A method, system, device and medium for noise suppression of CT axial scan images

Abstract

The application provides a CT axial scan image noise suppression method, system, device and medium, comprising: acquiring a plurality of original tomographic images of a phantom scanned by a CT scanning device; obtaining a plurality of offset reference images corresponding to any original tomographic image according to any offset parameter; selecting a target offset noise curve from a plurality of offset noise curves of the plurality of offset reference images, wherein the target offset noise curve and a combined noise curve obtained by fitting an original noise curve of the original tomographic image are uniformly distributed in the Z direction, and the offset parameter corresponding to the target offset noise curve is used as a target offset parameter; acquiring examination data of an examination site scanned by the CT scanning device; and reconstructing the examination data at a plurality of target offset reconstruction positions represented by the plurality of target offset parameters to obtain a plurality of examination tomographic images after noise suppression. After the above scheme is used, the axial scan image with noise uniformly distributed in the Z direction can be obtained.

Description

Technical Field

[0001] This invention relates to the field of medical image processing, and in particular to a method, system, device and medium for noise suppression of CT axial scan images. Background Technology

[0002] When using filtered back projection technology to reconstruct images from data obtained in the axial scan mode of a CT scanner, the reconstructed image near the center layer will have significantly high noise in the Z direction due to factors such as interpolation. Summary of the Invention

[0003] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a noise suppression method, system, device and medium for CT axial scan images.

[0004] This invention discloses a noise suppression method for CT axial scan images, comprising the following steps:

[0005] Acquire the original image sequence of the phantom scanned by the CT scanning device, wherein the original image sequence contains multiple original tomographic images arranged in sequence;

[0006] Multiple offset parameters are preset, and the offset reconstruction position is calculated for any original tomographic image based on any offset parameter. The multiple offset reconstruction positions corresponding to any original tomographic image are obtained. Reconstruction is performed at the multiple offset reconstruction positions respectively to obtain multiple offset reference images corresponding to any original tomographic image.

[0007] Obtain the original noise curve of any original tomographic image and the multiple offset noise curves of the multiple offset reference images corresponding to any original tomographic image. Select a target offset noise curve from the multiple offset noise curves. The merged noise curve obtained by fitting the target offset noise curve with the original noise curve is uniformly distributed in the Z direction. Use the offset parameter corresponding to the target offset noise curve as the target offset parameter of the original tomographic image.

[0008] The CT scanner acquires the data to be examined from the axial scan of the area to be examined, and reconstructs the data at the multiple target offset reconstruction positions represented by the multiple target offset parameters to obtain multiple tomographic images of the area to be examined after noise suppression.

[0009] Preferably, acquiring the original image sequence of the phantom scanned by the CT scanning device includes:

[0010] The original data of the CT scan of the phantom and multiple original reconstruction positions of the CT scan are obtained. The original data are reconstructed at the multiple original reconstruction positions to obtain the multiple original tomographic images arranged in sequence, forming the original image sequence.

[0011] Preferably, obtaining multiple offset reference images corresponding to any one of the original tomographic images includes:

[0012] Obtain any of the original tomographic images (img) i,0 The corresponding original reconstruction position z i The first offset reconstruction position z′ is calculated based on any of the offset parameters x. i =z i +x×d z Reconstructed position z″ with the second offset i =z i -x×d z , where d z The collimator single-layer opening width of the CT scanning device;

[0013] At the first offset reconstruction position z′ i Reconstructed position z″ with the second offset i The original data is reconstructed to obtain the first offset image img′. i,x and the second offset image img″ i,x For the first offset image img′ i,x With the second offset image img″ i,x The original tomographic image (img) is obtained by averaging. i,0 The offset reference image img corresponding to the offset parameter x i,x .

[0014] Preferably, the offset parameter x has a value range of (0, 0.5).

[0015] Preferably, the reconstruction of the data to be inspected includes:

[0016] Using any of the original tomographic images (img) i,0 The corresponding original reconstruction position z i and target offset parameter x t Calculate and obtain the first target offset reconstruction position z′ a =z i +x t ×d z Reconstructed position z″ with offset from the second target a =z i -x t ×d z;

[0017] At the first target offset reconstruction position z′ a Reconstructed position z″ offset from the second target a The data to be inspected is reconstructed to obtain the first offset image img′. a and the second offset image to be detected (img″) a For the first offset image to be detected, img′ a With the second offset image to be detected (img″) a The average is performed to obtain the tomographic image to be examined (img). a The tomographic image to be examined (img) a The layer sequence and the original tomographic image (img) i,0 The hierarchical order is consistent.

[0018] This invention also discloses a noise suppression system for CT axial scan images, including a signal processing module and a reconstruction module.

[0019] The signal processing module acquires the original image sequence of the phantom scanned by the CT scanning device, and the original image sequence contains multiple original tomographic images arranged in sequence.

[0020] The signal processing module presets multiple offset parameters, calculates and obtains the offset reconstruction position for any original tomographic image based on any offset parameter, obtains the multiple offset reconstruction positions corresponding to any original tomographic image, and performs reconstruction at the multiple offset reconstruction positions to obtain multiple offset reference images corresponding to any original tomographic image.

[0021] The signal processing module acquires the original noise curve of any original tomographic image and multiple offset noise curves of the multiple offset reference images corresponding to any original tomographic image. It selects a target offset noise curve from the multiple offset noise curves. The merged noise curve obtained by fitting the target offset noise curve with the original noise curve is uniformly distributed in the Z direction. The offset parameter corresponding to the target offset noise curve is used as the target offset parameter of the original tomographic image.

[0022] The reconstruction module acquires the data to be examined from the axial scan of the area to be examined by the CT scanning device, and reconstructs the data to be examined at multiple target offset reconstruction positions represented by the multiple target offset parameters to obtain multiple tomographic images of the area to be examined after noise suppression.

[0023] The present invention also discloses an electronic device, the electronic device including a memory processor storing computer-executable instructions, which, when executed by the processor, cause the electronic device to implement the aforementioned noise suppression method for CT axial scan images.

[0024] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, which, when run on a computer, causes the computer to perform the aforementioned noise suppression method for CT axial scan images.

[0025] Compared with the existing technology, the above technical solution has the following advantages: it obtains an axial scan image sequence with noise uniformly distributed in the Z direction, and it can process only the central tomographic image with high noise, reducing the amount of computation. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a noise suppression method for CT axial scan images disclosed in this invention.

[0027] Figure 2 This is a noise distribution curve of an original tomographic image and multiple offset reference images disclosed in this invention. Detailed Implementation

[0028] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0030] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0032] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0034] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0035] like Figure 1 As shown, this invention discloses a noise suppression method for CT axial scan images, comprising the following steps:

[0036] S100. Acquire the original image sequence of the phantom scanned by the CT scanning device. The original image sequence contains multiple original tomographic images arranged in sequence.

[0037] S200. Preset multiple offset parameters, calculate and obtain the offset reconstruction position for any original fault image based on any offset parameter, obtain multiple offset reconstruction positions corresponding to any original fault image, and reconstruct at the multiple offset reconstruction positions respectively to obtain multiple offset reference images corresponding to any original fault image.

[0038] S300. Obtain the original noise curve of any original fault image and multiple offset noise curves of multiple offset reference images corresponding to any original fault image. Select a target offset noise curve from the multiple offset noise curves. The merged noise curve obtained by fitting the target offset noise curve and the original noise curve is uniformly distributed in the Z direction. Use the offset parameter corresponding to the target offset noise curve as the target offset parameter of the original fault image.

[0039] S400: Acquire the axial scan data of the area to be examined by the CT scanning equipment, and reconstruct the data at multiple target offset reconstruction positions represented by multiple target offset parameters to obtain multiple tomographic images of the area to be examined after noise suppression.

[0040] Preferably, acquiring the original image sequence of the phantom scanned by the CT scanning device includes:

[0041] The raw data of the axial scan of the phantom by the CT scanning equipment and multiple raw reconstruction positions of the CT scanning equipment are acquired. The raw data is reconstructed at multiple raw reconstruction positions to obtain multiple raw tomographic images arranged in sequence, forming a raw image sequence.

[0042] Specifically, a CT scanner is used to perform an axial scan on the water phantom to obtain raw data. Multiple original reconstruction positions are then acquired from the CT scanner. Image reconstruction is performed on the raw data at each original reconstruction position, resulting in multiple original tomographic images arranged in the order of the original reconstruction positions, forming a raw image sequence. For example, a 64-slice CT scanner has 64 original reconstruction positions. Image reconstruction is performed at these 64 positions, forming a raw image sequence with 64 original tomographic images.

[0043] Preferably, obtaining multiple offset reference images corresponding to any one of the original tomographic images includes:

[0044] Get any original tomographic image (img) i,0 The corresponding original reconstruction position z i The first offset reconstruction position z′ is calculated based on any offset parameter x. i =z i +x×d z Reconstructed position z″ with the second offset i =z i -x×d z , where d z The width of a single-layer opening in the collimator of a CT scanning device;

[0045] At the first offset reconstruction position z′ i Reconstructed position z″ with the second offset i The original data is reconstructed to obtain the first offset image img′. i,x and the second offset image img″ i,x For the first offset image img′ i,x With the second offset image imgi″ i,x Averaging yields the original tomographic image (img). i,0 The offset reference image (img) corresponding to the offset parameter x i,x .

[0046] Specifically, let z be the i-th original reconstructed position. i , at z i The original tomographic image reconstructed from the original data (img)i,0 This is the i-th layer image in the original image sequence. Keeping the other reconstruction parameters unchanged, the first offset reconstruction position z′ is obtained based on any offset parameter x. i =z i +x×d z Reconstructed position z″ with the second offset i =z i -x×d z and in z′ i and z″ i Image reconstruction is performed on the original data at each location to obtain the first offset image img′. i,x and the second offset image img″ i,x Then, for the first offset image img′ i,x With the second offset image img″ i,x Averaging is performed to obtain the offset reference image. The above steps are repeated for different offset parameters x to obtain multiple offset reference images corresponding to any original tomographic image.

[0047] Preferably, the offset parameter x takes values ​​in the range of (0, 0.5). Multiple offset parameters x can be taken at fixed intervals within this range.

[0048] like Figure 2 As shown, Figure 2 (a) is the original tomographic image. i,0 The original noise curve along the z-direction. Figure 2 (b) is the offset reference image when x = 0.15. i,0.15 Offset noise curve along the z-direction, Figure 2 (c) is the offset reference image when x = 0.2. i,0.2 Offset noise curve along the z-direction, Figure 2 (d) is the offset reference image when x = 0.24. i,0.24 Offset noise curve along the z-direction, Figure 2 (e) The triangular part is the selected offset reference image (img) i,0.24 The offset noise curve is used as the merged noise curve after fitting the target noise curve and the original noise curve. The circled part is the original noise curve before processing. It can be seen that the merged noise curve is uniformly distributed in the z-direction. For each layer of the original tomographic image (img) i,0 After selecting the corresponding target offset noise curve, the original tomographic image (img) of each layer is obtained. i,0 The target offset parameters are used to reconstruct multiple target offset positions for subsequent data to be examined. It is understandable that for the original tomographic image (img) where the original noise curve itself is already uniformly distributed in the z-direction... i,0 Alternatively, its original reconstructed location z can be used directly.i For example, for a 64-slice CT scanner, the original reconstruction positions of the original tomographic images of slices 1-25 and 40-64 are maintained. The target offset parameter for the original tomographic images of slices 26-27 and 38-39 is x=0.15, the target offset parameter for the original tomographic images of slices 28 and 37 is x=0.2, and the target offset parameter for the original tomographic images of slices 29-36 is x=0.24.

[0049] Preferably, reconstructing the data to be examined includes:

[0050] Use any original tomographic image (img) i,0 The corresponding original reconstruction position z i and target offset parameter x t Calculate and obtain the first target offset reconstruction position z′ a =z i +x t ×d z Reconstructed position z″ with offset from the second target a =z i -x t ×d z ;

[0051] At the first target offset reconstruction position z′ a Reconstructed position z″ with offset from the second target a The data to be inspected is reconstructed separately to obtain the first offset image img′. a and the second offset image to be detected (img″) a For the first offset image to be detected, img′ a With the second offset image to be detected (img″) a Averaging is performed to obtain the tomographic image to be examined (img). a Among them, the tomographic image to be examined is shown in image. a sequence and original tomographic image (img) i,0 The hierarchical order is consistent.

[0052] For example, for a 64-slice CT scanner, if the target offset parameter of the previously acquired 28th slice original tomographic image is x = 0.2, and the 28th slice original tomographic image (img) is used... 28,0 The corresponding original reconstruction position z 28 Using its target offset parameter of 0.2, the first target offset reconstruction position z′ is calculated and obtained. 28 =z 28 +0.2×d z Reconstructed position z″ with offset from the second target 28 =z 28 -0.2×d z At the first target offset reconstruction position z′28 Reconstructed position z″ with offset from the second target 28 The data to be inspected is reconstructed separately to obtain the first offset image img′. 28 and the second offset image to be detected (img″) 28 For the first offset image to be detected, img′ 28 and the second offset image to be detected (img″) 28 Averaging yields the image of the 28th tomographic layer (img). 28 Similarly, the data to be examined is reconstructed multiple times, ultimately yielding a total of 64 tomographic images after noise suppression.

[0053] This invention also discloses a noise suppression system for CT axial scan images, including a signal processing module and a reconstruction module.

[0054] The signal processing module acquires the original image sequence of the phantom scanned by the CT scanning equipment. The original image sequence contains multiple original tomographic images arranged in sequence.

[0055] The signal processing module presets multiple offset parameters, calculates the offset reconstruction position for any original tomographic image based on any offset parameter, obtains multiple offset reconstruction positions corresponding to any original tomographic image, and performs reconstruction at each of the multiple offset reconstruction positions to obtain multiple offset reference images corresponding to any original tomographic image.

[0056] The signal processing module acquires the original noise curve of any original tomographic image and multiple offset noise curves of multiple offset reference images corresponding to any original tomographic image. It selects a target offset noise curve from the multiple offset noise curves. The merged noise curve obtained by fitting the target offset noise curve and the original noise curve is uniformly distributed in the Z direction. The offset parameter corresponding to the target offset noise curve is used as the target offset parameter of the original tomographic image.

[0057] The reconstruction module acquires the data to be examined from the axial scan of the area to be examined by the CT scanning equipment, and reconstructs the data to be examined at multiple target offset reconstruction positions represented by multiple target offset parameters, thereby obtaining multiple tomographic images of the area to be examined after noise suppression.

[0058] The present invention also discloses an electronic device, the electronic device including a memory processor storing computer-executable instructions, which, when executed by the processor, cause the electronic device to implement the aforementioned noise suppression method for CT axial scan images.

[0059] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, which, when run on a computer, causes the computer to perform the aforementioned noise suppression method for CT axial scan images.

[0060] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A noise suppression method for CT axial scan images, characterized in that, Includes the following steps: Acquire the original image sequence obtained by CT scanning equipment from axial scanning of the phantom, wherein the original image sequence contains multiple original tomographic images arranged in sequence; Multiple offset parameters are preset, and the offset reconstruction position is calculated for any original tomographic image based on any offset parameter to obtain multiple offset reconstruction positions corresponding to any original tomographic image. Reconstruction is performed at each of the multiple offset reconstruction positions to obtain multiple offset reference images corresponding to any original tomographic image. Obtain the original noise curve of any original tomographic image and the multiple offset noise curves of the multiple offset reference images corresponding to any original tomographic image. Select a target offset noise curve from the multiple offset noise curves. The merged noise curve obtained by fitting the target offset noise curve with the original noise curve is uniformly distributed in the Z direction. Use the offset parameter corresponding to the target offset noise curve as the target offset parameter of the original tomographic image. The CT scanning device acquires the data to be examined along the axis of the area to be examined, and reconstructs the data to be examined at multiple target offset reconstruction positions represented by multiple target offset parameters to obtain multiple tomographic images of the area to be examined after noise suppression. The step of obtaining multiple offset reference images corresponding to any one of the original tomographic images includes: Obtain any of the original tomographic images. The corresponding original reconstruction location According to any offset parameter Calculate and obtain the first offset reconstruction position Reconstructed position with second offset ,in, The collimator single-layer opening width of the CT scanning device; At the first offset reconstruction position Reconstructed position with the second offset The original data were reconstructed to obtain the first offset image. and the second offset image For the first offset image With the second offset image The original tomographic image was obtained by averaging. At the offset parameter Corresponding offset reference image .

2. The noise suppression method according to claim 1, characterized in that, The offset parameter The value range is (0, 0.5).

3. The noise suppression method according to claim 1, characterized in that, The reconstruction of the data to be inspected includes: Using any of the original tomographic images The corresponding original reconstruction location and target offset parameters Calculate and obtain the reconstructed position of the first target offset. Reconstructed position with offset from the second target ; At the first target offset reconstruction position Reconstructed position offset from the second target The data to be inspected is reconstructed to obtain the first offset image to be inspected. and the second offset image to be detected For the first offset image to be detected With the second offset image to be detected The tomographic image to be examined is obtained by averaging. The tomographic image to be examined The stratigraphic sequence and the original tomographic image The hierarchical order is consistent.

4. A noise suppression system for CT axial scan images, characterized in that, Includes signal processing module and reconstruction module, The signal processing module acquires the original image sequence obtained by the CT scanning device from the phantom axial scan, and the original image sequence contains multiple original tomographic images arranged in sequence. The signal processing module presets multiple offset parameters, calculates and obtains the offset reconstruction position for any original tomographic image based on any offset parameter, and obtains multiple offset reconstruction positions corresponding to any original tomographic image. Reconstruction is performed at each of the multiple offset reconstruction positions to obtain multiple offset reference images corresponding to any original tomographic image. The signal processing module acquires the original noise curve of any original tomographic image and multiple offset noise curves of the multiple offset reference images corresponding to any original tomographic image. It selects a target offset noise curve from the multiple offset noise curves. The merged noise curve obtained by fitting the target offset noise curve with the original noise curve is uniformly distributed in the Z direction. The offset parameter corresponding to the target offset noise curve is used as the target offset parameter of the original tomographic image. The reconstruction module acquires the data to be examined by the CT scanning device along the axis of the area to be examined, and reconstructs the data to be examined at multiple target offset reconstruction positions represented by multiple target offset parameters to obtain multiple tomographic images to be examined after noise suppression. The step of obtaining multiple offset reference images corresponding to any one of the original tomographic images includes: Obtain any of the original tomographic images. The corresponding original reconstruction location According to any offset parameter Calculate and obtain the first offset reconstruction position Reconstructed position with second offset ,in, The collimator single-layer opening width of the CT scanning device; At the first offset reconstruction position Reconstructed position with the second offset The original data were reconstructed to obtain the first offset image. and the second offset image For the first offset image With the second offset image The original tomographic image was obtained by averaging. At the offset parameter Corresponding offset reference image .

5. An electronic device, characterized in that, The electronic device includes a processor storing computer-executable instructions, which, when executed by the processor, cause the electronic device to perform a noise suppression method for CT axial scan images according to any one of claims 1-3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run on a computer, it causes the computer to perform a noise suppression method for CT axial scan images according to any one of claims 1-3.

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