Information processing system, information processing device, information processing method, and program

Abstract

To provide a technique that enables image reconstruction or supports reconstruction processing without assuming a constant periodicity in the motion of a subject.SOLUTION: An information processing system for processing a plurality of projection images captured by a CT apparatus, includes a feature quantity acquisition unit, a spectral decomposition unit, and a synchronization processing unit. The feature quantity acquisition unit acquires waveform data, and the waveform data is data represented as a feature quantity obtained from each of the plurality of projection images. The spectral decomposition unit applies a predetermined analytical technique to the waveform data to obtain decomposed waveform data. The decomposed waveform data is data on waveforms obtained by decomposing the waveform data. The synchronization processing unit determines projection images to be used for reconstruction from the plurality of projection images on the basis of the waveforms indicated by the decomposed waveform data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an information processing system, an information processing device, an information processing method, and a program. [Background technology]

[0002] Patent Document 1 discloses a technique for removing noise caused by either the heartbeat or the respiratory beat and easily extracting only the accurate periodic motion caused by the other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6348865 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the invention described in Patent Document 1 requires that a certain periodicity be assumed in the movement of the subject when processing the image.

[0005] In view of the above circumstances, the present invention provides a technique that makes it possible to reconstruct an image or to assist in the reconstruction process without assuming a fixed periodicity in the movement of a subject. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided an information processing system for processing multiple projection images captured by a CT apparatus. The information processing system includes a feature acquisition unit, a spectral decomposition unit, and a synchronization processing unit. The feature acquisition unit acquires waveform data, which is data indicated as feature amounts obtained from each of the multiple projection images. The spectral decomposition unit acquires decomposed waveform data by applying a predetermined analysis method to the waveform data, which is waveform data obtained by decomposing the waveform data. The synchronization processing unit determines a projection image to be used for reconstruction from the multiple projection images based on the waveform indicated by the decomposed waveform data.

[0007] According to the present disclosure, it is possible to reconstruct an image or to assist in the reconstruction process without assuming a fixed periodicity in the movement of a subject. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a system configuration and a hardware configuration of an information processing system 1. FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of functional units included in a processor 21. [Figure 3] FIG. 2 is a diagram illustrating an example of an activity executed by the information processing system 1. [Figure 4] FIG. 10 is a diagram for explaining how decomposed waveform data is obtained from waveform data. [Figure 5] FIG. 10 is a diagram for explaining a method for determining an exhalation region and an inhalation region. [Figure 6] FIG. 1 illustrates a method for determining the inhalation and exhalation of the lungs and the diastole and systole of the heart. [Figure 7] 1 is a diagram showing an example of the results of determining the expiration and inspiration of the lungs and the diastole and systole of the heart using the method of Patent Document 1. FIG. [Figure 8] FIG. 10 is a diagram showing an example of a screen 4. [Figure 9] FIG. 10 shows a reconstructed image of the lungs without synchronization. [Figure 10] FIG. 10 is a diagram showing a reconstructed image of the lungs when the ROI similar to that in FIG. 9 is synchronized with the expiration of the lungs. [Figure 11] FIG. 10 is a diagram showing a reconstructed image of the lungs when the same ROI as in FIG. 9 is used to synchronize with inspiration of the lungs. [Figure 12] FIG. 10 shows a reconstructed image of the heart without synchronization. [Figure 13] FIG. 13 is a diagram showing a reconstructed image of the heart when the diastole of the heart is synchronized with the ROI similar to that of FIG. 12. [Figure 14] FIG. 13 is a diagram showing a reconstructed image of the heart when the systole of the heart is synchronized with the ROI similar to that of FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

[0010] The program for realizing the software appearing in this embodiment may be provided as a non-transitory computer-readable medium, or may be provided so that it can be downloaded from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client device (so-called cloud computing).

[0011] In this embodiment, the term "unit" may include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. Furthermore, this embodiment handles various types of information, which may be represented by, for example, physical values ​​of signal values ​​representing voltages and currents, high and low signal values ​​as a binary bit set consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations may be performed on the circuit in the broad sense.

[0012] In a broad sense, a circuit is a circuit realized by at least an appropriate combination of a circuit, circuitry, a processor, a memory, etc. That is, a circuit includes an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc. The circuit also includes a serverless architecture that uses container-based services to run applications in an environment abstracted from the management of physical infrastructure.

[0013] 1. System configuration and hardware configuration of information processing system 1 First, the system configuration and hardware configuration of an information processing system 1 of this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the system configuration and hardware configuration of the information processing system 1.

[0014] (Information Processing System 1) The information processing system 1 shown in FIG. 1 can process a plurality of projection images captured by a CT device 3. The information processing system 1 includes an information processing device 2 and a CT (Computed Tomography) device 3. The information processing device 2 and the CT device 3 are configured to be able to communicate with each other via a communication cable or a network. This allows the information processing device 2 and the CT device 3 to transmit and receive various information to each other. Here, a system exemplified as the information processing system 1 is made up of one or more devices or components. Therefore, even the information processing device 2 alone or the CT device 3 alone is included in the system exemplified as the information processing system 1. The information processing device 2 and the CT device 3 are operated, for example, by a user who is the measurer.

[0015] (Information processing device 2) The information processing device 2 is a PC (Personal Computer). The information processing device 2 may be a tablet computer, a smartphone, or the like instead of a PC. The information processing device 2 can process multiple projection images captured by the CT device 3. Specifically, for example, the information processing device 2 is configured to be able to perform arbitrary information processing on measurement data acquired from the CT device 3, control X-rays generated by the X-ray generator 34, acquire projection images detected by the detector 35, control the movement of the sample holder 36, and control the rotation drive unit 37. Note that the information processing device 2 only needs to be able to ultimately perform arbitrary information processing related to the CT device 3, and another information processing device may be interposed between the information processing device 2 and the CT device 3. As shown in FIG. 1 , the information processing device 2 includes a processor 21, a storage unit 22, a communication unit 23, an input unit 24, and an output unit 25, and these components are electrically connected via a communication bus within the information processing device 2. The information processing device 2 executes the processing according to the embodiment.

[0016] The processor 21 processes and controls the overall operations related to the information processing device 2. The processor 21 is, for example, a central processing unit (CPU). Information processing by a program stored in the storage unit 22 is specifically realized by the processor 21, which is an example of hardware, and can be executed as each functional unit included in the processor 21. Each functional unit included in the processor 21 realizes, for example, the processing shown in FIG. 3, which will be described later. Note that the processor 21 is not limited to being single, and may be implemented with multiple processors 21 for each function. A combination of these may also be used.

[0017] The storage unit 22 stores various pieces of information defined above. This may be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs and the like related to the information processing device 2 executed by the processor 21, or as a memory such as a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to program operations. The storage unit 22 stores various programs and variables related to the information processing device 2 executed by the processor 21, as well as data and the like used when the processor 21 executes processing based on the programs. The storage unit 22 may be an example of a storage medium.

[0018] The communication unit 23 is preferably a wired communication means such as USB, IEEE1394, Thunderbolt (registered trademark), wired LAN network communication, etc., but may also include wireless LAN network communication, mobile communication such as LTE / 3G / 4G / 5G, BLUETOOTH (registered trademark) communication, etc. as needed. In other words, it is more preferable to implement it as a collection of multiple communication means. In other words, the information processing device 2 may communicate various information from the outside via the communication unit 23.

[0019] The input unit 24 may be included in the housing of the information processing device 2 or may be externally attached. For example, the input unit 24 may be implemented as a touch panel integrated with the output unit 25. A touch panel allows a user to input tapping, swiping, and the like. Of course, a switch button, a mouse, a keyboard, and the like may be used instead of a touch panel. That is, the input unit 24 accepts an input based on an operation performed by the user. The input is transferred as a command signal to the processor 21 via a communication bus, and the processor 21 can execute predetermined control or calculation as necessary.

[0020] The output unit 25 can function as a display device of the information processing device 2. The output unit 25 may be included in the housing of the information processing device 2, or may be externally attached. The output unit 25 displays a screen of a graphical user interface (GUI) that can be operated by the user. This is preferably implemented by selectively using display devices such as a CRT display, a liquid crystal display, an organic EL display, and a plasma display depending on the type of the information processing device 2.

[0021] (CT device 3) The CT device 3 is a device capable of irradiating a sample with X-rays and acquiring a projection image of the sample from the amount of transmitted X-rays. The CT device 3 may include, but is not limited to, a sample rotation type CT device that rotates a sample holder 36, a gantry type CT device that rotates an X-ray generator 34 and a detector 35 relative to the sample holder 36, and the like. The CT device 3 includes a processor 31, a storage unit 32, a communication unit 33, the X-ray generator 34, the detector 35, the sample holder 36, and a rotation drive unit 37, and these components are electrically connected via a communication bus within the CT device 3. The CT device 3 executes processing according to the embodiment. For the processor 31, the storage unit 32, and the communication unit 33 of the CT device 3, please refer to the processor 31, the storage unit 22, and the communication unit 23 of the information processing device 2.

[0022] The X-ray generator 34 irradiates X-rays toward an area including a sample placed on the sample holder 36. The X-ray generator 34 may also be configured to irradiate X-rays consisting of characteristic X-rays such as CuKα and FeKα.

[0023] The detector 35 is configured to be able to detect X-rays that have passed through a sample placed in the sample holder 36. The detected X-rays are analyzed as measurement data by the information processing device 2. The measurement data is data obtained by measurement using the CT device 3. The measurement data includes information indicating the angle at which the image was taken and information on the projection image corresponding to that angle. The detector 35 may be a two-dimensional detector that uses a CCD, an imaging plate, or the like.

[0024] The sample holder 36 is configured to be able to hold a sample stage. The sample holder 36 may be configured to be able to move the sample stage in any direction based on a movement instruction generated by the processor 21 or the processor 31. The sample stage is configured to allow a sample to be placed thereon.

[0025] The rotation drive unit 37 is configured to rotate the sample holder 36 and / or the X-ray generator 34 and the detector 35. The rotation drive unit 37 may be configured to include a mechanism capable of adjusting the magnification ratio of the projection image during imaging.

[0026] 2. Functional configuration of the processor 21 of the information processing device 2 2 is a diagram illustrating an example of functional units included in the processor 21. As illustrated in FIG. 2, the processor 21 of the information processing device 2, which is an example of the information processing system 1, includes a data transmission / reception unit 210, a data storage unit 211, a display control unit 212, a condition setting unit 213, a feature acquisition unit 214, a spectral decomposition unit 215, a synchronization processing unit 216, and a reconstruction unit 217. As described above, information processing by software stored in the storage unit 22 is specifically realized by the processor 21, which is an example of hardware, and can be executed as each functional unit (step) included in the processor 21. The processor 21 executes at least a feature acquisition step, a spectral decomposition step, a synchronization processing step, a condition setting step, and a display control step.

[0027] The data transmission / reception unit 210 accepts or acquires various data input from a user via the input unit 24. The data transmission / reception unit 210 transmits various data to the CT device 3 via the communication unit 23. The data transmission / reception unit 210 accepts, receives, or acquires various data from the CT device 3 via the communication unit 23.

[0028] The data storage unit 211 stores the data acquired from the CT device 3 in the storage unit 22 .

[0029] The display control unit 212 is configured to control display information to be displayed on the output unit 25. Note that the display information may be visual information itself, such as a screen, an image, an icon, or text, which is generated in a manner that is visible to the user, or may be rendering information for displaying visual information, such as a screen, an image, an icon, or text, on various terminals.

[0030] The condition setting unit 213 accepts setting of conditions such as ROI, lag value, singular value, and the like.

[0031] The feature amount acquisition unit 214 calculates the feature amount from the projection image.

[0032] The spectral decomposition section 215 applies a predetermined analysis method to the waveform data to obtain decomposed waveform data.

[0033] The synchronization processing unit 216 determines a projection image to be used for reconstruction from the plurality of projection images.

[0034] The reconstruction unit 217 reconstructs an image of the sample from the multiple projection images.

[0035] The data transmitter / receiver 210, data storage unit 211, display control unit 212, condition setting unit 213, feature amount acquisition unit 214, spectral decomposition unit 215, synchronization processing unit 216, and reconstruction unit 217 will be described in detail below.

[0036] 3. Operational flow of information processing system 1 Next, an example of preferred information processing executed by the information processing system 1 of this embodiment will be described. In this section, an example will be described with reference to the activity diagram of FIG. 3, in which measurement data is acquired, waveform data and decomposed waveform data are further acquired from the measurement data, a synchronized projection image is determined from the decomposed waveform data, and an image is reconstructed. In addition, in the following embodiment, singular spectrum analysis is applied as the predetermined analysis method. FIG. 3 is a diagram showing an example of activity executed by the information processing system 1. Note that this activity may include any exception processing not shown. Exception processing includes interrupting the information processing and omitting each process.

[0037] In this embodiment, the plurality of projection images include at least a part of the lungs or heart of a living being as a subject. The living being may include a human being and an animal.

[0038] (Activity A1) First, the data transmitter / receiver 210 receives an instruction (hereinafter referred to as a measurement start instruction) from the user via the input unit 24 to set measurement conditions and to start measurement by the CT device 3. The measurement conditions include, for example, the number of images to be captured, the scan speed, the exposure time, the magnification rate of the captured image, etc.

[0039] (Activity A2) Next, the data transmission / reception unit 210 transmits the measurement conditions and a measurement start instruction to the CT device 3 via the communication unit 23.

[0040] (Activity A3) Next, the processor 31 of the CT device 3 receives the measurement conditions and a measurement start instruction from the information processing device 2 via the communication unit 33.

[0041] (Activity A4) Next, the CT apparatus 3 acquires measurement data based on the received measurement conditions.

[0042] (Activity A5) Next, the processor 31 of the CT device 3 transmits the measurement data to the information processing device 2 via the communication unit 33.

[0043] (Activity A6) Next, the data transmitter / receiver 210 receives the measurement data from the CT device 3 via the communication unit 23.

[0044] (Activity A7) Subsequently, the data storage unit 211 stores the acquired measurement data in the storage unit 22.

[0045] When there is no need to acquire new measurement data (for example, when reconstruction is performed using already acquired measurement data), the information processing system 1 may omit the information processing of activities A1 to A7.

[0046] (Activity A8) Next, the display control unit 212 causes the output unit 25 to display a screen 4 on which the user can view the projected image. Details of the screen 4 will be described later with reference to FIG.

[0047] (Activity A9) Next, the condition setting unit 213 receives an input of the setting of the range of the ROI on the screen 4 via the input unit 24.

[0048] The "ROI (Region of Interest)" refers to a partial region in a projection image from which feature amounts are acquired, and is also referred to as a region of interest. In an embodiment, the ROI is a region that includes at least a part of the lungs and heart of a living organism.

[0049] (Activity A10) Next, the feature acquisition unit 214 acquires waveform data based on the range of the ROI and the projection image that have been received. For example, the feature acquisition unit 214 acquires feature amounts for the range of the input ROI for each of the multiple projection images. The feature acquisition unit 214 acquires waveform data by plotting the feature amount of the ROI for each projection image on the vertical axis and the number of frames indicated by the projection image on the horizontal axis. The display control unit 212 further displays the waveform data on the screen 4.

[0050] The "waveform data" is data expressed as feature quantities obtained from each of a plurality of projection images. In the embodiment, the waveform data is expressed as a waveform as will be described later with reference to FIG.

[0051] The "feature amount" is a value obtained by accumulating the intensity in an image. In this embodiment, the feature amount is a value obtained by accumulating the intensity in an ROI. The feature amount is expressed as x for each of the N projection images, as shown in the following equation 1. The intensity may be, for example, a brightness value, but is not limited to this.

[0052]

number

[0053] (Activity A11) Next, the condition setting unit 213 accepts input of settings for the lag value and singular value selection information from the user via the input unit 24 on the screen 4 where the user can view the waveform data. According to this aspect, it is possible to accept input of settings for the projection image conditions to which the singular spectrum analysis is applied while the user is viewing the projection image, waveform data, etc. Furthermore, it is possible to acquire more appropriate decomposed waveform data from the projection image based on the lag value arbitrarily set by the user.

[0054] The "lag value" is a value used to define the Hankel matrix of singular spectrum analysis from the feature. For example, the number of rows in a Hankel matrix is ​​expressed as L, and the number of columns in a Hankel matrix is ​​expressed as K. L is equal to the lag value, and K is the value obtained by subtracting L and 1 from N, the number of projection images, and can also be expressed as NL-1.

[0055] The "singular value selection information" is information indicating which singular value is to be selected from among the plurality of singular values ​​obtained from the matrix. In this embodiment, the singular value selection information is information indicating which singular value is to be used to obtain decomposed waveform data from among the plurality of singular values ​​obtained from the Hankel matrix.

[0056] (Activity A12) Next, the spectral decomposition unit 215 obtains decomposed waveform data by applying singular spectrum analysis to the feature quantities of the waveform data based on the lag value. More specifically, for example, the spectral decomposition unit 215 applies a Hankel transform based on the feature amount and lag value of Equation 1 to obtain a Hankel matrix shown in Equation 2. The spectral decomposition unit 215 applies singular value decomposition to the obtained Hankel matrix to obtain a plurality of matrices (X1, X2, ..., X r) is obtained. Each matrix is ​​defined as shown in Equation 4 according to the singular value i. The spectral decomposition unit 215 obtains trend waveform data by applying the inverse Hankel transform to a matrix indicated by the maximum singular value (i=1) corresponding to the largest singular value among the singular values ​​obtained by the singular spectrum analysis. The spectral decomposition unit 215 also obtains vibration waveform data by applying the inverse Hankel transform to a matrix indicated by at least one singular value (e.g., i=2, corresponding to a singular value selected by the singular value selection information) selected from the singular values ​​other than the maximum singular value among the singular values ​​obtained by the singular spectrum analysis. According to this aspect, more appropriate decomposed waveform data can be obtained from the projection image based on the set lag value and singular value.

[0057]

number

number

number

[0058] Here, the decomposed waveform data will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining how the decomposed waveform data is obtained from waveform data. As shown in Fig. 4, the waveform data is decomposed into trend components (trend waveform data), vibration components (vibration waveform data), noise components, etc. as decomposed waveform data. There may be one or more vibration waveform data and noise components. The intensities of all the decomposed waveform data are integrated to form the waveform data.

[0059] The "decomposed waveform data" is waveform data obtained by decomposing waveform data. The decomposed waveform data includes at least trend waveform data, vibration waveform data, and noise components.

[0060] "Trend waveform data" refers to waveform data that has been decomposed into components that indicate the trend of the waveform data. Trend waveform data reflects, for example, relatively large movements of the trunk, limbs, etc. of a living organism. Trend waveform data is also referred to as the first component.

[0061] "Vibration waveform data" refers to waveform data that has been decomposed into components that represent the vibration of the waveform data. Vibration waveform data reflects the behavior of periodically moving objects such as the lungs or heart of a living organism. Vibration waveform data is obtained from the second largest singular value and is also called the second component.

[0062] In activities A13 to A16, which will be described next, the synchronization processing unit 216 determines a projection image to be used for reconstruction from a plurality of projection images based on a waveform indicated by at least one of the trend waveform data and the vibration waveform data. In explaining this information processing, a method for determining the expiratory region, inhalation region, exhalation, inhalation, diastole, and systole using the trend waveform data and the vibration waveform data will be described with reference to Figures 5 to 7.

[0063] Fig. 5 is a diagram for explaining a method for determining the expiratory and inhalation regions. Fig. 5 includes vibration waveform data. The vibration waveform data indicates vibration components when the intensity indicated by the trend waveform data is set as the baseline (predetermined value is 0).

[0064] The "exhalation region" is a region that can be considered to correspond to the exhalation of a living organism. In this embodiment, the exhalation region is a region where the vibration intensity indicated by the vibration waveform data is lower than 0. In the example of FIG. 5, the exhalation region is a region where the intensity of the vibration waveform data is lower than 0 (regions where the frame number is around 40 to 70, around 90 to 110, around 150 to 180, etc.).

[0065] An "inhalation region" is a region that can be considered to correspond to the inhalation of a living organism. In this embodiment, the inhalation region is a region where the vibration intensity is higher than 0. In the example of FIG. 5, the inhalation region is a region where the intensity of the vibration waveform data is higher than 0 (regions where the frame number is around 0 to 40, around 70 to 90, around 110 to 150, etc.). Note that either an exhalation region or an inhalation region may be assigned to the location where the intensity is 0.

[0066] Next, a method for determining the expiration and inspiration of the lungs and the diastole and systole of the heart from the expiration and inspiration regions determined by the method of Fig. 5 will be described. Fig. 6 is a diagram for explaining a method for determining the expiration and inspiration of the lungs and the diastole and systole of the heart. In Fig. 6, trend waveform data and vibration waveform data reflecting the expiration and inspiration regions determined by the method of Fig. 5 are superimposed on the waveform data. In Fig. 6, the solid line represents the waveform data, the dashed line represents the trend waveform data, and the dotted line represents data obtained by combining the trend waveform data with the vibration waveform data. Furthermore, the trend waveform data in Fig. 6 shows disturbances in the respiratory beat and heart beat.

[0067] The exhalation is a point where the feature amount is minimum among the points of the waveform data corresponding to a plurality of exhalation regions, for example, the points indicated by the circles in FIG. Inhalation is a point where the feature amount is maximum among the points of waveform data corresponding to a plurality of inhalation regions, and is, for example, a point indicated by a triangle in FIG. The diastole is a point where the feature amount becomes a minimum value in each point of the waveform data corresponding to the expiratory region, and is, for example, a point indicated by a diamond in FIG. The systole is a point where the feature amount reaches a maximum value in each point of the waveform data corresponding to the expiratory region, and is, for example, a point indicated by a square in FIG.

[0068] Next, referring to FIG. 7, a case where the method of Patent Document 1 is applied to the same trend waveform data as in FIG. 6 will be described. FIG. 7 is a diagram showing an example of the results of determining the expiration and inspiration of the lungs and the diastole and systole of the heart using the method of Patent Document 1. In FIG. 7, as in FIG. 6, circles represent expiration, triangles represent inspiration, diamonds represent diastole, and squares represent systole. Compared to the present disclosure, the method of Patent Document 1 does not properly determine the expiration and inspiration of the lungs, and only a small amount of diastole and systole data can be obtained. Therefore, according to the present disclosure, even if the respiratory rate or cardiac cycle changes during measurement, it is possible to more appropriately determine the phase (exhalation, inspiration, diastole, systole, etc.).

[0069] (Activity A13) The synchronization processing unit 216 determines, from the vibrations indicated by the decomposed waveform data, a region where the intensity is lower than a predetermined value as an exhalation region. At each point in the waveform data corresponding to the multiple exhalation regions determined from the decomposed waveform data, the synchronization processing unit 216 determines each projection image with the smallest feature amount as a projection image corresponding to the exhalation of the living organism, and uses the projection image as a projection image to be used for reconstructing the exhalation of the lungs.

[0070] (Activity A14) Next, the synchronization processor 216 determines, from the vibrations indicated by the decomposed waveform data, a region where the intensity is higher than a predetermined value as an inhalation region. At each point of the waveform data corresponding to the multiple inhalation regions determined from the decomposed waveform data, the synchronization processor 216 determines each projection image where the feature amount is maximum as a projection image corresponding to the inhalation of the living organism, and sets the projection image as a projection image to be used for reconstructing the inhalation of the lungs.

[0071] (Activity A15) Next, the synchronization processing unit 216 determines the projection image in which the feature amount reaches a maximum value at a position corresponding to the expiratory region of the waveform data as the projection image corresponding to the systole of the heart. From the projection images corresponding to the determined systole, the synchronization processing unit 216 determines the projection image to be used for reconstructing the systole of the heart.

[0072] (Activity A16) Next, the synchronization processing unit 216 determines the projection image in which the feature amount is at a minimum value at a location corresponding to the expiration region of the waveform data as the projection image corresponding to the diastole of the heart. The synchronization processing unit 216 determines the projection image to be used for reconstructing the diastole of the heart from the determined projection images corresponding to the diastole. Note that the location corresponding to the expiration region is a location where the intensity of the vibration waveform data is smaller than the intensity of the trend waveform data, with the intensity of the trend waveform data being used as a reference.

[0073] When the information processing of activities A13 to A16 is completed, the display control unit 212 may display the decomposed waveform data divided into areas shown in Figure 5 and the waveform data with markers shown in Figure 6 in the waveform display area 41 described later.

[0074] If there is no need to synchronize inhalation and exhalation, the information processing system 1 may perform only the determination process in the processes of activities A13 and A14 and omit the remaining processes.If there is no need to synchronize systole and diastole, the information processing system 1 may omit the processes of activities A15 and A16.

[0075] Activities A13 to A16 allow for more appropriate determination of projection images used for reconstructing the lungs and heart from trend waveform data and vibration waveform data obtained by singular spectrum analysis. Furthermore, even when factors such as noise and vibration occur, clearer images can be reconstructed from the projection images.

[0076] In response to instructions from the user who has confirmed the synchronization results, the information processing system 1 may proceed to information processing regarding input of ROI range settings (activity A9), input of lag value and singular value selection information settings (activity A11), and acquisition and synchronization of decomposed waveform data (activity A12).

[0077] (Activity A17) Finally, the reconstruction unit 217 outputs images (hereinafter referred to as reconstructed images) reconstructed using a plurality of synchronized projection images for each of the exhalation, inhalation, systole, and diastole of the living organism.

[0078] The above is a description of the activities of this embodiment. Next, we will explain screen 4, which has been shown in FIG. 8 but whose detailed description has been omitted.

[0079] (Screen 4) 8 is a diagram showing an example of screen 4. Screen 4 is a screen on which information related to measurement data is displayed in a manner that is visible to the user. Screen 4 includes a projection image display area 40, a waveform display area 41, a condition reception area 42, a read button 43, a synchronization execution button 44, and a reconstruction execution button 45.

[0080] The projection image display area 40 is an area where the acquired projection image is displayed. To set the ROI, an X-axis and a Y-axis may be defined for the projection image in the projection image display area 40. The projection image display area 40 includes an ROI setting area 400. The ROI setting area 400 displays an area showing the ROI in the projection image. The range of the ROI may be set by any operation, such as a drag-and-drop operation into the ROI setting area 400, a range change operation using a cursor in the ROI setting area 400, or inputting a numerical value into a condition receiving area 42 (described later). The condition setting unit 213 sets the range of the ROI as activity A9 in FIG. 3.

[0081] The waveform display area 41 is an area where waveform data and / or resolved waveform data are displayed. More specifically, for example, the waveform display area 41 may be an area where waveform data is displayed before trend waveform data is acquired, and where the waveform data and trend waveform data are displayed superimposed on each other after the trend waveform data is acquired. Furthermore, the waveform display area 41 may be an area where at least two of the waveform data, trend waveform data, and vibration waveform data are displayed side by side so as to be comparable.

[0082] The condition receiving area 42 is an area for receiving input of settings related to singular spectrum analysis of waveform data. The condition receiving area 42 includes an ROI setting area 420, a lag setting area 421, and a singular value setting area 422.

[0083] The ROI setting area 420 is configured to allow the setting of an ROI as the range for acquiring waveform data from the projection image, and may be configured to allow the setting of an ROI by specifying coordinates along the X-axis and Y-axis defined in the projection image display area 40, for example, as shown in FIG. 8.

[0084] The lag setting area 421 is configured so that a lag value for defining a matrix for singular spectrum analysis can be set, and is configured so that, for example, "100" can be input as the lag value as shown in FIG.

[0085] The singular value setting area 422 is configured to allow setting of which vibration component singular value to use to acquire vibration waveform data, and is an area in which check boxes are displayed to determine which vibration component singular value to use in descending order of the singular value associated with the vibration component (1, 2, 3, etc.), as shown in FIG. 8, for example.

[0086] The read button 43 is a button for reading measurement data and displaying a projection image in the projection image display area 40. For example, in response to pressing of the read button 43, the display control unit 212 executes activity A8 in FIG.

[0087] The synchronization execution button 44 is a button for executing synchronization processing. In response to pressing of the synchronization execution button 44, for example, the spectral decomposition unit 215 starts activity A12 in Fig. 3, and then the synchronization processing unit 216 executes activities A12 to A16 in Fig. 3.

[0088] The reconstruction execution button 45 is a button for executing reconstruction using synchronized projection images. For example, in response to pressing of the reconstruction execution button 45, the reconstruction unit 217 executes activity A17 in FIG.

[0089] 4. Working Example Next, examples of changes in reconstructed images before and after applying synchronization according to the present disclosure will be described with reference to Figures 9 to 14. The subjects in the examples are the lungs and heart of a mouse.

[0090] FIG. 9 is a diagram showing a reconstructed image of the lungs when synchronization is not performed. FIG. 10 is a diagram showing a reconstructed image of the lungs when exhalation of the lungs is synchronized using the same ROI as in FIG. 9. FIG. 11 is a diagram showing a reconstructed image of the lungs when inhalation of the lungs is synchronized using the same ROI as in FIG. 9. In the reconstructed image before correction, the boundary between the lungs and space cannot be clearly recognized, particularly in the areas indicated by the arrows in FIG. 9 (heart, diaphragm, bone), and the contours of the lungs are blurred, resulting in blurred reconstructed images. On the other hand, as shown in FIGS. 10 and 11, in the reconstructed image after correction, the boundary between the lungs and space can be more clearly recognized in the areas indicated by the same arrows as in FIG. 9, and the reconstructed image is clearer.

[0091] FIG. 12 is a diagram showing a reconstructed image of the heart when synchronization is not performed. FIG. 13 is a diagram showing a reconstructed image of the heart when the diastole of the heart is synchronized using the same ROI as in FIG. 12. FIG. 14 is a diagram showing a reconstructed image of the heart when the systole of the heart is synchronized using the same ROI as in FIG. 12. In the reconstructed image before correction, for example, in the area surrounded by a frame in FIG. 12, the boundary between the heart and space is not clearly recognizable, the outline of the heart is blurred, and the reconstructed image is blurred. On the other hand, as shown in FIGS. 13 and 14, in the reconstructed image after correction, the boundary between the heart and space is relatively easy to recognize in the same area as in FIG. 12.

[0092] According to the present disclosure, it is possible to reconstruct an image or to assist in the reconstruction process without assuming a fixed periodicity in the movement of a subject.

[0093] [others] The program is a program that causes one or more computers to execute each function unit (step), or may be an information processing method executed by the information processing system 1 (or the processor 21 of the information processing device 2).

[0094] In the embodiment, the lag value is described as being input by the user. However, in a modified example, an optimal value may be automatically calculated and used. That is, the spectral decomposition unit 215 calculates the period of the frequency containing the maximum peak by applying frequency analysis to the waveform data. The spectral decomposition unit 215 acquires, as a lag value setting, a value representing the number of data items that at least contain the calculated period. According to this aspect, more appropriate decomposed waveform data can be acquired from the projection image based on the lag value set by calculation. Furthermore, because a reasonable lag value can be set by calculation, the user does not have to go through the trouble of searching for a lag value.

[0095] In the embodiment, the subject of the projection image has been described as being the lungs or heart of a living organism, but in modified examples, other moving objects may be included as the subject. For example, in modified examples, the subject of the projection image may include parts of a living organism such as the head or abdomen of a living organism, artificial lungs and hearts, or industrial objects such as operating mechanical parts (e.g., operational tests of mechanical parts such as gears and bearings), fluids (e.g., observation of fluid dynamics within a container), etc.

[0096] In the embodiment, the predetermined analysis method is singular spectrum analysis, and the singular spectrum analysis is an example in which singular value decomposition is applied to a Hankel matrix. In a modified example, the predetermined analysis method may be any method that can acquire decomposed waveform data from waveform data, and may be singular spectrum analysis using a Toeplitz matrix or other methods.

[0097] The present disclosure may be applied under conditions in which the beat cycle of an organism changes during measurement, for example, when photographing an organism on a heated bed, and may be applied under conditions in which the timing at which anesthesia begins to take effect on the organism, the timing at which anesthesia begins to wear off, etc.

[0098] Furthermore, it may be provided in the following manner.

[0099] (1) An information processing system for processing multiple projection images captured by a CT device, comprising a feature acquisition unit, a spectral decomposition unit, and a synchronization processing unit, wherein the feature acquisition unit acquires waveform data, the waveform data being data indicated as features obtained from each of the multiple projection images, the spectral decomposition unit acquires decomposed waveform data by applying a predetermined analysis method to the waveform data, the decomposed waveform data being waveform data obtained by decomposing the waveform data, and the synchronization processing unit determines a projection image to be used for reconstruction from the multiple projection images based on the waveform indicated by the decomposed waveform data.

[0100] According to this aspect, even if factors such as noise and vibration occur, a clearer image can be reconstructed from the projected image.

[0101] (2) The information processing system according to (1) above, further comprising a condition setting unit, wherein the analysis method is singular spectrum analysis, the condition setting unit accepts settings of a lag value and singular value selection information, the lag value being a value for defining a matrix for the singular spectrum analysis from the feature quantity, the singular value selection information being information indicating which singular value is to be selected from a plurality of singular values ​​obtained from the matrix, and the spectral decomposition unit applies the singular spectrum analysis to the waveform data based on the lag value, and obtains the decomposed waveform data corresponding to the singular value selected by the singular value selection information.

[0102] According to this aspect, more appropriate decomposed waveform data can be acquired from the projection image based on the set lag value and singular value.

[0103] (3) In the information processing system described in (2) above, the spectral decomposition unit accepts the setting of the lag value from the user on a screen on which the user can view the waveform data.

[0104] According to this aspect, more appropriate resolved waveform data can be acquired from the projection image based on the lag value arbitrarily set by the user.

[0105] (4) In the information processing system described in (2) above, the spectral decomposition unit calculates the period of the frequency including the maximum peak by applying frequency analysis to the waveform data, and obtains the value of the number of data items that at least include the calculated period as the setting of the lag value.

[0106] According to this aspect, it is possible to acquire more appropriate resolved waveform data from the projection image based on the lag value set by calculation. Furthermore, since a reasonable lag value can be set by calculation, it is possible to save the user the trouble of searching for a lag value.

[0107] (5) In the information processing system described in any one of (1) to (4) above, the analysis method is singular spectrum analysis, the decomposed waveform data includes trend waveform data and vibration waveform data, the trend waveform data is waveform data decomposed into components indicating a trend of the waveform data, and the vibration waveform data is waveform data decomposed into components indicating vibration of the waveform data, the spectral decomposition unit acquires the trend waveform data from a maximum singular value corresponding to the largest singular value among the singular values ​​obtained by the singular spectrum analysis, and acquires the vibration waveform data from at least one singular value selected from the singular values ​​obtained by the singular spectrum analysis other than the maximum singular value, and the synchronization processing unit determines a projection image to be used for reconstruction based on the waveform indicated by at least one of the trend waveform data and the vibration waveform data.

[0108] According to this aspect, it is possible to more appropriately determine the image to be used for reconstruction from the trend waveform data and vibration waveform data obtained by the singular spectrum analysis.

[0109] (6) In the information processing system described in any one of (1) to (5) above, the plurality of projection images include at least a portion of the lungs of the living organism as a subject, the decomposed waveform data includes waveform data as components of vibrations indicated by the waveform data, the synchronization processing unit determines an exhalation region and an inhalation region from the vibrations indicated by the decomposed waveform data, the exhalation region being a region where the vibration intensity is lower than a predetermined value, and the inhalation region being a region where the vibration intensity is higher than the predetermined value, determines a projection image in which the feature amount is smallest at a portion of the waveform data corresponding to the exhalation region as a projection image corresponding to the exhalation of the living organism, and determines a projection image in which the feature amount is largest at a portion of the waveform data corresponding to the inhalation region as a projection image corresponding to the inhalation of the living organism, and determines a projection image to be used for reconstructing the lungs from the determined projection images corresponding to the exhalation and the inhalation, respectively.

[0110] According to this aspect, the projection image to be used for reconstructing the lungs can be more appropriately determined from the vibration components indicated by the decomposed waveform data.

[0111] (7) In the information processing system described in (6) above, the plurality of projection images include at least a part of the heart of the living organism as a subject, and the synchronization processing unit determines a projection image in which a feature value is at a maximum value in a portion of the waveform data corresponding to the exhalation region as a projection image corresponding to the systole of the heart, and determines a projection image in which a feature value is at a minimum value in a portion of the waveform data corresponding to the exhalation region as a projection image corresponding to the diastole of the heart, and determines a projection image to be used for reconstructing the heart from the determined projection images corresponding to the systole and the diastole.

[0112] According to this aspect, it is possible to more appropriately determine the projection image to be used for reconstructing the heart from the vibration components indicated by the decomposed waveform data.

[0113] (8) An information processing system for processing a plurality of images captured by a CT device, comprising: a feature acquisition unit; and a display control unit; the feature acquisition unit acquires waveform data, the waveform data being data indicated as features obtained from each of the plurality of projection images; the display control unit displays a screen including a waveform display area and a condition acceptance area; the waveform display area is an area where the waveform data and decomposed waveform data are displayed superimposed; the decomposed waveform data is waveform data obtained by applying singular spectrum analysis to the waveform data; and the condition acceptance area is an area for accepting input of settings related to the singular spectrum analysis for the waveform data.

[0114] According to this aspect, it is possible to accept input of settings for the conditions of the singular spectrum analysis while the user is visually checking the waveform data and the decomposed waveform data.

[0115] (9) In the information processing system described in (8) above, the screen further displays a projection image display area, the projection image display area is an area in which the acquired projection image is displayed, and the condition reception area is configured to be able to receive settings for the range in which the waveform data is acquired from the projection image.

[0116] According to this aspect, it is possible to accept input of settings for the projection image to which the singular spectrum analysis is applied while the user is visually checking the projection image.

[0117] (10) An information processing device for processing multiple projection images captured by a CT device, comprising a feature acquisition unit, a spectral decomposition unit, and a synchronization processing unit, wherein the feature acquisition unit acquires waveform data, the waveform data being data indicated as features obtained from each of the multiple projection images, the spectral decomposition unit acquires decomposed waveform data by applying a predetermined analysis method to the waveform data, the decomposed waveform data being waveform data obtained by decomposing the waveform data, and the synchronization processing unit determines a projection image to be used for reconstruction from the multiple projection images based on the waveform indicated by the decomposed waveform data.

[0118] (11) An information processing method for processing multiple projection images captured by a CT device, wherein a feature acquisition unit acquires waveform data, the waveform data being data indicated as features obtained from each of the multiple projection images; a spectral decomposition unit acquires decomposed waveform data by applying a predetermined analysis method to the waveform data, the decomposed waveform data being data of a waveform obtained by decomposing the waveform data; and a synchronization processing unit determines a projection image to be used for reconstruction from the multiple projection images based on the waveform indicated by the decomposed waveform data.

[0119] (12) A program that causes the information processing system according to any one of (1) to (9) above to function as the one or more processors. Of course, this is not the case.

[0120] Finally, while various embodiments of the present invention have been described, they are presented by way of example only and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the accompanying claims. [Explanation of symbols]

[0121] 1: Information processing system 2: Information processing equipment 21: Processor 210: Data transmission / reception unit 211: Data storage unit 212: Display control unit 213: Condition setting section 214: Feature acquisition unit 215: Spectral decomposition unit 216: Synchronization processing section 217:Reconstruction part 22: Storage section 23: Communications Department 24: Input section 25: Output section 3:CT device 31: Processor 32: Storage section 33: Communications Department 34: X-ray generator 35: Detector 36: Sample holder 37: Rotation drive unit 4: Screen 40: Projected image display area 400 :ROI setting area 41: Waveform display area 42: Condition acceptance area 420 :ROI setting area 421: Lag setting area 422: Singular value setting area 43: Load button 44: Synchronization execution button 45: Reconfigure execution button

Claims

1. An information processing system for processing a plurality of projection images captured by a CT device, comprising: The apparatus includes a feature acquisition unit, a spectral decomposition unit, and a synchronization processing unit, the feature amount acquiring unit acquires waveform data, the waveform data being data indicated as feature amounts obtained from each of the plurality of projection images; the spectral decomposition unit applies a predetermined analysis method to the waveform data to obtain decomposed waveform data, the decomposed waveform data being waveform data obtained by decomposing the waveform data; the synchronization processing unit determines a projection image to be used for reconstruction from the plurality of projection images based on the waveform indicated by the decomposed waveform data. Information processing system.

2. 2. The information processing system according to claim 1, A condition setting unit is provided, the analysis method is singular spectrum analysis, the condition setting unit receives settings of a lag value and singular value selection information, the lag value being a value for defining a matrix for the singular spectrum analysis from the feature quantity, and the singular value selection information being information indicating which singular value is to be selected from a plurality of singular values ​​acquired from the matrix; the spectral decomposition unit applies the singular spectrum analysis to the waveform data based on the lag value, and acquires the decomposed waveform data corresponding to the singular value selected by the singular value selection information. Information processing system.

3. 3. The information processing system according to claim 2, The spectral decomposition unit accepting a setting of the lag value from the user on a screen on which the user can view the waveform data; Information processing system.

4. 3. The information processing system according to claim 2, The spectral decomposition unit applying frequency analysis to the waveform data to calculate a frequency period including a maximum peak; The information processing system acquires the value of the number of data items that includes at least the calculated period as the setting of the lag value.

5. 2. The information processing system according to claim 1, the analysis method is singular spectrum analysis, the resolved waveform data includes trend waveform data and vibration waveform data, the trend waveform data is waveform data decomposed into components indicating a trend of the waveform data, the vibration waveform data is waveform data decomposed into components indicating vibration of the waveform data, The spectral decomposition unit obtaining the trend waveform data from a maximum singular value corresponding to the largest singular value among the singular values ​​obtained by the singular spectrum analysis; acquiring the vibration waveform data from at least one singular value selected from singular values ​​other than the maximum singular value among the singular values ​​obtained by the singular spectrum analysis; the synchronization processing unit determines a projection image to be used for reconstruction based on the waveform indicated by at least one of the trend waveform data and the vibration waveform data. Information processing system.

6. 2. The information processing system according to claim 1, the plurality of projection images include at least a portion of a lung of the living organism as a subject; the resolved waveform data includes waveform data as vibration components represented by the waveform data, The synchronization processing unit determining an exhalation region and an inhalation region from the vibrations indicated by the decomposed waveform data, the exhalation region being a region where the vibration intensity is lower than a predetermined value, and the inhalation region being a region where the vibration intensity is higher than the predetermined value; determining a projection image in which the feature amount is minimum at a portion of the waveform data corresponding to the exhalation region as a projection image corresponding to the exhalation of the living organism; determining a projection image in which the feature amount is maximum at a portion of the waveform data corresponding to the inhalation region as a projection image corresponding to the inhalation of the living organism; determining a projection image to be used for reconstructing the lungs from the determined projection images corresponding to each of the expiration and the inspiration; Information processing system.

7. 7. The information processing system according to claim 6, the plurality of projection images include at least a part of the heart of the living organism as a subject; The synchronization processing unit determining a projection image in which a feature amount has a maximum value in a portion of the waveform data corresponding to the expiratory region as a projection image corresponding to a systole of the heart; determining a projection image in which a feature amount has a minimum value in a portion of the waveform data corresponding to the expiratory region as a projection image corresponding to a diastole of the heart; determining a projection image to be used for reconstructing the heart from the determined projection images corresponding to the systole and the diastole, respectively; Information processing system.

8. An information processing system for processing a plurality of images taken by a CT device, A feature acquisition unit and a display control unit are provided, the feature amount acquiring unit acquires waveform data, the waveform data being data indicated as feature amounts obtained from each of the plurality of projection images; the display control unit displays a screen including a waveform display area and a condition receiving area; the waveform display area is an area in which the waveform data and decomposed waveform data are displayed in a superimposed manner, and the decomposed waveform data is waveform data obtained by applying singular spectrum analysis to the waveform data; the condition receiving area is an area for receiving input of settings related to singular spectrum analysis of the waveform data; Information processing system.

9. 9. The information processing system according to claim 8, the screen further displays a projection image display area, the projection image display area being an area where the acquired projection image is displayed; the condition receiving area is configured to be able to receive setting of a range for acquiring the waveform data from the projection image. Information processing system.

10. An information processing device for processing a plurality of projection images captured by a CT device, The apparatus includes a feature acquisition unit, a spectral decomposition unit, and a synchronization processing unit, the feature amount acquiring unit acquires waveform data, the waveform data being data indicated as feature amounts obtained from each of the plurality of projection images; the spectral decomposition unit applies a predetermined analysis method to the waveform data to obtain decomposed waveform data, the decomposed waveform data being waveform data obtained by decomposing the waveform data; the synchronization processing unit determines a projection image to be used for reconstruction from the plurality of projection images based on the waveform indicated by the decomposed waveform data. Information processing device.

11. An information processing method for processing a plurality of projection images captured by a CT device, comprising: a feature amount acquiring unit acquires waveform data, the waveform data being data indicated as feature amounts obtained from each of the plurality of projection images; a spectral decomposition unit applies a predetermined analysis method to the waveform data to obtain decomposed waveform data, the decomposed waveform data being waveform data obtained by decomposing the waveform data; a synchronization processing unit determining a projection image to be used for reconstruction from the plurality of projection images based on the waveform indicated by the decomposed waveform data; Information processing methods.

12. A program, The information processing system according to any one of claims 1 to 9 functions as the one or more processors. program.

Images