Glass defect detection method and system based on reflective off-axis digital holographic microscopy technology
The glass defect detection system using reflective off-axis digital holographic microscopy technology solves the problems of existing technologies, such as the inability to distinguish between surface and internal defects, lack of depth information, and insufficient detection accuracy. It achieves high-precision glass defect detection and three-dimensional morphology reconstruction, and is suitable for industrial sites.
Patent Information
- Application Number
- CN202511131212.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-13
- Publication Date
- 2025-11-28
AI Technical Summary
Existing glass defect detection methods cannot accurately distinguish between surface and internal defects, lack depth information, have insufficient detection accuracy, and are complex and costly, making them difficult to promote in industrial settings.
A glass defect detection system based on reflective off-axis digital holographic microscopy is used. It includes a light source unit, an object light adjustment unit, a reference light adjustment unit, an image processing unit, a defect localization unit, a three-dimensional reconstruction unit, and a main control unit. The system obtains the depth information of the defect through holographic reconstruction and distinguishes between surface and internal defects by using phase and amplitude distribution characteristics, thereby realizing three-dimensional morphology reconstruction.
It achieves accurate identification of glass defects and reconstruction of three-dimensional morphology with a positioning accuracy down to the micrometer level, making it suitable for online inspection, avoiding damage to the glass, and facilitating installation and maintenance in industrial settings.
Smart Images
Figure CN121027163A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of optical detection, in particular to a glass defect detection method and system based on a reflective off-axis digital holographic microscopy technology. BACKGROUND
[0002] Glass, as an important basic material, is widely used in many fields such as building, automobile, electronics, optical instruments, etc. The quality of glass products directly affects their performance and safety, and the existence of glass defects can significantly reduce the strength, optical performance and other key indicators of glass, so it is crucial to accurately and efficiently detect glass defects.
[0003] Traditional glass defect detection methods mainly include manual visual inspection, mechanical contact detection and optical imaging-based detection methods, but still have the following defects: (1) unable to distinguish between surface and internal defects: existing technologies cannot accurately distinguish whether the defect is located on the surface or inside the glass, resulting in inaccurate quality assessment, (2) lack of depth information: traditional optical detection methods can only provide two-dimensional defect information, lacking characterization of three-dimensional morphology and depth position of defects, (3) insufficient detection accuracy: for micron-level defects, especially fine cracks and bubbles in transparent glass, existing methods have high omission rates, (4) complex system and high cost: some high-precision detection systems require complex optical elements and expensive equipment, making it difficult to promote and apply in industrial sites, and a glass defect detection method and system based on a reflective off-axis digital holographic microscopy technology is needed to solve this problem. SUMMARY
[0004] The purpose of the present application is to provide a glass defect detection method and system based on a reflective off-axis digital holographic microscopy technology to solve the problems raised in the background art.
[0005] To achieve the above purpose, the present application provides the following technical solution: a glass defect detection system based on a reflective off-axis digital holographic microscopy technology, comprising a light source unit, an object light adjustment unit, a reference light adjustment unit, an image processing unit, a defect positioning unit, a three-dimensional reconstruction unit and a main control unit. The light source unit is connected to the object light adjustment unit, the object light adjustment unit is connected to the reference light adjustment unit, the reference light adjustment unit is connected to the image processing unit, the image processing unit is connected to the defect positioning unit, the defect positioning unit is connected to the three-dimensional reconstruction unit, and the three-dimensional reconstruction unit is connected to the main control unit.
[0006] As a preferred technical solution of the present application, the light source unit is connected to a sample carrying and positioning unit, wherein the sample carrying and positioning unit can stably carry the glass sample to be detected and can accurately adjust the position and attitude of the sample.
[0007] As a preferred technical scheme of the present application, the defect positioning unit is connected with the defect classification unit, and the defect classification unit distinguishes surface defects based on the reconstructed phase and amplitude distribution characteristics.
[0008] As a preferred technical scheme of the present application, the main control unit is connected with a data storage and management module, wherein the data storage and management module stores and manages the collected holographic images and processing results, facilitating subsequent query, analysis and comparison.
[0009] As a preferred technical scheme of the present application, the image processing unit can process and analyze the collected holographic images to realize accurate identification, positioning and feature extraction of glass defects.
[0010] As a preferred technical scheme of the present application, the light source unit is connected with the power supply unit.
[0011] As a preferred technical scheme of the present application, the method comprises the following steps: S1, first fix the cleaned photovoltaic glass sample on a three-dimensional adjustment platform, and adjust the position and angle of the sample to ensure that the detection surface is perpendicular to the optical axis of the objective lens; S2, adjust the optical path adjustment mirror group of the reference light path, add a half-wave plate and a polarizer group in the reference light path, optimize the interference fringe contrast by adjusting the polarization direction to make the optical path difference between the reference light and the object light less than the laser coherence length; S3, use a 532nm semiconductor laser, and record the off-axis hologram of the glass sample surface by using an image sensor; S4, perform fast Fourier transform on the collected hologram to separate the object light field information, and then reconstruct the complex amplitude distribution of different depth planes through an angular spectrum algorithm; S5, obtain defect information of different depth layers by changing the focusing plane of the objective lens, determine the defect depth position by combining the hologram reconstruction algorithm, distinguish surface defects (strong reflection signal) and internal defects (weak scattering signal) based on the reconstructed phase and amplitude distribution characteristics; S6, reconstruct the three-dimensional topography of the defect by using a phase unwrapping algorithm and depth information fusion, display clear phase jump lines on the reconstructed plane on the glass surface, and the amplitude image presents a high-contrast feature; S7, the ring-shaped phase distribution appears on a specific depth plane inside the glass, and the amplitude image presents a low-contrast circular feature; S8, finally, the computer automatically identifies the defect type and labels the depth position, and generates a detection report.
[0012] As a preferred technical scheme of the present application, the image sensor in step 3 adopts a 2048*2048 pixel CMOS camera, and in order to improve the quality of the hologram and the accuracy of detection, the hologram under different angles or different conditions can be collected for multiple times.
[0013] As a preferred technical scheme of the present application, the object light and the reference light in step 2 are emitted by a laser in the light source unit.
[0014] Compared with the prior art, the present application has the following beneficial effects: (1) The present application is a glass defect detection method and system based on a reflective off-axis digital holographic microscopy technology, and has a depth resolution capability: the depth information of the defect can be obtained through hologram reconstruction, the surface and internal defects are distinguished, the positioning accuracy can reach the micron level, the interference measurement principle is used, the nanoscale deformation and micron-level defects have high sensitivity, and the invisible cracks that are difficult to be found by traditional methods can be detected.
[0015] (2) The present application is a glass defect detection method and system based on a reflective off-axis digital holographic microscopy technology, and not only detects the existence of the defect, but also obtains the three-dimensional topographic features of the defect, provides more comprehensive data support for quality evaluation, does not need to contact the sample, avoids potential damage to the glass surface, is suitable for online detection application, adopts a reflective off-axis optical path design, avoids a complex interferometer structure, and is convenient for industrial site installation and maintenance. BRIEF DESCRIPTION OF DRAWINGS
[0016] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below, and obviously, the drawings in the following description can only be some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0017] Figure 1 is a structural schematic diagram of a glass defect detection method and system based on a reflective off-axis digital holographic microscopy technology according to an embodiment of the present application. DETAILED DESCRIPTION
[0018] Next, the application will be further described in combination with the drawings and the specific embodiments: Embodiment 1 Reference Figure 1 It is illustrated that embodiment 1 includes a light source unit, an object light adjusting unit, a reference light adjusting unit, an image processing unit, a defect positioning unit, a three-dimensional reconstruction unit and a main control unit. The light source unit is connected with the object light adjusting unit, the object light adjusting unit is connected with the reference light adjusting unit, the reference light adjusting unit is connected with the image processing unit, the image processing unit is connected with the defect positioning unit, the defect positioning unit is connected with the three-dimensional reconstruction unit, and the three-dimensional reconstruction unit is connected with the main control unit. In the embodiment, the light source unit is connected with the sample bearing and positioning unit, the sample bearing and positioning unit can stably bear the glass sample to be detected and can accurately adjust the position and posture of the sample, the defect positioning unit is connected with the defect classification unit, the defect classification unit distinguishes surface defects based on the reconstructed phase and amplitude distribution characteristics, the main control unit is connected with the data storage and management module, the data storage and management module stores and manages the collected holographic images and processing results, and subsequent query, analysis and comparison are facilitated, the image processing unit can process and analyze the collected holographic images to realize accurate identification, positioning and feature extraction of glass defects, and the light source unit is connected with the power supply unit.
[0019] Example 2 Reference Figure 1 In the embodiment, the light source unit is connected with the sample bearing and positioning unit, the sample bearing and positioning unit can stably bear the glass sample to be detected and can accurately adjust the position and posture of the sample, the defect positioning unit is connected with the defect classification unit, the defect classification unit distinguishes surface defects based on the reconstructed phase and amplitude distribution characteristics, the main control unit is connected with the data storage and management module, the data storage and management module stores and manages the collected holographic images and processing results, and subsequent query, analysis and comparison are facilitated, the image processing unit can process and analyze the collected holographic images to realize accurate identification, positioning and feature extraction of glass defects, and the light source unit is connected with the power supply unit. S1, first fix the cleaned photovoltaic glass sample on the three-dimensional adjustment platform, and adjust the position and angle of the sample to ensure that the detection surface is perpendicular to the optical axis of the objective lens; S2, adjust the optical path adjusting mirror group of the reference light path, add a half-wave plate and a polarizer group to the reference light path, and optimize the interference fringe contrast by adjusting the polarization direction to make the optical path difference between the reference light and the object light less than the laser coherence length; S3, use a 532nm semiconductor laser, and record the off-axis hologram of the glass sample surface by using an image sensor; S4, perform fast Fourier transform on the collected hologram to separate the object light field information, and then reconstruct the complex amplitude distribution of different depth planes by using an angular spectrum algorithm; S5, obtain defect information of different depth layers by changing the focusing plane of the objective lens, determine the defect depth position by combining the hologram reconstruction algorithm, distinguish surface defects (strong reflection signal) and internal defects (weak scattering signal) based on the reconstructed phase and amplitude distribution characteristics; S6, reconstruct the three-dimensional topography of the defect by using a phase unwrapping algorithm and depth information fusion, display clear phase jump lines on the reconstructed plane of the glass surface, and present high-contrast features in the amplitude image; S7, ring-shaped phase distribution appears on a specific depth plane in the glass, and the amplitude image presents low-contrast circular features; S8, finally, the computer automatically identifies the defect type and labels the depth position, and generates a detection report.
[0020] In the embodiment, the image sensor in step 3 adopts a 2048*2048 pixel CMOS camera, in order to improve the quality of the hologram and the accuracy of detection, the hologram under different angles or different conditions can be collected for multiple times, and the object light and the reference light in step 2 are emitted by the laser in the light source unit.
[0021] In the description of the present application, it should be noted that the terms "top", "bottom", "one side", "the other side", "front", "back", "middle part", "inside", "top end", "bottom end" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between the two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0022] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for the limitation of the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalent. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A glass defect detection system based on reflective off-axis digital holographic microscopy, characterized in that, It includes a light source unit, an object light adjustment unit, a reference light adjustment unit, an image processing unit, a defect localization unit, a 3D reconstruction unit, and a main control unit; The light source unit is connected to the object light adjustment unit, the object light adjustment unit is connected to the reference light adjustment unit, the reference light adjustment unit is connected to the image processing unit, the image processing unit is connected to the defect localization unit, the defect localization unit is connected to the three-dimensional reconstruction unit, and the three-dimensional reconstruction unit is connected to the main control unit.
2. The glass defect detection system based on reflective off-axis digital holographic microscopy as described in claim 1, characterized in that, The light source unit is connected to the sample carrying and positioning unit, which can stably carry the glass sample to be tested and can accurately adjust the position and orientation of the sample.
3. The glass defect detection system based on reflective off-axis digital holographic microscopy as described in claim 1, characterized in that, The defect localization unit is connected to the defect classification unit, and the defect classification unit distinguishes surface defects based on the reconstructed phase and amplitude distribution characteristics.
4. The glass defect detection system based on reflective off-axis digital holographic microscopy as described in claim 1, characterized in that, The main control unit is connected to the data storage and management module, which stores and manages the acquired holographic images and processing results to facilitate subsequent querying, analysis and comparison.
5. A glass defect detection system based on reflective off-axis digital holographic microscopy as described in claim 1, characterized in that, The image processing unit can process and analyze the acquired holographic images to achieve accurate identification, location, and feature extraction of glass defects.
6. A glass defect detection system based on reflective off-axis digital holographic microscopy as described in claim 1, characterized in that, The light source unit is connected to the power supply unit.
7. The glass defect detection method based on reflective off-axis digital holographic microscopy according to claim 1, characterized in that, Includes the following steps: S1. First, fix the cleaned photovoltaic glass sample on the three-dimensional adjustment platform, and adjust the position and angle of the sample to ensure that the detection surface is perpendicular to the optical axis of the objective lens; S2. Adjust the optical path of the reference optical path by adjusting the reflector group. Add a half-wave plate and a polarizer group to the reference optical path. Optimize the contrast of the interference fringes by adjusting the polarization direction so that the optical path difference between the reference light and the object light is less than the laser coherence length. S3. Using a 532nm semiconductor laser, an off-axis hologram of the glass sample surface is recorded using an image sensor; S4. Perform a fast Fourier transform on the acquired hologram to separate the object light field information, and then reconstruct the complex amplitude distribution of different depth planes using the angular spectrum algorithm. S5. By changing the focusing plane of the objective lens, defect information at different depth layers is obtained. The defect depth location is determined by combining the holographic reconstruction algorithm. Based on the reconstructed phase and amplitude distribution characteristics, surface defects (strong reflection signals) and internal defects (weak scattering signals) are distinguished. S6. By using phase unfolding algorithm and depth information fusion, the three-dimensional morphology of the defect is reconstructed, and a clear phase change line is displayed on the reconstructed plane on the glass surface. The amplitude image presents high contrast characteristics. S7. A ring-shaped phase distribution appears in a plane at a specific depth inside the glass, and the amplitude image shows a low-contrast circular feature. S8. Finally, the computer automatically identifies the defect type and marks its depth and location, generating an inspection report.
8. A glass defect detection method based on reflective off-axis digital holographic microscopy according to claim 7, characterized in that, The image sensor in step 3 uses a 2048×2048 pixel CMOS camera. In order to improve the quality of the hologram and the accuracy of detection, holograms can be acquired multiple times from different angles or under different conditions.
9. A glass defect detection method based on reflective off-axis digital holographic microscopy as described in claim 7, characterized in that, The object light and reference light in step 2 are emitted by the laser in the light source unit.