CN-121978110-A - Device and method for detecting diseases of water conveyance tunnel based on laser line scanning camera array

CN121978110ACN 121978110 ACN121978110 ACN 121978110ACN-121978110-A

Abstract

Provided are a device and a method for detecting water conveyance tunnel diseases based on a laser scanning camera array. The device comprises a mobile detection platform, a laser line scanning camera array, a gesture and position measuring unit, a synchronous control unit, a data acquisition and processing unit and a disease identification module. The laser scanning camera array is annularly arranged along the circumferential direction of the tunnel section, line scanning gray imaging is carried out under the active illumination of near infrared laser, the synchronous control unit controls trigger line frequency and exposure time based on the minimum identifiable scale of the diseases to inhibit motion blur, the gesture and position measuring unit provides PPS time synchronization and event time marks to realize high-precision alignment of images and gesture data, the data acquisition and processing unit completes image correction, splicing and spatial registration to generate a two-dimensional expansion image of the tunnel inner wall, and the disease identification module automatically identifies cracks and leakage diseases based on the image. The invention can realize full coverage scanning of the inner wall of the tunnel under the condition of high-speed continuous movement, and obviously improves the inspection efficiency and the detection precision.

Inventors

YE SONG
WANG YING
ZHENG XUEDONG
LIAO BOCHENG
YAO ZHENGLI
QU YINGJIE
LI QIN
WANG JUNKE

Assignees

长江水利委员会长江科学院

Dates

Publication Date: 20260505
Application Date: 20260122

Claims (10)

1. Water delivery tunnel disease detection device based on camera array is swept to laser line, a serial communication port, include: The mobile detection platform is used for bearing the laser scanning camera array and continuously moving along the axial direction of the water delivery tunnel; The laser line scanning camera array is arranged on the mobile detection platform and comprises a plurality of laser line scanning cameras provided with near infrared laser active illumination assemblies, wherein the plurality of laser line scanning cameras are arranged in an array mode along the circumference of the section of the tunnel and are used for projecting linear near infrared laser to the inner wall of the tunnel in the moving process to form an illumination strip and synchronously acquiring line scanning gray image data of corresponding positions; the gesture and position measuring unit is used for acquiring displacement information and gesture information of the mobile detection platform in the moving process and providing a PPS time synchronization signal and an event input end; The synchronous control unit is used for receiving the PPS time synchronous signal to establish a unified time reference, carrying out cooperative control on the triggering line frequency and the single-line exposure integral time of the laser line scanning camera array, carrying out unified time sequence control on the laser line scanning camera array and the mobile detection platform so as to ensure the time synchronization of all acquired data in the moving process, and controlling the mobile detection platform to carry out uniform motion along the central axis of the water delivery tunnel through signals so as to keep stable speed and relative position; The data acquisition and processing unit is used for synchronously acquiring the line scanning gray image data of the laser line scanning camera array, the displacement information and the posture information acquired by the posture and position measuring unit, and carrying out image correction, splicing and space registration processing on the line scanning gray image data to generate two-dimensional expansion image information of the inner wall of the tunnel; And the disease identification module is used for identifying and analyzing cracks and/or seepage diseases of the inner wall of the tunnel based on the two-dimensional expansion image information.
2. The device according to claim 1, wherein the synchronization control unit is adapted to preset a maximum axial spatial sampling interval threshold based on a minimum identifiable measure of crack and/or leak disease And allowing a single line spatial image shift threshold And in the continuous moving process of the moving detection platform, the platform instantaneous speed is based Triggering line frequency of the laser line scanning camera array With single line exposure integration time And performing cooperative control such that: , ; Thereby simultaneously meeting the imaging conditions of axial sampling and single-row image shift control so as to ensure the effective identification of cracks and/or seepage diseases under the condition of continuous movement.
3. The apparatus of claim 2, wherein the single line spatial image shift is allowed threshold Not more than 1mm, or not more than the object space length corresponding to a single pixel or a preset multiple thereof, so as to ensure the resolution of fine cracks and seepage textures in the two-dimensional gray level image.
4. The apparatus of claim 1, wherein the array of laser line scan cameras are arranged in a ring or segmented ring along the tunnel cross-section to achieve full or near full coverage scanning of the tunnel inner wall and to reduce detection dead zones due to tunnel curved structures or ancillary structures.
5. The apparatus of claim 1, wherein the attitude and position measurement unit includes POS/IMU and DMI odometer interfaces and provides PPS time synchronization signal output and event input; the synchronous control unit comprises a time reference module, a trigger generation and distribution module and an event marking module; The time reference module is used for receiving the PPS time synchronization signal to establish a unified time reference; The trigger generation and distribution module is used for generating a camera array trigger signal based on the unified time reference and distributing the camera array trigger signal; The event marking module is used for inputting the camera array trigger signal, the exposure effective signal or the line effective signal into an event input end of the gesture and position measuring unit so as to record an event time mark and establish a time corresponding relation between the image acquisition reference moment and the displacement information and gesture information.
6. The apparatus of claim 3 wherein the trigger generation and distribution module is implemented using programmable logic devices, generates low jitter trigger pulses under the unified time reference constraint, and outputs the low jitter trigger pulses in parallel to each line scan camera trigger input through a fan-out, buffer and impedance matching distribution network, such that inter-camera trigger timing differences are controlled to within the order of microseconds, and single line exposure integration time Satisfy the following requirements Wherein Trigger line frequency of the laser line scanning camera is set, and Not less than 1 kHz.
7. The apparatus of claim 5, wherein the trigger generation and distribution module comprises at least two trigger modes: Time triggering mode, according to the triggering line frequency of the set laser line scanning camera Outputting trigger; Distance triggering mode, based on distance increment or pulse output by a DMI (digital media interface) odometer interface of the gesture and position measuring unit, according to preset axial distance step length Generating trigger signals to enable the axial space sampling interval of adjacent scanning lines to meet ; When the output difference of the double DMI exceeds a preset threshold value and an abnormal quality mark is output, the synchronous control unit is switched to a time triggering mode and/or performs self-adaptive adjustment on triggering parameters so as to improve the triggering stability and the consistency of the image scale under the complex working condition.
8. The apparatus of claim 1, wherein the data acquisition and processing unit comprises an image correction sub-module, an image stitching sub-module, and a spatial registration sub-module, wherein: The image correction sub-module is used for carrying out uniform correction processing on line scanning gray line data output by each laser line scanning camera line by line, and at least comprises dark current and gain uniformity and brightness balance; the image splicing sub-module is used for installing calibration parameters according to the camera array, registering and splicing imaging strips of the multiple cameras in the circumferential direction of the tunnel section, and carrying out splicing consistency check and splicing parameter constraint in the overlapping area of adjacent view fields so as to inhibit splicing dislocation and scale drift; The space registration sub-module is used for realizing one-to-one binding of line scanning data, displacement information, attitude information and DMI mileage by using an event time scale under a unified time reference and event time scale recording frame established by the synchronous control unit, carrying out motion compensation and space registration on a splicing result by using a binding result as a constraint, generating two-dimensional expansion image information by using an axial mileage as a row coordinate and a circumferential expansion coordinate as a column coordinate, wherein the two-dimensional expansion image information is a two-dimensional expansion gray level image or an image block, and outputting a synchronous index field bound with the two-dimensional expansion image information.
9. The apparatus of claim 1, wherein the near infrared laser active illumination assembly comprises a near infrared laser light source and a cylindrical lens for expanding the laser beam to form a linear illumination strip, and a bandpass filter matched with the emission band of the laser light source is arranged in front of the camera lens to suppress the influence of ambient stray light on line scan grayscale imaging.
10. A method for detecting a water conveyance tunnel disease based on a laser scanning camera array, which is performed by using the device of any one of claims 1 to 9, and is characterized in that the method comprises the following steps: s1, controlling a movement detection platform to continuously move along the axial direction of a water delivery tunnel at a preset speed; s2, synchronously acquiring line scanning gray image data of the inner wall of the tunnel through a laser line scanning camera array under the near infrared laser active illumination condition in the moving process, and recording event time marks; s3, acquiring displacement information and posture information of the mobile detection platform, performing time matching and binding on the line scanning gray image data and the displacement and posture information according to the event time scale, and completing motion compensation and space registration; s4, performing stitching processing on the line scanning gray image data subjected to motion compensation and spatial registration to generate two-dimensional expansion image information of the inner wall of the tunnel; And S5, based on the two-dimensional unfolding image information, carrying out automatic identification and analysis of cracks and/or seepage diseases.

Description

Device and method for detecting diseases of water conveyance tunnel based on laser line scanning camera array Technical Field The invention relates to the technical field of hydraulic engineering tunnel structure detection and safety monitoring, in particular to a device and a method for detecting inner wall cracks and/or seepage diseases of a hydraulic tunnel such as a water conveying tunnel, a diversion tunnel and a pressure tunnel under the working condition of emptying detection. Background The water delivery tunnel is a common water delivery and distribution structure in hydraulic engineering, and is large in space scale, moist in environment and long in service period. The inner wall of the tunnel is affected by factors such as surrounding rock stress change, construction quality difference, lining material aging, permeation, hydraulic flushing and the like, and diseases such as cracks, leakage and the like can occur in long-term operation, and the phenomena of local degradation, exposed ribs and the like can be accompanied. If the diseases can not be found and disposed in time, leakage expansion, reduction of lining performance and even local instability can be caused, and the engineering operation safety and the water supply reliability are influenced, so that periodic detection of the tunnel inner wall diseases is required to be carried out. The existing tunnel disease detection means mainly comprise manual inspection, image detection based on a common area array camera, three-dimensional laser scanning and the like. The manual inspection relies on experience, the efficiency is low, the result consistency is influenced by personnel factors, the illumination dependence is strong under the conditions of low illumination, moist reflection and the like of a tunnel, the common area camera is easily influenced by motion blur under the moving detection working condition, images meeting the identification requirements of micro cracks or leakage marks are difficult to stably acquire, the three-dimensional laser scanning can acquire space information, but the equipment cost and the deployment complexity are high, the scanning efficiency and the continuous movement adaptability are limited, and the detection efficiency and the data quality are difficult to be considered under the long-distance tunnel scene. In addition, the inner wall of the water delivery tunnel is usually of a continuous curved surface structure, structures such as a construction joint, a deformation joint or auxiliary facilities are locally arranged, and a single-view or single-point acquisition mode is easily influenced by shielding to form a detection blind area. In order to improve the detection efficiency, the detection equipment always needs to continuously move in the tunnel, but under the condition of high-speed continuous movement, how to inhibit the space image movement corresponding to the single-line scanning while guaranteeing the resolution, and enable the acquired image data to stably correspond to the pose, mileage and other information of the mobile platform under the same time reference is a key problem affecting the detection accuracy and repeatability. Therefore, there is a need for a disease detection device and method for tunnel curved surface environment and high-speed continuous moving working condition, which can realize synchronous correlation between image acquisition and pose and mileage information while full-section coverage acquisition, so as to improve engineering applicability and stability of disease detection such as crack and leakage. Drawings FIG. 1 is a schematic diagram of the overall structure of a device for detecting diseases of a water conveyance tunnel based on a laser scanning camera array according to an embodiment of the present invention; FIG. 2 is a schematic view of a laser line scan camera array arranged annularly along a section of a water conveyance tunnel; FIG. 3 is a schematic diagram of the structure and imaging relationship of a single laser line scan camera integrated line laser active illumination and performing scanning gray scale imaging; FIG. 4 is a block diagram of a synchronous control and trigger allocation connection based on PPS time base, event time stamp and DMI mileage constraints; FIG. 5 is a schematic diagram of the timing relationship between PPS, camera trigger/event input and exposure (or line sampling); FIG. 6 is a schematic diagram showing the relationship between the image line frequency, the shutter time and the movement speed under the condition of high-speed continuous movement and the single-line space image movement threshold; FIG. 7 is a block diagram of a data processing flow for a data acquisition and processing unit; FIG. 8 is a schematic diagram of a process flow of a disease recognition module (including image correction, image stitching, spatial registration and crack/leak recognition); FIG. 9 is a flow chart of a method for detecting tunnel disease ba