Method, system, device, equipment and medium for eliminating scattering and hardening artifacts of turbine blade CT (Computed Tomography) imaging

Abstract

The invention discloses a scattering and hardening artifact eliminating method, system, device and equipment for turbine blade CT imaging and a medium, and relates to the field of aero-engine turbine blade CT detection. The method comprises the following steps: acquiring an original multicolor projection image and a scattering correction projection image of the turbine blade before and after placing a grating correction plate by using a cone beam CT (Computed Tomography) system; the aluminum strips arranged on the grating correction plate at intervals have inclined angles; according to the two images, determining a multi-color projection image for scattering removal of the turbine blade, and further utilizing a beam hardening correction model to obtain a single-color projection image of the turbine blade; weighting the monochromatic projection image and the scattering-removed multicolor projection image by adopting a weighted compensation enhancement correction algorithm which introduces a trade-off factor to obtain a projection image of which the cup artifact is eliminated; and finally, performing three-dimensional reconstruction by adopting a filtered back projection algorithm to obtain a projection correction slice image of the turbine blade. The method can effectively eliminate cup-shaped artifacts caused by scattering and hardening, and improves the image reconstruction quality.

Description

Technical Field

[0001] The present application relates to the field of CT detection of aircraft engine turbine blades, and in particular to a method, system, device, equipment and medium for eliminating scattering and hardening artifacts in CT imaging of turbine blades. Background Art

[0002] Aircraft engine turbine blades have complex structures, operate in harsh environments, and place high demands on manufacturing quality. Therefore, non-destructive testing (NDT) technology is needed to locate defects on aircraft engine turbine blades and achieve quantitative, comprehensive, and accurate inspection.

[0003] X-ray industrial computed tomography (CBCT) is an imaging technology that projects rays at different angles onto an object, collects imaging data (i.e., ray attenuation) from the detector, and then reconstructs the object's cross-sectional information in three dimensions. This technology enables non-contact and non-destructive detection of internal defects such as the location and size, density variations, and levels of defects in objects like ceramic casings, turbine blades, and wheel hub castings. CBCT is widely used in product defect detection and assessment, playing a vital role in product quality assurance. In X-ray industrial CT systems, the ability to efficiently achieve high-quality, high-precision imaging directly impacts subsequent image processing, including segmentation, registration, and fusion.

[0004] Artifacts caused by scattering and hardening during ray attenuation significantly impact the quality of CT reconstructed images. In cone-beam CT systems based on flat-panel detectors, Compton scattering causes the photons received by the detector to not only be the original photons, but also polarization interference from scattered photons, resulting in blurred images and degraded edges. Furthermore, as rays attenuate within an object, high-energy rays decay normally, while low-energy rays are largely absorbed, increasing their average energy. This increases the proportion of high-energy rays in the outgoing radiation, causing the rays to gradually harden. This is when hardening artifacts appear. Compared to single-energy conditions, the measured projection values after hardening are always relatively low, and the grayscale values of the reconstructed image decrease, exhibiting a cup-shaped phenomenon with high grayscale information at the edges and low grayscale information at the center. Summary of the Invention

[0005] The purpose of this application is to provide a method, system, device, equipment and medium for eliminating scattering and hardening artifacts in turbine blade CT imaging, which can effectively eliminate cupping artifacts caused by scattering and hardening and improve image reconstruction quality.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a method for eliminating scattering and hardening artifacts in CT imaging of turbine blades, comprising: using a cone-beam CT system to obtain an original multi-color projection image of the turbine blade before a grating correction plate is placed, and a scattering-corrected projection image of the turbine blade after the grating correction plate is placed; the aluminum bars arranged at intervals on the grating correction plate have an inclination angle; determining a descattered multi-color projection image of the turbine blade based on the original multi-color projection image and the scattering-corrected projection image; establishing a beam hardening correction model; obtaining a monochrome projection image of the turbine blade based on the descattered multi-color projection image of the turbine blade using the beam hardening correction model; using a weighted compensation enhancement correction algorithm that introduces a trade-off factor to weight the monochrome projection image and the descattered multi-color projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated; using a filtered back-projection algorithm to perform three-dimensional reconstruction based on the projection image with cupping artifacts eliminated to obtain a projection-corrected slice image of the turbine blade.

[0008] Optionally, a de-scattered multi-color projection image of the turbine blade is determined based on the original multi-color projection image and the scattering-corrected projection image, specifically comprising: acquiring a projection image of a grating correction plate using a cone-beam CT system; determining a slit area between aluminum bars in the scattering-corrected projection image based on the projection image of the grating correction plate; interpolating and smoothing the slit area to obtain a scattering image; and subtracting the scattering image from the original multi-color projection image to obtain a de-scattered multi-color projection image of the turbine blade.

[0009] Optionally, a beam hardening correction model is established, specifically including:

[0010] defining a beam hardening correction model including a hardening curve and a correction line;

[0011] Establish the hardening curve: L = α·P p ·exp(β·(P p ) γ ), where L is the length of the ray passing through the object, α, β, and γ are all fitting parameters, and P P It is a descattered multi-color projection image;

[0012] The calibration line is established as: L = α·P m Where, P m The projected image is monochrome.

[0013] Optionally, based on the descattered multi-color projection image of the turbine blade, a beam hardening correction model is used to obtain a monochrome projection image of the turbine blade, specifically including: based on the descattered multi-color projection image of the turbine blade, using the hardening curve, obtaining the penetration length of the ray through the turbine blade; based on the penetration length of the ray through the turbine blade, using the correction straight line, obtaining the monochrome projection image of the turbine blade.

[0014] Optionally, a descattered multicolor projection image of the turbine blade is determined based on the original multicolor projection image and the scattering-corrected projection image, and then the method further includes: filtering the original multicolor projection image to obtain a filtered projection image; subtracting the filtered projection image from the original multicolor projection image to obtain an estimated value of the noise projection.

[0015] Optionally, a weighted compensation enhancement correction algorithm that introduces a trade-off factor is used to weight the monochrome projection image and the descattered multicolor projection image of the turbine blade to obtain a projection image that eliminates cupping artifacts, specifically including:

[0016] The construction trade-off factors are: Where λ is the trade-off factor, P m is a monochrome projection image, P P is the descattered multicolor projection image; a, b, c are all model coefficients, and a>0, b>0, c>0; (P m ) i is the monochrome projection grayscale of pixel i, (P P ) i is the descattered multicolor projection grayscale of pixel i, x i For (P P ) i The abbreviation of , M is the total number of pixels;

[0017] According to the estimated value of the trade-off factor and the noise projection, the weighted compensation enhancement correction model is established as y = (ax b +cx) / c+λ*x+Δ; where x is the descattered multi-color projection image, y is the monochromatic projection image, and Δ is the estimated value of the noise projection.

[0018] In a second aspect, the present application provides a system for eliminating scattering and hardening artifacts in turbine blade CT imaging, comprising: a cone-beam CT system, a grating correction plate, and a computer.

[0019] The cone-beam CT system is used to obtain an original multi-color projection image of the turbine blade before the grating correction plate is placed; after the grating correction plate is placed between the turbine blade and the detector of the cone-beam CT system, the cone-beam CT system is used to obtain a scatter-corrected projection image of the turbine blade again; the aluminum bars arranged at intervals on the grating correction plate have an inclined angle.

[0020] The computer is used to determine a descattered multicolor projection image of the turbine blade based on the original multicolor projection image and the scattering-corrected projection image; establish a beam hardening correction model; obtain a monochrome projection image of the turbine blade based on the descattered multicolor projection image of the turbine blade using the beam hardening correction model; use a weighted compensation enhancement correction algorithm that introduces a trade-off factor to weight the monochrome projection image and the descattered multicolor projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated; and use a filtered back-projection algorithm to perform three-dimensional reconstruction based on the projection image with cupping artifacts eliminated to obtain a projection-corrected slice image of the turbine blade.

[0021] In a third aspect, the present application provides a device for eliminating scattering and hardening artifacts in turbine blade CT imaging, comprising: an image acquisition module, a descattering module, a correction model establishment module, a hardening correction module, a weighting module and a reconstruction module.

[0022] An image acquisition module is configured to use a cone-beam CT system to acquire an original multi-color projection image of the turbine blade before placement of a grating correction plate, and a scattering-corrected projection image of the turbine blade after placement of the grating correction plate; the aluminum bars spaced apart on the grating correction plate have an inclined angle. A descattering module is configured to determine a descattered multi-color projection image of the turbine blade based on the original multi-color projection image and the scattering-corrected projection image. A correction model establishment module is configured to establish a beam hardening correction model. A hardening correction module is configured to obtain a monochromatic projection image of the turbine blade based on the descattered multi-color projection image of the turbine blade using the beam hardening correction model. A weighting module is configured to weight the monochromatic projection image and the descattered multi-color projection image of the turbine blade using a weighted compensation enhancement correction algorithm that introduces a trade-off factor to obtain a projection image with cupping artifacts eliminated. A reconstruction module is configured to perform three-dimensional reconstruction using a filtered back-projection algorithm based on the cupping artifact-eliminated projection image to obtain a projection-corrected slice image of the turbine blade.

[0023] In a fourth aspect, the present application provides a computer device comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described methods for eliminating scattering and hardening artifacts in turbine blade CT imaging.

[0024] In a fifth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-mentioned methods for eliminating scattering and hardening artifacts in CT imaging of turbine blades.

[0025] According to the specific embodiments provided in this application, this application has the following technical effects:

[0026] The present application provides a method, system, device, equipment and medium for eliminating scattering and hardening artifacts in CT imaging of turbine blades. When the aluminum bars arranged at intervals on the grating correction plate are placed parallel to the ground, the rays will hit the detector and produce a penumbra. The aluminum bars of the present application have an inclined angle, which avoids the generation of penumbra and can effectively eliminate scattering; a trade-off factor is introduced to weight the monochrome projection image and the descattered multi-color projection image of the turbine blade, neutralize the transition correction, eliminate the cupping artifact of the reconstructed slice, and improve the image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A flowchart of a method for eliminating scattering and hardening artifacts in CT imaging of turbine blades provided in one embodiment of the present application;

[0029] Figure 2 A schematic diagram of the projection principle of two sets of turbine blades provided in another embodiment of the present application;

[0030] Figure 3 A schematic diagram of the structure and position of a grating correction plate provided in another embodiment of the present application;

[0031] Figure 4 A schematic diagram of a projected scattering image provided by another embodiment of the present application;

[0032] Figure 5 A schematic diagram of scatter correction slice comparison provided by another embodiment of the present application;

[0033] Figure 6 A schematic diagram of a beam hardening process variation curve provided in another embodiment of the present application;

[0034] Figure 7 A schematic diagram of a beam descattering and hardening correction process according to another embodiment of the present application;

[0035] Figure 8 A schematic diagram showing the results of different hardening correction methods for the 512th slice provided in another embodiment of the present application;

[0036] Figure 9 A schematic diagram of a selected area of a slice layer 512 provided in another embodiment of the present application;

[0037] Figure 10A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0040] The idea behind the X-ray artifact correction process is to correct the projection domain of the industrial CT system, including the descattering part and the dehardening part. Scatter correction is first achieved through a combination of software and hardware. Then, a polynomial model and prior knowledge of the relationship between ray length and the corresponding projection are used to estimate the scatter-free monochromatic projection from the descattered multi-color projection.

[0041] In view of this, in an exemplary embodiment, Figure 1 As shown, a method for eliminating scattering and hardening artifacts in turbine blade CT imaging is provided, comprising the following steps 101 to 106. In which:

[0042] Step 101: Using a cone-beam CT system, an original multi-color projection image of the turbine blade before placement of a grating correction plate and a scatter-corrected projection image of the turbine blade after placement of the grating correction plate are acquired; the aluminum bars spaced apart on the grating correction plate have an inclined angle.

[0043] Step 102: Determine a descattered multi-color projection image of the turbine blade according to the original multi-color projection image and the scattering-corrected projection image.

[0044] Step 103: Establish a beam hardening correction model.

[0045] Step 104: Obtain a monochromatic projection image of the turbine blade using a beam hardening correction model based on the descattered multi-color projection image of the turbine blade.

[0046] Step 105: A weighted compensation enhancement correction algorithm that introduces a trade-off factor is used to weight the monochrome projection image and the descattered multi-color projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated.

[0047] Step 106: Based on the projection image with the cupping artifact eliminated, a filtered back-projection algorithm is used to perform three-dimensional reconstruction to obtain a projection-corrected slice image of the turbine blade.

[0048] By implementing the above steps 101 to 106 and using the scatter removal and weighted compensation enhancement correction algorithm, image scatter and cupping artifacts are eliminated.

[0049] In another exemplary embodiment of the present application, two sets of projection information are required to obtain the detection and calculation of the scattered field image. The first set is to perform a CT scan on the turbine blade to obtain the original multi-color projection image. The second set is to place a grating correction plate between the turbine blade and the detector (e.g., a flat panel detector) and perform another CT scan to obtain the scattered correction projection image. The two scans must ensure that the turbine blade position remains unchanged and the scanning parameters remain consistent. The principle of the two sets of turbine blade projections is as follows: Figure 2 As shown, Figure 2 Part (a) shows the projection principle of the first set of turbine blades, Figure 2 Part (b) shows the projection principle of the second set of turbine blades.

[0050] The grating correction plate is made of aluminum plate and is a slanted single grating correction plate. The structure and position of the grating correction plate are as follows: Figure 3 As shown, the aluminum bars spaced apart on the grating correction plate have an inclined angle. When each lead bar is placed parallel to the ground, the rays will strike the detector, creating a penumbra. The detector will only receive one-third or one-quarter of the effective information. However, using the tilted aluminum bars of this application can avoid the penumbra and retain more effective information.

[0051] In another exemplary embodiment of the present application, the projection data of the turbine blades is de-scattered by processing the projection data twice through interpolation and smoothing operations. Then the above step 102 can be replaced by the following steps 201 to 204:

[0052] Step 201: Acquire a projection image of a grating correction plate using a cone-beam CT system.

[0053] Step 202: Determine the slit areas between the aluminum strips in the scattering-corrected projection image based on the projection image of the grating correction plate.

[0054] Step 203: interpolating and smoothing the slit area to obtain a scattering image.

[0055] Exemplarily, the algorithm used for interpolation is Bicubic interpolation, and the algorithm used for smoothing is Gaussian smoothing algorithm.

[0056] The projected image of the grating correction plate is as follows Figure 4 As shown in part (a) of the figure, the scattering image is as follows: Figure 4 As shown in part (b) of .

[0057] Step 204: Subtract the scattered image from the original multi-color projection image to obtain a de-scattered multi-color projection image of the turbine blade.

[0058] Figure 5 Part (a) in FIG. 3 shows a raw multi-color projection image slice as an uncorrected raw projection. Figure 5 Part (b) in FIG. 5 shows a descattered multicolor projection image slice as a corrected grating scatter projection. Figure 5 Part (c) shows the projection grayscale curves before and after correction.

[0059] Descattered multicolor projection image P P Expressed as:

[0060]

[0061] Where S(E) is the initial ray spectrum, E is the incident photon energy, L is the path length of the object, dL is the integral differential element on the line L, and E max is the maximum incident photon energy, E min is the minimum incident photon energy, μ(x,y,E) is the attenuation coefficient on the straight line L.

[0062] In another exemplary embodiment of the present application, a beam hardening correction model is established using a weighted-compensation hardening correction (WCHC) algorithm. Establishing the beam hardening correction model includes establishing a hardening curve and a mathematical expression for the correction line. The process for establishing the beam hardening correction model is as follows:

[0063] The multicolor projection can be expressed as:

[0064] P P =L·μ a (E,L) (2)

[0065] Where L is the length of the ray passing through the object, μ a (E, L) is the average absorption coefficient over the integration interval [0, L].

[0066] The path length is a function of the hardened projection (polychromatic projection on the detector) and the constraint parameter as:

[0067] L=α·P p ·exp(β·(P p ) γ ) (3)

[0068] Where α, β, and γ are fitting parameters. Equation (3) is the hardening curve.

[0069] Monochromatic projections should have a linear growth law, which is the product of the path length and the attenuation coefficient, where the line traverses the coordinate origin. Therefore, Linear Hardening Correction (LHC) uses a corrected straight line to replace the hardening data caused by polychromaticity. The derivative of the function at zero in Equation (2) is regarded as the slope of the corrected line. Its expression is:

[0070] K=L′(0)=α (4)

[0071] Where K is the slope of the correction line, and L′(0) is the derivative of the function at zero.

[0072] The slope K of the correction line can be regarded as an equivalent monochromatic projection. After obtaining the hardening curve, the monochromatic length model based on the multicolor projection of the same path is corrected. Then:

[0073] L=K·P m =L′(0)·P m =α·P m (5)

[0074] Where, P m is a monochrome projection image. Equation (5) is the correction line.

[0075] Based on the established beam hardening correction model, the process of obtaining the monochrome projection image of the turbine blade in the above step 104 may include: obtaining the penetration length of the ray through the turbine blade using the hardening curve (Equation (3)) based on the descattered multi-color projection image of the turbine blade; and obtaining the monochrome projection image of the turbine blade using the correction line (Equation (5)) based on the penetration length of the ray through the turbine blade.

[0076] Figure 6 is the beam hardening process variation curve, Figure 6 Part (a) shows the relationship between the attenuation coefficient and the traversing length. Figure 6 Part (b) shows the relationship between the projection grayscale and the traversal length. Since the linear model has the problem of over-correction and cannot fully reflect the correction effect, the projection can be corrected by adding a trade-off factor to achieve accurate correction of different targets. After correcting the multi-color projection with the improved hardening model, the corrected projection is reconstructed into slices. The cupping artifact correction process based on descattering, projection compensation and hardening behavior is shown in the figure. Figure 7 shown.

[0077] In another exemplary embodiment of the present application, to accurately estimate noise, the original multi-color projection image is stored and filtered, and noise is estimated by subtracting the original multi-color projection image from the filtered projection image. Following step 102, the method may further include filtering the original multi-color projection image to obtain a filtered projection image; and subtracting the filtered projection image from the original multi-color projection image to obtain an estimated value of the noise projection.

[0078] In another exemplary embodiment of this application, due to the different hardening trends at different energies, the correction curve under a single model is too hard, resulting in excessive hardening correction in some locations, resulting in a phenomenon where the inner part is bright and the outer part is dark. Based on this, a weighted-compensation hardening correction algorithm (WCHC) is further used to weight the projections before and after the hardening correction to achieve the purpose of neutralizing the excessive correction.

[0079] Based on the multi-color projection and attenuation coefficient (i.e. μ a (E,L)) constructs a path length model that reflects the relationship between the two and introduces a trade-off factor as a compromise for the correction projection.

[0080] Based on the multi-color projection and attenuation coefficient, a path length model reflecting the relationship between the two is constructed, such as:

[0081] L(P p )=P p / μ a (E,L) (6)

[0082] According to Taylor's formula, L(P p ) can be approximately expressed as P based on differentiable functions p0 The derivative near the value, the length model can be rewritten as:

[0083] L(P p )=t(P p0 )·P p +t′(P p0 )·(P p -P p0 )+o((P p -P p0 ) n ) (7)

[0084] Where, P p0 is the average value of the multi-color projection, t(P p0 ) is the inverse of the linear attenuation coefficient under equivalent average energy: o((P p -P p0 ) n ) is the polynomial remainder, (P p-P p0 ) n is the remainder of the Taylor expansion.

[0085] The quadratic and subsequent polynomial residuals in formula (7) are approximately designed as nonlinear models. Then the beam hardening curve model can be constructed as:

[0086] L(P p )≈c·P p +a(P p ) b (8)

[0087] Since the path lengths for polychromatic and monochromatic are the same, the corrected projection can be addressed from the model obtained above:

[0088]

[0089] In order to reduce the influence of the slope of the initial line on the overall correction result, a trade-off factor λ is introduced as a compromise for the correction projection. The final projection (monochromatic projection) can then be calculated as:

[0090] y=(ax b +cx) / c+λ*x+Δ (10)

[0091] Formula (9) is equivalent to Formula (10). λ is the trade-off factor of the compromise model and is defined as follows:

[0092]

[0093] Among them, a, b, and c are all model coefficients, and a>0, b>0, and c>0. (P m ) i is the monochrome projection grayscale of pixel i, (P P ) i is the descattered multicolor projection grayscale of pixel i, x i For (P P ) i is the abbreviation of , x is the descattered multi-color projection image, y is the monochrome projection image, and Δ is the estimated value of the noise projection.

[0094] Figure 8 The slices show the reconstruction results of the projection after the artifact correction process of the embodiment. Figure 8 Part (a) in the figure is a reconstructed slice before hardening correction in the embodiment. It can be seen that the slice edge is bright and the middle is dark, cup-shaped artifacts exist, and the slice quality is not high. Figure 8Part (b) is the reconstructed slice after LHC hardening correction in the example. The cupping artifact is significantly improved and the quality is improved. However, due to the different hardening trends at different energies, the correction curve under the single model is too rigid, resulting in excessive hardening correction in some locations, resulting in a bright inside and dark outside phenomenon. Figure 8 Part (c) in the example is the reconstructed slice image obtained by applying the weighted neutralization projection compensation method before and after WCHC hardening correction. It can be seen that the image quality is greatly improved, the cupping artifact disappears, and the grayscale uniformity is greatly improved.

[0095] Figure 9 Reconstruct the slice selected area map for the 512th layer, Figure 9 Part (a) shows the original slice image of the 512th layer before hardening correction in the embodiment. Figure 9 Part (b) shows the 512th layer reconstructed slice image after LHC hardening correction in the embodiment. Figure 9 Part (c) shows the reconstructed slice image of slice 512 after WCHC hardening correction was applied in this embodiment. As can be seen in the figure, the slice without hardening correction exhibits large grayscale jumps at the outer edges and severe cupping artifacts. However, after model correction, the image improves, with a nearly uniform grayscale distribution and suppressed cupping artifacts. Finally, by applying weighted compensation correction to the projections before and after hardening correction, the cupping artifacts in the reconstructed slice are almost completely eliminated, significantly improving image quality and increasing the signal-to-noise ratio.

[0096] This application uses a cone-beam CT system to sample turbine blades and obtain projection data. An oblique single-grating correction plate is placed in front of the flat-panel detector in the cone-beam CT system, and the turbine blade is sampled again using the same parameters to obtain projection data of the turbine blade and the oblique single-grating correction plate. The projection data is processed twice through operations such as interpolation and smoothing to obtain de-scattered projection data of the turbine blade. The length of the ray passing through the binary image is calculated to obtain discrete beam hardening data, thereby constructing a weighted compensation correction model. Using this new model, beam hardening correction is performed on the unscattered projection information to obtain projection information that eliminates cupping artifacts. Finally, three-dimensional reconstruction is performed based on the FDK algorithm. This method effectively eliminates artifacts caused by scattering and hardening, providing a basis for post-CT reconstruction measurement and quantitative defect detection of blades.

[0097] Based on the same inventive concept, embodiments of the present application also provide a system for eliminating scatter and hardening artifacts in turbine blade CT imaging, which is used to implement the aforementioned method for eliminating scatter and hardening artifacts in turbine blade CT imaging. The solution provided by this system is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the system for eliminating scatter and hardening artifacts in turbine blade CT imaging provided below can be found in the aforementioned method for eliminating scatter and hardening artifacts in turbine blade CT imaging, and are not further elaborated here.

[0098] In an exemplary embodiment, a system for eliminating scatter and hardening artifacts in CT imaging of turbine blades is provided, comprising a cone-beam CT system, a grating correction plate, and a computer. The cone-beam CT system is configured to acquire an original multi-color projection image of the turbine blade before placement of the grating correction plate. After the grating correction plate is placed between the turbine blade and a detector of the cone-beam CT system, the cone-beam CT system is configured to acquire a second scatter-corrected projection image of the turbine blade. The aluminum bars arranged at intervals on the grating correction plate are inclined.

[0099] The computer is used to determine a descattered multicolor projection image of the turbine blade based on the original multicolor projection image and the scattering-corrected projection image; establish a beam hardening correction model; obtain a monochrome projection image of the turbine blade based on the descattered multicolor projection image of the turbine blade using the beam hardening correction model; use a weighted compensation enhancement correction algorithm that introduces a trade-off factor to weight the monochrome projection image and the descattered multicolor projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated; and use a filtered back-projection algorithm to perform three-dimensional reconstruction based on the projection image with cupping artifacts eliminated to obtain a projection-corrected slice image of the turbine blade.

[0100] In an exemplary embodiment, a device for eliminating scattering and hardening artifacts in turbine blade CT imaging is provided, comprising: an image acquisition module, a descattering module, a correction model building module, a hardening correction module, a weighting module, and a reconstruction module.

[0101] An image acquisition module is configured to use a cone-beam CT system to acquire an original multi-color projection image of the turbine blade before placement of a grating correction plate, and a scattering-corrected projection image of the turbine blade after placement of the grating correction plate; the aluminum bars spaced apart on the grating correction plate have an inclined angle. A descattering module is configured to determine a descattered multi-color projection image of the turbine blade based on the original multi-color projection image and the scattering-corrected projection image. A correction model establishment module is configured to establish a beam hardening correction model. A hardening correction module is configured to obtain a monochromatic projection image of the turbine blade based on the descattered multi-color projection image of the turbine blade using the beam hardening correction model. A weighting module is configured to weight the monochromatic projection image and the descattered multi-color projection image of the turbine blade using a weighted compensation enhancement correction algorithm that introduces a trade-off factor to obtain a projection image with cupping artifacts eliminated. A reconstruction module is configured to perform three-dimensional reconstruction using a filtered back-projection algorithm based on the cupping artifact-eliminated projection image to obtain a projection-corrected slice image of the turbine blade.

[0102] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 10 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store projection corrected slice images of turbine blades. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for eliminating scattering and hardening artifacts in CT imaging of turbine blades is implemented.

[0103] Those skilled in the art will understand that Figure 10 The structure shown in the figure is merely a block diagram of a portion of the structure related to the solution of the present application and does not constitute a limitation on the computer device to which the solution of the present application is applied. A specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement. In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps of the above-mentioned method embodiments when executing the computer program.

[0104] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0105] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0106] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0107] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0108] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, 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.

[0109] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for eliminating scattering and hardening artifacts in turbine blade CT imaging, characterized in that: include: Using a cone-beam CT system, an original multi-color projection image of the turbine blades before placement of a grating correction plate, and a scatter-corrected projection image of the turbine blades after placement of the grating correction plate, wherein the aluminum bars spaced apart on the grating correction plate have an inclined angle, are acquired; determining a descattered multicolor projection image of the turbine blade according to the original multicolor projection image and the scattering-corrected projection image; Establish a beam hardening correction model; Based on the descattered multi-color projection image of the turbine blade, a monochromatic projection image of the turbine blade is obtained using a beam hardening correction model; A weighted compensation enhancement correction algorithm with a trade-off factor is used to weight the monochrome projection image and the descattered multi-color projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated. Based on the projection image with cupping artifacts eliminated, a filtered back-projection algorithm is used to perform three-dimensional reconstruction to obtain projection-corrected slice images of the turbine blade.

2. The method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to claim 1, characterized in that: Determining a descattered multicolor projection image of a turbine blade according to the original multicolor projection image and the scattering-corrected projection image includes: The projection image of the grating correction plate is obtained using a cone-beam CT system; determining the slit regions between the aluminum strips in the scattering-corrected projection image based on the projection image of the grating correction plate; interpolating and smoothing the slit region to obtain a scattering image; The scattered image is subtracted from the original multi-color projection image to obtain the de-scattered multi-color projection image of the turbine blade.

3. The method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to claim 1, characterized in that: Establish a beam hardening correction model, including: defining a beam hardening correction model including a hardening curve and a correction line; Establish the hardening curve: L = α·P p ·exp(β·(P p ) γ ), where L is the length of the ray passing through the object, α, β, and γ are all fitting parameters, and P P It is a descattered multi-color projection image; The calibration line is established as: L = α·P m Where, P m The projected image is monochrome.

4. The method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to claim 3, characterized in that: Based on the descattered multi-color projection image of the turbine blade, a monochromatic projection image of the turbine blade is obtained using a beam hardening correction model, specifically including: According to the descattered multi-color projection image of the turbine blade, the hardening curve is used to obtain the ray's penetration length through the turbine blade. According to the traversal length of the ray through the turbine blade, a monochrome projection image of the turbine blade is obtained using a correction straight line.

5. The method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to claim 1, characterized in that: Determining a descattered multicolor projection image of the turbine blade according to the original multicolor projection image and the scattering-corrected projection image, and then further comprising: Filtering the original multi-color projection image to obtain a filtered projection image; The filtered projection image is subtracted from the original polychromatic projection image to obtain an estimate of the noisy projection.

6. The method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to claim 5, characterized in that: A weighted compensation enhancement correction algorithm with a trade-off factor is used to weight the monochrome projection image and the descattered multicolor projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated. Specifically, the algorithm includes: The construction trade-off factors are: Where λ is the trade-off factor, P m is a monochrome projection image, P P is the descattered multicolor projection image; a, b, c are all model coefficients, and a>0, b>0, c>0; (P m ) i is the monochrome projection grayscale of pixel i, (P P ) i is the descattered multicolor projection grayscale of pixel i, x i For (P P ) i The abbreviation of , M is the total number of pixels; According to the estimated value of the trade-off factor and the noise projection, the weighted compensation enhancement correction model is established as y = (ax b +cx) / c+λ*x+Δ; where x is the descattered multi-color projection image, y is the monochromatic projection image, and Δ is the estimated value of the noise projection.

7. A system for eliminating scattering and hardening artifacts in turbine blade CT imaging, characterized in that: include: Cone-beam CT system, grating correction plate and computer; The cone-beam CT system is used to obtain original multi-color projection images of the turbine blades before the placement of the grating correction plate; After the grating correction plate is placed between the turbine blade and the detector of the cone-beam CT system, the cone-beam CT system is used to obtain a scatter-corrected projection image of the turbine blade again; the aluminum bars arranged at intervals on the grating correction plate have an inclined angle; The computer is used to determine a descattered multicolor projection image of the turbine blade based on the original multicolor projection image and the scattering-corrected projection image; establish a beam hardening correction model; obtain a monochrome projection image of the turbine blade based on the descattered multicolor projection image of the turbine blade using the beam hardening correction model; use a weighted compensation enhancement correction algorithm that introduces a trade-off factor to weight the monochrome projection image and the descattered multicolor projection image of the turbine blade to obtain a projection image with cupping artifacts eliminated; and use a filtered back-projection algorithm to perform three-dimensional reconstruction based on the projection image with cupping artifacts eliminated to obtain a projection-corrected slice image of the turbine blade.

8. A device for eliminating scattering and hardening artifacts in turbine blade CT imaging, characterized in that: include: An image acquisition module is configured to acquire, using a cone-beam CT system, an original multi-color projection image of the turbine blades before a grating correction plate is placed, and a scatter-corrected projection image of the turbine blades after the grating correction plate is placed; the aluminum bars spaced apart on the grating correction plate have an inclined angle; A descattering module is used to determine a descattered multicolor projection image of the turbine blade based on the original multicolor projection image and the scattering-corrected projection image; A correction model building module, used for building a beam hardening correction model; a hardening correction module for obtaining a monochromatic projection image of the turbine blade using a beam hardening correction model based on the descattered multi-color projection image of the turbine blade; A weighting module is used to weight the monochrome projection image and the descattered multicolor projection image of the turbine blade by using a weighted compensation enhancement correction algorithm that introduces a trade-off factor, so as to obtain a projection image with cupping artifacts eliminated; The reconstruction module is used to perform three-dimensional reconstruction using a filtered back-projection algorithm based on the projection image with cup-shaped artifacts eliminated, so as to obtain a projection-corrected slice image of the turbine blade.

9. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for eliminating scattering and hardening artifacts in turbine blade CT imaging according to any one of claims 1 to 6 is implemented.

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