JP2023018233A - Image processing system, image processing method, and program - Google Patents

Abstract

To improve user convenience.SOLUTION: An image processing system includes an imaging unit and a determination unit. The imaging unit captures an optical image of a subject on the basis of a timing at which an instruction for light projection is given to a projector that projects light to a subject placed on a top plate. The determination unit determines a deviation amount of the subject from a first optical image of the subject captured by the imaging unit at first time and a second optical image of the subject captured by the imaging unit at second time.SELECTED DRAWING: Figure 1

Description

The embodiments disclosed in the specification and drawings relate to an image processing system, an image processing method, and a program.

2. Description of the Related Art In imaging by a medical image diagnostic apparatus, it is desirable to be able to perform imaging at the same cross section in order to observe the progress of an examination site before, for example, after surgery.

However, if the imaging section position is visually set to be the same as that of the previous imaging, an error occurs in the imaging section position and is troublesome for the user.

JP 2009-273597 A

One of the problems to be solved by the embodiments disclosed in this specification and drawings is to improve user convenience. However, the problems to be solved by the embodiments disclosed in this specification and drawings are not limited to the above problems. A problem corresponding to each effect of each configuration shown in the embodiments described later can be positioned as another problem.

An image processing system according to an embodiment includes an imaging unit and a determination unit. The imaging unit captures an optical image of the subject placed on the top plate based on the timing at which a light projection instruction is given to a light projector that projects light onto the subject. The determination unit determines the image of the subject from a first optical image of the subject captured by the imaging unit at a first time and a second optical image of the subject captured by the imaging unit at a second time. Determine the amount of deviation.

FIG. 1 is a diagram illustrating an example of the configuration of an image processing system according to an embodiment. FIG. 2 is a diagram explaining a projector and an imaging unit according to the embodiment. FIG. 3 is a flowchart describing the flow of processing performed by the image processing system according to the embodiment.

(embodiment)
Hereinafter, embodiments of an image processing system, an image processing method, and a program will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of an image processing system according to an embodiment, in which the image processing system is incorporated as part of a magnetic resonance imaging apparatus 100. As shown in FIG. However, the embodiment is not limited to the case where the image processing system is incorporated in the magnetic resonance imaging apparatus 100, and the image processing system may be configured independently from the magnetic resonance imaging apparatus 100. Also, the image processing system may be incorporated in a modality device other than the magnetic resonance imaging device 100, such as an X-ray CT device, an ultrasonic diagnostic device, or the like.

In FIG. 1, for example, the projector 10 and the camera 11 may be incorporated as part of the magnetic resonance imaging apparatus 100, or may be configured independently of the magnetic resonance imaging apparatus 100. FIG. The projector 10, the camera 11, and the image processing device 130 constitute, for example, an image processing system according to the embodiment.

As shown in FIG. 1, the magnetic resonance imaging apparatus 100 includes a static magnetic field magnet 101, a static magnetic field power supply (not shown), a gradient magnetic field coil 103, a gradient magnetic field power supply 104, a bed 105, and a bed control circuit 106. , a transmission coil 107 , a transmission circuit 108 , a reception coil 109 , a reception circuit 110 , a sequence control circuit 120 (sequence control unit), an image processing device 130 , a light projector 10 , and a camera 11 .

Note that the magnetic resonance imaging apparatus 100 does not include the subject P (eg, human body). Also, the configuration shown in FIG. 1 is merely an example. For example, each unit in the sequence control circuit 120 and the image processing device 130 may be configured by being integrated or separated as appropriate.

Moreover, as described above, the projector 10 and the camera 11 may be part of the magnetic resonance imaging apparatus 100 or may be configured independently of the magnetic resonance imaging apparatus 1100 .

The static magnetic field magnet 101 is a magnet formed in a hollow, substantially cylindrical shape, and generates a static magnetic field in the central axis (Z-axis) direction in the space inside the cylinder. The static magnetic field magnet 101 is, for example, a superconducting magnet or the like, and is excited by receiving current supply from a static magnetic field power supply. The static magnetic field power supply supplies current to the static magnetic field magnet 101 . As another example, the static magnetic field magnet 101 may be a permanent magnet, in which case the magnetic resonance imaging apparatus 100 does not need to have a static magnetic field power supply. Also, the static magnetic field power supply may be provided separately from the magnetic resonance imaging apparatus 100 .

The gradient magnetic field coil 103 is a coil formed in a hollow, substantially cylindrical shape, and is arranged inside the static magnetic field magnet 101 . The gradient magnetic field coil 103 is formed by combining three coils corresponding to the X, Y, and Z axes that are orthogonal to each other, and these three coils are individually supplied with current from the gradient magnetic field power supply 104. In response, a gradient magnetic field is generated along each of the X, Y, and Z axes in which the magnetic field strength in the Z direction changes according to the distance from the center of each axis. The gradient magnetic fields of the X, Y, and Z axes generated by the gradient magnetic field coil 103 are, for example, a slicing gradient magnetic field Gs, a phase encoding gradient magnetic field Ge, and a readout gradient magnetic field Gr. A gradient magnetic field power supply 104 supplies current to the gradient magnetic field coil 103 .

The bed 105 has a table 105a on which the subject P is placed. (imaging opening). The bed 105 is usually installed so that its longitudinal direction is parallel to the central axis of the static magnetic field magnet 101 . The bed control circuit 106 drives the bed 105 under the control of the image processing device 130 to move the top board 105a in the longitudinal direction and the vertical direction.

The transmission coil 107 is arranged inside the gradient magnetic field coil 103, receives supply of RF (Radio Frequency) pulses from the transmission circuit 108, and generates a high frequency magnetic field. The transmission circuit 108 supplies the transmission coil 107 with an RF pulse corresponding to a Larmor frequency determined by the type of target atom and the magnetic field strength.

The receiving coil 109 is arranged inside the gradient magnetic field coil 103 and receives magnetic resonance signals (hereinafter referred to as "MR signals" as necessary) emitted from the subject P under the influence of the high-frequency magnetic field. Upon receiving the magnetic resonance signal, the reception coil 109 outputs the received magnetic resonance signal to the reception circuit 110 .

Note that the transmission coil 107 and the reception coil 109 described above are merely examples. It may be configured by combining one or a plurality of coils having only a transmitting function, coils having only a receiving function, and coils having a transmitting/receiving function.

The receiving circuit 110 detects magnetic resonance signals output from the receiving coil 109 and generates magnetic resonance data based on the detected magnetic resonance signals. Specifically, the receiving circuit 110 generates magnetic resonance data by digitally converting the magnetic resonance signal output from the receiving coil 109 . The receiving circuit 110 also transmits the generated magnetic resonance data to the sequence control circuit 120 . Note that the receiving circuit 110 may be provided on the side of the gantry device including the static magnetic field magnet 101, the gradient magnetic field coil 103, and the like.

The sequence control circuit 120 images the subject P by driving the gradient magnetic field power supply 104 , the transmission circuit 108 and the reception circuit 110 based on the sequence information transmitted from the image processing device 130 . Here, the sequence information is information that defines the procedure for imaging. The sequence information includes the strength of the current supplied to the gradient magnetic field coil 103 by the gradient magnetic field power supply 104 and the timing of supplying the current, the strength of the RF pulse supplied to the transmission coil 107 by the transmission circuit 108, the timing of applying the RF pulse, and the timing of applying the RF pulse. The timing and the like for the circuit 110 to detect magnetic resonance signals are defined. For example, the sequence control circuit 120 is an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or an electronic circuit such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit). Details of the pulse sequence executed by the sequence control circuit 120 will be described later.

Furthermore, when the sequence control circuit 120 receives magnetic resonance data from the receiving circuit 110 as a result of imaging the subject P by driving the gradient magnetic field power supply 104, the transmitting circuit 108, and the receiving circuit 110, the received magnetic resonance data is imaged. Transfer to processor 130 . The image processing apparatus 130 performs overall control of the magnetic resonance imaging apparatus 100, image generation, and the like. Image processing device 130 includes memory 132 , input device 134 , display 135 and processing circuitry 150 . The processing circuit 150 comprises an interface function 131 , a control function 133 and a generation function 136 .

In the embodiment, each processing function performed by the interface function 131, the control function 133, the generation function 136, the determination function 137, and the acquisition function 138 is stored in the memory 132 as a storage unit in the form of a computer-executable program. ing. The processing circuit 150 is a processor that reads a program from the memory 132 and executes it to realize a function corresponding to each program. In other words, the processing circuit 150 with each program read has each function shown in the processing circuit 150 of FIG. In FIG. 1, the processing functions performed by the interface function 131, the control function 133, the generation function 136, the determination function 137, and the acquisition function 138 are realized by the single processing circuit 150. A plurality of independent processors may be combined to form the processing circuit 150, and each processor may implement a function by executing a program. In other words, each function described above may be configured as a program, and one processing circuit 150 may execute each program. As another example, certain functions may be implemented in dedicated, separate program execution circuitry. Note that in FIG. 1, the interface function 131, the control function 133, the generation function 136, the determination function 137, and the acquisition function 138 are examples of a reception unit, a control unit, a generation unit, a determination unit, and an acquisition unit, respectively. Also, the sequence control circuit 120 is an example of a sequence control unit. Specific processing of the generation function 136, determination function 137, and acquisition function 138 will be described later.

The term "processor" used in the above description includes, for example, a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), an Application Specific Integrated Circuit (ASIC), a programmable logic device (for example, a simple Circuits such as a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA). The processor implements its functions by reading and executing programs stored in the memory 132 .

Also, instead of storing the program in the memory 132, the program may be configured to be directly embedded in the circuitry of the processor. In this case, the processor implements its functions by reading and executing the program embedded in the circuit. Similarly, the bed control circuit 106, the transmission circuit 108, the reception circuit 110, and the like are also composed of electronic circuits such as the above processor.

The processing circuit 150 transmits sequence information to the sequence control circuit 120 and receives magnetic resonance data from the sequence control circuit 120 through the interface function 131 . Also, upon receiving the magnetic resonance data, the processing circuit 150 having the interface function 131 stores the received magnetic resonance data in the memory 132 .

The magnetic resonance data stored in memory 132 are arranged in k-space by control function 133 . As a result, memory 132 stores k-space data.

The memory 132 stores the magnetic resonance data received by the processing circuit 150 having the interface function 131, the k-space data arranged in k-space by the processing circuit 150 having the control function 133, and the k-space data generated by the processing circuit 150 having the generation function 136. The image data and the like that have been processed are stored. For example, the memory 132 is a RAM (Random Access Memory), a semiconductor memory device such as a flash memory, a hard disk, an optical disk, or the like.

The input device 134 receives various instructions and information input from the operator. The input device 134 is, for example, a pointing device such as a mouse or a trackball, a selection device such as a mode switch, or an input device such as a keyboard. The display 135 displays a GUI (Graphical User Interface) for accepting input of imaging conditions, an image generated by the processing circuit 150 having a generation function 136, and the like, under the control of the processing circuit 150 having a control function 133. . The display 135 is, for example, a display device such as a liquid crystal display.

The processing circuit 150 performs overall control of the magnetic resonance imaging apparatus 100 by the control function 133, and controls imaging, image generation, image display, and the like. For example, the processing circuit 150 having the control function 133 receives input of imaging conditions (imaging parameters, etc.) on the GUI, and generates sequence information according to the received imaging conditions. Also, the processing circuit 150 having the control function 133 transmits the generated sequence information to the sequence control circuit 120 .

The processing circuit 150 uses the generation function 136 to read the k-space data from the memory 132 and perform reconstruction processing such as Fourier transform on the read k-space data to generate an image.

Next, the projector 10 and camera 11 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a diagram illustrating the arrangement of the projector 10 and the camera 11 according to the embodiment.

The light projector 10 is a light projector that projects light onto the subject P placed on the top plate 105a. For example, as shown in FIG. 2, the light projected by the light projector 10 allows the user to perceive the location 12 of the magnetic field center of the magnetic resonance imaging 100 . The projector 10 is typically installed near the entrance of the bore of the magnetic resonance imaging apparatus 100 .

Also, the camera 11 is a camera for acquiring an optical image of the subject P. FIG. The camera 11 may be set, for example, near the projector 10, or may be set on the ceiling of the shield room in which the magnetic resonance imaging apparatus 100 is installed. The camera 11 can acquire an optical image of the whole body of the subject P, for example.

Next, the background of the embodiment will be described.

2. Description of the Related Art In imaging by a medical image diagnostic apparatus, it is desirable to be able to perform imaging at the same cross section in order to observe the progress of an examination site before, for example, after surgery.

However, if the magnetic resonance imaging apparatus is set so that, for example, the imaging cross-sectional position is the same as that of the previous imaging, an error occurs in the imaging cross-sectional position and is troublesome for the user.

Based on the background described above, the image processing system according to the embodiment is provided with the projector 10 and the camera 11, captures the first optical image of the subject P when the button of the projector 10 is pressed, and is stored in the memory 132 as photographing information. In the second and subsequent imaging, the processing circuit 150 uses the determination function 137 to correct the displacement of the subject P based on the second optical image and the first optical image captured by the camera 11 . As a result, the imaging plan can be set so that imaging can be performed in the same cross section as that previously imaged.

The above processing will be described in detail with reference to FIG. FIG. 3 is a flowchart describing the flow of processing performed by the image processing system according to the embodiment. In the flowchart of FIG. 3, the solid line indicates the flow of processing, and the dotted line indicates the flow of data.

First, in step S100, when the user presses the button of the light projector 10, as shown in FIG. This indicates the position 12 of the magnetic field center of the magnetic resonance imaging apparatus 100 . Further, in conjunction with the light projection of the light projector 10, the camera 11 as an imaging unit captures an optical image of the subject P in the imaging region 13 based on the timing at which the light projection instruction is given to the light projector 10. do. The camera 11 as a photographing unit stores the photographed first optical image as photograph information in the memory 132 as a storage unit.

Subsequently, the process proceeds to step S110, and in the case of the second and subsequent imaging, the image processing device 130 receives an input as to whether or not to image the same cross section as the previously imaged cross section again this time through the input device 134. (Step S110). If the same cross section as the previously imaged cross section is not to be imaged (step S110 No), the process proceeds to step S140, and the previously imaged cross section is not searched. On the other hand, if the same cross-section as the cross-section taken in the past is to be imaged (step S110 Yes), the process proceeds to step S120, and the processing circuit 150 uses the acquisition function 138 to obtain the photograph information and the imaging plan information of the past image. , from the memory 132 as a storage unit (step S120).

As an example, the processing circuit 150 causes the control function 133 to display a list of imaging plan information when imaging was performed in the past on the display 135 as a display unit, and through the input device 134, the same cross section as the imaging plan. An input of selection of past imaging plan information to be performed is received from the user. Subsequently, when the user selects imaging plan information for performing imaging in the same cross section as the imaging plan from the list of imaging plan information displayed on the display 135 as a display unit, the processing circuit 150 causes the acquisition function 138 Accordingly, information related to the imaging plan information is obtained from the memory 132 as a storage unit, and the first optical image associated with the imaging plan information is obtained as photograph information.

Subsequently, in step S130, the processing circuit 150 causes the determination function 137 to determine the image based on the previously captured optical image (first optical image) and the optical image captured in step S100 (second optical image). , to determine the displacement amount of the subject P. In other words, the processing circuit 150 uses the determination function 137 to extract the three-dimensional deviation from the first optical image captured at the first time and the second optical image captured at the second time, and A displacement amount of the sample P is determined.

As an example, the processing circuit 150 extracts some feature points from the first optical image and the second optical image by the determination function 137, and compares the extracted feature points to determine the displacement amount of the subject P. may As another example, the processing circuit 150 causes the determining function 137 to align the first optical image and the second optical image, for example, by the method disclosed in Japanese Patent Application Laid-Open No. 2009-273597. A deviation amount of P may be determined. For example, the processing circuitry 150 extracts a contour from the first optical image using the determination function 137, models the shape of the extracted contour with an implicit polynomial, and compares it with the second optical image to determine the displacement amount of the subject P. may be determined.

Subsequently, in step S135, the processing circuitry 150 causes the control function 133 to change the imaging plan information based on the displacement amount of the subject determined in step S135. As an example, the processing circuit 150 controls the feed amount of the tabletop 105a by the control function 133 based on the amount of deviation determined by the determination function 137 in step S130. As another example, the processing circuit 150 causes the control function 133 to control the pulse sequence executed by the sequence control circuit 120 of the magnetic resonance imaging apparatus 100 based on the amount of deviation determined by the determination function 137 in step S130. may be performed.

Subsequently, in step S140, the processing circuit 150 stores the imaging plan information changed in step S135 in the control function 133 and in the memory 132 as a storage unit. Subsequently, in step S150, the sequence control circuit 120 performs imaging based on the imaging plan changed in step S135. Subsequently, the processing circuit 150 uses the image generation function 136 to generate a magnetic resonance image based on the imaging performed in step S150.

As described above, in the image processing apparatus according to the embodiment, the first optical image of the subject P captured by the camera 11 as the imaging unit at the first time and the subject P captured by the camera 11 at the second time A displacement amount of the subject P is determined from the second optical image of P. As a result, it is possible to automatically calculate the displacement amount of the subject P, and it is possible to perform imaging in the same cross section as that of the past imaging, thereby improving the user's convenience.

Embodiments are not limited to the above examples.

As an example, in actual imaging, the user may press the button of the projector 10 multiple times, for example, to redo imaging. In such a case, the processing circuitry 150 causes the determination function 137 to shift the optical image of the subject P corresponding to the last time the button of the projector 10 was pressed, among the plurality of optical images of the subject P. It may be used as a first optical image for determining quantity. In other words, in step S130, the processing circuit 150 causes the determination function 137 to determine whether the camera 11 as the image capturing unit has captured the optical image a plurality of times before the second time. The optical image thus obtained may be used as the first optical image to determine the amount of deviation. As another example, the processing circuit 150 causes the determination function 137 to determine that, when the camera 11 as the imaging unit has captured optical images a plurality of times before the second time, the optical images are stored immediately before the table 105a is sent The amount of deviation may be determined using the optical image as the first optical image.

Further, in the embodiment, in step S135, for example, the amount of movement of the tabletop 105a or the pulse sequence executed by the sequence control circuit 120 is changed based on the amount of deviation determined in step S130, whereby the imaging plan is changed. Described when information is changed. However, embodiments are not limited to this. For example, the corrected image may be generated based on the deviation amount determined in step S130 after imaging without changing the imaging plan information. That is, instead of the process of step S135, after the end of step S150, the processing circuit 150 causes the generation function 136 to generate the result of the imaging of step S150 by the magnetic resonance imaging apparatus 100 based on the amount of deviation determined in step S130. A second image may be generated by performing correction on the generated first image.

Further, the image processing system according to the embodiment has been described for the case of processing a magnetic resonance image generated by the magnetic resonance imaging apparatus 100, but the embodiment is not limited to this. It may be the case of processing medical images generated by other modalities such as an X-ray CT apparatus. The modality described above has, for example, the same configuration as the image processing device 130 in FIG.

In the case of the X-ray CT apparatus, in the image processing system described above, for example, the projector 10 indicates the relative position of the subject P with respect to the tube position by projecting light. The camera 11 as an imaging unit captures an optical image of the subject P based on the timing at which a light projection instruction is given to a light projector that indicates the relative position of the subject P with respect to the tube position. In addition, the above-described image processing system uses the first optical image of the subject captured by the imaging unit at the first time and the second optical image of the subject P captured by the imaging unit at the second time. a processing circuit 150 having a determination function 137 for determining the amount of deviation of the .

According to at least one embodiment described above, user convenience can be improved.

While several embodiments have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations of embodiments can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

10 Projector 11 Camera 133 Control Function 136 Generation Function 137 Decision Function 138 Acquisition Function 150 Processing Circuit

Claims (8)

an imaging unit that captures an optical image of the subject placed on the tabletop based on the timing at which a light projection instruction is given to a light projector that projects light onto the subject;
Determining the displacement amount of the subject from a first optical image of the subject captured by the imaging unit at a first time and a second optical image of the subject captured by the imaging unit at a second time an image processing system, comprising: 2. The image processing system according to claim 1, wherein said light projector indicates the position of the magnetic field center of the magnetic resonance imaging apparatus by said light projection. 2. The image processing system according to claim 1, further comprising a control unit that controls the feeding amount of the tabletop based on the amount of deviation determined by the determined amount. 2. The image processing system according to claim 1, further comprising a control unit that controls a pulse sequence executed by the magnetic resonance imaging apparatus based on the amount of deviation determined by said determined amount. When the photographing unit has photographed the optical images a plurality of times before the second time, the determining unit selects the optical image last photographed before the second time as the first optical image. 2. The image processing system according to claim 1, wherein the amount of deviation is determined as . 2. The apparatus according to claim 1, further comprising a generation unit that generates a second image by correcting the first image generated by the medical image diagnostic apparatus based on the amount of deviation determined by the determination unit. image processing system. capturing an optical image of the subject at a first time and a second time based on the timing at which a light projector for projecting light onto the subject placed on the table is instructed to emit light;
An image processing method comprising: determining a shift amount of the subject from a first optical image of the subject captured at a first time and a second optical image of the subject captured at a second time. An optical image of the subject placed on the table is captured at a first time by an imaging unit that captures an optical image based on the timing at which a light projection instruction is given to a light projector that projects light onto the subject. A program for causing a computer to execute a process of determining the displacement amount of the subject from the first optical image of the subject captured by the imaging unit at a second time and the second optical image of the subject captured by the imaging unit at a second time.

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