Method and apparatus for artifact removal of ct images

Abstract

The application discloses a kind of CT image's artifact elimination method and device, method includes the original pixel of the CT detector change with time, and the original pixel is handled to obtain the response value corresponding to each pixel point change with time;The response value is normalized;Based on compensation model, the data after normalization is fitted, wherein the compensation coefficient is fine-tuned in the fitting process to achieve the specified target.Through compensation mode, the purpose of reducing the difference between the response speed and intensity of pixel points is achieved, and then the artifact is eliminated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of image processing, and particularly relates to a CT image artifact elimination method and device. BACKGROUND

[0002] A CT detector is composed of a scintillator, a photodiode (pd), an ad conversion board and related components. The scintillator converts into visible light after encountering X-rays, and then the photodiode converts the light signals into electrical signals, and finally a computer processes the electrical signals to generate an image. In this process, the image often has uneven artifacts.

[0003] How to avoid artifacts to the greatest extent is a technical problem to be solved by the present application. SUMMARY

[0004] The main purpose of the present application is to provide a CT image artifact elimination method and device to solve the problems in the related art.

[0005] In order to achieve the above purpose, according to the first aspect of the present application, a CT image artifact elimination method is provided, which comprises collecting original pixels of a CT detector changing with time, and processing the original pixels to obtain a response value corresponding to each pixel point changing with time; performing normalization processing on the response value; fitting the normalized data based on a compensation model, wherein the compensation coefficients are fine-tuned in the fitting process to achieve a specified target.

[0006] Optionally, the processing of the original pixels to obtain a response value corresponding to each pixel point changing with time comprises: removing the background data of the original pixels to obtain a response value corresponding to each pixel point changing with time.

[0007] Optionally, the fitting of the response value and the normalized data based on the compensation model comprises: fitting the response value and the normalized data based on the compensation model, wherein f fitting, wherein f comp (t) is the compensated pixel response value, f(t) is the response value, f n (t) is the normalized data, and r1 and r2 are compensation coefficients.

[0008] Optionally, the fine-tuning of the compensation coefficients in the fitting process to achieve a specified target comprises: adjusting the compensation coefficients r1 and r2 to make the response speed difference between each pixel point reach a specified value.

[0009] Optionally, the specified value is 1%.

[0010] According to a second aspect of the present invention, an artifact elimination device for CT images is provided, comprising: a preprocessing unit for acquiring raw pixels of a CT detector that change over time, and processing the raw pixels to obtain response values ​​that change over time for each pixel; a processing unit for normalizing the response values; and a fitting unit for fitting the normalized data based on a compensation model, wherein the compensation coefficients are fine-tuned during the fitting process to achieve a specified target.

[0011] Optionally, processing the original pixels to obtain the response values ​​of each pixel over time includes: removing background data from the original pixels to obtain the response values ​​of each pixel over time.

[0012] Optionally, fitting the response value and the normalized data based on the compensation model includes: based on Perform fitting, where f comp f(t) is the compensated pixel response value, and f(t) is the response value. n (t) represents the normalized data, and r1 and r2 are the compensation coefficients.

[0013] According to a third aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing the computer to perform the method described in any one of the first aspects.

[0014] According to a fourth aspect of the present invention, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to cause the at least one processor to perform the method described in any implementation of the first aspect.

[0015] This embodiment of the CT image artifact elimination method and apparatus includes acquiring raw pixels of the CT detector over time, processing the raw pixels to obtain the response value of each pixel over time, normalizing the response value, and fitting the normalized data based on a compensation model, wherein the compensation coefficient is fine-tuned during the fitting process to achieve a specified target. The compensation method reduces the differences in response speed and intensity between pixels, thereby eliminating artifacts. Attached Figure Description

[0016] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0017] Figure 1 is a flow chart of the artifact elimination method of the CT image of the embodiment of the present application;

[0018] Fig. 2 is a schematic diagram of the application of the artifact elimination method of the CT image of the embodiment of the present application;

[0019] Figure 3 is a schematic diagram of the electronic device of the embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should be within the scope of protection of the present application.

[0021] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0022] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0023] According to the embodiments of the present application, a CT image artifact elimination method is provided, as shown in Figure 1 including the following steps 101 to 103:

[0024] Step 101: Collecting the original pixel of the CT detector changing over time, and processing the original pixel to obtain the response value corresponding to each pixel changing over time.

[0025] In the daily imaging process, an important reason for the occurrence of artifacts is that the X-ray intensity distribution is not uniform, which may cause the X-ray intensity received by the pixel inside the scintillator to be different, the crosstalk of the adjacent pixel received by the pixel inside the scintillator, and the inconsistency of the response of the photodiode corresponding to each pixel to the light signal, which will cause the response speed and intensity of the pixel inside the scintillator to be different. The difference in pixel response speed and intensity will cause uneven artifacts in the image. Therefore, based on this reason, the method of the embodiment is used to solve the artifact problem.

[0026] As an optional implementation manner of the embodiment, processing the original pixel to obtain the response value corresponding to each pixel changing over time comprises: removing the background data of the original pixel to obtain the response value corresponding to each pixel changing over time.

[0027] In the optional implementation manner, the background data refers to the basic data generated by the detector itself without X-ray irradiation, which reflects the basic characteristics of the detector, and this part of data needs to be subtracted in actual use. The response data of each pixel of the detector is the original data without wave state. The response value is the response value obtained by removing the local data.

[0028] Step 102: Normalizing the response value.

[0029] Step 103: Fitting the normalized data based on the compensation model, wherein the compensation coefficient is fine-tuned in the fitting process to achieve a specified target.

[0030] In the embodiment, the original data is normalized, the normalized data is fitted by using the compensation formula, and the fitting method adopts nonlinear fitting based on the least square method.

[0031] As an optional implementation manner of the embodiment, fitting the response value based on the compensation model and fitting the normalized data based on the compensation model comprises: fitting, wherein f comp (t) is the compensated pixel response value, f(t) is the response value, f n (t) is the normalized data, and r1 and r2 are compensation coefficients.

[0032] In the optional implementation manner, the response speed difference of each pixel of the CT detector is compensated by establishing a compensation model, and the specific formula is as follows:

[0033] f comp (t) is the compensated pixel response value, f(t) is the response value of the original pixel after removing the background data, f n (t) is the normalized response value, r1 and r2 are compensation coefficients. It should be understood that the corresponding curve of the detector is similar to an exponential function, r1 is the intercept of the curve, that is, the position of the starting point of the curve, and r2 is the change speed of the curve.

[0034] As an optional implementation manner of the embodiment, the fine adjustment of the compensation coefficients in the fitting process to achieve the specified target comprises: adjusting the compensation coefficients r1 and r2 to make the response speed difference between the pixel points reach a specified value.

[0035] As an optional implementation manner of the embodiment, the specified value is 1%.

[0036] In the optional implementation manner, the normalized data is fitted by using the compensation formula, the fitting manner adopts a nonlinear fitting based on a least square method, the compensation coefficients are fine adjusted to ensure that the response speed difference between the pixel points is small. The compensation coefficients are saved in a related program for subsequent image scanning. The difference can be equal to or less than 1‰.

[0037] Reference is made to a variation diagram before and after compensation shown in FIG. 2, wherein, Figure 2a is the curve of the intensity of two pixel points changing with illumination time before compensation; Figure 2b is the intensity change curve of the pixel points after compensation, the x-axis is time, and the y-axis is the ratio of the original data after normalization.

[0038] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a group of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that herein.

[0039] According to the embodiment of the application, a CT image artifact elimination device is also provided, which comprises a preprocessing unit configured to collect original pixels of a CT detector changing with time and process the original pixels to obtain response values of each pixel point changing with time; a processing unit configured to normalize the response values; and a fitting unit configured to fit the normalized data based on a compensation model, wherein the compensation coefficients are fine adjusted in the fitting process to achieve a specified target.

[0040] As an optional implementation manner of the embodiment, the processing of the original pixels to obtain the response values of each pixel point changing with time comprises: removing the background data from the original pixels to obtain the response values of each pixel point changing with time.

[0041] As an optional implementation method in this embodiment, fitting the response value and the normalized data based on the compensation model includes: based on Perform fitting, where f comp f(t) is the compensated pixel response value, and f(t) is the response value. n (t) represents the normalized data, and r1 and r2 are the compensation coefficients.

[0042] According to embodiments of the present invention, the present invention also provides an electronic device, the electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to implement the methods described in any of the above embodiments.

[0043] According to embodiments of the present invention, the present invention also provides a readable storage medium storing computer instructions that enable a computer to perform the methods described in any of the above embodiments when executed.

[0044] According to embodiments of the present invention, the present invention also provides a computer program product that, when executed by a processor, can implement the methods described in any of the above embodiments.

[0045] Figure 2 shows a schematic block diagram of an example electronic device 300 that can be used to implement embodiments of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices.

[0046] As shown in Figure 2, the electronic device 300 includes a computing unit 301, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 302 or a computer program loaded from a storage unit 308 into a random access memory (RAM) 303. The RAM 303 can also store various programs and data required for the operation of the electronic device 300. The computing unit 301, ROM 302, and RAM 303 are interconnected via a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0047] A plurality of components in the electronic device 300 are connected to the I / O interface 305, including: an input unit 306, such as a keyboard, a mouse, etc.; an output unit 307, such as various types of displays, speakers, etc.; a storage unit 308, such as a magnetic disk, an optical disk, etc.; and a communication unit 309, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 309 allows the electronic device 300 to exchange information / data with other devices through a computer network, such as the Internet, and / or various telecommunication networks.

[0048] The computing unit 301 can be various general and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 301 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The computing unit 301 performs various methods and processes described above, such as the object matching method. For example, in some embodiments, the object matching method can be implemented as a computer software program, which is tangibly embodied in a machine-readable medium, such as the storage unit 308. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device 300 via the ROM 302 and / or the communication unit 309. When the computer program is loaded onto the RAM 303 and executed by the computing unit 301, one or more steps of the methods described above can be performed.

[0049] Various implementations of the systems and techniques described above herein can be realized in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a programmable logic device (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0050] Program code for carrying out methods of the present application can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, produces a means for implementing the functions / operations specified in the flowchart diagrams and / or block diagrams. The program code can be executed entirely on a machine, partially on a machine, partially on a machine as a stand-alone software package, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0051] In the context of the present application, a machine-readable medium can be a tangible medium that contains or stores a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium will include one or more lines of electrical connections, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash memory), optical fibers, portable compact disc read-only memories (CD-ROMs), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

Claims

1. A method for artifact removal in CT images, characterized in that, include: The raw pixels of the CT detector are acquired over time, and the raw pixels are processed to obtain the response value of each pixel over time. The response value is normalized. The normalized data is fitted based on the compensation model, and the compensation coefficient is fine-tuned during the fitting process to achieve the specified target. The process of processing the original pixels to obtain the time-varying response values ​​for each pixel includes: removing background data from the original pixels to obtain the time-varying response values ​​for each pixel; and fitting the response values ​​and normalized data based on a compensation model includes: based on... Perform fitting, where, The compensated pixel response value, The response value, For the normalized data, , The compensation coefficients are used for fine-tuning during the fitting process to achieve the specified target. This includes adjusting the compensation coefficients. , Adjustments are made to ensure that the difference in response speed between each pixel reaches a specified value.

2. The method for artifact elimination in CT images according to claim 1, characterized in that, The specified value is 1%.

3. A device for eliminating artifacts in CT images, characterized in that, include: The preprocessing unit is used to acquire the raw pixels of the CT detector as they change over time, and to process the raw pixels to obtain the response value of each pixel as it changes over time. The processing unit is used to normalize the response value; The fitting unit is used to fit the normalized data based on the compensation model, wherein the compensation coefficient is fine-tuned during the fitting process to achieve a specified target; the processing of the original pixels to obtain the response value of each pixel over time includes: removing the background data of the original pixels to obtain the response value of each pixel over time. Fitting the response value and the normalized data based on the compensation model includes: based on Perform fitting, where, The compensated pixel response value, The response value, For the normalized data, , This is the compensation coefficient.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method according to any one of claims 1-2.

5. An electronic device, characterized in that, include: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to cause the at least one processor to perform the method according to any one of claims 1-2.

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