Annular artifact correction method and device for photon counting detector, medium and terminal

Abstract

According to the photon counting detector ring artifact correction method, the photon counting detector ring artifact correction device, the terminal and the medium provided by the invention, block correction and fitting error compensation are respectively performed on the photon counting detector through a high-order polynomial fitting method, so that accurate correction of the photon counting detector ring artifact is realized; meanwhile, complex modeling and time-consuming calculation are avoided, the real response laws between different detectors and the calibration plate can be accurately fitted only through a small amount of data, an accurate and reliable solution is provided for ring artifact correction, material decomposition and image reconstruction, and the method has remarkable application potential in clinical practice. The problems that a large number of annular artifacts appear after projection data reconstruction of the photon counting detector and the image quality is seriously reduced due to the fact that response laws of different detectors to spectrums are different are solved.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to a method, device, medium and terminal for correcting ring artifacts in a photon counting detector. Background Art

[0002] Photon counting CT is an advanced medical imaging technology that utilizes photon counting technology and detectors to acquire high-resolution three-dimensional images, providing physicians with more accurate diagnoses and treatment planning. In photon counting CT, photon counting detectors record the path of each photon, enabling detailed imaging of the body's internal structures. Compared to traditional energy-integrating detectors, photon counting detectors offer higher spatial resolution, lower noise, lower radiation dose, and superior color imaging performance.

[0003] In photon-counting detectors, X-ray photons, absorbed by semiconductor materials, generate positive and negative charges, which, under the influence of a strong electric field, form an electrical signal. Unlike traditional detectors that rely on signal integration, photon-counting detectors directly measure the energy of each photon event, accurately reconstructing the image. This technology not only improves image quality but also reduces patient radiation exposure, bringing more possibilities and convenience to medical diagnosis and treatment.

[0004] However, in existing technologies, photon-counting detector panels are composed of multiple detector modules. Different photon-counting detectors have different spectral responses. This variation results in numerous ring artifacts when reconstructing projection data in photon-counting tomography systems, severely degrading image quality. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present application is to provide a method for solving the problem that a large number of ring artifacts appear in photon counting detectors after reconstructing projection data due to differences in the response patterns of different detectors to the spectrum, which seriously reduces the image quality.

[0006] To achieve the above-mentioned objectives and other related objectives, the first aspect of the present application provides a method for correcting ring artifacts of a photon counting detector, comprising: collecting first real-time projection data using a photon counting detector pre-installed with a calibration plate, and preprocessing the first real-time projection data; performing block correction on the photon counting detector according to standard projection data to generate a material decomposition correction coefficient; performing fitting error compensation on the first real-time projection data based on the material decomposition correction coefficient to generate error fitting parameters; collecting second real-time projection data again using the calibration plate and preprocessing the data, and performing material decomposition and ring artifact correction on the second real-time projection data based on the material decomposition correction coefficient and the error fitting parameters to generate a material decomposition correction result.

[0007] In some embodiments of the first aspect of the present application, the process of performing block correction on the standard projection data includes: performing polynomial fitting based on the calibration plate thickness and photon counting detector data included in the standard projection data to generate a block correction function, and extracting a material decomposition correction coefficient from the block correction function. In some embodiments of the first aspect of the present application, the block correction function includes:

[0008]

[0009]

[0010] Among them, T M1 and T M2 represents the true thickness of the two different preset plates, k represents the kth detector pixel in the S calibration blocks, and n i represents the power of the i-th term of the p-order polynomial, α and β represent the material decomposition correction coefficients, Represents the logarithmic projection value of the i-th energy bin of the current detector.

[0011] In some embodiments of the first aspect of the present application, the fitting error compensation process includes: substituting the projection data into the block correction function containing the material decomposition correction coefficient to calculate the calibration plate thickness prediction value; calculating the thickness difference based on the calibration plate thickness true value and the calibration plate thickness prediction value; fitting the thickness difference and the first real-time projection data to generate an error fitting function; due to the nonlinear characteristics of the error fitting function, the Gauss-Newton method is used to iteratively solve the parameter P that makes the objective function reach the optimal solution, and the error fitting parameter is extracted from the error fitting function.

[0012] In some embodiments of the first aspect of the present application, the process of material decomposition and ring artifact correction includes: performing a material decomposition operation on the second real-time projection data according to the material decomposition block correction coefficient to generate a material decomposition thickness; calculating the fitting thickness difference of the second real-time projection data based on the error fitting parameter; and performing the fitting error compensation on the material decomposition thickness based on the fitting thickness difference to generate a material decomposition correction result.

[0013] In some embodiments of the first aspect of the present application, the process of preprocessing the projection data includes: performing logarithmic normalization on the projection data; and predicting the unknown flux in the projection data using numerical interpolation based on the known flux in the projection data using the logarithmic normalization method.

[0014] To achieve the above-mentioned objectives and other related objectives, the second aspect of the present application provides a photon counting detector ring artifact correction device, comprising: a data acquisition module: configured to acquire first real-time projection data through a photon counting detector pre-set with a calibration plate, and to pre-process the first real-time projection data; a block correction module: configured to perform block correction on the photon counting detector according to standard projection data to generate a material decomposition correction coefficient; a fitting error compensation module: configured to perform fitting error compensation on the first real-time projection data based on the material decomposition correction coefficient to generate an error fitting parameter; and a ring artifact correction module: configured to acquire second real-time projection data again through the calibration plate and to pre-process the data, and to perform material decomposition and ring artifact correction on the second real-time projection data based on the material decomposition correction coefficient and the error fitting parameter to generate a material decomposition correction result.

[0015] To achieve the above-mentioned purpose and other related purposes, the third aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the photon counting detector ring artifact correction method is implemented.

[0016] To achieve the above-mentioned objectives and other related objectives, the fourth aspect of the present application provides an electronic terminal, comprising: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the photon counting detector ring artifact correction method.

[0017] As described above, the present invention relates to a method, device, medium, and terminal for correcting ring artifacts in a photon counting detector in the field of signal processing technology, which has the following beneficial effects: The present invention performs block correction on the photon counting detectors separately by high-order polynomial fitting, and adds a fitting error compensation module based on the first step of correction, thereby achieving accurate correction of the ring artifacts in the photon counting detectors. While also avoiding complex modeling and time-consuming calculations, only a small amount of data is required to accurately fit the true response patterns between different detectors and calibration plates, providing an accurate and reliable solution for ring artifact correction, material decomposition, and image reconstruction, and having significant application potential in clinical practice. The present invention solves the problem that a large number of ring artifacts appear in photon counting detectors after reconstructing projection data due to differences in the response patterns of different detectors to the spectrum, which seriously reduces the image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flow chart of an embodiment of a method for correcting ring artifacts in a photon counting detector of the present application is shown.

[0019] Figure 2A structural diagram of data acquisition in an embodiment of a method for correcting ring artifacts in a photon counting detector of the present application is shown.

[0020] Figure 3 A flow chart showing another embodiment of the method for correcting ring artifacts in a photon counting detector of the present application is shown.

[0021] Figure 4 A schematic diagram of the process of material decomposition and data reconstruction in an embodiment of the method for correcting ring artifacts in a photon counting detector of the present application is shown.

[0022] Figure 5 A structural schematic diagram of an embodiment of a ring artifact correction device for a photon counting detector of the present application is shown.

[0023] Figure 6 A schematic diagram of the structure of the ring artifact correction electronic terminal of the photon counting detector of the present application is shown. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0025] It should be noted that in the following description, reference is made to the accompanying drawings, which describe several embodiments of the present application. It should be understood that other embodiments may also be used, and that mechanical, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is limited only by the claims of the published patents. The terms used herein are only for describing specific embodiments and are not intended to limit the present application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between one element or feature shown in the figure and another element or feature.

[0026] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," "holding," and the like should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0027] Furthermore, as used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B, and C". Exceptions to this definition occur only when the combination of elements, functions, or operations is inherently mutually exclusive in some way.

[0028] To address the problems described above in the background art, the present invention provides a method, device, medium, and terminal for correcting ring artifacts in photon-counting detectors. These methods aim to address the problem of significant ring artifacts appearing after reconstructing projection data due to differences in the spectral response patterns of different detectors, severely degrading image quality. To further clarify the objectives, technical solutions, and advantages of the present invention, the following examples, in conjunction with the accompanying drawings, further illustrate the technical solutions in the embodiments of the present invention. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the invention.

[0029] Before further explaining the present invention in detail, the nouns and terms involved in the embodiments of the present invention are explained. The nouns and terms involved in the embodiments of the present invention are subject to the following interpretations:

[0030] <1> Photon counting detector: A detector used to measure the number of photons, usually including components such as photomultiplier tubes and photodiodes, which are used to convert light signals into electrical signals and count them.

[0031] <2> Ring artifact: A ring-shaped artifact that appears in the imaging system. It may be caused by detector design, uneven optical path, or sensor failure, affecting image quality.

[0032] <3> Material Decomposition: Decomposes a material into multiple different materials with their equivalent projected attenuation.

[0033] <4> Energy bin: This refers to the part of a photon detector that stores the energy received. It typically includes devices such as an energy integrator or spectrometer, which are used to measure the energy distribution and energy spectrum of photons. In photon counting detectors, the energy bin can help determine the energy range and energy spectrum of photons.

[0034] Embodiments of the present invention provide a method for correcting ring artifacts in photon counting detectors, an apparatus for performing the method, and a storage medium storing an executable program for implementing the method. Regarding the implementation of the method, the present embodiment will describe an exemplary implementation scenario for correcting ring artifacts in photon counting detectors.

[0035] like Figure 1 FIG. 1 is a flow chart showing a method for correcting ring artifacts in a photon counting detector according to an embodiment of the present invention. The method for correcting ring artifacts in a photon counting detector according to this embodiment mainly includes the following steps:

[0036] Step S11: collecting first real-time projection data through a photon counting detector preset with a calibration plate, and preprocessing the first real-time projection data.

[0037] like Figure 2 The first real-time projection data acquisition process in one embodiment of the present invention is demonstrated. The acquisition process involves first combining a high-density calibration plate and a low-density calibration plate of fixed thickness. After exposure to a radiation source, the detector obtains first real-time projection data for calibration. Subsequently, the two calibration plates are changed in thickness and the above detection process is repeated to obtain multiple sets of calibration data.

[0038] In this embodiment, the high-density calibration plate has a large attenuation coefficient and is used to simulate portions of the irradiated object with higher attenuation numbers. Materials that can be used include, but are not limited to, aluminum, copper, lead, bismuth, and tungsten. The low-density calibration plate has a small attenuation coefficient and is used to simulate the soft tissue of the irradiated object. Materials that can be used include, but are not limited to, aluminum oxide, polyethylene, polypropylene, and styrene foam. In this embodiment, a linear combination of basis vectors formed by the photoelectric effect and Compton scattering components of the high-density and low-density calibration plates is used to convert this set of basis vectors into a linearly independent attenuation coefficient basis for the two different plates. The attenuation coefficient basis describes the material's ability to absorb photons, thereby measuring the photon energy and intensity.

[0039] In one embodiment of the present invention, the first real-time projection data collected for correction is a four-dimensional array, which includes the number of detector rows, the number of detectors in each row, the number of correction calibration plate combinations, and the number of energy channels.

[0040] In one embodiment of the present invention, the process of preprocessing the projection data includes: performing logarithmic normalization on the projection data; and using the logarithmic normalization process to predict the unknown flux in the projection data based on the known flux in the projection data using a third-order spline numerical interpolation method. Exemplarily, the logarithmic normalization process includes dividing the number of photons after attenuation by the number of photons before attenuation and taking the negative logarithm of the division result to obtain a total attenuation value for the path.

[0041] Step S12: performing block calibration on the photon counting detector according to standard projection data to generate a material decomposition correction coefficient.

[0042] In one embodiment of the present invention, the process of performing block correction on standard projection data includes: performing polynomial fitting based on calibration plate thickness and photon energy data contained in the standard projection data to generate a block correction function, and extracting a material decomposition correction coefficient from the block correction function.

[0043] Furthermore, the block correction function includes:

[0044]

[0045]

[0046] Among them, T M1 and T M2 represents the true thickness of the two different preset plates, k represents the kth detector pixel in the S calibration blocks, and n i represents the i-th term of the p-order polynomial, α and β represent the material decomposition correction coefficients, Represents the energy value of the i-th energy bin among m energy bins.

[0047] Furthermore, the fitted thickness difference is the difference between the actual thickness and the predicted thickness. For example, the actual thickness of the calibration plate may be 100 mm or 200 mm. This application obtains the error fitting parameters α and β using Equation 1 and Equation 2 and the least squares method, and then substitutes these error fitting parameters α and β into Equation 1 and Equation 2 to obtain the predicted value of the calibration plate.

[0048] It is worth noting that the ring artifact correction method of the photon counting detector of the present invention adopts the method of embedding the energy spectrum response function of different pixel points into a high-order polynomial. The difference between the coefficients represents the slight difference in the energy spectrum response of different pixel points. This slight difference can be used to efficiently correct the ring artifact of the photon counting detector. For the above-mentioned high-order polynomial fitting, the solution process can adopt the above-mentioned least squares fitting method, that is, through the pseudo-inverse matrix and The correction coefficients α and β are directly calculated, without the need for iterative fine-tuning of the model, making the entire ring artifact correction process simple and fast. Furthermore, this application uses an error compensation method to fit the residual error, making the correction result more accurate. The following section describes the fitting error compensation involved in this application in detail.

[0049] Step S13: Based on the material decomposition correction coefficient, performing fitting error compensation on the first real-time projection data to generate error fitting parameters.

[0050] In one embodiment of the present invention, the fitting error compensation process includes: fitting the thickness difference and the first real-time projection data to construct an error fitting function; due to the nonlinear characteristics of the error fitting function, the Gauss-Newton method is used to iteratively solve the parameter P that makes the objective function reach the optimal solution, and the error fitting parameter is extracted from the error fitting function.

[0051] Furthermore, in this embodiment, considering that there is still a large fitting error in the parameters after only block correction, a model is built for the above fitting error to further predict the fitting error.

[0052] Error fitting functions include, but are not limited to, exponential function fitting, high-order polynomial fitting, and interpolation table methods. For example, a high-order polynomial is used to construct a correlation between the fitting error and the logarithmic projection value. When the fitting error does not reach a predetermined accuracy, the order of the high-order polynomial is further increased and the fitting error compensation operation is performed again. In the fitting error compensation operation, the input values ​​include the fitting error, the first real-time projection data, and the material thickness, and the output value is the error fitting parameter P.

[0053] Step S14: collecting the second real-time projection data again through the calibration plate and performing preprocessing, performing material decomposition and ring artifact correction on the second real-time projection data based on the material decomposition correction coefficient and the error fitting parameter to generate a material decomposition correction result.

[0054] In one embodiment of the present invention, the process of material decomposition and ring artifact correction includes: performing a material decomposition operation on the second real-time projection data according to the material decomposition block correction coefficient to generate a material decomposition thickness; calculating the fitting thickness difference of the second real-time projection data based on the error fitting parameter; and performing the fitting error compensation on the material decomposition thickness based on the fitting thickness difference to generate a material decomposition correction result.

[0055] Furthermore, after the block correction and error fitting compensation operations are completed, the material decomposition correction coefficients α and β, as well as the error fitting parameter P, are obtained. When the second real-time projection data is reacquired, the material decomposition correction coefficients, error fitting parameters, and the second real-time projection data can be substituted into Formula 1, Formula 2, and the error fitting function to calculate the thickness estimate and error estimate of the second real-time projection data. The thickness estimate and the error estimate are added together to obtain the material decomposition thickness value.

[0056] Notably, the present invention innovatively employs a high-order polynomial fitting approach during the block correction process. Its advantages are: first, block correction fully accounts for the structural characteristics of photon-counting detector panels. The response patterns of detector elements on different detector panels are affected by the material and process of the detector sensor, resulting in differences in photon counts; however, detector elements on the same detector panel exhibit similar response patterns. Furthermore, the polynomial fitting method is simple to construct and calculate, allowing it to fit sums of products of different orders to different energy projection data. Second, the high-order polynomial fitting algorithm runs very quickly, and fitting operations between different detectors do not affect each other, allowing for rapid parallel execution of fitting and material decomposition operations. For example, second-order polynomial fitting is commonly used in the art. While this approach performs well on simulated data, it suffers from significant fitting errors on experimental data. Therefore, this patent, taking into account the structural characteristics of the detector array, specifically incorporates an error compensation algorithm based on the second-order polynomial fitting, significantly reducing fitting errors while ensuring high speed and real-time data processing capabilities, enabling the generation of material decomposition results free of ring artifacts. Finally, the present application can also use different functions for error fitting. For example, exponential function form, high-order polynomial form and interpolation table form can be used for fitting to establish a correlation between projection data and material thickness, so as to better realize the ring artifact correction of photon counting detectors.

[0057] like Figure 3FIG. 1 is a flow chart illustrating a method for correcting ring artifacts in a photon counting detector according to another embodiment of the present invention. First, PCCT (Photon Counting Computed Tomography) photon counting sub-data of a specific flux are obtained using a stack of high-density and low-density calibration plates. A preliminary correction of the channel data is performed using the PCCT data. The preliminarily corrected channel data is compared with the channel correction data in a historical database. If the historical database contains channel correction data, the channel correction data is interpolated; otherwise, block correction is performed directly on the preliminarily corrected channel data. High-order polynomial error correction is performed on the block-corrected data, and the fitted error is calculated. If the fitted error meets the preset accuracy requirements, material decomposition and ring artifact correction are performed based on the data after the high-order polynomial error correction. Otherwise, the order of the polynomial is increased, and high-order polynomial error correction is performed again.

[0058] Furthermore, the process of performing preliminary channel data calibration using the PCCT data includes recording PCCT data from a photon counting detector at different fluxes using a photon source of known flux. This data is used to establish a relationship between flux and PCCT, illustratively, by creating a curve between flux and PCCT. Finally, the actual measured PCCT data is converted into corresponding flux data based on the established calibration curve.

[0059] like Figure 4 FIG. 1 shows a flow chart of the detector raw data reconstruction process and the ring artifact and material decomposition process in a method for correcting ring artifacts in a photon counting detector in another embodiment of the present invention. First, the raw data is split into energy bin sinusoidal image data of material 1 and material 2 by means of detector raw data reconstruction. The energy bin sinusoidal image data of material 1 and material 2 are subjected to the above-mentioned block correction operation and fitting error compensation operation to generate sinusoidal image data of material 1 and material 2 that have undergone error fitting compensation. Image reconstruction is then performed based on the error fitting compensated sinusoidal image data to generate a virtual monoenergetic image with ring artifacts eliminated. The virtual monoenergetic image refers to an idealized photon energy spectrum image obtained by analyzing and processing the photon energy measured by the detector in a photon counting experiment, i.e., image data with ring artifacts eliminated in the present invention.

[0060] like Figure 5 FIG. 5 shows a schematic diagram of the structure of a ring artifact correction device for a photon counting detector according to an embodiment of the present invention. In this embodiment, the ring artifact correction device 500 for a photon counting detector includes:

[0061] The data acquisition module 501 is configured to acquire first real-time projection data through a photon counting detector with a preset calibration plate, and pre-process the first real-time projection data.

[0062] The block correction module 502 is configured to perform block correction on the photon counting detector according to the standard projection data to generate a material decomposition correction coefficient.

[0063] The fitting error compensation module 503 is configured to perform fitting error compensation on the first real-time projection data based on the material decomposition correction coefficient to generate error fitting parameters.

[0064] The ring artifact correction module 504 is used to collect the second real-time projection data again through the calibration plate and perform preprocessing, and perform material decomposition and ring artifact correction on the second real-time projection data based on the material decomposition correction coefficient and the error fitting parameter to generate a material decomposition correction result.

[0065] It should be noted that the aforementioned embodiments of the device for correcting ring artifacts in photon-counting detectors use the aforementioned division of program modules as an example only to illustrate the process of correcting ring artifacts in photon-counting detectors. In actual applications, the aforementioned processes can be assigned to different program modules as needed, i.e., the internal structure of the device can be divided into different program modules to complete all or part of the aforementioned processes. Furthermore, the aforementioned embodiments of the device for correcting ring artifacts in photon-counting detectors and the aforementioned embodiments of the method for correcting ring artifacts in photon-counting detectors share the same concept. The specific implementation process is detailed in the method embodiments and will not be further elaborated here.

[0066] The photon counting detector ring artifact correction method provided in the embodiment of the present invention can be implemented on the terminal side or the server side. As for the hardware structure of the photon counting detector ring artifact correction terminal, please refer to Figure 6 , which is an optional hardware structure diagram of the photon counting detector ring artifact correction terminal 600 provided in an embodiment of the present invention. The terminal 600 can be a mobile phone, a computer device, a tablet device, a personal digital processing device, a factory background processing device, etc. The photon counting detector ring artifact correction terminal 600 includes: at least one processor 601, a memory 602, at least one network interface 604 and a user interface 606. The various components in the device are coupled together through a bus system 605. It can be understood that the bus system 605 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 605 also includes a power bus, a control bus and a status signal bus. However, for the sake of clarity, Figure 6 In the text, various buses are labeled as bus systems.

[0067] The user interface 606 may include a display, a keyboard, a mouse, a trackball, a click gun, keys, buttons, a touch pad or a touch screen.

[0068] It will be appreciated that the memory 602 may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. The non-volatile memory may be a read-only memory (ROM) or a programmable read-only memory (PROM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM) and synchronous static random access memory (SSRAM). The memories described in the embodiments of the present invention are intended to include, but are not limited to, these and any other suitable types of memories.

[0069] The memory 602 in this embodiment of the present invention is used to store various types of data to support the operation of the photon-counting detector ring artifact correction terminal 600. Examples of this data include any executable program used to operate on the photon-counting detector ring artifact correction terminal 600, such as an operating system 6021 and an application 6022. The operating system 6021 includes various system programs, such as a framework layer, a core library layer, and a driver layer, for implementing various basic services and processing hardware-based tasks. The application 6022 can include various application programs, such as a media player and a browser, for implementing various application services. The implementation of the photon-counting detector ring artifact correction method provided in this embodiment of the present invention can be included in the application 6022.

[0070] The methods disclosed in the above embodiments of the present invention can be applied to or implemented by processor 601. Processor 601 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in processor 601 or by software instructions. The above processor 601 may be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Processor 601 can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor 601 can be a microprocessor or any conventional processor. The steps of the accessory optimization method provided in the embodiments of the present invention can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium located in a memory. The processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method.

[0071] In an exemplary embodiment, the photon counting detector ring artifact correction terminal 600 can be used by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), and complex programmable logic devices (CPLDs) to execute the aforementioned photon counting detector ring artifact correction method.

[0072] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with a computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When executed, the program performs the steps in the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0073] In the embodiments provided herein, the computer readable and writable storage medium may include a read-only memory, a random access memory, an EEPROM, a CD-ROM or other optical disk storage device, a magnetic disk storage device or other magnetic storage device, a flash memory, a USB flash drive, a mobile hard disk, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection can be appropriately referred to as a computer readable medium. For example, if the instruction is sent from a website, a server or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves are included in the definition of the medium. However, it should be understood that computer readable and writable storage media and data storage media do not include connections, carriers, signals or other temporary media, but are intended to be non-temporary, tangible storage media. Disk and disc, as used in this application, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

[0074] In summary, the present application provides a method, device, terminal and medium for correcting ring artifacts of photon counting detectors. The present invention provides a method for improving the efficiency of ring artifact correction of photon counting detectors. Block correction is performed on the photon counting detectors by a high-order polynomial fitting method, and fitting error compensation is performed on the basis of block correction, thereby achieving accurate correction of ring artifacts of photon counting detectors. At the same time, complex modeling and time-consuming calculations are avoided. Only a small amount of data is needed to accurately fit the true response law between different detectors and calibration plates, providing an accurate and reliable solution for ring artifact correction, material decomposition, and image reconstruction, and having significant application potential in clinical practice. It solves the problem that due to the differences in the response laws of different detectors to the spectrum, a large number of ring artifacts appear in the photon counting detector after reconstructing the projection data, which seriously reduces the image quality. Therefore, the present application effectively overcomes the various shortcomings of the existing technology and has a high industrial utilization value.

[0075] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A method for correcting ring artifacts in a photon counting detector, characterized in that: include: collecting first real-time projection data by using a photon counting detector preset with a calibration plate, and preprocessing the first real-time projection data; performing block correction on the photon counting detector according to standard projection data to generate a material decomposition correction coefficient; performing fitting error compensation on the first real-time projection data based on the material decomposition correction coefficient to generate an error fitting parameter; Second real-time projection data is collected again through the calibration plate and preprocessed, and material decomposition and ring artifact correction are performed on the second real-time projection data based on the material decomposition correction coefficient and the error fitting parameter to generate a material decomposition correction result.

2. The method for correcting ring artifacts in a photon counting detector according to claim 1, wherein: The process of performing block correction on the standard projection data includes: performing polynomial fitting based on calibration plate thickness and photon energy data contained in the standard projection data to generate a block correction function, and extracting a material decomposition correction coefficient from the block correction function.

3. The method for correcting ring artifacts in a photon counting detector according to claim 2, wherein: The block correction function includes: Among them, T M1 and T M2 represents the true thickness of two different preset plates, k represents the detector pixel of the kth correction block in the correction block, n i represents the power of the i-th term of the p-order polynomial, α and β represent the material decomposition correction coefficients, represents the logarithmic projection value of the i-th energy bin.

4. The method for correcting ring artifacts in a photon counting detector according to claim 2, wherein: The fitting error compensation process includes: Substituting the projection data into the block correction function including the material decomposition correction coefficient to calculate a predicted value of the calibration plate thickness; Calculating a thickness difference based on the actual thickness of the calibration plate and the predicted thickness of the calibration plate; fitting the thickness difference and the first real-time projection data to generate an error fitting function; Error fitting parameters are extracted from the error fitting function.

5. The method for correcting ring artifacts in a photon counting detector according to claim 1, wherein: The process of material decomposition and ring artifact correction includes: performing a material decomposition operation on the second real-time projection data according to the material decomposition block correction coefficient to generate a material decomposition thickness; Calculating a fitting thickness difference value of the second real-time projection data based on the error fitting parameter; The fitting error compensation is performed on the material decomposition thickness based on the fitting thickness difference to generate a material decomposition correction result.

6. The method for correcting ring artifacts in a photon counting detector according to claim 1, wherein: The process of preprocessing the projection data includes: performing logarithmic normalization processing on the projection data; The projection data after logarithmic normalization is used to predict unknown flux in the projection data according to known flux in the projection data using a cubic spline numerical interpolation method.

7. A photon counting detector ring artifact correction device, characterized in that: include: Data acquisition module: used for collecting first real-time projection data through a photon counting detector preset with a calibration plate, and preprocessing the first real-time projection data; A block correction module is configured to perform block correction on the photon counting detector according to standard projection data to generate a material decomposition correction coefficient; A fitting error compensation module is configured to perform fitting error compensation on the first real-time projection data based on the material decomposition correction coefficient to generate an error fitting parameter; a ring artifact correction module configured to collect the second real-time projection data again through the calibration plate and perform preprocessing, and perform material decomposition and ring artifact correction on the second real-time projection data based on the material decomposition correction coefficient and the error fitting parameter to generate a material decomposition correction result.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for correcting ring artifacts in a photon counting detector according to any one of claims 1 to 6 is implemented.

9. An electronic terminal, characterized in that: include: processor and memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so as to enable the terminal to perform the photon counting detector ring artifact correction method according to any one of claims 1 to 6.

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