Image enhancement method and device suitable for defect detection and storage medium
By acquiring defect images and matching image enhancement parameters in the re-inspection system, the problem of low re-inspection efficiency in AI vision inspection systems is solved, achieving more efficient and accurate defect detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-14
AI Technical Summary
Existing AI visual inspection systems are prone to misjudgment during the re-inspection process, making it difficult for re-inspection personnel to effectively identify subtle differences, resulting in low inspection efficiency and insufficient accuracy.
By acquiring defect images and their type information of the material to be inspected, matching corresponding image enhancement parameters, and performing enhancement processing on the re-inspection system interface, clear and easy-to-analyze images are displayed to improve inspection accuracy and efficiency.
Enhanced images enable inspectors to identify defects more intuitively and quickly, improving the accuracy and efficiency of inspections and helping companies optimize production processes and product quality.
Smart Images
Figure CN121860903A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of image processing technology, specifically to an image enhancement method, apparatus, and storage medium suitable for defect detection. Background Technology
[0002] With the widespread application of Artificial Intelligence (AI) algorithms and computer vision technology in modern industrial production and quality inspection processes, machine vision products, i.e., image acquisition devices, convert the captured target into image signals, which are then transmitted to a dedicated image processing system to detect defects on the captured target based on AI algorithms.
[0003] In practical applications, although AI vision inspection systems have high accuracy, misjudgments can still occur. For example, in the inspection of some complex industrial products, factors such as surface texture and reflection may cause the AI vision inspection system to misidentify normal appearance features as defects or miss minor defects. Manual re-inspection can carefully identify these suspected cases, thereby correcting the system's erroneous judgments, ensuring the accuracy of the inspection results, and simultaneously feeding back the relevant results to the AI vision inspection system to further optimize the accuracy of the inspection results.
[0004] However, the inventors discovered that manual re-inspection often presents challenges for inspectors. For example, due to various factors, some images deemed non-compliant (NG) by AI visual inspection systems may have unclear color gradations, easily leading to misreading or oversight by inspectors, significantly hindering the re-inspection process and potentially affecting the accurate judgment of product quality. Current AI visual inspection systems often lack effective solutions for such situations. Inspectors can only rely on their naked eyes and experience to distinguish subtle differences in these images, which is not only inefficient but also prone to misjudgment. Therefore, there is an urgent need for an image enhancement method suitable for defect detection to improve inspectors' ability to recognize NG images and ensure the accuracy and reliability of product quality inspection. Summary of the Invention
[0005] In view of this, this application provides an image enhancement method, apparatus and storage medium suitable for defect detection, in order to solve the technical problem of relatively low re-inspection efficiency in existing re-inspection systems.
[0006] In a first aspect, this application provides an image enhancement method suitable for defect detection, applied to a defect re-inspection system, the method comprising:
[0007] Obtain defect images of the first inspection of the material to be inspected, where the defect images carry corresponding defect type information;
[0008] Based on the defect type information, match the corresponding image enhancement parameters from the enhancement settings database;
[0009] The re-inspection system displays an image after the defect image has been enhanced based on the image enhancement parameters.
[0010] Preferably, the image enhancement method suitable for defect detection further includes:
[0011] Upon detecting the triggering of the image enhancement settings event on the display interface of the re-inspection system, the image enhancement settings interface pops up.
[0012] The image enhancement settings interface displays data information from the enhancement settings database.
[0013] Each set of data includes defect type information and enhancement parameter information corresponding to the defect type.
[0014] Preferably, each set of data information includes an information box, and the information box contains at least one defect type information. All defect types in the information box correspond to the same enhancement parameter information.
[0015] Preferably, the information box is provided with a drop-down button, and the drop-down information displays all defect type information.
[0016] Preferably, the enhanced parameter information includes brightness and contrast.
[0017] Preferably, the threshold range for brightness is [-1, 1]; and the threshold range for contrast is [-1, 1].
[0018] Preferably, in the re-inspection system display interface, after the original image display event is detected, the original defect image is displayed according to the selected image.
[0019] Secondly, this application provides an image enhancement device suitable for defect detection, applied in a defect re-inspection system, the device comprising:
[0020] The acquisition module is used to acquire defect images of the first inspection of the material to be inspected, wherein the defect images carry corresponding defect type information;
[0021] The parameter matching module is used to match the corresponding image enhancement parameters from the enhancement setting database based on the defect type information;
[0022] The display module is used to display the image after the defect image has been enhanced based on the image enhancement parameters on the display interface of the re-inspection system.
[0023] Thirdly, this application provides a computer device, including: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to implement the image enhancement method suitable for defect detection described in the first aspect.
[0024] Fourthly, this application provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the image enhancement method suitable for defect detection described in the first aspect.
[0025] The image enhancement method, apparatus, and storage medium suitable for defect detection provided in this application have at least the following beneficial effects:
[0026] The technical solution provided in this application can more effectively utilize defect images and the defect type information they carry. Through targeted image enhancement processing, it provides clearer and easier-to-analyze images to re-inspection personnel or automated re-inspection systems on the re-inspection system display interface, helping to improve the accuracy and efficiency of detection. By displaying the enhanced image on the re-inspection system display interface, re-inspection personnel can view the defect situation more intuitively and quickly. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort. It should be noted that the drawings described below are illustrative and should not be construed as imposing any limitations on this application. In the drawings:
[0028] Figure 1 A schematic diagram of an image enhancement method suitable for defect detection according to one embodiment of this application is shown;
[0029] Figure 2 A schematic diagram of the display interface of the re-inspection system according to one embodiment of this application is shown;
[0030] Figure 3 A schematic diagram of an image enhancement settings interface is shown;
[0031] Figure 4 A schematic diagram of another image enhancement settings interface is shown;
[0032] Figure 5 A schematic diagram of yet another image enhancement settings interface is shown;
[0033] Figure 6 A schematic diagram of another image enhancement settings interface is shown;
[0034] Figure 7 A schematic diagram of an image enhancement apparatus suitable for defect detection according to one embodiment of this application is shown;
[0035] Figure 8 A schematic diagram of a computer device according to one embodiment of this application is shown. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0037] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0039] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0040] Although the processes described below include multiple operations that occur in a specific order, it should be clearly understood that these processes may also include more or fewer operations, which may be executed sequentially or in parallel.
[0041] Example 1
[0042] The image enhancement method for defect detection provided in this application can be applied to the application scenario of defect re-inspection system for defect re-inspection. In this application scenario, the initial inspection system uses visual inspection technology to detect appearance defects in materials and generates small defect images corresponding to the defects. The small defect images carry defect type information. The initial inspection system transmits the detected defect images to the re-inspection system, and the re-inspection personnel use the re-inspection system to re-evaluate the defect images.
[0043] Please see Figure 1 An image enhancement method suitable for defect detection, provided in one embodiment of this application and applied to a defect re-inspection system, may include the following multiple steps.
[0044] S101. Obtain the defect image of the first inspection of the material to be inspected, wherein the defect image carries the corresponding defect type information.
[0045] Specifically, the first-pass inspection system uses visual inspection technology to detect appearance defects in the material to be inspected and generates corresponding defect thumbnails. The defect thumbnails carry corresponding defect type information, including scratches on gold fingers, foreign objects on gold fingers, gold surface dents, exposed copper on gold surfaces, solder resist bubbles, short circuits, etc.
[0046] S102. Based on the defect type information, match the corresponding image enhancement parameters from the enhancement setting database.
[0047] Specifically, the enhancement settings database has a dedicated record area for material defects, and its overall architecture is designed to facilitate quick and accurate matching of image enhancement parameters corresponding to each defect type. For example, each record in the database corresponds to a specific circuit board defect type and contains a series of image enhancement parameters suitable for that defect type. The defect type information carried in the defect image is used as a query condition in the enhancement settings database. For example, if the defect type is "cold solder joint," the query statement executed in the database would be similar to "SELECT * FROM enhancement_parameters_table WHERE defect_type = 'cold solder joint'" (assuming the database table name is enhancement_parameters_table). Through the corresponding database architecture and matching process, appropriate image enhancement parameters can be accurately matched according to different defect types of the circuit board.
[0048] S103. Display the image after the defect image has been enhanced based on the image enhancement parameters on the re-inspection system display interface.
[0049] Specifically, the enhanced defect images are displayed on the re-inspection system's interface. These interfaces typically offer excellent visualization, clearly presenting the details of the enhanced images for easy viewing and analysis by inspectors. For example, in a circuit board re-inspection system, inspectors can see enhanced images of circuit board defects on their computer screens, clearly observing changes in solder joint morphology at cold solder joints, increased contrast between short circuits and surrounding areas, etc., allowing for a more accurate assessment of the defect's nature and severity, providing a strong basis for subsequent processing decisions. Similarly, in an automotive parts re-inspection system, inspectors can see enhanced images of parts defects on their computer screens, clearly observing changes in casting corrosion, surface depressions, etc., allowing for a more accurate assessment of the defect's nature and severity, providing a strong basis for subsequent processing decisions.
[0050] In this embodiment, defect images and the defect type information they carry can be utilized more effectively. Through targeted image enhancement processing, clearer and easier-to-analyze images are provided to re-inspection personnel or automated re-inspection systems on the re-inspection system display interface, helping to improve the accuracy and efficiency of inspection. Presenting the enhanced image on the re-inspection system display interface allows re-inspection personnel to view defects more intuitively and quickly. Compared to the unprocessed original image, the enhanced image eliminates the need for re-inspection personnel to spend excessive time carefully identifying blurry defects, enabling them to make quick judgments and thus accelerating the re-inspection process and improving the efficiency of the entire inspection workflow. Based on the clearer and more accurate information obtained after defect image enhancement processing, enterprises have a stronger basis for making quality improvement decisions. It can be clearly identified which aspects require key improvements, such as adjustments to production equipment, operator training, or raw material control, thereby effectively improving product quality and enhancing the enterprise's market competitiveness.
[0051] Preferably, the image enhancement method suitable for defect detection further includes:
[0052] Upon detecting the triggering of the image enhancement settings event on the display interface of the re-inspection system, the image enhancement settings interface pops up.
[0053] The image enhancement settings interface displays data information from the enhancement settings database.
[0054] Each set of data includes defect type information and enhancement parameter information corresponding to the defect type.
[0055] In this embodiment, during the operation of the re-inspection system's display interface, various events triggered by re-inspection personnel or within the system are monitored. The image enhancement setting event mentioned here might be triggered by a re-inspection personnel actively clicking a specific button (such as...). Figure 2 The "Image Enhancement" button in the system is either triggered by the system setting itself or by meeting certain preset system conditions (such as when a new batch of materials with initial inspection defects is detected and enters the re-inspection process). Once the system detects that this event has been triggered, it will initiate corresponding subsequent operations to meet the re-inspection personnel's needs for image enhancement settings. When the image enhancement setting event is triggered, the system will immediately pop up a dedicated interface for image enhancement settings. This interface is designed to allow re-inspection personnel to intuitively view and operate various settings related to image enhancement. For example, see... Figure 3 As shown, it may pop up as a separate window. The window layout will rationally arrange various controls and display areas to clearly display data information and facilitate interactive operations by review personnel. The main content displayed in the pop-up image enhancement settings interface is the relevant data information extracted from the enhancement settings database. Each record (each set of data information) in the database corresponds to a specific defect type and contains enhancement parameter information closely related to that defect type. By displaying this data information on the interface, review personnel can clearly understand the specific enhancement settings corresponding to different defect types.
[0056] In this embodiment, the defect type information clearly indicates the specific defect type targeted by each set of data. For example, in a circuit board inspection scenario, defect type names such as "cold solder joint," "short circuit," and "component damage" may be displayed. This information allows re-inspection personnel to quickly identify which type of defect image the data set is used to process. The enhancement parameter information corresponding to the defect type is the core part of each set of data, detailing various parameters set to enhance the display effect of that defect type in the image. Specific parameters such as brightness and contrast can be displayed, as well as specific parameters such as the slope and intercept value of grayscale transformation (used to adjust image contrast and brightness), the window size for filtering and denoising (used to remove noise interference in the image), and the intensity threshold for edge enhancement (used to highlight the edges of the cold solder joint).
[0057] In this embodiment, the re-inspection system display interface provides re-inspection personnel with convenient and quick access to comprehensive image enhancement settings. When re-inspection personnel need to make further fine adjustments to the defect image or view standard enhancement settings for different defect types, they can do so through this pop-up image enhancement settings interface. This also facilitates timely modification of relevant parameter settings by re-inspection personnel, further accelerating the re-inspection process and improving the efficiency of the entire inspection workflow.
[0058] Preferably, each set of data information includes an information box, and the information box contains at least one defect type information. All defect types in the information box correspond to the same enhancement parameter information.
[0059] In this embodiment, a structural unit called an information box is specifically set up within each set of data information in the image enhancement settings database. This information box is a container used to classify and integrate related data, providing a clearer and more organized way for data presentation and management. The main function of the information box is to centrally load defect type y information with certain related characteristics. It's like a folder, putting related content together to facilitate more convenient and efficient operation when using this data later. For example, see... Figure 4 As shown, "text misalignment," "text omission," and "text misprint" correspond to the same enhancement parameter information. If a fourth type, "printing defect," appears, requiring the same image enhancement processing, then "printing defect" can be added to the information box. See [link to relevant documentation]. Figure 5 As shown. Regardless of the different defect types contained in this information box, the same set of pre-set enhancement parameters will be used when enhancing the images related to these defect types. For example, in the database of an automotive parts appearance re-inspection system, there can be a dedicated information box for storing defect type information related to surface scratches but potentially exhibiting different specific forms (such as shallow scratches, deep scratches, etc.), allowing these seemingly different but essentially related defect types to be managed uniformly. This implementation simplifies the operation and management of image enhancement settings, reduces potential errors during setup, greatly improves efficiency, and makes it easier for re-inspection personnel to promptly modify the corresponding parameter settings. This further accelerates the re-inspection process and improves the overall efficiency of the inspection workflow.
[0060] Preferably, see Figure 6 As shown, the information box includes a drop-down menu button, displaying all defect type information. When a corresponding defect type is selected, a checkmark appears next to the defect type text, and the selected defect type information is recorded in the information box. Clicking "Select All" loads all defect type information into the information box. In this embodiment, the drop-down menu and the "Select All" button allow for quick filtering of the target defect type information, making it easier for re-inspection personnel to promptly modify the corresponding parameter settings. This further accelerates the re-inspection process and improves the overall efficiency of the inspection workflow.
[0061] Preferably, the enhanced parameter information includes brightness and contrast.
[0062] Preferably, the threshold range for brightness is [-1, 1]; and the threshold range for contrast is [-1, 1].
[0063] In this embodiment, brightness and contrast are two important parameters in image enhancement processing. Using appropriate contrast makes bright areas brighter and dark areas darker, thereby enhancing the contrast between light and dark areas and making the boundaries between different brightness areas more distinct, highlighting the image's depth and three-dimensionality. It also emphasizes the defective subject in the image, making it more prominent and eye-catching. Furthermore, it enhances the expressiveness of details, making previously blurry details such as object textures and edges more clearly discernible. This further speeds up the re-inspection process and improves the overall efficiency of the inspection workflow.
[0064] Preferably, in the re-inspection system display interface, after the original image display event is detected, the original defect image is displayed according to the selected image.
[0065] In this embodiment, after the re-inspection personnel have performed a series of enhancement operations on the defect image, they may want to view the original defect image for comparison. By triggering the original image display event and popping up the original defect image, the re-inspection personnel can intuitively compare the enhanced image with the original image. For example, in circuit board inspection, after image enhancement processing, short circuit points may become more obvious and have clearer edges in the image. However, by viewing the original defect image, they can accurately understand the relatively blurred state of the short circuit points in the original state, thereby better evaluating the effect of the enhancement processing and determining whether the intended purpose of highlighting defect features has been achieved. The original defect image can serve as an important reference, especially when there are doubts about the defect situation or when further in-depth analysis is required. It preserves the true state of the defect when it was initially discovered, allowing the inspection personnel to re-examine the defect based on the original image. This further speeds up the re-inspection process and improves the efficiency of the entire inspection workflow.
[0066] Example 2
[0067] This embodiment provides an image enhancement apparatus suitable for defect detection, which is applied to the image enhancement method for defect detection provided in Embodiment 1 above for illustration. Please refer to... Figure 7 As shown, an image enhancement device suitable for defect detection provided in one embodiment of this application, applied to a defect re-inspection system, may include the following multiple modules.
[0068] The acquisition module is used to acquire defect images of the first inspection of the material to be inspected, wherein the defect images carry corresponding defect type information;
[0069] The parameter matching module is used to match the corresponding image enhancement parameters from the enhancement setting database based on the defect type information;
[0070] The display module is used to display the image after the defect image has been enhanced based on the image enhancement parameters on the display interface of the re-inspection system.
[0071] The image enhancement device suitable for defect detection provided in this application embodiment can be applied to the image enhancement method suitable for defect detection provided in Embodiment 1 above. For relevant details, please refer to the above method embodiment. The implementation principle and technical effect are similar, and will not be repeated here.
[0072] It should be noted that the image enhancement device suitable for defect detection provided in this embodiment is only illustrated by the above-described division of functional modules / units when performing image enhancement for defect detection. In practical applications, the above functions can be assigned to different functional modules / units as needed, that is, the internal structure of the image enhancement device suitable for defect detection can be divided into different functional modules / units to complete all or part of the functions described above. Furthermore, the implementation method of the image enhancement method suitable for defect detection provided in the above-described embodiment 1 and the implementation method of the image enhancement device suitable for defect detection provided in this embodiment 2 belong to the same concept. The specific implementation process of the image enhancement device suitable for defect detection provided in this embodiment 2 is detailed in the above-described embodiment 1, and will not be repeated here.
[0073] Example 3
[0074] Please see Figure 8 As shown, one embodiment of this application also provides a computer device, which may be a desktop computer, a laptop computer, a handheld computer, or a cloud server, etc. This computer device may include, but is not limited to, a processor and a memory. The processor and memory may be connected via a bus or other means.
[0075] The processor can be a central processing unit (CPU). It can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, graphics processing units (GPUs), embedded neural network processing units (NPUs) or other dedicated deep learning coprocessors, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips.
[0076] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods in the above embodiments of this application. The processor executes various functional applications and data processing by running the non-transitory software programs, instructions, and modules stored in the memory, thereby implementing the methods in the above embodiments.
[0077] The memory may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor, etc. Furthermore, the memory may include high-speed random access memory and non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include memory remotely located relative to the processor, which can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.
[0078] One embodiment of this application also provides a computer-readable storage medium for storing a computer program that, when executed by a processor, implements the method described in the above-described method embodiments.
[0079] Those skilled in the art will understand that all or part of the processes in the methods described above in this application can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the methods described above. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.
[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0081] While embodiments of this application have been described in conjunction with the accompanying drawings, this should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various variations or modifications based on the above description without departing from the concept of this application. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom still fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. An image enhancement method suitable for defect detection, characterized in that, The method includes: Obtain defect images of the first inspection of the material to be inspected, where the defect images carry corresponding defect type information; Based on the defect type information, match the corresponding image enhancement parameters from the enhancement settings database; The re-inspection system displays an image after the defect image has been enhanced based on the image enhancement parameters.
2. The image enhancement method suitable for defect detection according to claim 1, characterized in that, Also includes: Upon detecting the triggering of the image enhancement settings event on the display interface of the re-inspection system, the image enhancement settings interface pops up. The image enhancement settings interface displays data information from the enhancement settings database. Each set of data includes defect type information and enhancement parameter information corresponding to the defect type.
3. The image enhancement method suitable for defect detection according to claim 1, characterized in that, Each set of data information includes an information box, which contains at least one defect type information. All defect types in the information box correspond to the same enhancement parameter information.
4. The image enhancement method suitable for defect detection according to claim 3, characterized in that, The information box is equipped with a drop-down button, and the drop-down information displays all defect type information.
5. The image enhancement method suitable for defect detection according to claim 2, 3, or 4, characterized in that, The enhanced parameter information includes brightness and contrast.
6. The image enhancement method suitable for defect detection according to claim 1, characterized in that, The threshold range for brightness is [-1, 1]; the threshold range for contrast is [-1, 1].
7. The image enhancement method suitable for defect detection according to claim 1, in the re-inspection system display interface, after the original image display event is detected, the original defect image is displayed according to the selected image.
8. An image enhancement device suitable for defect detection, characterized in that, include: The acquisition module is used to acquire defect images of the first inspection of the material to be inspected, wherein the defect images carry corresponding defect type information; The parameter matching module is used to match the corresponding image enhancement parameters from the enhancement setting database based on the defect type information; The display module is used to display the image after the defect image has been enhanced based on the image enhancement parameters on the display interface of the re-inspection system.
9. A computer device, characterized in that, include: A memory and a processor are communicatively connected, the memory storing computer instructions, and the processor executing the computer instructions to implement the image enhancement method suitable for defect detection as described in any one of claims 1-7.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the image enhancement method suitable for defect detection as described in any one of claims 1-7.