Method and device for testing image detection sensitivity of flat panel detector

Abstract

The invention relates to a method for testing the image detection sensitivity of a flat panel detector, which is realized by a device for testing the image detection sensitivity of the flat panel detector, and the device for testing the image detection sensitivity of the flat panel detector comprises a radiation source and a test block made of the same material as a detected composite material part, the test block is of a right trapezoid structure, and a plurality of grooves with different depths are processed in the inclined plane along the inclined direction; the method for testing the image detection sensitivity of the flat panel detector comprises the following steps: carrying out transillumination imaging on a test block along a direction facing an inclined plane through a ray source, and obtaining a transillumination image of the test block on the flat panel detector; and determining the image detection sensitivity at different transillumination thicknesses according to the gray difference between the grooves with different depths at different transillumination thicknesses on the transillumination image and the normal area. According to the invention, the image detection sensitivity of the flat panel detector at different thickness positions can be conveniently and quickly tested when the thickness-variable composite material part is detected.

Description

Technical Field

[0001] The present application relates to the technical field of X-ray nondestructive testing, and in particular to a method and device for testing the image detection sensitivity of a flat panel detector. Background Art

[0002] X-ray digital imaging uses the fact that X-ray intensity will attenuate when passing through the object being inspected. The attenuated ray intensity is received by the detector and displayed in the form of an image. Since there is a difference in ray intensity between the defective part and the normal part, the defects or material distribution inside the object being inspected can be determined. The difference in ray intensity between the defective part and the normal area is displayed on the image as the grayscale difference ΔD.

[0003] Assume that the image grayscale of the normal area is H 1 , the image grayscale of the defective part is H 2 , then ΔD=H 1 -H 2 However, the grayscale difference ΔD must reach a certain value to be recognized. There are three main factors affecting it: the signal-to-noise ratio of the detector, the grayscale difference ΔD is large enough, and the uniformity of the object itself. The signal-to-noise ratio of the detector and the uniformity of the object itself are unchangeable. Without considering the spatial resolution, only the ΔD value is the key factor that determines whether the defect can be recognized. If the ΔD value is too small, the grayscale difference displayed is very small, and it is difficult for the human eye to recognize it during the judgment process. Therefore, for a detection image, its ability to detect defects needs to be tested, which is usually called detection sensitivity or density resolution.

[0004] Composite parts have been widely used in the aerospace field. X-ray detection methods (X-ray digital imaging and industrial CT) are currently important means of detecting internal defects in composite parts. Among them, the image detection sensitivity of the detector is an important means to evaluate the quality of the detection results, especially for composite parts with variable thickness. It is very necessary to evaluate the image detection sensitivity of the detection results in different thickness areas. Summary of the invention

[0005] (1) Technical issues to be solved

[0006] The present application provides a method for testing the image detection sensitivity of a flat-panel detector. For a composite material with variable thickness, information such as the image detection sensitivity at different thickness positions can be obtained by a simple method.

[0007] (2) Technical solution

[0008] In a first aspect, the present application provides a method for testing the image detection sensitivity of a flat-panel detector, which is implemented by a testing device for the image detection sensitivity of a flat-panel detector;

[0009] The test device for the image detection sensitivity of the flat panel detector comprises a ray source and a test block made of the same material as the composite material product to be tested; the test block is a right-angle trapezoidal structure, and the inclined surface is processed with a plurality of grooves of different depths along the inclined direction;

[0010] The method for testing the image detection sensitivity of the flat panel detector comprises:

[0011] Performing transillumination imaging on the test block along a direction toward the inclined surface by means of the ray source, and obtaining a transillumination image of the test block on the flat panel detector;

[0012] The image detection sensitivity at different transillumination thicknesses is determined according to the grayscale differences between the grooves of different depths and the normal area at different transillumination thicknesses on the transillumination image.

[0013] Further, the determining of the image detection sensitivity at different transillumination thicknesses according to the grayscale difference between the grooves of different depths and the normal area at different transillumination thicknesses on the transillumination image includes:

[0014] The grayscale difference corresponding to grooves of different depths at each transillumination thickness is determined on the transillumination image, and the image detection sensitivity at each transillumination thickness is determined according to the grayscale difference.

[0015] Furthermore, the step of determining the grayscale difference corresponding to grooves of different depths at each transillumination thickness on the transillumination image, and determining the image detection sensitivity at each transillumination thickness according to the grayscale difference, comprises:

[0016] Determining the grayscale difference and identification status corresponding to grooves of different depths at each transillumination thickness on the transillumination image;

[0017] The minimum grayscale difference that enables the groove to be identified is determined as the image detection sensitivity at each transillumination thickness.

[0018] Furthermore, after the radiation source is directed to trans-irradiate the test block in the direction of the inclined surface and a trans-irradiated image of the test block is obtained on the flat panel detector, the method further includes:

[0019] According to the transillumination image, grayscale distribution curves at different transillumination thicknesses are obtained;

[0020] According to the grayscale distribution curve, the range of transillumination thickness that meets the image detection sensitivity requirement is determined.

[0021] Furthermore, the grayscale distribution curves at different transillumination thicknesses are obtained according to the transillumination image, including:

[0022] According to the grayscales corresponding to the grooves of different depths at each transillumination thickness on the transillumination image and the grayscale of the normal area, a grayscale distribution curve at each transillumination thickness is obtained.

[0023] Furthermore, determining the range of transillumination thickness that meets the image detection sensitivity requirement according to the grayscale distribution curve includes:

[0024] Determine the image detection sensitivity at each transillumination thickness according to the grayscale distribution curve at each transillumination thickness;

[0025] According to the image detection sensitivity at each penetration thickness, the penetration thickness range that meets the image detection sensitivity requirements is determined.

[0026] Furthermore, the method for testing the image detection sensitivity of the flat panel detector further includes:

[0027] The detectable thickness range is determined according to the dynamic range of the flat panel detector and the image detection sensitivity at each transillumination thickness.

[0028] In a second aspect, the present application provides a device for testing the image detection sensitivity of a flat-panel detector, which is used to implement the method for testing the image detection sensitivity of a flat-panel detector as described above;

[0029] The test device for the image detection sensitivity of the flat panel detector comprises a ray source and a test block made of the same material as the composite material product to be detected; the test block is a right-angle trapezoidal structure, and a plurality of grooves of different depths are processed along the inclined surface.

[0030] Furthermore, the widths of the grooves of different depths are equal.

[0031] Furthermore, the spacing between grooves of different depths is equal to the width of the groove.

[0032] (3) Beneficial effects

[0033] The above technical solution of the present application has the following advantages:

[0034] The first aspect of the present application provides a method for testing the image detection sensitivity of a flat-panel detector. By machining grooves of different depths on a trapezoidal composite material test block and testing the grayscale difference of the grooves at different thickness positions of the trapezoidal test block, the image detection sensitivity of the flat-panel detector at different thickness positions when detecting composite material parts of variable thickness can be conveniently and quickly tested. This is of great significance for controlling the quality of detection images, optimizing detection process parameters, and improving detection efficiency.

[0035] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic diagram of the test block provided for this application;

[0038] Figure 2 A schematic diagram of the test block provided for this application;

[0039] Figure 3 A schematic diagram of the image detection sensitivity of the test composite material provided for this application;

[0040] Figure 4 Schematic diagram of the test block provided for this application. DETAILED DESCRIPTION

[0041] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0042] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0043] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0044] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0045] At present, the method for testing the image detection sensitivity of composite materials generally adopts linear image quality meter or slot image quality meter. The existing technology has certain shortcomings and limitations in certain specific fields: (1) Linear image quality meter is made of metal wires of different diameters arranged in groups, such as AL13-19 and FE10-16 image quality meters. However, linear image quality meters are mainly used for metal detection. Due to the anisotropic distribution of composite fiber and its complex internal structure, after it is processed into a wire diameter of less than 1mm, it is easy to deform and break, and it is not easy to process and shape. Therefore, there is no linear image quality meter specifically used for composite materials at home and abroad. (2) Slot image quality meter is generally suitable for composite parts of equal thickness. The image quality meter can be placed on a certain part of the part to determine whether the image detection sensitivity of this part meets the specified requirements. However, for composite parts of variable thickness, it is impossible to give the image detection sensitivity or grayscale curve of each thickness part.

[0046] The present application aims to provide a method and device for testing the image detection sensitivity of a flat-panel detector. The device is made of a composite material that is the same or similar to the workpiece being detected. By optimizing the design scheme, the image detection sensitivity and grayscale curve of different thickness parts of the composite material workpiece can be quickly obtained. The design scheme is to process grooves of different depths on a trapezoidal composite material test block, and by testing the grayscale change curve of the grooves at different thickness parts of the trapezoidal test block to calculate the grayscale difference ΔD, the image detection sensitivity of different thickness parts can be further obtained.

[0047] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0048] The test method for the image detection sensitivity of the flat panel detector provided in this embodiment is implemented by a test device for the image detection sensitivity of the flat panel detector. The test device for the image detection sensitivity of the flat panel detector includes a radiation source and a test block made of the same material as the composite material product to be tested; Figure 1As shown, the test block is a right-angled trapezoidal structure, and the inclined surface is processed with multiple grooves of different depths along the inclined direction.

[0049] The method for testing the image detection sensitivity of the flat-panel detector comprises: performing transillumination imaging on the test block along the direction toward the inclined surface by the radiation source, and obtaining the transillumination image of the test block on the flat-panel detector; and determining the image detection sensitivity at different transillumination thicknesses according to the grayscale difference between grooves of different depths and a normal area at different transillumination thicknesses on the transillumination image.

[0050] In some embodiments, determining the image detection sensitivity at different penetration thicknesses based on the grayscale difference between the grooves of different depths at different penetration thicknesses on the penetration image and the normal area includes: determining the grayscale difference corresponding to the grooves of different depths at each penetration thickness on the penetration image, and determining the image detection sensitivity at each penetration thickness based on the grayscale difference.

[0051] In some embodiments, the grayscale difference corresponding to grooves of different depths at each penetration thickness is determined on the penetration image, and the image detection sensitivity at each penetration thickness is determined based on the grayscale difference, including: determining the grayscale difference and recognition status corresponding to grooves of different depths at each penetration thickness on the penetration image; and determining the minimum grayscale difference that enables the grooves to be recognized as the image detection sensitivity at each penetration thickness.

[0052] In some embodiments, after the radiation source is directed toward the oblique surface to penetrate the test block and an irradiation image of the test block is obtained on the flat-panel detector, the method further includes: obtaining a grayscale distribution curve at different irradiation thicknesses based on the irradiation image; and determining a irradiation thickness range that meets the image detection sensitivity requirements based on the grayscale distribution curve.

[0053] In some embodiments, obtaining the grayscale distribution curves at different penetration thicknesses based on the penetration image includes: obtaining the grayscale distribution curve at each penetration thickness based on the grayscale corresponding to the grooves of different depths at each penetration thickness on the penetration image and the grayscale of the normal area.

[0054] In some embodiments, determining the range of transillumination thickness that meets the image detection sensitivity requirements based on the grayscale distribution curve includes: determining the image detection sensitivity at each transillumination thickness based on the grayscale distribution curve at each transillumination thickness; determining the range of transillumination thickness that meets the image detection sensitivity requirements based on the image detection sensitivity at each transillumination thickness.

[0055] In some embodiments, the method for testing the image detection sensitivity of the flat panel detector further includes: determining a detectable thickness range according to the dynamic range of the flat panel detector and the image detection sensitivity at each penetration thickness.

[0056] In application, test blocks with different thickness differences can be made of materials with the same thickness as the composite material to be tested. For example, to test a 10mm thick composite material, a flat test block can be made of a 10mm thick composite material, and grooves of different depths can be processed on the surface of the test block. The groove depth is generally designed to be 0.2mm, 0.3mm, 0.4mm... The test block is subjected to transillumination testing, so that the grayscale difference ΔD of grooves of different depths can be obtained. According to the identifiable situation of ΔD, the detection sensitivity of detecting 10mm thick composite materials under the current parameter conditions is determined.

[0057] However, for composite parts, their thickness and internal composition are diverse. To test each thickness, many test blocks need to be prepared, which is usually difficult to achieve. Therefore, it is necessary to make a test block that can cover a certain thickness range. Through this test block, the detection sensitivity within this range can be tested. The test block is designed as a right-angle trapezoidal structure, such as Figure 1 As shown, grooves of different depths are designed on the bevel, so that the detection sensitivity of composite material parts within a certain thickness range can be obtained at one time.

[0058] like Figure 2 As shown, the sides of the trapezoidal test block are defined as L, W, and H. 1 and H 2 , the depth of the test block groove is defined as h 1 、h 2 ……h 7 , the width of each groove is equal, defined as w 1 , the groove spacing is equal to the groove width, through Figure 3 Detection layout diagram for transillumination imaging. In the image obtained by the detector, since the designed grooves run through the entire detection thickness, a grayscale difference ΔD caused by grooves of different depths will be generated at each transillumination thickness. 1 , ΔD 2 ……ΔD 7 , so that the image detection sensitivity test can be carried out through the recognition of the groove and the grayscale distribution curve can be obtained.

[0059] The method of determining the transillumination thickness through the transillumination image is as follows: if the transillumination thickness to be tested is set to T, the height of the measuring part from the trapezoidal test block is H 2 The vertical distance between the sides is L 1 , then the tested penetration thickness Therefore, by actually measuring L 1The value of can determine the penetration thickness at different positions.

[0060] For example, to test composite parts with a thickness range of 5 to 20 mm, the length of the trapezoidal test block is designed as L side is 200 mm, W side is 95 mm, and H side is 1. 1 and H 2 They are 5mm and 20mm respectively, and the groove depth h 1 、h 2 ……h 7 Designed to be 0.2mm, 0.3mm...0.8mm, through transillumination imaging, the detection sensitivity and grayscale distribution curve of each thickness within the transillumination range of 5-20mm can be obtained under the current transillumination parameters. If the grayscale difference between the normal area and the groove on the grayscale curve is greater than 1.0%, the groove is considered to be identifiable, and when it is equal to 1.0%, it is the limit detection sensitivity. In this way, the thickness range that meets the detection sensitivity requirements under the current detection conditions can be obtained.

[0061] Because under certain parameter conditions, the detectable thickness range is restricted by the dynamic range of the detector, it is generally required that the grayscale of the detected image be controlled between 20% and 80% of the dynamic range of the detector. In this way, the detectable thickness range under the current test conditions, namely the thickness tolerance, can be obtained through the dynamic range and detection sensitivity.

[0062] The test method for the image detection sensitivity of a flat-panel detector provided in the embodiment of the present application is designed to test the image detection sensitivity of the detector when performing digital X-ray detection or CT detection on composite material parts. The device can cover detection thicknesses in different thickness ranges, which not only solves the problem of difficulty in testing the image detection sensitivity of composite material parts, but also takes into account important parameters such as test thickness tolerance. It is convenient and fast in the actual detection process, has strong applicability, and provides accurate and reliable data basis for the selection and optimization of detection parameters.

[0063] For composite materials of equal thickness, this device can be used to test the image detection sensitivity of the detector; for areas of different thicknesses in composite materials of variable thickness, this device can be used to obtain the detection sensitivity of areas of different thicknesses at one time. For composite materials of different thicknesses, this device can be used to test the image detection sensitivity of the detector for each part; this device can be used to obtain the detection sensitivity curve of different thicknesses and calculate ΔD, and according to the change of ΔD, the thickness tolerance that can be detected under different detection parameters can be calculated.

[0064] This embodiment also provides a test device for the image detection sensitivity of a flat panel detector, which is used to implement the above-mentioned test method for the image detection sensitivity of a flat panel detector. The test device for the image detection sensitivity of a flat panel detector includes a radiation source, a test block made of the same material as the composite material product to be tested; Figure 1 As shown, the test block is a right-angled trapezoidal structure, and the inclined surface is processed with multiple grooves of different depths along the inclined direction.

[0065] In some embodiments, the widths of grooves of different depths are equal.

[0066] In some embodiments, the spacing between grooves of different depths is equal to the width of the grooves.

[0067] The following is an explanation through specific embodiments.

[0068] Example

[0069] This device is used to detect the image resolution of the digital imaging detector for X-ray inspection of composite parts. Taking the inspection of composite laminates made of 5-20 thick carbon fiber reinforced resin-based composite materials as an example, a high-resolution digital detector is used for digital X-ray imaging inspection. During the inspection process, it is necessary to test the detector image detection sensitivity. The design is based on the requirements of the trapezoidal test block designed by this device. Figure 4 As shown, the L side is designed to be 200mm, the W side is designed to be 95mm, and the H side is designed to be 1 and H 2 They are 5mm and 20mm respectively, and the groove depth h 1 、h 2 ……h 7 Designed to be 0.2mm, 0.3mm...0.8mm, using the penetration parameters of 50KV penetration voltage, 1mA current, 10s integration time, and 1200mm focal length for penetration imaging, digital imaging detection results can be obtained. By testing the grayscale curve at different thickness positions, the image detection sensitivity of different thicknesses can be obtained. The grayscale curve can also be used to obtain the penetration thickness range that meets the sensitivity requirements under the currently used penetration parameters, that is, the thickness tolerance.

[0070] By using this device, the detector image detection sensitivity of a certain thickness range of composite material products can be obtained at one time, and more detection sensitivity information can be provided; this device is suitable for the detector image detection sensitivity test of digital imaging or CT of composite material products with equal or variable thickness, and has a wide range of applications. By using this device, the information and rules of the detector image detection sensitivity changing with the thickness of composite material products in the process of digital imaging of radiographic detection can be quickly obtained; by using this device, the thickness tolerance of the transillumination parameters used when detecting composite material products with variable thickness, that is, the thickness range that can be detected at one time, can be quickly obtained.

[0071] The device has a simple design and good applicability, and solves the problem that the detector image detection sensitivity is difficult to detect during digital radiographic imaging or CT detection of composite material parts. It has good application prospects and promotion significance in the actual detection process.

[0072] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0073] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for testing the image detection sensitivity of a flat panel detector, characterized in that: This is achieved through a test device for the image detection sensitivity of a flat panel detector; The test device for the image detection sensitivity of the flat panel detector comprises a ray source and a test block made of the same material as the composite material product to be tested; the test block is a right-angle trapezoidal structure, and the inclined surface is processed with a plurality of grooves of different depths along the inclined direction; The method for testing the image detection sensitivity of the flat panel detector comprises: Performing transillumination imaging on the test block along a direction toward the inclined surface by means of the ray source, and obtaining a transillumination image of the test block on the flat panel detector; The image detection sensitivity at different transillumination thicknesses is determined according to the grayscale differences between the grooves of different depths and the normal area at different transillumination thicknesses on the transillumination image.

2. The method for testing the image detection sensitivity of a flat panel detector according to claim 1, characterized in that: Determining the image detection sensitivity at different transillumination thicknesses according to the grayscale difference between the grooves of different depths and the normal area at different transillumination thicknesses on the transillumination image includes: The grayscale difference corresponding to grooves of different depths at each transillumination thickness is determined on the transillumination image, and the image detection sensitivity at each transillumination thickness is determined according to the grayscale difference.

3. The method for testing the image detection sensitivity of a flat panel detector according to claim 2, characterized in that: Determining the grayscale difference corresponding to grooves of different depths at each transillumination thickness on the transillumination image, and determining the image detection sensitivity at each transillumination thickness according to the grayscale difference, comprises: Determining the grayscale difference and identification status corresponding to grooves of different depths at each transillumination thickness on the transillumination image; The minimum grayscale difference that enables the groove to be identified is determined as the image detection sensitivity at each transillumination thickness.

4. The method for testing the image detection sensitivity of a flat panel detector according to claim 1, characterized in that: After the radiation source is directed to trans-irradiate the test block in the direction of the inclined surface and a trans-irradiated image of the test block is obtained on the flat panel detector, the method further includes: According to the transillumination image, grayscale distribution curves at different transillumination thicknesses are obtained; According to the grayscale distribution curve, the range of transillumination thickness that meets the image detection sensitivity requirement is determined.

5. The method for testing the image detection sensitivity of a flat panel detector according to claim 4, characterized in that: The step of obtaining grayscale distribution curves at different transillumination thicknesses according to the transillumination image comprises: According to the grayscales corresponding to the grooves of different depths at each transillumination thickness on the transillumination image and the grayscale of the normal area, a grayscale distribution curve at each transillumination thickness is obtained.

6. The method for testing the image detection sensitivity of a flat panel detector according to claim 4, characterized in that: Determining the range of transillumination thickness that meets the image detection sensitivity requirement according to the grayscale distribution curve includes: Determine the image detection sensitivity at each transillumination thickness according to the grayscale distribution curve at each transillumination thickness; According to the image detection sensitivity at each penetration thickness, the penetration thickness range that meets the image detection sensitivity requirements is determined.

7. The method for testing the image detection sensitivity of a flat panel detector according to claim 1, characterized in that: The method for testing the image detection sensitivity of the flat panel detector further includes: The detectable thickness range is determined according to the dynamic range of the flat panel detector and the image detection sensitivity at each transillumination thickness.

8. A device for testing the image detection sensitivity of a flat panel detector, characterized in that: A method for testing the image detection sensitivity of a flat panel detector according to any one of claims 1 to 7; The test device for the image detection sensitivity of the flat panel detector comprises a ray source and a test block made of the same material as the composite material product to be detected; the test block is a right-angle trapezoidal structure, and a plurality of grooves of different depths are processed along the inclined surface.

9. The device for testing the image detection sensitivity of a flat panel detector according to claim 8, characterized in that: The widths of grooves of different depths are all equal.

10. The device for testing the image detection sensitivity of a flat panel detector according to claim 9, characterized in that: The spacing between grooves of different depths is equal to the width of the groove.

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