Method and apparatus for measuring structural damage size

Abstract

A method and apparatus for measuring structural damage size are disclosed. The method includes projecting an initial density of discretized grid to a damage area with a digital light processing (DLP) projection module in a measuring pen, identifying a damage suspicious area by analyzing distortion of the projected grid on the damage surface, projecting a denser grid to the identified suspicious area with the DLP projection module, simultaneously measuring the height of each center point of the denser grid with a laser triangulation module in the measuring pen, and determining the damage size based on the height measurement data of each measurement point and a profile curve of an undamaged structure.

Description

Technical Field

[0001] This invention relates to the field of structural damage measurement technology, and in particular to a method and apparatus for measuring the size of structural damage. Background Technology

[0002] In fields such as aviation maintenance, once damage is discovered in structures (such as aircraft skin and beams), it is necessary to accurately measure the dimensions of the damage (such as length, width, depth / thickness) to assess the extent of the damage and guide subsequent maintenance. Among these, measuring the thickness of the damage is particularly challenging.

[0003] Currently, the commonly used measurement methods are mainly divided into two categories: one is to measure the remaining thickness of the damaged structure through radiation (such as X-rays) or ultrasound, and then subtract the remaining thickness from the original thickness to obtain the damaged thickness; the other is to directly measure the damaged thickness using mechanical thickness gauges such as micrometers.

[0004] However, existing technologies have the following obvious limitations: X-ray or ultrasonic measurements are often difficult to implement due to limitations of structural materials, thickness, measuring equipment, and on-site environment (such as spatial accessibility); mechanical measurement methods such as micrometers rely on manual point-by-point searching for the deepest damage, which is inefficient and the measurement accuracy is difficult to guarantee, and is greatly affected by human factors.

[0005] Therefore, there is an urgent need in this field for a structural damage size measurement device and method that is versatile, easy to operate, highly accurate, and less restricted by on-site conditions. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for measuring structural damage dimensions.

[0007] According to one aspect of the present invention, a method for measuring the size of structural damage is provided, the method comprising: projecting a discrete grid of initial density onto a damaged area using a digital light processing (DLP) projection module in a measuring pen; identifying suspected damaged areas by analyzing the distortion of the projected grid on the damaged surface; projecting a denser grid onto the identified suspected areas using the DLP projection module, while simultaneously measuring the height of each center point of the denser grid using a laser triangulation module in the measuring pen; and determining the damage size based on the height measurement data of each measurement point and the contour curve of the undamaged structure.

[0008] According to a further embodiment of the present invention, the contour curve of the undamaged structure is determined by: measuring several points on the undamaged structure near the damaged area using a measuring pen to obtain the location of the initial damaged area points; and using the data processing chip in the measuring pen to fit and generate the contour curve of the undamaged structure based on the location of the initial damaged area points.

[0009] According to a further embodiment of the present invention, the contour curve of the undamaged structure is determined by: using a height-adjustable telescopic platform as a support platform, adjusting the measuring pen and camera to a height and angle adapted to the damaged area; taking a picture of the damaged area using the camera; comparing the image with a pre-stored digital model to determine the position of the damaged area in the digital model; and extracting the contour curve of the undamaged structure at that position from the digital model.

[0010] According to a further embodiment of the present invention, determining the damage size based on the height measurement data of each measurement point and the contour curve of the undamaged structure includes: obtaining a height difference by comparing the height measurement data of each measurement point with the theoretical height of the projection position of the contour curve of the undamaged structure at that point; and determining the damage size based on these height differences.

[0011] According to another aspect of the present invention, an apparatus for measuring the size of structural damage is provided. The apparatus includes: a measuring pen comprising: a digital light processing (DLP) projection module configured to project a discrete grid of variable density onto a damaged area; a laser triangulation module configured to measure the height of each center point of the DLP-projected grid; and a data processing chip configured to: identify suspected damaged areas by analyzing the distortion of the projected grid on the damaged surface; and determine the damage size based on the height measurement data of each measurement point and the contour curve of the undamaged structure.

[0012] According to a further embodiment of the present invention, the DLP projection module and the laser triangulation module in the measuring pen are integrated using an optical path folding topology.

[0013] According to a further embodiment of the present invention, the data processing chip is further configured to: receive the location of initial damage range points; and fit and generate a contour curve of the undamaged structure based on the location of these initial damage range points.

[0014] According to a further embodiment of the present invention, the data processing chip is further configured to: obtain a height difference by comparing the height measurement data of each measurement point with the theoretical height of the projection position of the contour curve of the undamaged structure at that point; and determine the damage size based on these height differences.

[0015] According to a further embodiment of the present invention, the device further includes auxiliary equipment, which includes: a camera for assisting the measuring pen in positioning; a height-adjustable telescopic platform including a multi-section telescopic rod, a rotating screw, and a support frame for supporting and adjusting the height and angle of the measuring pen and the camera; movable casters mounted on the bottom of the support frame for moving the device, and the movable casters are provided with fixed brake pads; adjustable feet mounted on the bottom of the support frame for stably supporting the entire device during measurement; and a central processing unit, communicatively connected to the measuring pen and the camera, for receiving data, performing digital-analog comparison, and generating contour curves of undamaged structures.

[0016] According to another aspect of the present invention, a computer-readable storage medium is provided for storing a computer program that, when executed by a processor, implements the method for measuring structural damage dimensions as described above.

[0017] Compared with the prior art, the structural damage size measurement scheme provided by the present invention has at least the following advantages: 1. By combining DLP grid projection for rapid positioning with laser triangulation for precise authentication, rapid screening and high-precision measurement of damaged areas are achieved, avoiding the inefficiency and inaccuracy of purely manual measurement; 2. The device features a modular design, allowing the measuring pen to be used independently. The telescopic table provides a stable measuring platform, which is not limited by structural materials or thickness. It is especially suitable for on-site and in-service structural inspections, solving the problem that large and complex structures are difficult to measure using traditional methods. 3. It integrates data processing and curve fitting functions, and can automatically generate undamaged contours, identify damaged areas, and calculate damage dimensions, which greatly reduces the technical threshold and subjective error for operators. 4. Depending on the site conditions, you can choose to use the complete set of equipment or just the measuring pen, adapting to different maintenance scenarios and space constraints.

[0018] These and other features and advantages will become apparent from the following detailed description and with reference to the accompanying drawings. It should be understood that the foregoing general description and the following detailed description are illustrative only and do not limit the scope of the claims. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a device for measuring the size of structural damage according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the measuring pen according to an embodiment of the present invention.

[0021] Figure 3This is a schematic diagram of the optical path folding topology of the DLP projection and laser triangulation integrated module in the measuring pen according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of a telescopic platform with lifting function according to an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of a movable caster according to an embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the structure for adjusting the foot according to an embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram of discretized mesh and structural damage thickness measurement according to an embodiment of the present invention.

[0026] Figure 8 This is a block diagram of an apparatus for measuring the size of structural damage according to an embodiment of the present invention.

[0027] Figure 9 This is a flowchart of a method for measuring structural damage dimensions according to an embodiment of the present invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings, and its features will become further apparent from the following specific description. In this detailed description, numerous specific details are set forth to provide a thorough understanding of the exemplary embodiments described. However, it will be apparent to those skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other exemplary embodiments, well-known structures or processing steps have not been described in detail to avoid unnecessarily obscuring the concepts of this disclosure.

[0029] Figure 1 A schematic diagram of the overall structure of a device 100 for measuring the size of structural damage according to an embodiment of the present invention is shown. (Refer to...) Figure 1 The complete device 100 includes a measuring pen 1, a camera 2, a telescopic rod 3, a rotating screw 4, a support frame 5, casters 6, adjustable feet 7, and a central processing unit. Multiple casters 6 and adjustable feet 7 are mounted on the bottom of the support frame 5. The telescopic rod 3 is mounted on the support frame 5 via the rotating screw 4, forming a height-adjustable telescopic platform. The measuring pen 1 and camera 2 can be mounted on the top of the telescopic rod 3.

[0030] Figure 2 A schematic diagram of the structure of a measuring pen 200 according to an embodiment of the present invention is shown. (Refer to...) Figure 2The measuring pen 200 can be used with a height-adjustable telescopic platform, or it can be used independently to measure the dimensions of structural damage; its DLP projection module can project a discrete mesh (such as...). Figure 7 (As shown); its laser triangulation module is used to accurately measure the height of a specific point. The measuring pen 200 may also include an image display screen, a functional touch screen, a wireless communication module, a charging port, and some chips that can connect to a computer and fit polynomial curves. The DLP projection module can project a variable density grid, and determine the location of the damage by comparing the degree of distortion of the projected pattern on the intact surface and the damaged surface. The laser triangulation module can achieve local high-precision dimensional verification.

[0031] Figure 3 A schematic diagram of the optical path folding topology 300 of the DLP projection and laser triangulation integrated module in a measuring pen according to an embodiment of the present invention is shown. (Refer to...) Figure 3 The optical paths of both the DLP projection module and the triangulation module can be integrated through a folded topology, reducing their size (e.g., Figure 2 The measuring pen 200 shown integrates a DLP projection and laser triangulation module.

[0032] Figure 4 A schematic diagram of a telescopic platform 400 with lifting function according to an embodiment of the present invention is shown. (Refer to...) Figure 4 The telescopic platform 400 can be a support bracket with lifting function, which may include 3 telescopic rods (the bottom may include a limit rod), 4 rotating screws and a support frame, and has 3 matching movable casters and an interface for adjusting the feet. At the same time, a camera and a measuring pen can be placed on the telescopic platform. It can adapt to the measurement needs of different heights and angles by adjusting the telescopic rods and rotating screws.

[0033] Figure 5 A schematic diagram of the structure of a movable caster 500 according to an embodiment of the present invention is shown. (Refer to...) Figure 5 The movable caster 500 may contain brake pads for the fixed caster. When the support bracket device is not in use, opening the brake pads can keep the entire support bracket device stationary. When the support bracket device needs to be used, closing the brake pads allows the movable caster to move the entire support bracket device.

[0034] Figure 6 A schematic diagram of the adjusting foot 600 according to an embodiment of the present invention is shown. (Refer to...) Figure 6 The adjustable foot 600 may include a rocker arm, a screw, and foot pads. When the support bracket device is required for support, the rocker arm and screw device are used to ensure that the foot pads are in full contact with the ground to maintain stability; when the support bracket device is not required, the adjustable foot is raised to make the movable casters contact the ground, thereby moving the support bracket device.

[0035] Figure 7 A schematic diagram 700 of a discretized mesh and structural damage thickness measurement according to an embodiment of the present invention is shown. (Refer to...) Figure 7 This demonstrates the distortion of a mesh projected onto a damaged surface and how to calculate damage thickness using the height difference between mesh points combined with the undamaged contour curve. For example, after damage is detected on an aircraft, on-site personnel need to grind away all the damage according to its location and ensure a smooth transition on the damaged surface before measuring the damage dimensions. Based on the height measurement data of the mesh points and the undamaged contour curve, the damage dimensions (such as depth and area) are automatically calculated, and the deepest point of the damage is determined by finding the minimum height.

[0036] Figure 8 A block diagram of an apparatus 800 for measuring the size of structural damage according to an embodiment of the present invention is shown. (Refer to...) Figure 8 The device 800 may include a measuring pen 810, which may include: a digital light processing (DLP) projection module configured to project a discrete grid of variable density onto the damaged area; a laser triangulation module configured to measure the height of each center point of the DLP-projected grid; and a data processing chip configured to: identify suspected damaged areas by analyzing the distortion of the projected grid on the damaged surface; and determine the damaged size based on the height measurement data of each measurement point and the contour curve of the undamaged structure.

[0037] According to an exemplary embodiment, the DLP projection module and the laser triangulation module in the measuring pen 810 can be integrated using an optical path folding topology.

[0038] According to an exemplary embodiment, the data processing chip may be further configured to: receive the location of initial damage range points; and fit and generate a contour curve of an undamaged structure based on the location of these initial damage range points.

[0039] According to an exemplary embodiment, the data processing chip may be further configured to: obtain a height difference by comparing the height measurement data of each measurement point with the theoretical height of the projection position of the contour curve of the undamaged structure at that point; and determine the damage size based on these height differences.

[0040] Further reference Figure 8The device 800 may also include auxiliary equipment 820, which may include: a camera for assisting the measuring pen in positioning; a height-adjustable telescopic platform, including a multi-section telescopic rod, a rotating screw, and a support frame, for supporting and adjusting the height and angle of the measuring pen and the camera; movable casters, installed at the bottom of the support frame for moving the device, and the movable casters are equipped with fixed brake pads; adjustable feet, installed at the bottom of the support frame for stabilizing the entire device during measurement; and a central processing unit, which is communicatively connected to the measuring pen and the camera for receiving data, performing digital-analog comparison, and generating contour curves of the undamaged structure.

[0041] Figure 9 A flowchart of a method 900 for measuring structural damage dimensions according to an embodiment of the present invention is shown. Method 900 is an apparatus for measuring structural damage dimensions (e.g., as described above). Figure 1 Structural damage size measuring device 100 Figure 2 The measuring pen 200 Figure 8 Examples of methods for measuring structural damage dimensions (such as the device 800 for measuring structural damage dimensions).

[0042] Reference Figure 9 Method 900 may include: projecting a discretized grid of initial density onto the damaged area using a digital light processing (DLP) projection module in a measuring pen, and identifying suspected damaged areas by analyzing the distortion of the projected grid on the damaged surface (box 910).

[0043] Further reference Figure 9 Method 900 may include: using a DLP projection module to project a denser grid onto the identified suspicious area, while using a laser triangulation module in a measuring pen to measure the height of each center point of the dense grid (box 920).

[0044] Further reference Figure 9 Method 900 may include: determining the damage size based on height measurement data at each measurement point and the profile curve of the undamaged structure (box 930).

[0045] According to an exemplary embodiment, the contour curve of the undamaged structure can be determined by: measuring several points on the undamaged structure near the damaged area using a measuring pen to obtain the location of the initial damaged area points; and using the data processing chip in the measuring pen to fit and generate the contour curve of the undamaged structure based on the location of the initial damaged area points.

[0046] According to an exemplary embodiment, the contour curve of the undamaged structure can also be determined by: using a liftable telescopic platform as a support platform, adjusting the measuring pen and camera to a height and angle adapted to the damaged area; taking a picture of the damaged area using the camera; comparing the image with a pre-stored digital model to determine the position of the damaged area in the digital model; and extracting the contour curve of the undamaged structure at that position from the digital model.

[0047] According to an exemplary embodiment, determining the damage size based on the height measurement data of each measurement point and the contour curve of the undamaged structure may include: obtaining a height difference by comparing the height measurement data of each measurement point with the theoretical height of the projection position of the contour curve of the undamaged structure at that point; and determining the damage size based on these height differences.

[0048] As an example, the measurement process of this invention can be performed according to the following steps: 1) The operator first visually or with the aid of simple tools confirms the approximate extent of the damage on the structure to be tested (such as aircraft skin). Turn on the measuring pen and set or mark this initial damage area on its function touch screen.

[0049] 2) If using the complete set of equipment, push the support bracket to a suitable location below the damaged area of ​​the aircraft using the swivel casters. Depress the brake pads of the swivel casters to initially secure it, and then adjust the rocker arm of the leveling feet to ensure that the leveling pads are firmly in contact with the ground, ensuring that the support bracket is level and stable.

[0050] 3) Activate the camera to capture or scan the damaged area, and send the image and location data to the central processing unit (such as a laptop or dedicated industrial computer). The central processing unit compares the image with a pre-stored 3D digital model of the aircraft to accurately locate the position of the current measurement area in the digital model.

[0051] 4) Generate undamaged contour curves: If digital model support is available: The central processing unit directly extracts the original undamaged structural contour curve at that location from the three-dimensional digital model based on the positioning results in step 3.

[0052] If no models are available or connections are not possible: The operator holds or manipulates the measuring pen to collect the three-dimensional coordinates of multiple points on the undamaged structural surface surrounding the damaged area. The data processing chip built into the measuring pen uses these points to generate a smooth contour curve representing the undamaged state through a curve fitting algorithm (such as polynomial fitting).

[0053] Regardless of the method used, the generated contour curve must be consistent with the coordinate system of the initial positioning point.

[0054] 5) Operate the measuring pen to project a discrete mesh of initial density onto the damaged area using its DLP projection module. Due to the depression in the damage, the projected mesh will be distorted. By analyzing the distorted mesh images captured by the camera or the measuring pen's own sensors, the system can automatically identify areas with abnormal mesh deformation, i.e., areas suspected of being damaged.

[0055] 6) For identified suspicious areas, the DLP projection module is controlled by a measuring pen to project a denser grid into that area. Simultaneously, the laser triangulation module is automatically activated to precisely measure the height of each center point of the denser grid. This process combines the advantages of rapid DLP scanning and high-precision laser verification.

[0056] 7) The central processing unit or measuring pen receives the height data of all measurement points. By comparing the height of each measurement point with the theoretical height of the undamaged contour curve projected at that point in step 4, the height difference (i.e., the damage depth) is obtained. The system automatically finds the minimum height value among all measurement points, which is the deepest point of the damage. Finally, the system can output the maximum depth of the damage, the damage area, volume, and other dimensional information, which can be visualized on the display screen.

[0057] The various steps and modules of the methods, apparatus, and systems described above can be implemented in hardware, software, or a combination thereof. If implemented in hardware, the various illustrative steps, modules, and circuits described in connection with this disclosure can be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic components, hardware components, or any combination thereof. A general-purpose processor can be a processor, microprocessor, controller, microcontroller, or state machine, etc. If implemented in software, the various illustrative steps and modules described in connection with this disclosure can be stored as one or more instructions or codes on a computer-readable medium or transmitted. Software modules implementing the various operations of this disclosure can reside in storage media such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, removable disks, CD-ROMs, cloud storage, etc. The storage medium can be coupled to a processor so that the processor can read and write information from / to the storage medium and execute corresponding program modules to implement the various steps of this disclosure. Moreover, software-based embodiments can be uploaded, downloaded, or remotely accessed through appropriate communication means. Such appropriate means of communication include, for example, the Internet, the World Wide Web, intranets, software applications, cables (including fiber optic cables), magnetic communication, electromagnetic communication (including RF, microwave and infrared communication), electronic communication, or other such means of communication.

[0058] The numerical values ​​given in the various embodiments are merely examples and are not intended to limit the scope of the invention. Furthermore, as a whole, there are other components or steps not listed in the claims or specification of this invention. Moreover, a single name for a component does not preclude other names for that component.

[0059] It should also be noted that these embodiments may be described as processes depicted as flowcharts, flow diagrams, structure diagrams, or block diagrams. Although a flowchart may describe the operations as a sequential process, many of these operations can be executed in parallel or concurrently. Furthermore, the order of these operations can be rearranged.

[0060] The disclosed methods, apparatuses, and systems should not be limited in any way. Rather, this disclosure covers all novel and non-obvious features and aspects of the various disclosed embodiments (individually and in various combinations and sub-combinations of each other). The disclosed methods, apparatuses, and systems are not limited to any particular aspect or feature or combination thereof, and no disclosed embodiment is required to have any one or more specific advantages or to solve any particular or all technical problems.

[0061] This invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications based on the teachings of this invention without departing from the spirit and scope of the claims. All of these modifications are within the scope of protection of this invention.

Claims

1. A method for measuring the size of structural damage, characterized in that, include: The digital light processing (DLP) projection module in the measuring pen projects a discretized grid of initial density onto the damaged area. By analyzing the distortion of the projected grid on the damaged surface, suspected damaged areas are identified. The DLP projection module is used to project a denser grid into the identified suspicious area, while the laser triangulation module in the measuring pen is used to measure the height of each center point of the encrypted grid. as well as Damage dimensions are determined based on height measurements at each measurement point and the profile curve of the undamaged structure.

2. The method as described in claim 1, characterized in that, The contour curve of the undamaged structure is determined in the following way: Using the measuring pen, several points are measured on the undamaged structure near the damaged area to obtain the location of the initial damage range points; as well as The data processing chip in the measuring pen is used to fit and generate the contour curve of the undamaged structure based on the location of the points in the initial damage range.

3. The method as described in claim 1, characterized in that, The contour curve of the undamaged structure is determined in the following way: Using a height-adjustable telescopic platform as a support platform, the measuring pen and camera are adjusted to a height and angle that are adapted to the damaged area; The damaged area is photographed using the camera. The location of the damaged area in the digital model is determined by comparing the image with a pre-stored digital model; as well as Extract the contour curve of the undamaged structure at the location from the digital model.

4. The method as described in claim 1, characterized in that, The damage dimensions are determined based on the height measurement data at each measurement point and the contour curve of the undamaged structure, including: The height difference is obtained by comparing the height measurement data at each measurement point with the theoretical height of the undamaged structure's contour curve projected at that point; and The damage size is determined based on the height difference.

5. A device for measuring the size of structural damage, characterized in that, include: The measuring pen includes: The digital light processing (DLP) projection module is configured to project a discrete mesh of variable density onto the damaged area; A laser triangulation module is configured to measure the height of each center point of a grid projected by a DLP; and The data processing chip is configured to: identify suspected damage areas by analyzing the distortion of the projected mesh on the damaged surface; and determine the damage size based on the height measurement data of each measurement point and the contour curve of the undamaged structure.

6. The apparatus as claimed in claim 5, characterized in that, The DLP projection module and the laser triangulation module in the measuring pen are integrated using an optical path folding topology.

7. The apparatus as claimed in claim 5, characterized in that, The data processing chip is further configured to: The location of the initial damage area is received; and The contour curve of the undamaged structure is generated by fitting the location of the points within the initial damage range.

8. The apparatus as claimed in claim 5, characterized in that, The system further includes auxiliary equipment, which includes: A camera is used to assist the measuring pen in positioning; The height-adjustable telescopic platform includes multiple telescopic rods, a rotating screw, and a support frame, used to support and adjust the height and angle of the measuring pen and the camera; Movable casters are installed at the bottom of the support frame for moving the device, and fixed brake pads are provided on the movable casters; Adjust the feet, installed at the bottom of the support frame, to stably support the entire device during measurement; and The central processing unit, which is communicatively connected to the measuring pen and the camera, is used to receive data, perform digital-analog comparison, and generate contour curves of undamaged structures.

9. The apparatus as claimed in claim 5, characterized in that, The data processing chip is further configured to: The height difference is obtained by comparing the height measurement data at each measurement point with the theoretical height of the undamaged structure's contour curve projected at that point; and The damage size is determined based on the height difference.

10. A computer-readable storage medium for storing a computer program that, when executed by a processor, implements the method as described in any one of claims 1-4.

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