Method and system for correcting uneven illumination of tunnel lining image

Abstract

The invention belongs to the technical field of image data processing, and particularly relates to a tunnel lining image illumination non-uniformity correction method and correction system, and the method comprises the steps: building an image index database; obtaining a tunnel lining image, and extracting an area to be corrected; comparing the to-be-corrected area with an image in the image index database, and marking harmful feature points in the to-be-corrected area; acquiring the illuminance of an image around an area to be corrected in the tunnel lining image, and adjusting the illuminance of the area to be corrected; re-inserting the adjusted region to be corrected into the tunnel lining image; according to the method, image classification and indexing can be realized by establishing the image index database, the reference image similar to the current image can be quickly retrieved, the part with non-uniform illumination in the image can be identified, harmful feature points such as cracks or pollution traces in the area needing to be corrected can be marked, the overall brightness of the image can be effectively balanced, and the accuracy of image correction can be improved. And the image is more uniform and natural.

Description

Technical Field

[0001] The present invention belongs to the technical field of image data processing, and specifically relates to image analysis equipment, and in particular to a method and system for correcting uneven illumination of a tunnel lining image. Background Art

[0002] In the prior art, although there are a variety of methods for correcting uneven illumination, such as homomorphic filtering, histogram equalization, and the Retinex method, these methods still have limitations when processing images under complex illumination conditions. For example, although the Retinex algorithm can handle illumination changes, it may cause loss of image details or color distortion in some cases. In addition, although histogram equalization can improve the overall contrast of the image, it may not be able to effectively handle the problem of local uneven illumination.

[0003] In the process of illumination correction of tunnel lining images, it is usually necessary to extract feature points in the image and compare them to determine the area to be corrected. However, this process may be affected by image noise and background complexity, resulting in inaccurate feature extraction. For example, in crack detection on the surface of tunnel lining, it is difficult to distinguish crack pixels from background pixels due to factors such as uneven illumination and surface contamination. In addition, the image acquisition environment is complex and changeable, such as unstable lighting conditions in the tunnel, which makes illumination correction in the image preprocessing stage particularly important.

[0004] Therefore, there is an urgent need to develop a new tunnel lining image illumination unevenness correction method and correction system to solve the technical problem of how to accurately identify feature points and correct image illumination under different illumination intensities.

[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0006] The embodiments of the present disclosure at least provide a method and system for correcting uneven illumination of a tunnel lining image.

[0007] In a first aspect, an embodiment of the present disclosure provides a method for correcting uneven illumination of a tunnel lining image, which includes: establishing an image index database; acquiring a tunnel lining image, and extracting an area to be corrected in the tunnel lining image that exceeds a normal illumination threshold; comparing the area to be corrected with an image in the image index database, and marking hazardous feature points in the area to be corrected; acquiring the illumination of images around the area to be corrected in the tunnel lining image, and adjusting the illumination of images in the area to be corrected except for the hazardous feature points according to the illumination; and reinserting the adjusted area to be corrected into the tunnel lining image.

[0008] In an optional embodiment, a position with any type of hazard feature point is obtained in the tunnel; a tunnel lining image with the type of hazard feature point at the position is obtained with different illuminations; and each tunnel lining image is stored to establish an image index database.

[0009] In an optional implementation, a tunnel lining image is acquired and divided into a plurality of image blocks; it is determined in turn whether there is an area exceeding a normal light illumination threshold in each image block to extract an image block requiring correction having an area exceeding the normal light illumination threshold; and the image blocks requiring correction are spliced.

[0010] In an optional implementation, the sizes of the image blocks are consistent.

[0011] In an optional implementation, it is determined in turn whether each image block to be corrected is completely covered by the area exceeding the normal light illumination threshold; if the image block to be corrected is not completely covered by the area exceeding the normal light illumination threshold, the dividing line between the area exceeding the normal light illumination threshold and the area not exceeding the normal light illumination threshold in the image block to be corrected is identified, and the dividing line is highlighted; the area to be corrected that exceeds the normal light illumination threshold is extracted from each image block to be corrected through the dividing line.

[0012] In an optional implementation, the area to be corrected is compared with tunnel lining images with different types of hazard feature points under different illuminations; if any type of hazard feature point exists in the area to be corrected, the category information of the hazard feature point is obtained through the image index database; and the hazard feature points in the area to be corrected are marked with corresponding highlight colors according to the category information.

[0013] In an optional implementation, when the illumination of an image around the area to be corrected in the tunnel lining image is obtained, the illumination of the image other than the hazardous feature point in the area to be corrected is adjusted according to the illumination.

[0014] In an optional embodiment, when the illumination of at least two images around the area to be corrected in the tunnel lining image is obtained, the illumination of the image except for the hazardous feature points in the area to be corrected is adjusted according to the average value of each illumination or a gradual change from one illumination to another.

[0015] In a second aspect, the embodiment of the present disclosure also provides a correction system, which includes: a tunnel lining image acquisition device, a host computer and a server; wherein the host computer acquires a number of tunnel lining images through the tunnel lining image acquisition device and sends them to the server; an image index database is established in the server; the host computer obtains the tunnel lining image, and extracts the area to be corrected in the tunnel lining image that exceeds the normal illumination threshold; the host computer sends the area to be corrected to the server for comparison with the image in the image index database, and marks the hazardous feature points in the area to be corrected; the server acquires the illumination of the image around the area to be corrected in the tunnel lining image, and adjusts the illumination of the image except the hazardous feature points in the area to be corrected according to the illumination; the server reinserts the adjusted area to be corrected into the tunnel lining image, and sends it to the host computer.

[0016] In an optional embodiment, the tunnel lining image acquisition device includes: a mobile cart, a high-definition camera and an adjustable light source; the high-definition camera and the adjustable light source are installed on the mobile cart; the mobile cart moves in the tunnel to a position with any type of hazard feature point; the high-definition camera cooperates with the adjustable light source to obtain the tunnel lining image with this type of hazard feature point at this position with different light intensities.

[0017] The beneficial effect of the present invention is that the present invention can efficiently extract basic features such as color, texture and shape of the image by establishing an image index database, and classify and index these features, so as to quickly retrieve a reference image similar to the current image, provide data support for image comparison and correction, extract the area exceeding the normal illumination threshold, that is, identify the part with uneven illumination, and mark the harmful feature points in the area to be corrected, such as cracks or pollution marks, by comparing the area to be corrected with the image in the image index database, and obtain the illumination of the image around the area to be corrected, and adjust the image illumination except the harmful feature points in the area to be corrected accordingly, and adopt illumination compensation technology, such as low-pass filtering, median filtering, etc., to effectively balance the overall brightness of the image, make the image more uniform and natural, reinsert the adjusted area to be corrected into the tunnel lining image, restore the integrity of the image, and improve the overall visual effect of the image, significantly improve the quality of the tunnel lining image, realize the effective correction of the uneven illumination of the tunnel lining image, and provide reliable data support for subsequent structural health monitoring and maintenance.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A flow chart of a method for correcting uneven illumination of a tunnel lining image provided by an embodiment of the present disclosure; Figure 2 A flowchart of establishing an image index database provided by an embodiment of the present disclosure; Figure 3 A flowchart for extracting an image block to be corrected provided in an embodiment of the present disclosure; Figure 4 A flowchart for extracting an area to be corrected provided in an embodiment of the present disclosure; Figure 5 A flow chart of marking hazardous feature points in an area to be corrected provided in an embodiment of the present disclosure; Figure 6 A schematic diagram of a tunnel lining image in an image index database provided by an embodiment of the present disclosure; Figure 7 A schematic diagram of a tunnel lining image before correction provided by an embodiment of the present disclosure; Figure 8 A schematic diagram of a region to be corrected before correction provided in an embodiment of the present disclosure; Fig. 9 A schematic diagram of a corrected area to be corrected provided in an embodiment of the present disclosure; Fig.10 A schematic diagram of a corrected tunnel lining image provided in an embodiment of the present disclosure.

[0022] In the figure: 1. Images in the image index database; 2. Hazard feature points; 3. Image blocks; 4. Areas to be corrected; 5. Separation lines. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "include", "comprise" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0025] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0027] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0028] like Figures 1 to 10As shown, at least one embodiment provides a method for correcting uneven illumination of a tunnel lining image, which includes: establishing an image index database; acquiring a tunnel lining image, and extracting an area 4 to be corrected in the tunnel lining image that exceeds a normal illumination threshold; comparing the area 4 to be corrected with an image 1 in the image index database, and marking hazardous feature points 2 in the area 4 to be corrected; acquiring the illumination of images around the area 4 to be corrected in the tunnel lining image, and adjusting the illumination of images in the area 4 to be corrected except for the hazardous feature points 2 according to the illumination; and reinserting the adjusted area 4 to be corrected into the tunnel lining image.

[0029] In at least one embodiment, by establishing an image index database to efficiently extract basic features of the image such as color, texture and shape, and classifying and indexing these features, a reference image similar to the current image can be quickly retrieved to provide data support for image comparison and correction. By extracting the area exceeding the normal illumination threshold, that is, identifying the part with uneven illumination, the area to be corrected 4 can be compared with the image in the image index database to mark the hazardous feature points 2 in the area to be corrected 4, such as cracks or traces of pollution, and obtain the illumination of the image around the area to be corrected 4, and adjust the image illumination of the area to be corrected 4 except for the hazardous feature points 2 accordingly. By using illumination compensation technology, such as low-pass filtering, median filtering, etc., the overall brightness of the image can be effectively balanced to make the image more uniform and natural. The adjusted area to be corrected 4 can be reinserted into the tunnel lining image to restore the integrity of the image and improve the overall visual effect of the image, significantly improving the quality of the tunnel lining image, and realizing effective correction of uneven illumination of the tunnel lining image, providing reliable data support for subsequent structural health monitoring and maintenance.

[0030] In at least one embodiment, see Figure 2 and Figure 6 , obtain a position with any type of hazard feature point 2 in the tunnel; obtain a tunnel lining image with the type of hazard feature point 2 at the position with different illumination intensities; store each tunnel lining image to establish an image index database.

[0031] Specifically, lighting is provided when taking the initial tunnel lining image to improve the lighting conditions on the tunnel surface and make the surface lighting as uniform as possible. At the same time, the illumination is continuously adjusted to associate the tunnel lining images at the same location.

[0032] Specifically, the collected images are preprocessed, such as grayscale erosion, local histogram stretching, and connected region-based filtering algorithms, to alleviate the impact of illumination changes and lighting differences. The image matrix is ​​reduced in size and divided into m×n block regions. The regional grayscale features are judged by adjusting the parameters δ1 and δ2, and adaptive threshold segmentation is performed.

[0033] Specifically, when creating a dataset, you need to enter the dataset name, select the data annotation status and import method to add pictures to the dataset, and ensure that the more scenarios the training set covers, the stronger the generalization ability of the model.

[0034] Specifically, by establishing an effective image index database and correcting the positions of the hazardous feature points 2 in the images under different illumination in the tunnel, continuous monitoring and repeatable detection of tunnel diseases can be achieved, thus improving the scientificity and accuracy of tunnel maintenance decisions.

[0035] In at least one embodiment, see Figure 3 and Figure 7 , obtain the tunnel lining image and divide it into several image blocks 3; determine in turn whether there is an area exceeding the normal illumination threshold in each image block 3, so as to extract the image block 3 that needs to be corrected with the area exceeding the normal illumination threshold; splice the image blocks 3 that need to be corrected.

[0036] Specifically, the tunnel lining image is divided into several small image blocks 3 and processed separately, which can better adapt to the influence of illumination changes and improve the segmentation effect. For the problem of detail loss or misjudgment caused by uneven illumination, a finer image can be extracted through local segmentation, and then the coarse image and the overlapping part of the detail image are combined to obtain the final corrected image.

[0037] In at least one embodiment, the sizes of the image blocks 3 are consistent.

[0038] Specifically, the sizes of the image blocks 3 are set to be consistent, so as to facilitate segmentation and splicing of the tunnel lining images.

[0039] In at least one embodiment, see Figure 4 and Figure 8 , determine in turn whether each image block 3 to be corrected is completely covered by the area exceeding the normal light illumination threshold; if the image block 3 to be corrected is not completely covered by the area exceeding the normal light illumination threshold, identify the dividing line 5 between the area exceeding the normal light illumination threshold and the area not exceeding the normal light illumination threshold in the image block 3 to be corrected, and highlight the dividing line 5; extract the area 4 to be corrected that exceeds the normal light illumination threshold from each image block 3 to be corrected through the dividing line 5.

[0040] Specifically, the identified areas exceeding the normal illumination threshold are marked with highlighted colors to facilitate manual inspection and subsequent processing. At the same time, due to the uneven illumination on the tunnel lining surface, the interference of illumination differences can be overcome by processing local images.

[0041] In at least one embodiment, see Figure 5 and Fig. 9, compare the area 4 to be corrected with the tunnel lining images with different types of hazardous feature points 2 under different illuminations; if any type of hazardous feature point 2 exists in the area 4 to be corrected, obtain the category information of the hazardous feature point 2 through the image index database; mark the hazardous feature point 2 in the area 4 to be corrected with the corresponding highlight color according to the category information.

[0042] Specifically, using different colors or brightness to distinguish different types and levels of hazardous feature points 2 can effectively detect and identify tunnel lining images and provide a basis for the safety assessment of tunnel structures.

[0043] In at least one embodiment, see Fig.10 When the illuminance of an image around the area 4 to be corrected in the tunnel lining image is obtained, the illuminance of the image other than the hazardous feature point 2 in the area 4 to be corrected is adjusted according to the illuminance.

[0044] In at least one embodiment, see Fig.10 When the illuminance of at least two images around the area 4 to be corrected in the tunnel lining image is obtained, the illuminance of the image except the hazardous feature point 2 in the area 4 to be corrected is adjusted according to the average value of each illuminance or a gradual change from one illuminance to another.

[0045] Based on the same technical concept, at least one embodiment also provides a correction system, which includes: a tunnel lining image acquisition device, a host computer and a server; wherein the host computer acquires a number of tunnel lining images through the tunnel lining image acquisition device and sends them to the server; an image index database is established in the server; the host computer obtains the tunnel lining image, and extracts the area 4 to be corrected in the tunnel lining image that exceeds the normal illumination threshold; the host computer sends the area 4 to be corrected to the server for comparison with the image 1 in the image index database, and marks the hazardous feature point 2 in the area 4 to be corrected; the server acquires the illumination of the image around the area 4 to be corrected in the tunnel lining image, and adjusts the illumination of the image in the area 4 to be corrected except the hazardous feature point 2 according to the illumination; the server reinserts the adjusted area 4 to be corrected into the tunnel lining image, and sends it to the host computer.

[0046] In at least one embodiment, the tunnel lining image acquisition device includes: a mobile cart, a high-definition camera and an adjustable light source; the high-definition camera and the adjustable light source are installed on the mobile cart; the mobile cart moves in the tunnel to a position with any type of hazard feature point 2; the high-definition camera cooperates with the adjustable light source to obtain the tunnel lining image with this type of hazard feature point 2 at this position with different light intensities.

[0047] In at least one embodiment, a tunnel lining image is obtained and divided into a plurality of image blocks 3; it is determined in turn whether there is an area exceeding a normal light illumination threshold in each image block 3 to extract the image block 3 requiring correction having an area exceeding the normal light illumination threshold; and the image blocks 3 requiring correction are spliced.

[0048] In at least one embodiment, the sizes of the image blocks 3 are consistent.

[0049] In at least one embodiment, it is determined in turn whether each image block 3 to be corrected is completely covered by the area exceeding the normal light illumination threshold; if the image block 3 to be corrected is not completely covered by the area exceeding the normal light illumination threshold, the dividing line 5 between the area exceeding the normal light illumination threshold and the area not exceeding the normal light illumination threshold in the image block 3 to be corrected is identified, and the dividing line 5 is highlighted; the area 4 to be corrected that exceeds the normal light illumination threshold is extracted from each image block 3 to be corrected through the dividing line 5.

[0050] In at least one embodiment, the area to be corrected 4 is compared with tunnel lining images with different types of hazardous feature points 2 under different illuminations; if any type of hazardous feature point 2 exists in the area to be corrected 4, the category information of the hazardous feature point 2 is obtained through the image index database; and the hazardous feature point 2 in the area to be corrected 4 is marked with a corresponding highlight color according to the category information.

[0051] In at least one embodiment, when the illuminance of an image around the area to be corrected 4 in the tunnel lining image is obtained, the illuminance of the image other than the hazardous feature point 2 in the area to be corrected 4 is adjusted according to the illuminance.

[0052] In at least one embodiment, when the illumination of at least two images around the area to be corrected 4 in the tunnel lining image is obtained, the illumination of the image except the hazardous feature point 2 in the area to be corrected 4 is adjusted according to the average value of each illumination or a gradual change from one illumination to another.

[0053] In summary, the present invention efficiently extracts basic features such as color, texture and shape of the image by establishing an image index database, and classifies and indexes these features, so that a reference image similar to the current image can be quickly retrieved, providing data support for image comparison and correction. By extracting the area exceeding the normal illumination threshold, that is, identifying the part with uneven illumination, the area to be corrected can be compared with the image in the image index database, and the harmful feature points in the area to be corrected, such as cracks or pollution marks, can be marked, and the illumination of the image around the area to be corrected can be obtained, and the image illumination except for the harmful feature points in the area to be corrected can be adjusted accordingly. By using illumination compensation technology, such as low-pass filtering, median filtering, etc., the overall brightness of the image can be effectively balanced to make the image more uniform and natural. The adjusted area to be corrected can be reinserted into the tunnel lining image to restore the integrity of the image and improve the overall visual effect of the image, significantly improving the quality of the tunnel lining image, and realizing effective correction of uneven illumination of the tunnel lining image, providing reliable data support for subsequent structural health monitoring and maintenance.

[0054] The disclosure and other solutions, examples, embodiments, modules and functional operations described in this document can be implemented in digital electronic circuits, or computer software, firmware or hardware, including the structures disclosed in this document and their structural equivalents, or a combination of one or more thereof. The disclosure and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible and non-volatile computer-readable medium for execution by a data processing device or to control the operation of the data processing device. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a storage device, a material composition that affects a machine-readable propagation signal, or a combination of one or more thereof. The term "data processing unit" or "data processing device" includes all devices, equipment and machines for processing data, including, for example, a programmable processor, a computer or a multiprocessor or a computer group. In addition to hardware, the device may also include code that creates an execution environment for a computer program, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more thereof. A propagated signal is an artificially generated signal, for example, a machine-generated electrical, optical or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[0055] A computer program (also referred to as a program, software, software application, script, or code) may be written in any form of programming language (including compiled or interpreted languages) and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program, or in multiple coordinated files (e.g., files that store one or more modules, subroutines, or portions of code). A computer program may be deployed for execution on one or more computers that are located at one site or distributed across multiple sites and interconnected by a communications network.

[0056] The processes and logic flows described in this document may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and the apparatus may also be implemented as, special purpose logic circuits, such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0057] For example, processors suitable for executing computer programs include general and special purpose microprocessors, and any one or more of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic components of a computer are a processor that executes instructions and one or more storage devices that store instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or operably coupled to receive data from a mass storage device or transfer data to a mass storage device, or both. However, a computer does not necessarily have such a device. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and compact disk read-only memory (CD ROM) and digital versatile disk read-only memory (DVD-ROM) disks. The processor and memory can be supplemented by dedicated logic circuits, or incorporated in dedicated logic circuits.

[0058] Although this patent document contains many details, they should not be construed as limitations on the scope of any invention or the claims, but rather as descriptions of features of particular embodiments of particular inventions. Certain features described in this patent document in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various functions described in the context of a single embodiment may also be implemented separately in multiple embodiments, or in any suitable subcombination. In addition, although the above-mentioned features may be described as working in certain combinations, or even initially claimed to be so, in some cases, one or more features in the claim combination may be removed from the combination, and the claim combination may be directed to subcombinations or variations of subcombinations.

[0059] Likewise, although operations are described in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order or order shown, or that all illustrated operations be performed, in order to achieve the desired results. In addition, the separation of various system components in the embodiments of this patent document should not be understood as requiring such separation in all embodiments.

[0060] Only a few implementations and examples are described, and other implementations, enhancements, and variations can be made based on what is described and illustrated in this patent document.

[0061] A first component is directly coupled to a second component when there are no intermediate components other than a line, trace, or another medium between the first component and the second component. A first component is indirectly coupled to a second component when there are intermediate components other than a line, trace, or another medium between the first component and the second component. The term "coupled" and its variations include direct coupling and indirect coupling. Unless otherwise specified, the use of the term "about" is meant to include a range of 10% above and below the value.

[0062] Although several embodiments are provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are considered to be illustrative rather than restrictive and are not limited to the details given. For example, various elements or components may be combined or integrated in another system, or certain features may be omitted or not implemented.

[0063] In several embodiments provided herein, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0064] In addition, without departing from the scope of the present disclosure, the discrete or separate techniques, systems, subsystems, and methods described and illustrated in the various embodiments may be combined or integrated with other systems, modules, techniques, or methods. Other items shown or discussed as coupled may be directly connected, or may be indirectly coupled or communicated electrically, mechanically, or otherwise through some interface, device, or intermediate component. Other examples of changes, substitutions, and alterations may be determined by those skilled in the art without departing from the spirit and scope disclosed herein.

Claims

1. A method for correcting uneven illumination of a tunnel lining image, characterized in that: include: Establish image index database; Acquire a tunnel lining image, and extract the area to be corrected that exceeds a normal illumination threshold in the tunnel lining image; Compare the area to be corrected with the image in the image index database, and mark the hazardous feature points in the area to be corrected; Obtain the illumination of the image around the area to be corrected in the tunnel lining image, and adjust the illumination of the image except for the hazardous feature points in the area to be corrected according to the illumination; The adjusted area requiring correction is reinserted into the tunnel lining image.

2. The method for correcting uneven illumination of a tunnel lining image according to claim 1, characterized in that: Obtaining the location of any type of hazard feature point in the tunnel; The tunnel lining image with the characteristic points of the hazard at the location is obtained at different illumination intensities; The images of each tunnel lining are stored to build an image index database.

3. The method for correcting uneven illumination of a tunnel lining image according to claim 2, characterized in that: Acquire the tunnel lining image and segment it into several image blocks; Determine in sequence whether there is an area exceeding the normal illumination threshold in each image block, so as to extract the image block to be corrected with the area exceeding the normal illumination threshold; Stitch the image blocks that need to be corrected.

4. The method for correcting uneven illumination of a tunnel lining image according to claim 3, characterized in that: The sizes of each image block are consistent.

5. The method for correcting uneven illumination of a tunnel lining image according to claim 3, characterized in that: Determine in turn whether each image block to be corrected is completely covered by the area exceeding the normal illumination threshold; If the image block to be corrected is not completely covered by the area exceeding the normal light illumination threshold, identify a dividing line between the area exceeding the normal light illumination threshold and the area not exceeding the normal light illumination threshold in the image block to be corrected, and highlight the dividing line; The area to be corrected that exceeds the normal illumination threshold is extracted from each image block to be corrected through the separation line.

6. The method for correcting uneven illumination of a tunnel lining image according to claim 5, characterized in that: Compare the area to be corrected with tunnel lining images with different types of hazard feature points under different illumination levels; If any type of hazardous feature point exists in the area to be corrected, the category information of the hazardous feature point is obtained through the image index database; Mark the hazardous feature points in the area to be corrected with corresponding highlight colors according to the category information.

7. The method for correcting uneven illumination of a tunnel lining image according to claim 6, characterized in that: When the illumination of an image around the area to be corrected in the tunnel lining image is obtained, the illumination of the image except for the hazardous feature points in the area to be corrected is adjusted according to the illumination.

8. The method for correcting uneven illumination of a tunnel lining image according to claim 6, characterized in that: When the illuminance of at least two images around the area to be corrected in the tunnel lining image is obtained, the illuminance of the image except the hazardous feature points in the area to be corrected is adjusted according to the average value of each illuminance or a gradual change from one illuminance to another.

9. A correction system, characterized in that: include: Tunnel lining image acquisition equipment, host computer and server; in The host computer collects a number of tunnel lining images through a tunnel lining image acquisition device and sends them to the server; Establishing an image index database in the server; The host computer acquires a tunnel lining image and extracts the area to be corrected that exceeds a normal illumination threshold in the tunnel lining image; The host computer sends the area to be corrected to the server for comparison with the images in the image index database, and marks the harmful feature points in the area to be corrected; The server obtains the illumination of the image around the area to be corrected in the tunnel lining image, and adjusts the illumination of the image except the hazardous feature points in the area to be corrected according to the illumination; The server reinserts the adjusted area to be corrected into the tunnel lining image and sends it to the host computer.

10. The correction system according to claim 9, characterized in that The tunnel lining image acquisition device includes: a mobile vehicle, a high-definition camera and an adjustable light source; The high-definition camera and adjustable light source are installed on a mobile vehicle; The mobile vehicle moves in the tunnel to a position with any type of hazard feature point; The high-definition camera cooperates with the adjustable light source to obtain the tunnel lining image with the hazard feature point at the location with different light intensities.

Images