A visual displacement measurement device based on parallel laser

Abstract

The utility model discloses a visual displacement measuring device based on parallel laser, laser emission module adopts the parallel setting of at least two laser emitters, and multiple laser beams can form a measurement system of mutual check, effectively reduce single point measurement error, and laser has the characteristics of strong directivity and energy concentration, and the stability of the measurement datum formed by laser far exceeds that of a traditional target, and the accurate capture of laser signals by a visual acquisition module can realize effective identification of millimeter-level subtle displacement of a bridge, and the interference of laser signals by rain, fog and strong light and other bad weather is far less than that of traditional image signals, combined with the far field acquisition mode of the visual acquisition module, manual close-range operation is not needed, all-weather and automatic continuous monitoring can be realized, the laser emitter and industrial camera of the device core assembly are all mature production devices, the purchase cost is controllable, each module structure is simple and reliable, has better economy, and is convenient for large-scale popularization and application.

Description

Technical Field

[0001] This utility model relates to the field of engineering structure health monitoring technology, specifically a visual displacement measurement device based on parallel laser. Background Technology

[0002] In structural health monitoring, displacement and deformation monitoring of long-span bridges is crucial for ensuring operational safety. The accuracy and stability of monitoring data directly impact maintenance decisions and structural lifespan. Currently, mainstream monitoring technologies include total stations, GPS, and traditional visual measurement, but all have significant drawbacks, making it difficult to simultaneously meet the requirements of high precision, all-weather operation, low cost, and absolute displacement measurement. Total stations rely on manual operation, making automated continuous monitoring impossible and unsuitable for routine monitoring in complex environments. While GPS can perform automatic monitoring, its vertical accuracy is only at the centimeter level, making it difficult to capture millimeter-level deformations, and it is also costly. Traditional visual measurement calculates displacement by identifying targets with a camera, but it is greatly affected by the environment; poor image quality in adverse weather conditions such as rain, fog, and strong light leads to data distortion and insufficient stability.

[0003] In summary, existing technologies for monitoring the displacement of long-span bridges generally suffer from technical bottlenecks that cannot simultaneously achieve high-precision measurement, continuous operation around the clock, low-cost deployment, and absolute displacement acquisition. These limitations make it difficult to meet the stringent requirements of actual engineering projects for bridge health monitoring. Therefore, we need to propose a visual displacement measurement device based on parallel lasers. Utility Model Content

[0004] The purpose of this invention is to provide a visual displacement measurement device based on parallel lasers. By setting up a laser module containing at least two parallel laser emitters and a far-field visual acquisition module, a calibration system is formed and the benchmark stability is improved. This achieves the effects of reducing errors, identifying millimeter-level displacements, all-weather monitoring, obtaining absolute data, and controlling costs, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A visual displacement measurement device based on parallel lasers includes: a laser emitting module disposed on the measurement point of a bridge; a visual acquisition module disposed on a far-field reference point; and a data processing unit connected to the visual acquisition module via signals. The laser emitting module includes at least two laser emitters, and multiple laser emitters are connected to the measurement point of the bridge via an adjustable support mechanism. The visual acquisition module includes an imaging screen, an industrial camera, and a sealing cover.

[0007] Preferably, the imaging screen is fixedly embedded inside the large opening at the front end of the sealing cover, and the lens of the industrial camera is fixedly embedded inside the small opening at the rear end of the sealing cover.

[0008] Preferably, the imaging screen is made of a semi-transparent diffuse reflective material, and the laser beam emitted by the laser emitter forms a light spot on the imaging screen.

[0009] Preferably, the industrial camera is located behind the imaging screen, and its optical axis is perpendicular to the plane of the imaging screen.

[0010] Preferably, the data processing unit includes an image acquisition module, which is signal-connected to the image processing module, which is signal-connected to the data storage module, which is signal-connected to the data output module, and the data output module outputs displacement data.

[0011] Preferably, the industrial camera is signal-connected to the image acquisition module.

[0012] Preferably, the adjustable support mechanism includes a positioning frame fixedly connected to the bridge test point, a universal joint is installed on the top of the positioning frame, and the top of the universal joint is connected to a laser emitter.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This utility model's laser emission module employs a parallel configuration of at least two laser emitters. Multiple laser beams can form a mutually verifying measurement system, effectively reducing single-point measurement errors and significantly improving the accuracy of displacement calculation. Simultaneously, lasers possess strong directivity and concentrated energy, resulting in a measurement benchmark with stability far exceeding that of traditional targets. Combined with the precise capture of laser signals by the vision acquisition module, it enables effective identification of millimeter-level minute displacements of bridges. The interference from adverse weather conditions such as rain, fog, and strong light is far less than that of traditional image signals. Combined with the far-field acquisition mode of the vision acquisition module, no close-range manual operation is required, enabling all-weather, automated, and continuous monitoring. The vision acquisition module is positioned at a far-field reference point, which remains fixed relative to the bridge structure. The laser emission module moves synchronously with the bridge's measurement point. By capturing the positional changes of the laser beam through the vision acquisition module, and analyzing the data through the data processing unit, the absolute displacement data of the measurement point can be directly output. The core components of the device, such as the laser emitter and industrial camera, are mature, mass-produced devices with controllable procurement costs. Furthermore, each module has a simple structure and high reliability, offering superior economic efficiency and facilitating large-scale application. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall system layout of this utility model;

[0016] Figure 2 This is an exploded view of the visual acquisition module of this utility model;

[0017] Figure 3 This is a schematic diagram of the structure of the laser emitting module of this utility model;

[0018] Figure 4 This is a schematic diagram of the data processing unit of this utility model.

[0019] In the diagram: 1. Laser emitting module; 101. Laser emitter; 102. Adjustable support mechanism; 1021. Positioning frame; 1022. Universal joint; 2. Bridge; 3. Vision acquisition module; 301. Imaging screen; 302. Industrial camera; 303. Sealing cover; 4. Data processing unit; 401. Image acquisition module; 402. Image processing module; 403. Data storage module; 404. Data output module; 5. Laser beam; 6. Light spot. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figure 1-4 This utility model provides a technical solution:

[0022] A visual displacement measurement device based on parallel lasers includes: a laser emitting module 1, installed at the measurement points on a bridge 2. These measurement points are typically selected from stress concentration or deformation-sensitive areas such as the mid-span of the main beam or near the supports of the bridge 2. The mounting base of the laser emitting module 1 is rigidly connected to the structure of the bridge 2 using fastening components such as expansion bolts, ensuring that the laser emitting module 1 can move synchronously with the displacement of the bridge 2 without relative slippage, providing a direct and reliable carrier for the accurate acquisition of subsequent displacement signals; and a visual acquisition module 3 installed at a far-field reference point. The far-field reference point is preferably a stable, non-deformable structure such as a concrete pier or a dedicated monitoring bracket around the bridge 2. By deploying the visual acquisition module 3 at a location far from the bridge 2 and... The stable location ensures that the visual acquisition module 3 is unaffected by the deformation and vibration of the bridge 2, providing a stable and reliable absolute benchmark for measurement. This achieves the effect of establishing a fixed measurement reference system and avoiding measurement errors caused by benchmark displacement. The data processing unit 4 is connected to the visual acquisition module 3 via a signal connection. The signal connection can be a wired Ethernet or an industrial-grade wireless communication module. A wired connection ensures the stability of data transmission, while a wireless connection adapts to the deployment requirements in complex terrain. By establishing an efficient signal transmission link between the data processing unit 4 and the visual acquisition module 3, the real-time transmission and efficient processing of the image data acquired by the visual acquisition module 3 are realized, achieving the effect of quickly converting image information into displacement data and ensuring the real-time nature of monitoring.

[0023] The laser emission module 1 includes at least two laser emitters 101. The laser emitters 101 preferably use semiconductor lasers with wavelengths of 635nm or 532nm. All laser emitters 101 are connected to the test point of the bridge 2 through an adjustable support mechanism 102. By setting at least two laser emitters 101 to form a parallel measurement structure, and with the installation and fixation of the adjustable support mechanism 102, the synchronous deployment and fine adjustment of the direction of multiple laser beams can be realized. This achieves the effect of building a multi-reference calibration system, improving measurement redundancy and installation flexibility. When a single laser emitter 101 experiences a temporary failure, the remaining equipment can still maintain basic measurement functions, ensuring monitoring continuity.

[0024] The visual acquisition module 3 includes an imaging screen 301, an industrial camera 302, and a sealing cover 303. The industrial camera 302 is a CMOS industrial camera with a resolution of no less than 2 million pixels and a frame rate that can be adjusted between 1 and 30 frames per second. By integrating the imaging screen 301, the industrial camera 302, and the sealing cover 303, an integrated visual acquisition structure is formed. Each component is fixed by an internal bracket, and their relative positions are precisely locked. They work together to achieve laser signal reception, imaging, and protection, thereby optimizing the module integration and ensuring the stability of the acquisition process, and avoiding the component misalignment problem caused by scattered deployment.

[0025] The imaging screen 301 is fixedly embedded inside the large opening at the front end of the sealing cover 303, and the embedding area is sealed with a rubber sealing ring. The lens of the industrial camera 302 is fixedly embedded inside the small opening at the rear end of the sealing cover 303. The lens and the opening are connected by threads and sealed with sealant to ensure no gaps. By embedding the imaging screen 301 and the industrial camera 302 into the corresponding openings of the sealing cover 303 and fixing and sealing them, a closed acquisition space is formed. The front opening of the sealing cover 303 can also be fitted with a transparent dustproof lens as needed to further improve the protection effect. This achieves the effect of isolating external dust, rain, sand and other environmental interference, protecting the normal operation of core components, and enabling the device to adapt to the complex outdoor service environment of Bridge 2.

[0026] The imaging screen 301 is made of a semi-transparent diffuse reflective material, preferably polymethyl methacrylate (PMMA) substrate with a frosted finish. The diffuse reflectance is controlled between 70% and 90%, which ensures the clarity of the light spot 6 and avoids damage to the lens of the industrial camera 302 caused by laser reflection. The laser beam 5 emitted by the laser emitter 101 forms a circular light spot 6 with a diameter of 1 to 3 mm on the imaging screen 301. The edge of the light spot 6 is clearly distinguishable. By using a semi-transparent diffuse reflective material for the imaging screen 301, the laser beam 5 forms a clear and uniform light spot 6 after projection, avoiding overexposure or blurring of the light spot caused by direct laser light. Even in strong light environments, the contrast between the light spot 6 and the background of the screen can be maintained above 30:1, which achieves the effect of improving the recognition of the light spot 6 and providing a clear imaging basis for subsequent coordinate positioning.

[0027] The industrial camera 302 is located behind the imaging screen 301. The distance between the two is determined by the focal length of the industrial camera 302, ensuring that the imaging screen 301 is completely within the clear imaging range of the industrial camera 302, and that its optical axis is perpendicular to the plane of the imaging screen 301. By arranging the industrial camera 302 behind the imaging screen 301 and ensuring that the optical axis is perpendicular, the industrial camera 302 can capture the image of the light spot 6 on the imaging screen 301 at the optimal angle, avoiding the shape distortion of the light spot 6 and the coordinate measurement error caused by the tilt of the viewing angle, thereby achieving the effect of improving the image acquisition accuracy and ensuring the accuracy of the coordinate measurement of the light spot 6.

[0028] The data processing unit 4 includes an image acquisition module 401, which uses a dedicated image acquisition card and supports USB 3.0 or GigE interfaces to achieve high-speed image data acquisition. The image acquisition module 401 is signal-connected to an image processing module 402, which uses an embedded processor or industrial control computer and incorporates machine vision-based spot recognition and coordinate calculation algorithms. The image processing module 402 is signal-connected to a data storage module 403, which uses a solid-state drive with a capacity of at least 1TB and can store at least three months of continuous monitoring data. The data storage module 403 is signal-connected to the data output module 404. The data output module 404 has RS485, Ethernet and 4G / 5G wireless output interfaces, which can transmit displacement data to the monitoring center platform or local display terminal in real time. The data output module 404 outputs displacement data. By setting up a hierarchical connection structure of image acquisition module 401, image processing module 402, data storage module 403 and data output module 404, the entire process of data acquisition, processing, storage and output is automated, which improves data processing efficiency, ensures data traceability and output convenience.

[0029] The industrial camera 302 is connected to the image acquisition module 401 via signal connection. The connection method uses a dedicated shielded cable based on the interface type. The cable is wrapped with an anti-interference shielding mesh to reduce the impact of electromagnetic interference in the industrial environment on image data transmission. By establishing a direct signal connection between the industrial camera 302 and the image acquisition module 401, real-time transmission of acquired images is achieved, avoiding the delay caused by intermediate transfer equipment. This reduces data transmission delay and ensures the continuity of the processing flow, ensuring that each frame of image can enter the subsequent processing stage in a timely manner.

[0030] The adjustable support mechanism 102 includes a positioning frame 1021 fixedly connected to the test point on the bridge 2. The positioning frame 1021 is made of stainless steel and is rigidly fixed to the structure of the bridge 2 by welding or expansion bolts to ensure load-bearing stability. A universal joint 1022 is installed on the top of the positioning frame 1021. The universal joint 1022 is a damped universal joint with 360-degree horizontal rotation and ±90-degree pitch adjustment capability. After adjustment, the angle can be fixed by tightening the lock nut. The top of the universal joint 1022 is connected to the laser emitter 101. The connection part adopts threaded engagement and is equipped with anti-loosening gaskets. By setting the positioning frame 1021, a stable connection with the bridge 2 is achieved. With the angle adjustment function of the universal joint 1022, the laser beam 5 is accurately positioned, which improves the reliability of the support fixation and ensures that the laser beam 5 is accurately pointed to the imaging screen 301, ensuring that the laser beam 5 is always projected within the effective area of ​​the imaging screen 301.

[0031] Working Principle: First, the positioning frame 1021 and universal joint 1022 of the adjustable support mechanism 102 fix multiple laser emitters 101 of the laser emitting module 1 to the test point of the bridge 2, and calibrate the output direction of the laser emitters 101 so that the laser beam 5 is accurately projected onto the imaging screen 301 of the far-field reference point, forming a stable light spot 6. The sealing cover 303 provides a sealed protective environment for the imaging screen 301 and the industrial camera 302 to avoid environmental factors from affecting the imaging quality. The industrial camera 302 acquires images of the light spot 6 on the imaging screen 301 at a preset frequency and sends the image data to the image acquisition module 401 of the data processing unit 4 through signal transmission. After receiving the image, the image acquisition module 401 transmits it to the image processing module 402. The image processing module 402 extracts the center coordinates of each light spot 6 through an image recognition algorithm, compares them with the pre-calibrated initial coordinates, and calculates the absolute displacement value of the test point of the bridge 2 by combining the conversion coefficient between pixel displacement and actual displacement. The data storage module 403 synchronously stores the original image and the calculated displacement data, and the data output module 404 outputs the displacement data in real time, realizing high-precision, all-weather automated monitoring of the multi-point displacement of bridge 2.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A visual displacement measurement device based on parallel laser, characterized in that, include: A laser emitting module (1) is installed at the test point on the bridge (2); The visual acquisition module (3) is set on the far-field reference point; The data processing unit (4) is connected to the vision acquisition module (3) via signal. The laser emitting module (1) includes at least two laser emitters (101), and all of the laser emitters (101) are connected to the test point of the bridge (2) through an adjustable support mechanism (102); The visual acquisition module (3) includes an imaging screen (301), an industrial camera (302), and a sealing cover (303).

2. The visual displacement measurement device based on parallel laser according to claim 1, characterized in that: The imaging screen (301) is fixedly embedded inside the large opening at the front end of the sealing cover (303), and the lens of the industrial camera (302) is fixedly embedded inside the small opening at the rear end of the sealing cover (303).

3. The visual displacement measurement device based on parallel laser according to claim 2, characterized in that: The imaging screen (301) is made of a semi-transparent diffuse reflective material, and the laser beam (5) emitted by the laser emitter (101) forms a light spot (6) on the imaging screen (301).

4. The visual displacement measurement device based on parallel laser according to claim 3, characterized in that: The industrial camera (302) is located behind the imaging screen (301), and its optical axis is perpendicular to the plane of the imaging screen (301).

5. The visual displacement measurement device based on parallel laser according to claim 1, characterized in that: The data processing unit (4) includes an image acquisition module (401), which is signal-connected to an image processing module (402). The image processing module (402) is signal-connected to a data storage module (403), and the data storage module (403) is signal-connected to a data output module (404). The data output module (404) outputs displacement data.

6. The visual displacement measurement device based on parallel laser according to claim 5, characterized in that: The industrial camera (302) is connected to the image acquisition module (401) via signal.

7. The visual displacement measurement device based on parallel laser according to claim 1, characterized in that: The adjustable support mechanism (102) includes a positioning frame (1021) fixedly connected to the test point of the bridge (2). A universal joint (1022) is installed on the top of the positioning frame (1021), and the top of the universal joint (1022) is connected to the laser emitter (101).

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