of trigger line frequency and exposure integration time under high-speed continuous relative motion conditions, thereby effectively suppressing single-line motion blur and improving imaging quality while ensuring sufficient axial spatial sampling; optional motion monitoring and motion control functions further enhance imaging stability under complex working conditions.

[0166] Example 2: Linear Scanning Imaging Cooperative Control Device under High-Speed ​​Continuous Relative Motion Conditions

[0167] like Figure 4 As shown, this embodiment provides a line scan imaging collaborative control device for implementing the collaborative control method described in Embodiment 1. This device can be integrated into the line scan camera control unit or set up as a separate imaging control unit. During the imaging process, the device acquires the relative motion speed between the line scan imaging system and the object under test in real time, and collaboratively controls the trigger line frequency and single-line exposure integration time based on a preset threshold to ensure that the axial sampling density, motion image shift, and trigger / exposure timing meet the constraints under high-speed continuous relative motion conditions.

[0168] The device includes at least: a speed acquisition module, a parameter setting module, a trigger line frequency control module, an exposure integration time control module, a constraint control module, and an imaging execution module.

[0169] To facilitate communication Figure 4 Correspondingly, in one embodiment, the modules may correspond to: speed acquisition module 30, parameter setting module 31, trigger line frequency control module 32, exposure integration time control module 33, constraint control module 34, imaging execution module 35, and output interface 36 respectively; and may optionally include filtering / update module 40, motion monitoring module 50, and motion control module 60, and preset trajectory data may be provided by module 31 or integrated with it (such as 53).

[0170] Explanation of variable symbols: The variable symbols involved in this embodiment ( , , , , , , , For the definition and meaning of (etc.), please refer to Example 1. Figure 1 The variable descriptions are omitted here.

[0171] To facilitate an accurate description of the functions of each module of the device, the key constraint relationships are numbered and labeled as follows ((1)-(5)). These constraint relationships are mathematically consistent with the constraints described in step CE of Embodiment 1.

[0172] 1. Speed ​​Acquisition Module 30

[0173] Used to obtain the relative motion velocity between the line scan imaging system and the object being measured. (See Example 1 for variable definitions). In one embodiment, the speed acquisition module includes an encoder, an odometer (such as a DMI), and / or an inertial measurement unit (IMU), or a combination thereof.

[0174] In some implementations, the speed acquisition module may filter and / or fuse multiple sensors on the measured speed to obtain a more stable speed estimate. It can be updated according to a preset update cycle. For subsequent calculations and .

[0175] In a preferred embodiment, the speed acquisition module can use a dual-odometer configuration for consistency verification: when the speed difference between the two channels exceeds a preset threshold, an abnormal quality flag is output, and the speed source can be switched or an alarm is triggered; the above threshold and switching strategy are exemplary implementations and are not limited by this invention.

[0176] 2. Parameter setting module 31

[0177] Threshold parameters used to set the imaging control requirements include: the maximum permissible axial spatial sampling interval threshold. With the allowed single-line spatial image shift threshold .

[0178] In one embodiment, the parameter setting module can also preset the axial spatial sampling target step size. ,in .

[0179] 3. Trigger line frequency control module 32

[0180] Used for relative motion velocity and (and optional) Control trigger line frequency This allows for the axial spatial sampling interval between adjacent scan lines in the direction of relative motion. satisfy:

[0181]

[0182] The trigger line frequency can be determined as follows: :

[0183]

[0184] in, This represents the function for rounding up.

[0185] 4. Exposure Integration Time Control Module 33

[0186] Used for relative motion velocity With single-line spatial image shift threshold Controlling single-line exposure integration time This causes the spatial image shift generated along the direction of relative motion during single-line exposure integration. satisfy:

[0187]

[0188] The single-line integral exposure time can be determined using the following formula. :

[0189]

[0190] in, This is a function that takes the minimum value.

[0191] 5. Constraint Control Module 34

[0192] Used to trigger line frequency and exposure points time Apply consistency constraints:

[0193]

[0194] This avoids overlap caused by the exposure window spanning adjacent trigger intervals; this constraint relationship is... Figure 3 Triggering cycle shown and exposure window Their relative positions are consistent.

[0195] In some embodiments, the apparatus may also include a parameter validity check unit for outputting a prompt or quality indicator when the parameters exceed the camera's capabilities, thereby improving engineering usability.

[0196] 6. Imaging execution module 35 and output interface 36

[0197] The imaging execution module 35 is used to determine the trigger line frequency. With single-line exposure time The output trigger control signal and exposure control parameters drive the line scan imaging system to perform line scan imaging acquisition. The imaging execution module 35 outputs at least:

[0198] (1) Trigger control signal: according to the trigger line frequency Generates periodic trigger pulses, trigger period ;

[0199] (2) Exposure control parameters: including exposure integration time It also allows for the selection of imaging parameters, including gain and aperture.

[0200] Output interface 36 can be used to send trigger / exposure parameters to the line scan imaging system and receive image data. The interface type may include, but is not limited to, Camera Link, GigE Vision, USB3 Vision, etc.

[0201] like Figure 4 As shown, the data flow and control flow relationships between the modules can be as follows:

[0202] 1) Speed ​​acquisition module 30 → triggers line frequency control module 32 and exposure integration time control module 33: output or;

[0203] 2) Parameter setting module 31 → Trigger line frequency control module 32: Output With optional ;

[0204] 3) Parameter setting module 31 → Exposure integration time control module 33: Output ;

[0205] 4) Trigger line frequency control module 32 → exposure integration time control module 33, constraint control module 34: output ;

[0206] 5) Exposure integration time control module 33 → Constraint control module 34: Output ;

[0207] 6) Constraint control module 34 → Imaging execution module 35: Output verified data and ;

[0208] 7) Imaging execution module 35 / Output interface 36 → Line scan imaging system: Outputs trigger control signals and exposure control parameters.

[0209] 8) Parameter setting module 31 (or preset trajectory data module / integration unit) → Motion monitoring module 50: Outputs preset motion trajectory data;

[0210] 9) Velocity acquisition module 30 (and optional pose / position acquisition unit) → Motion monitoring module 50: Output and actual trajectory / pose;

[0211] 10) Motion monitoring module 50 → Human-computer interaction / alarm unit: Outputs alert signals;

[0212] 11) Motion control module 60 → Motion drive device: Outputs motion control commands .

[0213] Note: The control basis of motion control module 60 is... With preset motion trajectory; reminder signals can be used to initiate or enhance control intensity, but are not required input for motion control.

[0214] like Figure 4 As shown, in an optional application embodiment, the device of the present invention can be integrated as a sub-module into the parent patent "A Device and Method for Detecting Diseases in Water Conveyance Tunnels Based on Laser Line Scan Camera Array" (Application No.: 2026100831582):

[0215] Line scanning imaging systems can be laser line scanning camera arrays / line scanning imaging systems;

[0216] The image data acquired through imaging can be sent to the disease identification and processing unit, and can be further output to the data storage / display terminal (optional);

[0217] An optional lighting component can be configured to meet imaging illumination requirements.

[0218] The above integration methods are merely exemplary application implementations and do not constitute a limitation on the scope of protection of this invention.

[0219] In another alternative implementation, the motion control module 60 outputs motion control commands. The motion drive device in the mobile detection platform (parent patent system) can be connected via a control interface to adjust the motion speed and / or direction of motion during the imaging process; the motion status / odometer / IMU (optional) of the mobile detection platform can provide speed input or auxiliary information to the speed acquisition module 30.

[0220] The above examples are only used to illustrate the integrability of the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0221] In one embodiment, the imaging execution module may generate the trigger control signal in the following manner:

[0222] (1) Time base trigger: Triggered according to the set trigger line frequency At fixed time intervals Output trigger pulse; the trigger signal can be generated by a hardware timer or FPGA.

[0223] (2) Mileage reference trigger (optional): When the speed acquisition module includes mileage timing, a trigger signal can be generated based on the accumulated displacement: for example, when the accumulated displacement reaches the preset spatial step size. A trigger signal is generated periodically to make the actual spatial intervals of adjacent scan lines closer together. This allows for better adaptability to speed fluctuations. In a dual-odometer configuration, one path can be designated as the trigger reference, while the other is used for consistency verification and slippage identification; in case of anomalies, the trigger can be switched to a time reference or the trigger parameters can be adjusted.

[0224] In one embodiment, the device is applied to high-speed line scan imaging of objects such as the inner wall of a water conveyance tunnel, and is used to implement the cooperative control method described in Embodiment 1 to calculate and update the trigger line frequency. With single-line exposure time For explanations of application scenarios and numerical examples, please refer to the corresponding section of Example 1. This Example 2 will not repeat them.

[0225] In some embodiments, the device may further include a motion monitoring module 50 and a motion control module 60:

[0226] Motion monitoring module 50: used to monitor the relative motion speed in real time. The system measures the fluctuations and deviations of the line-scan imaging system from a preset motion trajectory. When the fluctuations or deviations exceed a preset threshold, a corresponding alert signal (e.g., a uniform motion alert signal or a trajectory adjustment alert signal) is generated. The calculation of fluctuations and deviations can be implemented using methods commonly used in the field, and this invention is not limited thereto.

[0227] Motion control module 60: for using the relative motion speed Generate motion control commands based on preset motion trajectories The motion control command is used to control the motion drive device of the line scanning imaging system to adjust the motion speed and / or direction of the line scanning imaging system. Optionally, the motion control module can activate or increase the control intensity when the alert signal is generated, but the motion control is still based on the aforementioned command. With the preset motion trajectory.

[0228] In one alternative implementation, motion control uses a control period ∆ Execute, will the first The speed value for each control cycle is denoted as... (in For the (values ​​taken in discrete periods), construction error The speed regulation is generated using discrete PID control, and its control law can be expressed as:

[0229]

[0230] in , , These are the proportional, integral, and differential coefficients, respectively.

[0231] It should be noted that the above PID control law is an exemplary implementation. In practical applications, other control algorithms (such as fuzzy control, adaptive control, etc.) can be adopted according to specific needs. This invention does not limit the specific form of the control algorithm.

[0232] In some implementations, the apparatus may also include an exception handling mechanism to improve the robustness of the system:

[0233] (1) Abnormal speed signal: When an out-of-range, sudden change or loss is detected, an abnormal flag is output and the speed source / limiting hold / alarm prompt is switched;

[0234] (2) Parameter out of bounds: or When the camera's capabilities are exceeded, limit the frame and recalculate, and output a quality flag;

[0235] (3) Constraint conflict: Priority is given to guaranteeing in extreme cases. The timing constraints are implemented, and an image shift exceeding the limit flag is output while recording quality information.

[0236] (4) Communication error: When communication with the camera or drive device is abnormal, enter safe mode and record fault information.

[0237] The above processing strategy is an example and is not intended to limit the scope of this invention.

[0238] This device can be implemented based on an embedded processor, FPGA, industrial computer, or a combination thereof. For example: the FPGA is responsible for high-speed trigger signal generation and timing control; the processor is responsible for speed acquisition / filtering (reflected in the speed input). The acquisition method and parameter calculation are described; the host computer is responsible for human-computer interaction, parameter setting, and optional monitoring and control. The device can connect to sensors and motion drive devices via industrial buses such as CAN and EtherCAT. The above implementation is merely an example and is not intended to limit the scope of the invention.

[0239] The line scan imaging collaborative control device provided in this embodiment achieves dynamic optimization control of the trigger line frequency and single-line integration exposure time under high-speed continuous relative motion conditions through the coordinated operation of speed acquisition, parameter setting, trigger line frequency control, integral exposure time control, timing constraints, and imaging execution. This ensures that the axial sampling interval, motion image shift, and exposure timing meet preset constraints, thereby improving imaging quality and sampling accuracy. Optional motion monitoring and motion control modules further enhance stability and robustness under complex operating conditions.

[0240] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for coordinated control of line scan imaging under high-speed continuous relative motion conditions, characterized in that, Includes the following steps: A) Pre-set the maximum permissible axial spatial sampling interval threshold along the direction of relative motion between the line scan imaging system and the object under test. And the allowed single-line spatial image shift threshold ; B) Acquire the relative motion velocity between the line scan imaging system and the object under test during the imaging process. ; C) Based on the relative motion velocity With the maximum allowable axial space sampling interval threshold The trigger line frequency of the control line scanning imaging system The axial spatial sampling interval of adjacent scan lines in the direction of relative motion is increased. satisfy and ; D) Based on the relative motion velocity With the single-row spatial image shift threshold The single-line exposure integration time of the control line scan imaging system This causes the spatial image generated during a single-line exposure along the direction of relative motion to shift... satisfy and ; E) Control the trigger line frequency With the single-line exposure integration time The relationship between the single-line exposure integration time and the time between the two lines makes the single-line exposure integration time... Not exceeding the adjacent trigger interval, that is: ; F) Based on the aforementioned trigger line frequency With the single-line exposure integration time It outputs trigger control signals and exposure control parameters to drive the line scan imaging system to perform line scan imaging acquisition.

2. The method according to claim 1, characterized in that, Preset the target step size for axial spatial sampling The Not greater than The expected sampling interval; Triggering line frequency in step C) according to Confirmed, among which It is a rounding function; The single-line exposure integration time mentioned in step D) according to Confirmed, among which This is a function that takes the minimum value.

3. The method according to claim 1, characterized in that, The velocity estimate obtained by filtering and / or fusing multiple sensors from the measured velocity is used as the relative motion velocity. The relative motion velocity is updated according to a preset update cycle. This is used for subsequent calculations and updating of the trigger line frequency. With single-line exposure time .

4. The method according to claim 1, characterized in that, Also includes: Real-time monitoring of the relative motion velocity The system monitors the speed fluctuations, generating a uniform motion alert signal when the speed fluctuations exceed a first preset threshold; and / or monitors the deviation of the line scan imaging system from the preset motion trajectory in real time, generating a trajectory adjustment alert signal when the deviation exceeds a second preset threshold.

5. The method according to claim 1, characterized in that, Also includes: Based on the relative motion speed Motion control commands are generated based on a preset motion trajectory. These commands are used to control the motion drive device of the line scan imaging system to adjust the motion speed and / or direction of the line scan imaging system.

6. A linear scanning imaging collaborative control device under high-speed continuous relative motion conditions, characterized in that, include: The velocity acquisition module is used to acquire the relative velocity between the line scan imaging system and the object under test during the imaging process. ; The parameter setting module is used to set the maximum allowable axial space sampling interval threshold. And the allowed single-line spatial image shift threshold ; Trigger the line frequency control module to control the relative motion speed. and the maximum allowable axial space sampling interval threshold Control trigger line frequency This allows for the axial spatial sampling interval between adjacent scan lines in the direction of relative motion. satisfy and ; The exposure integration time control module is used to control the relative motion speed. and the single-line spatial image shift threshold Controlling single-line exposure integration time This causes the spatial image generated along the direction of relative motion during single-line exposure integration to shift... satisfy and ; The constraint control module is used to control the trigger line frequency. and the single-line exposure integration time The relationship makes ; The imaging execution module is used to determine the trigger line frequency. and the single-line exposure integration time It outputs trigger control signals and exposure control parameters to drive the line scan imaging system to perform line scan imaging acquisition.

7. The apparatus according to claim 6, characterized in that, The speed acquisition module includes one or a combination of an encoder, an odometer, and an inertial measurement unit.

8. The apparatus according to claim 6, characterized in that, The trigger line frequency control module is according to Determine the trigger line frequency, where The target sampling step size is a preset axial space and is no greater than 1. The expected sampling interval is It is a rounding function; The single-line exposure integral time control module is according to Determine the single-line exposure integral time, where This is a function that takes the minimum value.

9. The apparatus according to claim 6, characterized in that, Also includes: The motion monitoring module is used to monitor the relative motion speed in real time. The system monitors the speed fluctuations, generating a uniform motion alert signal when the speed fluctuations exceed a first preset threshold; and / or monitors the deviation of the line scan imaging system from the preset motion trajectory in real time, generating a trajectory adjustment alert signal when the deviation exceeds a second preset threshold.

10. The apparatus according to claim 9, characterized in that, Also includes: Motion control module, used for based on the relative motion speed Motion control commands are generated based on a preset motion trajectory. These commands are used to control the motion drive device of the line scan imaging system to adjust the motion speed and / or direction of the line scan imaging system.

Images