Bridge displacement deformation monitoring device integrated with large-field-of-view imaging function

Abstract

The utility model discloses a bridge displacement deformation monitoring device integrated with a large-view-field imaging function. The bridge displacement deformation monitoring device comprises a target unit installed on a bridge and an imaging unit arranged at the far end. The imaging unit comprises a holder, a camera, a servo motor, a switching mechanism and a controller, the switching mechanism is a strip-shaped piece, a narrow-band optical filter and a low-pass cut-off optical filter are installed on the two sides of the strip-shaped piece respectively, and the middle of the strip-shaped piece is installed on a rotating shaft of the servo motor; the camera and the servo motor are electrically connected with the controller; the target unit comprises a plurality of measuring targets and at least one reference target which are arranged at a bridge monitoring part; according to the utility model, while bridge displacement and deformation monitoring is carried out, large-range and large-view-field video imaging can be switched, the camera can be ensured to be in situ before and after switching, the continuity of displacement deformation data measurement is ensured, and the purpose of saving software and hardware and laying cost is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of monitoring large structures such as bridges, and in particular relates to a bridge displacement deformation monitoring device integrating a large-field-of-view imaging function. Background Art

[0002] With the rapid development of social economy, the traffic volume on bridges has increased rapidly, and the impact of bridge safety hazards has intensified. Bridges are damaged and damaged due to factors such as harsh operating environment, load, and long service life, which threaten bridge safety and cause bridge accidents. Through safety monitoring of bridge structures, we can fully grasp the environmental parameters and structural response parameters of bridges during operation, and conduct early warning and preliminary evaluation of the use status and mechanical behavior of bridges through data analysis, providing strong guarantees for the safe operation of bridges.

[0003] As an emerging detection method in recent years, digital image detection has shown an increasingly broad application prospect in the field of engineering structure detection with its advantages of non-contact, high precision, convenience, strong platform scalability, and good connection with artificial intelligence technology. At present, digital image method has been successfully applied to the dynamic and static displacement measurement of bridge structures and cable force measurement, with good application effect. The digital image detection method arranges photoelectric targets at the monitoring structure of the bridge, and uses a camera at the remote end to obtain the displacement of the photoelectric target to calculate the displacement or deformation of the key structure of the bridge, and then analyzes the structural response parameters and safety performance of the bridge.

[0004] The Chinese patent application number 201922087008.7 discloses a displacement sensor with a video monitoring function, including a housing and an optical lens, an image sensor and a core control unit arranged inside the housing. The optical lens aims at a photoelectric target set on a remote monitoring target, and a position-switching narrow-band filter is arranged between the optical lens and the image sensor; the transmission wavelength of the narrow-band filter matches the emission wavelength of the photoelectric target; during the use of the sensor of the utility model, once the monitored displacement or deformation parameter exceeds the set threshold, it is forced to switch to the second target imaging state, and then the image sensor directly obtains the real-life morphological image of the monitoring target, and transmits the image to a remote data center for manual intervention. The problem in the application is that when using the second target imaging state, the observing camera can only observe in the original field of view, otherwise when the camera rotates the angle, it cannot be guaranteed to switch to the original field of view, thereby affecting the continuity of the displacement measurement data. Utility Model Content

[0005] The utility model proposes a bridge displacement and deformation monitoring device integrating a large field of view imaging function, which can switch to large-range, large-field-of-view video imaging while monitoring the displacement and deformation of the bridge, and can ensure that the camera is in place before and after switching to ensure the continuity of the measured displacement and deformation data, thereby achieving the purpose of saving software, hardware and layout costs.

[0006] The technical solution of the utility model is as follows:

[0007] A bridge displacement deformation monitoring device integrating a large field of view imaging function comprises a target unit installed on the bridge and an imaging unit arranged at a remote end; the imaging unit comprises a pan / tilt, a camera, a servo motor, a switching mechanism and a controller, the switching mechanism is a strip sheet, a narrow-band filter and a low-pass cut-off filter are respectively installed on both sides of the strip sheet, and the middle part of the strip sheet is installed on the rotating shaft of the servo motor, so that the narrow-band filter and the low-pass cut-off filter are switched in front of the camera lens; the camera and the servo motor are electrically connected to the controller; the target unit comprises a plurality of measuring targets and at least one reference target arranged at the monitoring position of the bridge; the target unit is imaged in the field of view of the camera.

[0008] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the reference target is fixed on a base with negligible deformation.

[0009] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the imaging unit further comprises a fill light arranged in the same direction as the optical axis of the camera, and the fill light is electrically connected to the controller.

[0010] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the central wavelength of the fill light is 532nm or 805nm, and the cut-off wavelength of the low-pass cut-off filter is 850nm.

[0011] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the pan / tilt platform includes a pitch mechanism and a horizontal rotation mechanism.

[0012] In the above-mentioned bridge displacement and deformation monitoring device integrating a large field of view imaging function, a waterproof cover is provided on the top of the imaging unit.

[0013] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the measurement target and the reference target are LED lights with a central wavelength of 915 or 975 nm.

[0014] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the central wavelength of the narrow-band filter matches the wavelength of light of the measurement target.

[0015] In the above-mentioned bridge displacement deformation monitoring device integrating a large field of view imaging function, the controller is connected to a terminal of a command and control center via a wireless module.

[0016] The beneficial technical effects of the utility model are as follows:

[0017] 1. The utility model is improved on the basis of the traditional image displacement sensor: on the one hand, a switching mechanism is added in front of the lens of the imaging unit, which can move the narrow-band filter of the measuring photoelectric target away from the lens, so as to observe the bridge target in special occasions. At the same time, a two-dimensional pan-tilt is installed at the bottom to drive the camera to scan and observe the target of the entire bridge; on the other hand, a reference target with negligible displacement deformation is set in front of the target unit. After rotating the pan-tilt and observing the target, the pan-tilt is readjusted to the same coordinates before and after the adjustment of the imaging point of the reference target, thereby ensuring that other measuring targets are in the original position, so that their measurement data maintains good continuity.

[0018] Second, when observing the condition of the bridge deck, the utility model sets a cut-off filter in front of the camera that can cut off the light wave of the photoelectric target, so that the spectrum emitted by the photoelectric target will not interfere with and affect the imaging of the camera, thereby ensuring the authenticity of the bridge deck imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the composition and working principle of the monitoring device of the utility model;

[0020] Figure 2 It is a three-dimensional structural diagram of the imaging unit of the utility model;

[0021] Figure 3 This is a front view of the imaging unit of the utility model;

[0022] Figure 4 It is a side view of the imaging unit of the utility model;

[0023] The reference numerals are: 1-bridge; 2-measurement target; 3-reference target; 4-camera; 5-servo motor; 6-switching mechanism; 7-narrowband filter; 8-cutoff filter; 9-fill light; 10-pan head; 11-controller; 12-waterproof cover; 14-base; 20-imaging unit; 21-target unit; DETAILED DESCRIPTION

[0024] Existing digital image bridge monitoring uses a remote camera to capture images of measurement targets set on the bridge to achieve displacement deformation monitoring. If a special event occurs and the overall condition of the bridge needs to be photographed and observed, another camera needs to be set up. Is it possible to multiplex the two functions into one, that is, the camera usually measures the real-time displacement parameters. Once the measurement data exceeds the set threshold or the operator needs to see the full view of the bridge, it is used to shoot the video of the entire bridge and transmit the video to the background for the duty officer to observe whether there is any abnormality.

[0025] The main problem is that during measurement, the camera usually only captures a number of optoelectronic targets deployed in a small area, and when the system is deployed, the original pixel coordinates of each optoelectronic target are recorded on the image sensor, and the image is processed in real time to obtain the pixel coordinate values ​​of the optoelectronic target for each frame of the image, and then the displacement or deformation real-time change parameters of the monitored component are obtained. Therefore, when it is necessary to observe the bridge deck image, the camera lens can only be kept still to capture the bridge deck image in a small local area. Otherwise, when the camera rotates, it cannot be guaranteed to switch to the original field of view, that is, each optoelectronic target may not be able to return to its original position for accurate measurement, which affects the continuity of the displacement measurement data.

[0026] The utility model proposes a bridge displacement and deformation monitoring device integrating a large field of view imaging function, which can switch to large-range, large-field-of-view video imaging while monitoring the displacement and deformation of the bridge, and can ensure that the camera is in place before and after switching to ensure the continuity of the displacement and deformation data measured.

[0027] like Figures 1 to 4 As shown, a bridge displacement deformation monitoring device integrating a large field of view imaging function of the present invention comprises a target unit 21 installed on the bridge and an imaging unit 20 arranged at a remote end. Figure 2 and Figure 3In the figure, the imaging unit 20 includes a pan-tilt platform 10, a camera 4, a servo motor 5, a switching mechanism 6 and a controller 11. The switching mechanism 6 is a strip sheet, and a narrow-band filter 7 and a low-pass cut-off filter 8 are respectively installed on both sides of the strip sheet. The middle part of the strip sheet is installed on the rotating shaft of the servo motor 5, so that the narrow-band filter 7 and the low-pass cut-off filter 8 are switched in front of the lens of the camera 4; the camera 4 and the servo motor 5 are electrically connected to the controller 11; the pan-tilt platform 10 includes a pitch mechanism and a horizontal rotation mechanism, which can drive the camera 4 to perform scanning imaging of a target in a large range and a large field of view. The controller 11 is electrically connected to a computer, a mobile phone and other terminals of the command center through a wireless module, and can transmit the video and measurement results to the command center. It can also drive the pan-tilt platform 10 to rotate and the switching mechanism 6 to switch according to the instructions of the command center, so as to realize video shooting in a large range and a large field of view. The imaging unit 20 also includes a fill light 9 arranged in the same direction as the optical axis of the camera 4, and the fill light 9 is electrically connected to the controller 11 to realize the illumination fill light of the target when the video is shot.

[0028] The target unit 21 includes several measuring targets 2 and at least one reference target 3 set at the monitoring part of the bridge; the reference target 3 is fixed on a base 14 with negligible deformation such as a bridge pier, and the target unit is imaged in the field of view of the camera 4. The measuring target 2 and the reference target are LED lights that are invisible to the human eye, preferably with a central wavelength of 915 or 975nm, so as to avoid affecting the human eye during measurement. The central wavelength of the narrowband filter 7 matches the wavelength of the light of the measuring target 2, and also takes the corresponding central wavelength of 915 or 975nm, with a half-width of 20-50nm.

[0029] During normal displacement deformation measurement, the servo motor 5 drives the switching mechanism 6 to face the narrowband filter 7 to the camera lens. At this time, the camera only images the 915 or 975nm LED and avoids interference from external sunlight on the imaging. At the same time, the target light will not interfere with the human eye.

[0030] When the measurement result exceeds the threshold or an abnormal situation occurs, the command center remotely operates the servo motor 5 to drive the switching mechanism 6 to face the low-pass cutoff filter 8 to the lens of the camera 4. At the same time, the horizontal rotation and up and down pitch can be manually or automatically controlled to allow the camera to scan the entire bridge deck area to look for abnormal phenomena.

[0031] The purpose of the low-pass cutoff filter 8 is to prevent the light emitted by the target from being too strong and thus affecting the imaging of the entire bridge deck. The central wavelength of the target is 915 or 975nm, and the cutoff wavelength of the low-pass cutoff filter is 850nm. The light waves of 400-850nm can be incident on the camera, and the light waves exceeding 850nm can be cut off. In other words, the light of the target can be filtered out to avoid the interference of the photoelectric target on the video imaging. If fill light is needed for shooting videos at night, the lens is equipped with a lighting lamp. The wavelength of the lighting lamp is 532nm green light or 805nm infrared light, which can pass through the cutoff filter and illuminate the target.

[0032] After the pan-tilt scan is completed, the command center can remotely control the pan-tilt to rotate to the original measurement position. In order to ensure the continuity of the measurement data before and after, the image of the measurement target needs to return to the position corresponding to the original pixel. Therefore, a reference target with negligible displacement deformation is set in front of the target unit. After the observation is completed, the imaging point of the reference target on the camera is used as the reference to readjust the pan-tilt to the original coordinates of the imaging point of the reference target on the image plane. Since the pan-tilt can only move in two dimensions, under the premise of ignoring the equipment error, as long as the reference target is adjusted back to the original position, the other measurement targets are also in the original position, so the measurement data maintains the continuity before and after.

[0033] The bridge displacement and deformation monitoring device of the utility model can switch to large-range and large-field-of-view video imaging as needed while meeting the needs of bridge displacement and deformation monitoring, saving hardware and software costs. It is particularly suitable for safe operation detection of small and medium-sized bridges and has broad application prospects.

Claims

1. A bridge displacement deformation monitoring device integrating a large field of view imaging function, characterized in that: It comprises a target unit (21) installed on a bridge and an imaging unit (20) arranged at a far end; The imaging unit (20) comprises a pan / tilt head (10), a camera (4), a servo motor (5), a switching mechanism (6) and a controller (11); the switching mechanism (6) is a strip-shaped sheet, and a narrow-band filter (7) and a low-pass cut-off filter (8) are respectively installed on both sides of the strip-shaped sheet, and the middle part of the strip-shaped sheet is installed on the rotating shaft of the servo motor (5), so that the narrow-band filter (7) and the low-pass cut-off filter (8) are switched in front of the lens of the camera (4); the camera (4) and the servo motor (5) are electrically connected to the controller (11); The target unit (21) comprises a plurality of measurement targets (2) and at least one reference target (3) arranged at a monitoring position of the bridge; the target unit is imaged within the field of view of a camera (4).

2. The bridge displacement and deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: The reference target (3) is fixed on a base (14) with negligible deformation.

3. The bridge displacement deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: The imaging unit (20) further comprises a fill light (9) arranged in the same direction as the optical axis of the camera (4), and the fill light (9) is electrically connected to the controller (11).

4. The bridge displacement and deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: The central wavelength of the fill light (9) is 532 nm or 805 nm, and the cut-off wavelength of the low-pass cut-off filter is 850 nm.

5. The bridge displacement deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: The pan / tilt platform (10) comprises a pitch mechanism and a horizontal rotation mechanism.

6. The bridge displacement and deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: A waterproof cover (12) is provided on the top of the imaging unit (20).

7. The bridge displacement and deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: The measuring target (2) and the reference target are LED lamps with a central wavelength of 915 or 975 nm.

8. The bridge displacement and deformation monitoring device integrating a large field of view imaging function according to claim 6 is characterized in that: The central wavelength of the narrowband filter (7) matches the wavelength of light of the measurement target (2).

9. The bridge displacement and deformation monitoring device integrating a large field of view imaging function according to claim 1 is characterized in that: The controller (11) is connected to a terminal of a control center via a wireless module.

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