JP2010250458A - Image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor that allows observation of a hidden part which is hardly displayed in point rotation of a three-dimensional image. <P>SOLUTION: A CPU 101 of an image processor 100 extracts a target region from a series of tomographic images obtained by imaging the target region. When a line along the extracted target region is set as an axial line, an axial rotation image is generated and displayed by rotating each point included in the target region along a plane vertical to the axial line, around the set axial line. An axial rotation mode and a point rotation mode are prepared. When the axial rotation mode is selected, an axial rotation image is generated by rotating each point of the target region along the plane vertical to the set axial line (core line). When the point rotation mode is selected, the point rotation image is generated by rotating each point of the target region only by a predetermined angle to a predetermined direction. around an arbitrary point, in the same way as before. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that generates a three-dimensional image from a plurality of tomographic images.

  2. Description of the Related Art Conventionally, a method for generating a three-dimensional image of an object using, for example, a plurality of tomographic images taken by an X-ray CT (computed tomography) apparatus, an MRI (magnetic resonance imaging) apparatus, or the like is known.

  In particular, as a method for displaying the inside of a luminal organ such as the large intestine, a virtual endoscopic image called CEV (Cruising Eye View (registered trademark)) (Patent Document 1) or a tube is opened and the inner surface is expanded and displayed. Such an unfolding display method (Patent Document 2) has been developed. The virtual endoscopic image shown in Patent Document 1 described above is a display method in which a virtual ray (ray) is irradiated from a virtual viewpoint onto a projection target, and voxels on the line of sight are projected onto a projection plane. Yes, the inside of an organ can be observed like an image obtained by an endoscope. Further, the developed image shown in Patent Document 2 described above has an advantage that a doctor or the like can easily find a lesion candidate because the entire surface inside the hollow organ can be seen.

Patent Document 3 discloses a method of deforming a tubular structure image by creating a mesh model suitable for a three-dimensional tubular structure image and deforming divided segments of the mesh model. ing.
On the other hand, in a conventional three-dimensional image, it is possible to perform an operation in which the image can be rotated around a certain point and observed from an angle that a doctor or the like wants to observe.

JP-A-8-16813 Japanese Patent No. 3627066 JP 2006-517042 A

  However, when attempting to observe a bent part of a tubular structure or a part that intersects and overlaps in a complicated manner, it cannot be observed with the above-described virtual endoscopic image or developed image. Further, in Patent Document 3, there is a description that the image is deformed or rotated, but there are places where it is difficult to observe by simply rotating the image around a certain point.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image processing apparatus capable of observing a hidden part of a three-dimensional image that is difficult to display by point rotation.

  In order to achieve the above-described object, the present invention is an image processing apparatus that constructs and displays a three-dimensional image based on a series of tomographic images obtained by photographing a target region, and is based on the three-dimensional image or the tomographic image. Included in the target area with an extraction means for extracting the target area, an axis setting means for setting a line along the target area extracted by the extracting means as an axis, and an axis set by the axis setting means A first rotated image generating means for generating an axially rotated image obtained by rotating and moving each point along a plane perpendicular to the axis, and an axially rotated image generated by the first rotated image generating means. An image processing apparatus comprising: display means for displaying.

  With the image processing apparatus of the present invention, it is possible to observe a hidden part of a three-dimensional image that is difficult to display by point rotation.

The figure which shows schematic structure of the image processing apparatus 1 The flowchart explaining the flow of the image processing which the image processing apparatus 1 which concerns on this invention performs An example of a three-dimensional image of the luminal organ 10 Example of operation / display screen (1) Example of operation / display screen (2) An image diagram in which each point of the luminal organ region is rotated on a plane perpendicular to the core line and projected with the axis line (core line 20) as an axis Example of operation / display screen after axis rotation image generation and display

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, the configuration of an image processing system 1 to which the image processing apparatus 100 of the present invention is applied will be described with reference to FIG.

  As shown in FIG. 1, the image processing system 1 includes an image processing device 100 having a display device 107 and an input device 109, an image database 111 connected to the image processing device 100 via a network 110, and an image photographing device 112. With.

The image processing apparatus 100 is a computer that performs processing such as image generation and image analysis. For example, a medical image processing apparatus installed in a hospital or the like is included. The image processing apparatus 100 performs processing for generating images of various display formats.
As shown in FIG. 1, the image processing apparatus 100 includes an external device such as a CPU (Central Processing Unit) 101, a main memory 102, a storage device 103, a communication interface (communication I / F) 104, a display memory 105, and a mouse 108. Interface (I / F) 106, and each unit is connected via a bus 113.

  The CPU 101 calls a program stored in the main memory 102 or the storage device 103 to the work memory area on the RAM of the main memory 102 and executes the program, drives and controls each unit connected via the bus 113, and the image processing apparatus Various processes performed by 100 are realized.

  Further, the CPU 101 extracts a target area such as the large intestine from a series of tomographic images in an image processing (see FIG. 2) described later, sets an axis line along the extracted target area, and focuses on the axis line. Calculation for generating an axis rotation image obtained by rotating each point of the target area along a plane perpendicular to the axis is executed, and the image after the axis rotation is displayed.

Hereinafter, an image obtained by rotating each point of the target area around the axis along a plane perpendicular to the axis is referred to as an axis rotation image.
Further, an image rotated around an arbitrary point, which is performed in a conventional three-dimensional image display operation, is referred to as a point rotation image.

  The main memory 102 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The ROM permanently holds a computer boot program, a program such as BIOS, data, and the like. The RAM temporarily stores programs, data, and the like loaded from the ROM, the storage device 103, and the like, and includes a work area used by the CPU 101 for performing various processes.

  The storage device 103 is a storage device that reads and writes data to and from an HDD (hard disk drive) and other recording media, and stores a program executed by the CPU 101, data necessary for program execution, an OS (operating system), and the like. . As for the program, a control program corresponding to the OS and an application program are stored. Each of these program codes is read by the CPU 101 as necessary, transferred to the RAM of the main memory 102, and executed as various means.

The communication I / F 104 includes a communication control device, a communication port, and the like, and mediates communication between the image processing apparatus 100 and the network 110. The communication I / F 104 performs communication control with the image database 111, another computer, or an image capturing apparatus 112 such as an X-ray CT apparatus or an MRI apparatus via the network 110.
The I / F 106 is a port for connecting a peripheral device, and transmits / receives data to / from the peripheral device. For example, a pointing device such as a mouse 108 or a stylus pen may be connected via the I / F 106.

  The display memory 105 is a buffer that temporarily accumulates display data input from the CPU 101. The accumulated display data is output to the display device 107 at a predetermined timing.

  The display device 107 includes a display device such as a liquid crystal panel and a CRT monitor, and a logic circuit for executing display processing in cooperation with the display device, and is connected to the CPU 101 via the display memory 105. The display device 107 displays display data stored in the display memory 105 under the control of the CPU 101.

  The input device 109 is an input device such as a keyboard, for example, and outputs various instructions and information input by the operator to the CPU 101. The operator interactively operates the image processing apparatus 100 using external devices such as the display device 107, the input device 109, and the mouse 108.

  The network 110 includes various communication networks such as a LAN (Local Area Network), a WAN (Wide Area Network), an intranet, and the Internet, and connects the image database 111, a server, other information devices, and the like to the image processing apparatus 100. Mediate.

  The image database 111 stores and stores image data captured by the image capturing device 112. In the image processing system 1 shown in FIG. 1, the image database 111 is connected to the image processing apparatus 100 via the network 110, but the image database 111 is provided in, for example, the storage device 103 in the image processing apparatus 100. May be.

  Next, the operation of the image processing apparatus 100 will be described with reference to FIGS.

  The CPU 101 of the image processing apparatus 100 reads the program and data related to the image processing of FIG. 2 from the main memory 102, and executes processing based on the program and data.

  Note that when the following image processing is started, the image data is taken from the image database 111 or the like via the network 110 and the communication I / F 104 and stored in the storage device 103 of the image processing apparatus 100.

  In the image processing of FIG. 2, first, the CPU 101 of the image processing apparatus 100 reads a series of tomographic images obtained by capturing an area including the target area as input image data. The image read here is, for example, a tomographic image taken using a hollow organ such as a large intestine or a blood vessel as a target region. In the present embodiment, an X-ray CT image of the large intestine is used as a suitable example of input image data. Note that the target region is not limited to the large intestine, and may be another organ.

  The CPU 101 extracts a target organ region from the read image data (step S1). Extraction of the target organ region may be performed using a known method such as CT value threshold processing.

Next, the CPU 101 constructs a three-dimensional image for the target organ extracted in step S1, and displays it on the display device 107 (step S2). As a shading method as a three-dimensional image, for example, any method such as volume rendering, ray casting, surface, depth, or the like may be used.
In the case where a surface three-dimensional image is generated and displayed in step S2, the organ region extraction in step S1 may be performed only on the surface portion.

Next, the CPU 101 sets an axis line as a rotation axis of the axis rotation image (step S3). As the axis, it is preferable to adopt the core wire of the target organ. The core line is a substantially center line of the lumen.
CPU101 extracts a core wire.
For the extraction of the core line, various known methods such as, for example, a method in which pixels are sequentially deleted from around the target region and the remaining several pixels are used as the core line, or the viewpoint coordinates of CEV (virtual endoscopic image) are used as the core line coordinates. A technique may be used.

  In the setting of the axis line in step S3, when the core line is the axis line, the axis shape is rotated around the core line, so that the organ shape is maintained in the almost original shape, and the image of the whole organ is not impaired during observation. There are advantages. However, when the shape of the axis rotation image to be generated may be deformed from the original shape, any curve or straight line may be set as the axis as long as it is a line along the target organ. In this case, the line may be any of the inside, outside, or line along the surface of the target organ region.

  Assume that the three-dimensional image 10 as shown in FIG. 3 is displayed on the display device 107 in the steps S1 to S3. A one-dot chain line in the three-dimensional image 10 is a core line 20.

  At the stage where the axis line (here, the core line 20 is set as the axis line) is set, the CPU 101 receives the input of the rotation angle θ (step S4) and the selection of the rotation mode (step S5).

  In the present embodiment, GUIs 31 and 33 shown in FIG. 4 are displayed on the display device 107 as a GUI (Graphical User Interface) for inputting the rotation angle θ and selecting the rotation mode.

The GUI 31 is operated when the displayed three-dimensional image is rotated around an arbitrary point (point rotation mode) as in the conventional case. An up button 31a, a right button 31b, a down button 31c, and a left button 31d are provided as point rotation direction operators for designating the point rotation direction.
The GUI 33 is operated when the displayed three-dimensional image is rotated about the axis set in step S3 (axis rotation mode). The GUI 33 includes a circle 33a and a needle 33b (shaft rotation angle indicator) indicating an arbitrary angle (0 to 360 degrees) around the circle 33a.

When an operation is performed on the GUI 33, the CPU 101 shifts to the shaft rotation mode. The CPU 101 sets the movement angle of the needle 33b of the GUI 33 as the shaft rotation angle θ.
On the other hand, when there is an operation on the GUI 31, the CPU 101 shifts to the point rotation mode. That is, when any button 31a, 31b, 31c, 31d of the GUI 31 is pressed, the CPU 101 is assumed to input a rotation angle of a predetermined angle in the direction of the pressed button. This predetermined angle may be set in advance or may be an angle input by the operator through another operation.

As another example of the operation element, a GUI 35 shown in FIG. 5 may be used.
The GUI 35 shown in FIG. 5 includes an axis rotation angle indicator 51 that specifies an angle of axis rotation, and upper, lower, left, and right direction indicators 52, 53, 54, and 55 that specify the direction of point rotation.

When an operation is performed on the shaft rotation angle indicator 51 of the GUI 35, the CPU 101 shifts to the shaft rotation mode and sets the movement angle of the shaft rotation angle indicator 51 as the shaft rotation angle θ.
On the other hand, when there is an operation on the direction indicators 52, 53, 54, and 55 of the GUI 35, the CPU 101 shifts to the point rotation mode, and a predetermined angle in the direction of the pressed direction indicators 52, 53, 54, and 55. It is assumed that the rotation angle is input.

  Returning to the description of FIG. In the axis rotation mode (step S5; rotation around the axis), the CPU 101 determines each point included in the extracted target area (including each point inside the target area or each point on the surface) as the input rotation angle θ. Only, the calculation for rotating along the plane perpendicular to the axis is performed (step S6).

FIG. 6 is a diagram for explaining the generation of the shaft rotation image.
As shown in FIG. 6, each point (FIG. 6 is a part of the target area) included in the target area 10 extracted from the plurality of tomographic images SL1, SL2,. This shows how it is projected onto the screen. In FIG. 6, for the sake of explanation, it is assumed that the planes perpendicular to the core wire 20 that is the axis coincide with the paper surface at both ends of the target region 10.

  In the calculation of the axis rotation, the CPU 101 rotates the point A at one end of the target area 10 by an angle θ along the plane perpendicular to the core wire 20 and moves it to the point a. Further, an operation for projecting the point a onto the projection plane Q is performed. Similarly, the point B is also rotated along the plane perpendicular to the core wire 20 by the angle θ, moved to the point b, and the point b is projected onto the projection plane Q. Similarly, the CPU 101 rotates and moves each point in the target area around the axis line (core line 20) or on the surface by an angle θ, projects it onto the projection plane Q, performs desired shading, and performs three-dimensional axis rotation. Generate an image.

  The CPU 101 displays the generated shaft rotation image on the display device 107 (step S7).

  In the step of generating and displaying the axial rotation image in steps S6 to S7, when the point inside the bent portion of the target region is axially rotated outward about the core line 20, the inside of the lumen at the bent portion Due to the difference in curvature between the outer side and the outer side, pixels that are not correctly depicted may partially occur. In that case, interpolation processing by neighboring pixels may be performed to avoid an unnatural image.

In the point rotation mode (step S5; rotation around the point), the CPU 101 arbitrarily sets each point in the target area (including each point in the target area or each point on the surface) by a predetermined angle in the designated direction. A calculation for rotating around a point (for example, the center of gravity of the target region in the original three-dimensional image) is performed and projected onto the projection plane Q to generate a three-dimensional point rotation image (step S9). The generation of the three-dimensional point rotation image is the same as that of a conventionally known method.
The CPU 101 displays the generated point rotation image on the display device 107 (step S7).

  Note that the two-step processing from step S6 to step S7 and the two-step processing from step S9 to step S7 are performed by using a rotation formula (step S6 or step S9) and three-dimensional when generating a surface three-dimensional image. By integrating the image structural formula (step S7), it is possible to process each step in one step.

Thereafter, until an end instruction is input (step S8; No), the rotation (shaft rotation, point rotation) processing of steps S4 to S7 is repeated according to the user's operation.
If an end instruction is input (step S8; Yes), a series of image processing ends.

  FIG. 7 shows a display example of a shaft rotation image 13 obtained by rotating the target region 10 shown in FIG. 4 around the core wire 20 by the above-described image processing. The parts 21, 22, and 23 shown in FIG. 4 and the parts 21, 22, and 23 shown in FIG. 7 are corresponding parts, respectively. In FIG. 4, since these portions 21, 22, and 23 are located inside the bent portion of the lumen, even if the point is rotated, the lumen itself may be hindered by the display and may be observed. Hateful. Therefore, by rotating the parts 21, 22, and 23 around the core wire 20 by the processing of step S6 to step S7, the parts that are hidden in FIG. 4 are displayed on the display screen. Further, since the core wire 20 is used as an axis, the shape of the target area itself is not greatly deformed, and the arrangement image of the observation target is not impaired.

As described above, the image processing apparatus 100 according to the present embodiment is set by extracting a target region from a series of tomographic images obtained by photographing the target region and setting a line along the extracted target region as an axis. An axis rotation image is generated and displayed by rotating each point included in the target region along a plane perpendicular to the axis with the axis as a center.
Therefore, it is possible to easily observe a portion hidden by bending or crossing.

In particular, as in this embodiment, by setting the core 20 of the luminal organ as an axis, the part hidden by bending or crossing is rotated and displayed while maintaining the original shape of the target region. Is possible.
Therefore, it is easy to confirm the original position even if the lumens intersect and bend in a complicated manner.
Furthermore, if the image processing of the present invention is applied to an image used in the medical field, it is possible to observe a site that could not be observed by conventional rotation display or the like, and it becomes easy to find a lesion site such as cancer.

  In this embodiment, an axis rotation mode and a point rotation mode are provided, and when the axis rotation mode is selected, each point of the target area is along a plane perpendicular to the set axis (core line). When the rotated shaft rotation image 13 is generated and the point rotation mode is selected, the point rotation is performed by rotating each point of the target area around the arbitrary point by a predetermined angle as in the conventional case. Generate an image. Therefore, a combination of the conventional point rotation and the shaft rotation according to the present invention makes it possible to observe a desired part from a desired angle, which improves user convenience. In addition, since the GUIs 31, 33, and 35 that can input the rotation direction or rotation angle of the point rotation or the shaft rotation with a simple operation are provided, the operability is improved.

  In this embodiment, the target image is an image used in the medical field. However, the present invention is not limited to this, and various tubular structures such as tubes, pipes, cords, and the like can be used. It is applicable to. Moreover, not only an X-ray CT image but also any image capable of photographing the inside such as an MRI image and an ultrasonic image can be used as an input image.

  The preferred embodiments of the image processing apparatus according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

DESCRIPTION OF SYMBOLS 1 ... Image processing system 100 ... Image processing apparatus 101 ... CPU
102... Main memory 103... Storage device 104 .. Communication I / F
105 ... Display memory 106 ... I / F
107... Display device 108 Mouse 109 Input device 110 Network 111 Image database 113 Image photographing device 10 ... Target area 20 ... Axis (core wire)
31 ...... GUI for point rotation
33 ... GUI for shaft rotation
35... GUI that operates both point rotation and shaft rotation

Claims (7)

An image processing apparatus that constructs and displays a three-dimensional image based on a series of tomographic images obtained by photographing a target region,
Extracting means for extracting a target region from the three-dimensional image or the tomographic image;
An axis setting means for setting a line along the target area extracted by the extracting means as an axis;
First rotation image generation means for generating an axis rotation image obtained by rotating and moving each point included in the target area along a plane perpendicular to the axis centering on the axis set by the axis setting means When,
Display means for displaying the shaft rotation image generated by the first rotation image generation means;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein the axis set by the axis setting unit is a core line of the target area.   The image processing apparatus according to claim 1, wherein the target area is an area showing a lumen shape.   The image processing apparatus according to claim 1, wherein the three-dimensional image is an image used in a medical field. An angle designating unit for designating the rotation angle of the image;
The first rotation image generation means rotates each point included in the target area about the axis along a plane perpendicular to the axis by the rotation angle designated by the angle designation means. The image processing apparatus according to claim 1, wherein a shaft rotation image is generated. Second rotated image generation means for generating a point rotation image obtained by rotating the three-dimensional image around an arbitrary point;
A selection means for generating either the axis rotation image or the point rotation image;
According to the selection by the selection unit, the first rotation image generation unit generates a shaft rotation image, or the second rotation image generation unit generates a point rotation image, and the generated shaft rotation image or point rotation image is generated. First display control means for displaying on the display means;
The image processing apparatus according to claim 1, further comprising: Second rotated image generation means for generating a point rotation image obtained by rotating the three-dimensional image around an arbitrary point;
An operating means provided with both an axis rotation angle indicator that specifies the angle of axis rotation and a point rotation direction indicator that specifies the direction of point rotation;
When the operation means performs an operation on the shaft rotation angle indicator, the first rotation image generation means generates the shaft rotation image, and the operation on the point rotation direction indicator is performed. A second display control unit that causes the second rotation image generation unit to generate the point rotation image and causes the display unit to display the generated shaft rotation image or the point rotation image;
The image processing apparatus according to claim 1, further comprising:

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