Artifact correction method and system

Abstract

This application relates to an artifact correction method and system. The method includes: acquiring projection data of a scanned object; performing artifact correction on the projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual and ideal projection data of various water phantoms with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data. This method enables convenient artifact correction.

Description

Technical Field

[0001] This application relates to the field of image processing technology, and in particular to an artifact correction method and system. Background Technology

[0002] Artifacts in computed tomography (CT) images refer to abnormal images that are unrelated to the scanned object and affect the quality of the CT image. Examples of abnormal images include ring artifacts and cup artifacts.

[0003] To reduce the impact of artifacts on image quality, related technologies require different correction algorithms for different types of artifacts, such as ring artifacts and cup artifacts. This makes artifact correction in related technologies overly complicated and affects the convenience of artifact correction. Summary of the Invention

[0004] Therefore, it is necessary to provide an artifact correction method and system that can conveniently perform artifact correction to address the aforementioned technical problems.

[0005] In a first aspect, this application provides an artifact correction method, including:

[0006] Obtain the projection data of the scanned object;

[0007] The projection data is corrected for artifacts based on a preset artifact correction function to obtain the artifact-corrected projection data. The preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters. Different types of artifacts exist in the tomographic images corresponding to the projection data.

[0008] In one embodiment, before acquiring the projection data of the scanned object, the method further includes:

[0009] The actual projection data corresponding to various water models of different diameters were obtained by scanning them with a computed tomography (CT) scanner.

[0010] Based on the actual projection data, obtain the ideal projection data corresponding to various water models with different diameters;

[0011] Based on the actual projection data and the ideal projection data, the artifact correction function is determined.

[0012] In one embodiment, based on the actual projection data, ideal projection data corresponding to various water models of different diameters are obtained, including:

[0013] Based on the actual projection data, the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography (CT) scanner is obtained.

[0014] Based on the ideal linear attenuation coefficient and various actual projection data, ideal projection data corresponding to water models of different diameters are obtained.

[0015] In one embodiment, based on each actual projection data, the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography (CT) scanner is obtained, including:

[0016] Select the target water model image with the smallest size from multiple actual water model images corresponding to each actual projection data;

[0017] Obtain the average linear attenuation coefficient of the water region in the target water model image;

[0018] The average linear attenuation coefficient is used as the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography (CT) equipment.

[0019] In one embodiment, ideal projection data for various water models of different diameters are obtained based on the ideal linear attenuation coefficient and the actual projection data, including:

[0020] Obtain the actual water model image after reconstruction from each actual projection data;

[0021] Based on the ideal linear attenuation coefficient and various actual water model images, multiple ideal water model images are determined;

[0022] By projecting the images of each ideal water model forward, ideal projection data corresponding to various water models with different diameters are obtained.

[0023] In one embodiment, multiple ideal water model images are determined based on the ideal linear attenuation coefficient and each actual water model image, including:

[0024] The water regions in each actual water model image are filled and smoothed using an ideal linear attenuation coefficient, and the air regions in each actual water model image are zeroed out to obtain multiple ideal water model images.

[0025] In one embodiment, an artifact correction function is determined based on each actual projection data and each ideal projection data, including:

[0026] Calculate the ratio of the projection difference at any pixel to the ideal projection data; the projection difference represents the difference between the ideal projection data and the corresponding actual projection data of a pixel.

[0027] Based on the artifact correction function model, the correction coefficient corresponding to any pixel is determined.

[0028] The correction coefficients corresponding to each pixel are used as the artifact correction function.

[0029] In one embodiment, obtaining initial projection data of the scanned object includes:

[0030] The object is scanned using a computed tomography (CT) scanner to obtain its projection data.

[0031] Secondly, this application also provides an artifact correction system, which includes a computer device and a computed tomography (CT) scanner, wherein the computer device is connected to the CT scanner.

[0032] Computed tomography (CT) scanners are used to scan objects and obtain projection data.

[0033] Computer equipment is used to perform artifact correction on projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data.

[0034] In one embodiment, the above-described artifact correction system further includes water phantoms of different diameters.

[0035] The computed tomography (CT) scanner is also used to scan water models of various diameters to obtain the actual projection data corresponding to the water models of various diameters.

[0036] The computer equipment is also used to obtain ideal projection data corresponding to various water models of different diameters based on the actual projection data; and to determine the artifact correction function based on the actual projection data and the ideal projection data.

[0037] Thirdly, this application also provides an artifact correction device, comprising:

[0038] The acquisition module is used to acquire the projection data of the scanned object;

[0039] The correction module is used to correct artifacts in the projection data based on a preset artifact correction function to obtain artifact-corrected projection data. The preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters. Different types of artifacts exist in the tomographic images corresponding to the projection data.

[0040] Fourthly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the content of any embodiment of the artifact correction method in the first aspect described above.

[0041] Fifthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the content of any embodiment of the artifact correction method in the first aspect described above.

[0042] Sixthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the content of any embodiment of the artifact correction method in the first aspect described above.

[0043] The aforementioned artifact correction method and system acquire projection data of the scanned object; perform artifact correction on the projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual and ideal projection data of various water phantoms with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data. For tomographic images with different types of artifacts, this method can remove different types of artifacts from the tomographic image using a single artifact correction function, eliminating the need for multiple correction algorithms. This simplifies the artifact correction process for tomographic images containing various types of artifacts and improves the convenience of artifact correction. Furthermore, since the artifact correction function is constructed based on actual and ideal projection data of various water phantoms with different diameters and does not rely on prior knowledge such as X-ray source spectra, the constructed artifact correction function is more accurate. Therefore, the correction process using this artifact correction function is more accurate, and the obtained correction results are also more accurate. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a diagram illustrating the application environment of an artifact correction method in one embodiment.

[0046] Figure 2 This is a flowchart illustrating an artifact correction method in one embodiment;

[0047] Figure 3 This is a scanned image before artifact correction in one embodiment;

[0048] Figure 4 This is a scanned image after artifact correction in one embodiment;

[0049] Figure 5 This is a flowchart illustrating an artifact correction method in one embodiment;

[0050] Figure 6 This is a schematic diagram of the water model scanning process in one embodiment;

[0051] Figure 7 This is a flowchart illustrating an artifact correction method in one embodiment;

[0052] Figure 8 This is a flowchart illustrating an artifact correction method in one embodiment;

[0053] Figure 9 This is a flowchart illustrating an artifact correction method in one embodiment;

[0054] Figure 10 This is a flowchart illustrating the process of obtaining the artifact correction function in one embodiment;

[0055] Figure 11 This is a flowchart illustrating an artifact correction method in one embodiment;

[0056] Figure 12 This is a flowchart illustrating an artifact correction method in one embodiment;

[0057] Figure 13 This is a flowchart illustrating an artifact correction method in one embodiment;

[0058] Figure 14 This is a structural block diagram of an artifact correction device in one embodiment. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0060] Before providing a detailed introduction to the technical solution of this application, let me first briefly introduce the background technology of this application.

[0061] In CT imaging systems, ring artifacts caused by inconsistent spectral response and cup artifacts caused by beam hardening effects can affect the quality of CT images.

[0062] To reduce the impact of artifacts on image quality, related technologies mainly utilize different correction algorithms to correct corresponding artifacts. For example, for annular artifacts, correction can be achieved by using a combination of multiple materials such as aluminum plates of different thicknesses or acrylic plates of different thicknesses, or by using water models of different diameters, or by employing image-domain de-ringing algorithms. For cup-shaped artifacts, correction is mainly based on prior knowledge such as X-ray source spectra, multi-material correction methods, or deep learning methods.

[0063] However, for annular artifacts and cup artifacts, different types of artifacts require different correction algorithms, making artifact correction in related technologies too complicated and affecting the convenience of artifact correction.

[0064] To address the aforementioned problems, this application provides an artifact correction method and system. This method can remove different types of artifacts from scanned images using a single artifact correction function, eliminating the need for multiple correction algorithms. This simplifies the artifact correction process for scanned images containing various types of artifacts and improves the convenience of artifact correction. Of course, the technical solutions provided in this application are not limited to solving only the above problems and also offer other technical effects, which can be found in the following embodiments. The technical solutions of this application will now be described in detail.

[0065] The artifact correction method provided in this application can be applied to, for example, Figure 1 The application environment shown is a computer device that can be a server, personal computer, laptop, smartphone, tablet, or mobile phone. This computer device may include a processor, memory, and network interface connected via a system bus or wirelessly. The processor provides computing and control capabilities. The memory may include non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database stores data used in the artifact correction process. The network interface of the computer device communicates with external terminals via a network connection, and the computer program, when executed by the processor, implements an artifact correction method.

[0066] In one exemplary embodiment, such as Figure 2 As shown, an artifact correction method is provided, which is applied to... Figure 1 The following steps are used as an example of computer equipment, including steps 201 to 202.

[0067] in:

[0068] S201, Obtain the projection data of the scanned object.

[0069] The scanned object refers to the object being scanned using CT equipment, such as a human body or animal body. After the CT equipment scans the object at a certain thickness, the detectors in the CT equipment receive the X-rays that pass through that layer, convert them into visible light, then into electrical signals, and finally into digital signals via an analog-to-digital converter (A / D converter) for processing and imaging by a computer. The data collected by the detectors during this process is called projection data, which records information about how X-rays pass through the object in different directions.

[0070] In this embodiment, it is assumed that the CT scanner has completed the scanning process of the object, and all scan data is stored in a database. Then, the computer can search the database for scan data matching the object's identification information and use the found scan data as the scan data for the object. For example, the identification information could be the object's name, number, or other information.

[0071] If the CT scanner does not scan the object, the computer can generate a scan command based on the scanning requirements and send it to the CT scanner. Upon receiving the scan command, the CT scanner scans the object and forwards the resulting projection data to the computer.

[0072] S202, perform artifact correction on the projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data.

[0073] Among them, different types of artifacts can be ring artifacts caused by inconsistent spectral responses, or cup artifacts caused by beam hardening effects.

[0074] In this embodiment, the tomographic image reconstructed from the projection data of the scanned object contains different types of artifacts. The computer device can use a preset artifact correction function to correct the projection data of the scanned object, ensuring that the tomographic image corresponding to the corrected projection data does not contain different types of artifacts. The artifact-corrected projection data p corr It can be represented as:

[0075]

[0076] Where, p real Represents projection data, c n This represents the coefficients of the artifact correction function.

[0077] Furthermore, after artifact correction, the projection data can be reconstructed using an image reconstruction algorithm to obtain a scanned image of the object. This image reconstruction algorithm can be back-projection, Fourier transform reconstruction, filtered back-projection reconstruction, convolutional back-projection, or iterative reconstruction, among others.

[0078] Figure 3 This represents the scanned image before artifact correction. Figure 4 This indicates the scanned image after artifact correction, for comparison. Figure 3 and Figure 4 It can be seen that Figure 3 The image quality is poor due to significant artifact interference. After artifact correction, Figure 4 The quality of the scanned images is relatively good.

[0079] In the aforementioned artifact correction method, projection data of the scanned object is acquired; artifact correction is performed on the projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual and ideal projection data of various water phantoms with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data. For tomographic images with different types of artifacts, this method can remove different types of images from the tomographic image using a single artifact correction function, eliminating the need for multiple correction algorithms. This simplifies the artifact correction process for tomographic images containing various types of artifacts and improves the convenience of artifact correction. Furthermore, since this artifact correction function is constructed based on actual and ideal projection data of various water phantoms with different diameters and does not rely on prior knowledge such as the X-ray source spectrum, the constructed artifact correction function is more accurate. Therefore, the correction process using this artifact correction function is more accurate, and the obtained correction results are also more accurate.

[0080] For the artifact correction process of projection data, the artifact correction function is the most important. Therefore, in one embodiment, such as... Figure 5 As shown, the method for obtaining the artifact correction function is described in detail. Specifically, before obtaining the projection data of the scanned object, the method further includes:

[0081] S301 uses a computed tomography (CT) scanner to scan various water models of different diameters and obtain the actual projection data corresponding to these water models.

[0082] Here, a water phantom refers to a correction phantom used to determine the artifact correction function. For example, the diameters of various water phantoms can be d1, d2, d3, ..., d N , and d1 <d2<d3<...<d N Water-based wall panels can be made of epoxy resin materials.

[0083] In this embodiment, for water models of different diameters, scanning is required separately for each water model at different eccentric positions. Therefore, for any water model of any diameter, it needs to be set in a fixed position before scanning. Based on this, the computer device can control the computed tomography (CT) scanner to scan the water model and obtain its actual projection data. The actual projection data corresponding to water models of different diameters can be represented as: realProj1, realProj2,..., realProj N After directly reconstructing the actual projection data, the resulting actual water model image can be represented as: realImage1, realImage2,..., realImage... N .

[0084] Figure 6 This diagram illustrates the water model scanning process, which includes: fixing any given water model, scanning it, and acquiring data. The acquired data is preprocessed to obtain projection data (i.e., actual projection data). This projection data is then reconstructed to obtain the corresponding tomographic image (i.e., the actual water model image). This process is repeated for all water models until all water model scanning is complete.

[0085] S302, based on the actual projection data, obtains the ideal projection data corresponding to various water models with different diameters.

[0086] In this embodiment, after obtaining actual projection data corresponding to multiple water models of different diameters, the computer device can input the actual projection data into a data processing model. The model then analyzes the actual projection data to obtain the ideal projection data for each water model. Alternatively, the computer device can determine the ideal linear attenuation coefficient of the water model under the current scanning parameters based on the image of the smallest diameter water model. Based on this ideal linear attenuation coefficient, ideal projection data corresponding to multiple water models of different diameters can be obtained. This embodiment does not limit the specific method for obtaining ideal projection data for multiple water models of different diameters based on the actual projection data.

[0087] S303, determine the artifact correction function based on each actual projection data and each ideal projection data.

[0088] In this embodiment, after obtaining actual and ideal projection data of various water models with different diameters, the computer device can calculate the data difference between the ideal and actual projection data for each pixel. Based on this data difference, a correction coefficient for that pixel is determined.

[0089] In the aforementioned artifact correction method, a computed tomography (CT) scanner is used to scan water models of various diameters to obtain actual projection data corresponding to these models. Based on this actual projection data, ideal projection data corresponding to the different diameter water models is obtained. Finally, an artifact correction function is determined based on both the actual and ideal projection data. This method, through the scanning process of water models of different diameters using a CT scanner, can obtain actual projection data containing artifacts. Furthermore, based on the actual projection data containing artifacts and the ideal projection data without artifacts, it can accurately determine the difference between the two, thereby accurately obtaining the artifact correction function.

[0090] The specific process of obtaining the ideal projection data described above will be described next. In one embodiment, such as... Figure 7 As shown, the specific steps for obtaining ideal projection data for various water models of different diameters based on actual projection data include the following:

[0091] S401, based on each actual projection data, obtains the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography (CT) scanner.

[0092] In this embodiment, since the hardening effect of the smallest diameter water model is the weakest, the ideal linear attenuation coefficient of the water model is obtained based on the image of the smallest diameter water model. Based on this, the computer device can filter out the actual projection data of the smallest diameter from various actual projection data, perform image reconstruction on the actual projection data of the smallest diameter, and obtain the image of the smallest diameter water model. Then, based on the image of the smallest diameter water model, the ideal linear attenuation coefficient of the water model under the current scanning parameters is determined by the computed tomography (CT) scanner.

[0093] S402, based on the ideal linear attenuation coefficient and various actual projection data, obtains the ideal projection data corresponding to various water models with different diameters.

[0094] In this embodiment, after obtaining the ideal linear attenuation coefficient of the water model under the current scanning parameters by the computed tomography (CT) device, the computer device can input the ideal linear attenuation coefficient and the tomographic image corresponding to the actual projection data of each water model into the data processing model. The data processing model analyzes the tomographic image corresponding to the actual projection data of each water model to obtain the ideal projection data corresponding to various water models with different diameters.

[0095] In the aforementioned artifact correction method, the ideal linear attenuation coefficient of the water model under the current scanning parameters is obtained based on each actual projection data. Then, ideal projection data corresponding to various water models of different diameters is obtained based on the ideal linear attenuation coefficient and each actual projection data. This method accurately obtains the ideal linear attenuation coefficient of the water model under the current scanning parameters by analyzing each actual projection data, and analyzes the tomographic image corresponding to each water model's actual projection data based on the ideal linear attenuation coefficient to accurately obtain the corresponding ideal projection data.

[0096] In one embodiment, such as Figure 8 As shown, the specific details of obtaining the ideal linear attenuation coefficient of the water model under the current scanning parameters based on various actual projection data include:

[0097] S501, select the target water model image with the smallest size specification from multiple actual water model images corresponding to each actual projection data.

[0098] In this embodiment, since the beam hardening artifact of the smallest diameter water model is the weakest, the computer device can use an image reconstruction algorithm to reconstruct each actual projection data to obtain the actual water model image corresponding to each actual projection data. Then, the target water model image with the smallest size specification is selected from multiple actual water model images. It should be noted that the smallest size specification refers to the smallest diameter, which can be a water model with a diameter of d1.

[0099] S502, obtain the average linear attenuation coefficient of the water area in the target water model image.

[0100] In this embodiment, after obtaining the target water model image of the smallest size, the computer device can substitute the relevant data of the target water model image of the smallest size into the calculation formula of the average linear attenuation coefficient, and obtain the average linear attenuation coefficient of the water area in the water model image of the smallest diameter through the calculation process. The calculation formula of the average linear attenuation coefficient can be expressed as:

[0101]

[0102] Where nSlice represents the number of target water model images corresponding to a water model with diameter d1; μ 1,i denoted as the average linear attenuation coefficient of the water region in the i-th target water model image with diameter d1.

[0103] S503, and uses the average linear attenuation coefficient as the ideal linear attenuation coefficient for computed tomography equipment during the current scanning process.

[0104] In this embodiment of the application, after obtaining the average linear attenuation coefficient, the computer device can directly use the average linear attenuation coefficient μ1 as the ideal linear attenuation coefficient μ of the material water under the current scanning parameters of the computed tomography (CT) scanner. ideal That is, μ ideal =μ1.

[0105] In the aforementioned artifact correction method, the smallest-sized target water model image is selected from multiple actual water model images corresponding to each actual projection data; the average linear attenuation coefficient of the water region in the target water model image is obtained; and the average linear attenuation coefficient is used as the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography (CT) scanner. Since the beam hardening artifact of the smallest diameter water model is the weakest, by selecting from the actual water model images corresponding to each actual projection data, the smallest-sized target water model image can be accurately determined, and then the average linear attenuation coefficient of the water region in the smallest-sized target water model image can be obtained, thereby accurately obtaining the ideal linear attenuation coefficient.

[0106] In one embodiment, such as Figure 9 As shown, based on the ideal linear attenuation coefficient and various actual projection data, ideal projection data corresponding to water models of different diameters are obtained, including:

[0107] S601, Obtain the actual water model image after reconstruction of each actual projection data.

[0108] In this embodiment, after obtaining the actual projection data corresponding to multiple water models of different diameters, for any one water model, the computer device can use an image reconstruction algorithm to reconstruct the image of the actual projection data corresponding to that water model, thereby obtaining the actual water model image. The image reconstruction algorithm can be a back-projection method, a Fourier transform reconstruction method, a filtered back-projection reconstruction method, a convolutional back-projection method, or an iterative reconstruction algorithm, etc.

[0109] S602, based on the ideal linear attenuation coefficient and each actual water model image, determine multiple ideal water model images.

[0110] In this embodiment, the computer device can analyze each actual water model image using an ideal linear attenuation coefficient, and determine the corresponding ideal water model image based on the analysis results, thus using the ideal water model image as the ideal water model image. Multiple ideal water model images can be represented as: idealImage1, idealImage2, ..., idealImage... N .

[0111] S603, perform forward projection on each ideal water model image to obtain ideal projection data corresponding to various water models with different diameters.

[0112] In this embodiment, the computer device can project all ideal water model images forward based on a forward projection method. The projection data obtained after forward projection is the ideal projection data corresponding to various water models with different diameters. The ideal projection data corresponding to various water models with different diameters can be represented as: idealProj1, idealProj2, ..., idealProj N The relationship between the ideal projection data idealProj and the ideal water model image idealImage can be expressed as:

[0113] idealProj=ForwardProjection(idealImage)

[0114] In the aforementioned artifact correction method, actual water model images are obtained after reconstruction from each actual projection data; multiple ideal water model images are determined based on the ideal linear attenuation coefficient and each actual water model image; and forward projection is performed on each ideal water model image to obtain ideal projection data corresponding to various water models with different diameters. This method, through reconstruction of the actual projection data, can accurately obtain actual water model images corresponding to water models of different diameters. Furthermore, based on the ideal linear attenuation coefficient and the actual water model images, ideal water model images excluding artifacts are accurately determined, and using forward projection, ideal projection data corresponding to water models of different diameters can be accurately determined.

[0115] The following section details the process of determining multiple ideal water model images based on the ideal linear attenuation coefficient and various actual water model images. This detailed process includes:

[0116] The water regions in each actual water model image are filled and smoothed using an ideal linear attenuation coefficient, and the air regions in each actual water model image are zeroed out to obtain multiple ideal water model images.

[0117] In this embodiment, the scanning process of the computed tomography (CT) scanner on the water model mainly includes scanning two regions: the water region and the air region. Therefore, the actual water model image obtained through image reconstruction includes images corresponding to the water region and the air region. Based on this, for any given actual water model image, the computer device can obtain the pixel values ​​of all pixels in the actual water model image and divide the actual water model image into images corresponding to the water region and images corresponding to the air region based on multiple pixel values. Further, the image corresponding to the water region is filled and smoothed, and the image corresponding to the air region is zeroed out to obtain multiple ideal water model images. The actual water model image processing process for any pixel (i,j) can be represented as follows:

[0118]

[0119] Figure 10 To obtain a flowchart of the artifact correction function, the water regions in each actual water model image are filled and smoothed, and the air regions are zeroed out. After the smoothing and zeroing process is completed, the processed data is forward-projected to obtain the ideal projection value (i.e., ideal projection data). The artifact correction function is then determined using the ideal projection value and the actual projection data.

[0120] In the aforementioned artifact correction method, an ideal linear attenuation coefficient is used to fill and smooth the water areas in each actual water model image, and the air areas in each actual water model image are zeroed out, resulting in multiple ideal water model images. Different regions in the actual water model images can be processed in a targeted manner using different methods. Thus, the processed ideal water model images not only remove background areas and avoid interference from them, but also improve the quality of the region of interest through smoothing.

[0121] The following example illustrates the specific details of determining the artifact correction function based on actual and ideal projection data. Figure 11 As shown, the specific content includes the following steps:

[0122] S701, calculate the ratio of the projection difference at any pixel to the ideal projection data; the projection difference represents the difference between the ideal projection data and the corresponding actual projection data of the pixel.

[0123] In this embodiment, for any pixel, the computer device can subtract the ideal projection data from the actual projection data to obtain the projection difference value. Then, it calculates the ratio of this projection difference value to the preset projection data. This ratio can be expressed as:

[0124] S702 determines the correction coefficient for any pixel based on the artifact correction function model.

[0125] S703 uses the correction coefficients corresponding to each pixel as the artifact correction function.

[0126] In this embodiment, each pixel includes at least one correction coefficient. A mapping relationship exists between the ratio of the projection difference to the ideal projection data and the correction coefficient, which can be expressed as:

[0127]

[0128] Where n represents the order of the artifact correction function for that pixel; for example, n can be 1 or 2; c n p represents the correction coefficient for that pixel.ideal This represents the ideal projection data of the pixel; p real This represents the actual projection data of the pixel.

[0129] Based on this, after obtaining the ratio of the projection difference of any pixel to the ideal projection data, the computer device can map this ratio according to the above mapping relationship to obtain the correction coefficient corresponding to any pixel. The correction coefficients of all pixels are then used as the artifact correction function. Alternatively, the computer device can list all pixels and their corresponding correction coefficients to obtain a correction table, and use this correction table as the artifact correction function.

[0130] In the aforementioned artifact correction method, the ratio of the projection difference at any pixel to the ideal projection data is calculated. The projection difference represents the difference between the ideal projection data and the corresponding actual projection data of a pixel. Based on the artifact correction function model, the correction coefficient corresponding to any pixel is determined. The correction coefficients corresponding to each pixel are used as the artifact correction function. This method, by calculating the difference between the ideal projection data and the corresponding actual projection data at any pixel, and based on this difference and the artifact correction function model, can accurately determine the proportion of projection error in the ideal projection data. Therefore, it can specifically determine the correction coefficient for each pixel, resulting in a more accurate artifact correction function.

[0131] In one embodiment, the specific content of obtaining the initial projection data of the scanned object includes:

[0132] The object is scanned using a computed tomography (CT) scanner to obtain its projection data.

[0133] In this embodiment, when it is necessary to obtain the projection data of the object to be scanned, the computer device can generate a scanning instruction according to the scanning requirements and send the scanning instruction to the computed tomography (CT) scanner. After receiving the scanning instruction, the CT scanner scans the object at a certain thickness. The detector in the CT scanner receives the data transmitted through this layer and sends the received data as projection data to the computer device.

[0134] In the aforementioned artifact correction method, the object is scanned using a computed tomography (CT) scanner to obtain its projection data. This method directly scans the object using a CT scanner before artifact correction, ensuring that the obtained projection data is not affected by other noise. This results in a higher quality scanned image after artifact correction.

[0135] As a specific embodiment of this application, the artifact correction process will now be described in detail. In one embodiment, such as Figure 12As shown, the artifact correction method includes:

[0136] S801 uses a computed tomography (CT) scanner to scan various water models of different diameters and obtain the actual projection data corresponding to these water models.

[0137] S802, select the target water model image with the smallest size from multiple actual water model images corresponding to each actual projection data;

[0138] S803, obtain the average linear attenuation coefficient of the water region in the target water model image;

[0139] S804, and uses the average linear attenuation coefficient as the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography equipment;

[0140] S805, acquire the actual water model image after reconstruction of each actual projection data;

[0141] S806 uses an ideal linear attenuation coefficient to fill and smooth the water area in each actual water model image, and sets the air area in each actual water model image to zero to obtain multiple ideal water model images.

[0142] S807, perform forward projection on each ideal water model image to obtain ideal projection data corresponding to various water models with different diameters;

[0143] S808 determines the artifact correction function based on each actual projection data and each ideal projection data;

[0144] S809, scans the object using a computed tomography (CT) scanner to obtain projection data of the object;

[0145] S810 performs artifact correction on the projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data.

[0146] Figure 13 This diagram illustrates a flowchart of an artifact correction method, which includes: scanning the object to obtain initial projection values ​​(i.e., projection data of the object); correcting the initial projection values ​​using a correction table (i.e., an artifact correction function) to obtain corrected initial projection values; and then reconstructing the image from the corrected initial projection values ​​to obtain a scanned image of the object.

[0147] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0148] In one exemplary embodiment, an artifact correction system is provided, which includes a computer device and a computed tomography (CT) scanner, wherein the computer device is connected to the CT scanner.

[0149] Computed tomography (CT) scanners are used to scan objects and obtain projection data.

[0150] Computer equipment is used to perform artifact correction on projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data.

[0151] Based on the same inventive concept, this application also provides an artifact correction apparatus for implementing the artifact correction method described above. The solution provided by this apparatus is similar to the implementation described in the above method; therefore, the specific limitations in one or more artifact correction apparatus embodiments provided below can be found in the limitations of the artifact correction method described above, and will not be repeated here.

[0152] In one exemplary embodiment, such as Figure 14 As shown, an artifact correction device is provided, including: an acquisition module 11 and a correction module 12, wherein:

[0153] Module 11 is used to acquire the projection data of the scanned object;

[0154] The correction module 12 is used to perform artifact correction on the projection data based on a preset artifact correction function to obtain the artifact-corrected projection data. The preset artifact correction function is constructed based on the actual projection data and ideal projection data of various water models with different diameters. Different types of artifacts exist in the tomographic images corresponding to the projection data.

[0155] In one embodiment, the artifact correction device further includes: a scanning module, a prediction module, and a function determination module, wherein:

[0156] The scanning module is used to scan water models of various diameters using a computed tomography (CT) scanner to obtain the actual projection data corresponding to the various water models of different diameters.

[0157] The prediction module is used to obtain ideal projection data for various water models of different diameters based on the actual projection data.

[0158] The function determination module is used to determine the artifact correction function based on the actual projection data and the ideal projection data.

[0159] In one embodiment, the prediction module includes: a coefficient acquisition unit and a data acquisition unit, wherein:

[0160] The coefficient acquisition unit is used to obtain the ideal linear attenuation coefficient of the water model under the current scanning parameters based on each actual projection data.

[0161] The data acquisition unit is used to acquire ideal projection data corresponding to various water models of different diameters based on the ideal linear attenuation coefficient and the actual projection data.

[0162] In one embodiment, the coefficient acquisition unit is further configured to select the target water model image with the smallest size from multiple actual water model images corresponding to each actual projection data; obtain the average linear attenuation coefficient of the water area of ​​the target water model image; and use the average linear attenuation coefficient as the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography scanning device.

[0163] In one embodiment, the data acquisition unit is further configured to acquire actual water model images reconstructed from each actual projection data; determine multiple ideal water model images based on the ideal linear attenuation coefficient and each actual water model image; and perform forward projection on each ideal water model image to obtain ideal projection data corresponding to multiple water models with different diameters.

[0164] In one embodiment, the data acquisition unit is further configured to fill and smooth the water areas in each actual water model image using an ideal linear attenuation coefficient, and to zero out the air areas in each actual water model image to obtain multiple ideal water model images.

[0165] In one embodiment, the function determination module includes: a calculation unit, a coefficient determination unit, and a function determination unit, wherein:

[0166] The calculation unit is used to calculate the ratio of the projection difference to the ideal projection data at any pixel; the projection difference represents the difference between the ideal projection data and the corresponding actual projection data of the pixel.

[0167] The coefficient determination unit is used to determine the correction coefficient corresponding to any pixel based on the artifact correction function model.

[0168] The function determination unit is used to use the correction coefficients corresponding to each pixel as the artifact correction function.

[0169] In one embodiment, the acquisition module includes a scanning unit, wherein:

[0170] The scanning unit is used to scan the object using a computed tomography (CT) scanner to obtain the projection data of the object.

[0171] Each module in the aforementioned artifact correction device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0172] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the content of any of the embodiments of the above-described artifact correction methods.

[0173] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the content of any embodiment of the above-described artifact correction method.

[0174] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the content of any embodiment of the above-described artifact correction method.

[0175] 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, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0176] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can 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 can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0177] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0178] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An artifact correction method, characterized in that, The method includes: Obtain the projection data of the scanned object; The projection data is corrected for artifacts based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data.

2. The method according to claim 1, characterized in that, Before acquiring the projection data of the scanned object, the method further includes: The actual projection data corresponding to the various water models of different diameters were obtained by scanning them with a computed tomography (CT) scanner. Based on the actual projection data, obtain the ideal projection data corresponding to the various water models with different diameters; The artifact correction function is determined based on the actual projection data and the ideal projection data.

3. The method according to claim 2, characterized in that, The step of obtaining ideal projection data corresponding to the various water models of different diameters based on the actual projection data includes: Based on the actual projection data, the ideal linear attenuation coefficient of the water model of the computed tomography device under the current scanning parameters is obtained. Based on the ideal linear attenuation coefficient and the actual projection data, the ideal projection data corresponding to the various water models with different diameters are obtained.

4. The method according to claim 3, characterized in that, The step of obtaining the ideal linear attenuation coefficient of the water model under the current scanning parameters based on the actual projection data includes: Select the target water model image with the smallest size from multiple actual water model images corresponding to each of the actual projection data; Obtain the average linear attenuation coefficient of the water region in the target water model image; The average linear attenuation coefficient is used as the ideal linear attenuation coefficient of the water model under the current scanning parameters of the computed tomography (CT) device.

5. The method according to claim 3, characterized in that, The step of obtaining the ideal projection data corresponding to the various water models of different diameters based on the ideal linear attenuation coefficient and the actual projection data includes: Obtain the actual water model image after reconstruction from the actual projection data; Based on the ideal linear attenuation coefficient and each of the actual water model images, multiple ideal water model images are determined; By projecting each of the ideal water model images forward, ideal projection data corresponding to the various water models with different diameters are obtained.

6. The method according to claim 5, characterized in that, The step of determining multiple ideal water model images based on the ideal linear attenuation coefficient and each of the actual water model images includes: The water regions in each of the actual water model images are filled and smoothed using the ideal linear attenuation coefficient, and the air regions in each of the actual water model images are set to zero to obtain the plurality of ideal water model images.

7. The method according to any one of claims 2-6, characterized in that, The step of determining the artifact correction function based on the actual projection data and the ideal projection data includes: Calculate the ratio of the projection difference at any pixel to the ideal projection data; the projection difference represents the difference between the ideal projection data and the corresponding actual projection data of the pixel. Based on the artifact correction function model, the correction coefficient corresponding to any one pixel is determined. The correction coefficients corresponding to each pixel are used as the artifact correction function.

8. The method according to any one of claims 1-6, characterized in that, The acquisition of the projection data of the scanned object includes: The object is scanned using a computed tomography (CT) scanner to obtain the projection data of the object.

9. An artifact correction system, characterized in that, The artifact correction system includes a computer device and a computed tomography (CT) scanner, and the computer device is connected to the CT scanner. The computed tomography (CT) scanner is used to scan the object and obtain projection data. The computer device is used to perform artifact correction on the projection data based on a preset artifact correction function to obtain artifact-corrected projection data; the preset artifact correction function is constructed based on actual projection data and ideal projection data of various water models with different diameters; different types of artifacts exist in the tomographic images corresponding to the projection data.

10. The system according to claim 9, characterized in that, The artifact correction system also includes water phantoms of different diameters. The computed tomography scanning device is also used to scan multiple water models of different diameters to obtain the actual projection data corresponding to the multiple water models of different diameters. The computer device is further configured to acquire ideal projection data corresponding to the various water models of different diameters based on the actual projection data; and to determine the artifact correction function based on the actual projection data and the ideal projection data.

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