JP2003091735A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor capable of excellently displaying a part even when the part desired to see in a three-dimensional image display is obstructed and hidden by another structure, and not restricted in view point position for allowing reading of an image. SOLUTION: A volume model obtained by being divided into voxels is formed, and a volume rendering image is displayed by being projected from the prescribed view point position. An operation means designates and operates a designating point to a specific area on the displayed volume rendering image. An arithmetic operation means correlates a weight factor of becoming large in weight of at least the designating point, and becoming small in weight of respective voxel values of a voxel space to the respective voxel values of the voxel space existing on the view point position side more than the designating point, and executes arithmetic processing for changing transparency of the respective voxels. An image processing means projects image information by a correction voxel value arithmetically operated by the arithmetic operation means on respective pixels of a plane of projection, and displays and processes the volume rendering image for changing the transparency on a display image screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly to an apparatus for displaying a three-dimensional image.

[0002]

2. Description of the Related Art In recent years, an image created on a medical image diagnostic apparatus such as an X-ray CT apparatus, an X-ray diagnostic apparatus, a nuclear magnetic resonance imaging (MRI) apparatus, etc., in a place where a medical action such as diagnosis and treatment is performed. , Three-dimensional images are displayed for the purpose of diagnosis or treatment. In the field of such three-dimensional image diagnosis, for example, an image is taken with a volume and a three-dimensional image is displayed by volume rendering, or an axial, coronal, and sagittal cross section is read by MPR or the like to obtain a three-dimensional image. Often grasp the image.

The volume rendering method is, for example, CT.
After stacking slice images obtained by an apparatus, an MRI device, etc., a volume model (voxel space) having a three-dimensional structure in which the respective values (for example, CT values) of a plurality of slice images are filled in a square called a voxel. Make,
For this volume model, the line-of-sight direction is determined and voxel tracking (ray tracing) is performed from an arbitrary viewpoint, the brightness (CT value or voxel value) at the voxel is calculated, and image information based on this brightness is displayed on the projection surface. A three-dimensional image is obtained by projecting onto a pixel and extracting an organ or the like three-dimensionally.

On the other hand, MIP (Maximum Intensity P) is used as an image display in an image diagnostic apparatus.
Projection processing is known. Where M
IP processing means that for all original images to be processed,
For all pixels in each viewing direction,
Projection image <IP (ImagePr
object) image>.
In this process, the obtained MIP image makes it possible to observe the lesion site, which is considered to be useful for precise determination of tumor size and malignancy / benignity. Further, it is expected that diagnosis can be facilitated by obtaining one image from a large number of image data obtained by helical scanning or the like.

[0005]

By the way, when a tumor or the like is viewed by a three-dimensional image display, for example, a volume rendering image, the doctor does not want to see only the tumor when viewing the image, but for some reason, for example, It is also necessary to have information such as how the blood vessels around the tumor itself are running, and there is a desire to understand the surrounding structure while grasping the positional relationship with the structures of the surrounding blood vessels. .

However, in the image display by the normal volume rendering, for example, the CT value of the tumor and the CT value of the blood vessel region are close to each other.
As shown in FIG. 7, the position of the tumor ai or the like is displayed in a state of being hidden by the blood vessels bi and di. For this reason, there is a problem in that it is impossible to see the part that is blocked and hidden. Since the CT values of the tumor and the blood vessel are close to each other, there is a problem that the objects located behind cannot be seen when the objects overlap each other. further,
Even if the "semi-transparent display" mode is set, the device user cannot perform accurate processing on the image because the image is not well understood and which region should be made semi-transparent is unknown. There was a problem.

Furthermore, since the site of interest such as a tumor is hidden by being obstructed by other structures, the direction in which the tumor can be seen is limited when the tumor is viewed from all directions. I will end up. Therefore, there is a problem that it is necessary to view the tumor from a direction without blood vessels, and it is not easy to simultaneously view the relationship between the tumor and surrounding blood vessels on one screen.

When it is desired to read images as original images for the purpose of diagnosing the presence of tumors or differential diagnosis, it is not too difficult to display tens of images one by one for interpretation. However, with the popularization of helical scan CT and the like, high-speed CT usually produces several tens to several hundreds of images per patient, which increases the number of images. Displaying and interpreting was a time-consuming and laborious task.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to perform viewing even when a portion desired to be viewed in a three-dimensional image display is hidden by another structure. The image of the part can be displayed well, and further,
An object of the present invention is to provide an image processing device in which the direction (viewpoint position) through which the desired region can be interpreted is not limited.

A second object of the present invention is to provide an image processing apparatus capable of reading images in a short time when the images are read by a highly accurate medical image diagnostic apparatus for generating images of hundreds of sheets. To provide.

[0011]

In order to achieve the first object, the invention according to claim 1 generates a volume model obtained by dividing into voxels, and the volume model is obtained from a predetermined viewpoint position. An image processing device for projecting the information of each voxel onto a projection surface by projecting a volume rendering image on the display screen and displaying the volume rendering image of the projection surface on a display screen, on the volume rendering image displayed on the display screen. With respect to each voxel value of the voxel space located closer to the viewpoint position than the specified designation point, the operating means for designating a designated point for the specific area, and at least the weight of the designated point becomes large, and the voxel space becomes larger. Calculation means for performing a calculation process for changing the transparency of each voxel by correlating the weighting factors with which the weight of each voxel value becomes small, and the calculation means Image information projected on each pixel of the projection surface by the correction voxel value, and image processing means for displaying processing the volume rendering image of varying transparency on the display screen, comprising a.

In order to achieve the second object, the invention according to claim 4 displays a projection image obtained by projecting the three-dimensional original image from a predetermined direction on a projection surface based on the three-dimensional original image. An image processing apparatus for performing image processing, comprising setting means for setting the plurality of original tomographic images into a plurality of groups of a predetermined number in the stacking direction, and the setting means set by the setting means. For each of the plurality of groups, a predetermined process is performed on each of the original tomographic images forming one group by performing a predetermined process on the pixel values of the pixels of one group in the stacking direction of the original tomographic images. And an image creating unit for creating a projected image of the direction.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of a preferred embodiment of the present invention will be specifically described with reference to the drawings.

[First Embodiment] (Overall Configuration of System) First, one example in which the "image processing apparatus" or "medical image diagnostic apparatus" according to the present invention is applied to a so-called "medical image diagnostic system" The embodiment will be described.

Here, a feature of the present invention is that the CT apparatus or M
A stereoscopic image based on a slice image obtained by RI or the like is displayed on the screen by volume rendering, and when a designated point of a specific region (object) is pressed with a pointer or the like on the volume rendering image, the designated object is displayed. By correlating the weighting coefficient with the CT value so that (tumor ai) is clearly displayed, the transparency of another object (blood vessel bi) or the like displayed in front of the object is converted, and, for example, tumor ai Of the blood vessel bi while grasping the tissue relationship between the blood vessel bi and the like.
The shape of the tumor ai shielded by is clearly displayed.

Prior to a detailed description of the features of the present invention, the overall schematic configuration of the medical image diagnostic system will be described with reference to FIGS. 1 and 2. Figure 1
2 and FIG. 2 are functional block diagrams showing a schematic configuration of the medical image diagnostic system of this embodiment.

The medical image diagnostic system 1 of this embodiment is
As shown in FIGS. 1 and 2, X such as “X-ray CT device”
A modality 2 including a mechanism for collecting data such as a radiation source and an X-ray detector, and an image processing device 10 for displaying, for example, a three-dimensional image based on various image information from the modality 2. ,have.

The modality 2 (medical image diagnostic apparatus)
Is, for example, an "X-ray CT apparatus". When the modality 2 is an X-ray CT apparatus, the X-ray tube 3d, the X-ray detector 3e, and the X-ray detector provided in the pedestal 3a are included. Three
A data collecting unit 4 for collecting data from e, a pre-processing unit 5 for performing various data processing, a reconstructing unit 6 for performing image reconstruction processing, a data processing unit 7 for processing various data, and the like. It also includes a storage unit for storing various data, a transfer processing unit for data transfer, an operation unit for operating the X-ray CT apparatus main body, a display unit (all not shown), and the like.

As shown in FIG. 2, the medical image diagnostic system 1 is configured such that an "X-ray CT apparatus" is provided with the function of the image processing apparatus (2a) on the console side, or "X-ray CT apparatus". Hardware of the system such as when the function of the image processing apparatus (10) is installed in an image reference computer (configured separately from the X-ray CT apparatus main body) connected to the "ray CT apparatus" via a network. The configuration may be any or a combination thereof.

At this time, the respective constituent elements of the X-ray CT apparatus generally operate as follows. That is, the X-rays emitted by the X-ray tube 11 and transmitted through the subject are converted into analog electric signals by the X-ray detector 3e, and hereinafter, digital conversion processing by the data collection unit 4 and various corrections by the preprocessing unit 5 are performed. It is processed and stored as projection data in a storage unit (not shown). Then, the X-ray tube 3d and the X-ray detector 3e
However, based on projection data obtained as a result of, for example, one round (= 360 °) around the subject, the reconstruction unit 6 reconstructs other image information such as a tomographic image, and the data processing unit 7 performs various reconstructions. Image information such as a tomographic image can be displayed by performing processing. An annular hole 3c is provided in the gantry 3a, and the bed top plate 3b on which the subject is placed can move at a predetermined speed in the direction of the arrow to perform a helical scan or the like. A tomographic image (slice image) is obtained.

On the other hand, returning to the description of FIG. 1, the image processing apparatus 1 sequentially reads the slice images stored by stacking the slice images obtained by the CT apparatus or MR or the like to give the slice images a thickness. , Its spatial resolution (x,
y) and the slice thickness (z) are equal to each other, the voxel space having a three-dimensional structure that forms a three-dimensional space is generated to have a function of displaying a three-dimensional image, and various image information from the modality 2 and The image storage unit 11 is configured to store other information (such as additional information). The image storage unit 11 includes a slice image information storage unit 11a that stores information such as slice images and a slice image information storage unit 11a.
And a volume model information storage unit 11b for storing volume model information such as volume rendering based on the slice image.

The image processing apparatus 1 also generates a stereo model such as a 3D image based on the volume model information stored in the volume model information storage section 11b, and a stereo model generation section 12 for the generated stereo model. A projection processing unit 15 that performs projection processing, a line-of-sight direction position calculation unit 13,
Volume model position calculation unit 14 and projection processing unit 15
A line-of-sight direction distance calculation unit 16, an image processing unit 17, a graphic data generation unit 18, and a region of interest calculation unit 19
, Weight calculation means 20, display section 31, and operation section 32
And other processing 33, and the control unit 3 that controls these.
4 and.

The stereo model generation unit 12 (volume model generation means, 3D image generation unit) generates a three-dimensional image by, for example, rendering processing, and generates a volume model based on tissue color information or transparency in a file. The 3D object is defined as a model by allocating transparency or color information according to the numerical value of each voxel in the voxel space of the 3D structure described above, and the inside as well as the surface of the 3D object is defined. Generates a volume model with a structure in which the multiple structure of is visible. Then, the slice images (X, Y) of the file are sequentially extracted to form a three-dimensional spatial coordinate system (X, Y, Z) in which the spatial resolution (x, y) of the slice images and the slice thickness (z) are equal. Then, the volume model to which the color information corresponding to the numerical value of each voxel is assigned is defined in the file.

For the three-dimensional object (object) defined in the object space, the three-dimensional model generation unit 12 uses the CT device or M
A slice image of a subject obtained by a modality 2 such as RI is given a thickness to form a three-dimensional space (voxel space) whose spatial resolution (x, y) and slice thickness (z) are basically the same, A numerical value such as a CT value is assigned to each voxel to generate it.

The line-of-sight direction position calculation unit 13 includes an operation unit 32.
The position of the instruction point (pointer) on the image (volume rendering image) displayed on the screen of the display unit 31 in association with the occurrence of an event associated with the operation of the mouse (for example, the mouse) is determined by It is read out from the drawing) or the like to notify the volume model position calculation unit 14 of the position of the designated point. The above-mentioned image memory temporarily stores the same image as the projection space and the projection surface (screen space) in the projection processing unit 15. The coordinate system has the same two-dimensional coordinates as the projection surface and is proportional to the display resolution of the screen. ing. Note that the above-mentioned instruction point is a pointer on the screen (image memory) that the image processing unit 17 can be moved by operating the mouse. In addition, the line-of-sight direction position calculation unit 1
Reference numeral 6 obtains the line-of-sight direction from the operation amount associated with the operation of the operation unit 32.

The volume model position calculation unit 14 determines a three-dimensional position via the projection surface of the projection processing unit 15, and a designated position (screen) on the volume rendering image obtained by the line-of-sight direction position calculation unit 13. The two-dimensional position in the space) is read, and the coordinates of this designated position are converted into three-dimensional positions (Xi, Yi, Z) so as to correspond to the coordinates using voxels.
i) is obtained, and this is used as the three-dimensional position (Xi, Yi, Zi) of the volume model of the designated point in the projection processing unit 15
Send to.

The projection processing unit 15 directs the projection plane toward a three-dimensional object (object) defined by voxels in the object space based on the line-of-sight direction, and virtual rays (light ) To perform voxel tracking,
The light from the front or the light reflected by the light illuminated by the light source is combined and passed to the voxels one after another, and the light emitted from the last voxel is projected to the pixel on the projection surface as the pixel value of the rendering image. To do. Then, ray tracing is performed on a three-dimensional object defined by voxels from a predetermined viewpoint position and line-of-sight direction, and the brightness (C) is calculated from the distance to the bumped voxel and the ray direction at the voxel.
Then, the transparency αi of the opacity curve is read and the image information obtained by integrating the brightness hi and the transparency is sequentially synthesized.

Specifically, ray casting or the like is performed on the volume model with reference to the two-dimensional line-of-sight direction and line-of-sight position corresponding to the coordinates of the projection plane 8 screen space obtained by the line-of-sight direction position calculator 13. And project it onto the projection surface. The projection onto the projection plane is performed by conversion according to the projection method from the object space. In addition, the projection processing unit 15 is a three-dimensional image of the volume model when projected from the three-dimensional position obtained by the volume model position calculation unit 14 and the line-of-sight direction from the viewpoint direction position calculation unit 13 (volume rendering image). Is obtained on the projection surface and displayed on the screen.

When the projection surface is projected, the projection processing section 15 projects the transparency with the opacity curve of the image storage section 11 when, for example, the pixel to be projected is the region of interest ai.

The line-of-sight direction distance calculating unit 16 is a distance in the line-of-sight direction (visual axis, projection line) from the viewpoint position in the three-dimensional space to the position designated by the pointer, based on the pointed position and the viewpoint position. To calculate. Gaze direction distance calculation unit 1
6 obtains information from the line-of-sight direction position calculation unit 13 which position in the voxel space the designated position is, and intersects the axis L in the voxel space with the plane H (FIG. 5: details will be described later). The distance from the position to be designated to the designated position is calculated.

The image processing section 17 temporarily stores the image in the screen space in the image memory and displays the image data of the image memory on the display screen of the display section 31. Further, a cursor or the like based on the operation of the operation unit 32 (mouse or the like) is displayed on the display screen of the display unit 31. The image processing section and the control section can constitute the "image processing means" in the present invention.

The graphic data generation unit 18 generates various graphic display data such as an operation cursor displayed together with the three-dimensional image on the display screen of the display unit 31.
The image data from the graphic data generation unit 18 is input to the image processing unit 17, and is displayed on the display unit 31 via the image processing unit 17.

The region-of-interest calculating unit 19 performs various control calculations for the region of interest, opacity, etc., and based on the position of the voxel in the designated region designated by the operating unit 32 and the line-of-sight direction, the region of interest is calculated. The voxel value of the area is calculated. Here, the ROI calculator 19 extracts the voxel value of the ROI based on the voxel position and the ROI parameter that defines the display mode of the ROI. When the voxel information of the three-dimensional object defined in the object space is projected on the projection surface, the coordinates of the region of interest in the projection area of the projection surface are set in the image storage unit 11. The image display parameter of the region of interest may be opacity or the like.
The opacity indicates the degree of emphasis in highlighting the region of interest of the object.

The weight calculation means 20 extracts a weighting coefficient for a voxel in the case of a preset weighting coefficient, and in the case of a preset weighting function, corresponds to each voxel based on the weighting function. And a position on the volume model of each voxel in the voxel space in the voxel space on the viewpoint position side from the boundary based on the voxel value of the position instructed by the operation unit 32. The voxel position extraction unit 22 that extracts from the viewpoint position, the line-of-sight direction, and the position designated by the operation unit 32, the position information calculated by the voxel position extraction unit 22, and the weighting factor calculation unit 21. CT value (voxel value) for calculating each CT value (each voxel value) of each voxel based on the weighting coefficient corresponding to the position
The calculation unit 23 and various other calculation processes (for example, when a voxel value obtained by correlating a weighting coefficient with respect to each voxel is calculated for the visual axis portion on the volume model, calculation is performed over the voxel space. Other arithmetic processing units 24 that perform processing, or processing that controls these arithmetic operations). The weight calculation means corresponds to the "calculation means" according to the present invention, and the weight coefficient calculation unit corresponds to the "weight coefficient calculation means" according to the present invention.

The weighting coefficient calculator 21 calculates a weighting coefficient (correction value for correcting transparency) according to the distance in the line-of-sight direction, based on a predefined weighting function.

The display unit 31 has a function of displaying the image from the stereo model generation unit 12, and is formed of, for example, a TV monitor as shown in FIG. 3, and can display single or dual (two screens or composite) display. And

As shown in FIG. 3, the operation unit 32 is configured by using an input device such as a mouse, a trackball and / or a keyboard, and specifies a diagnostic region on the display unit 31 and various image display parameters. This is for making input settings and the like. As a result, the control unit 34 controls the change based on the point on the display screen designated by the operation unit 32 so that the image of the tumor or the like can be displayed easily. This operation unit corresponds to the "operation means" according to the present invention.

The display unit 31 may be provided with a weighting coefficient setting unit or a weighting function setting unit 31a (not shown) which is a display operation unit displayed on the display screen. The weighting function setting unit 31a uses, for example, a certain weighting function for setting each weighting coefficient (transparency) for each voxel in the voxel space on the viewpoint position side from the boundary position of the specific area of the volume rendering image on the screen. It is set arbitrarily. Specifically, each parameter of the weighting function (C of the gradient part
T value and weighting factor) are input, a weighting function based on this parameter is generated, and stored in the image storage unit 11 in association with the voxel space.

The weighting function setting section 31a stores a plurality of weighting functions for determining the weighting coefficient of the entire volume rendering image displayed on the screen in the image storage section 11. For example, the weighting function F1 of FIGS.
The weighting function has a function that changes so that the transparency in the range from to point C is 0 to 1. At this time, a CT value calculated using a weighting function is assigned to the pixel coordinates P1 (Xi, Yi), P2, P3, ... Corresponding to each pixel coordinate ki of the projection surface in the image storage unit 11. Remembered The weighting function setting unit according to the present embodiment is
It corresponds to the "weight function setting means" in the present invention.

The display unit 31 may be provided with an opacity curve setting unit (not shown) for generating the opacity curve of the region of interest input by the operator and setting it in the image storage unit 11.

The image processing apparatus 10 configured as described above.
When the volume display is performed, the following roughly operates.

When the slice image information transferred from the modality 2 is stored in the image storage unit 11, the stereo model generation unit 12 causes the slice image information storage unit 11a of the image storage unit 11 to store a plurality of slice images (multi-slice images). Image) is acquired.

The stereo model generation unit 12 sequentially extracts the slice images (X, Y) of the file in accordance with the volume display, and the spatial resolution (x, y) of the slice images is equal to the slice thickness (z). Three-dimensional space coordinate system (X, Y, Z)
And a volume model to which color information is assigned according to the numerical value of each voxel is defined in the file. For example, a volume model in which color information corresponding to the CT value is assigned to each voxel, that is, a model in which not only the boundary surface between tissues but also the internal information structure can be seen multiplex is generated.

Further, the three-dimensional model generating unit 12 generates a volume model, and the three-dimensional space coordinate system (X, Y,
In Z), the inside of each voxel is defined from the adjacency relation of a plurality of binary voxels that have been thresholded for each voxel in the voxel space of the three-dimensional structure.

Then, the projection processor 15 displays a volume rendering image when the volume model of the file is projected from a predetermined line-of-sight position and line-of-sight direction.
For example, a volume rendering image as shown in FIG. 4 is displayed. FIG. 4 is a volume rendering image of the head, in which tumors, blood vessels, other organs, etc. can be seen.

Here, in the case where a three-dimensional image is formed by using the ray tracing method among the rendering processing, the line-of-sight direction, that is, the projection plane (projection plane) is determined for the three-dimensional image and the voxel is determined. A ray (= ray) is skipped from the line-of-sight direction, and the amount of rays to be attenuated and transmitted is calculated according to the opacity determined by the voxel data value passing through, and the total amount of reflected light at each sample point on the ray is subjected to brightness and color processing. Obtain a three-dimensional image.

When such a volume rendering image is displayed on the display unit 31, for example, when the operator designates a specific position with the mouse of the operation unit 32 and the viewpoint position is jumped, the line-of-sight position calculation unit Thirteen
Reads the current two-dimensional position (two-dimensional position in screen space) on the volume rendering image displayed on the screen and informs the two-dimensional position and the line-of-sight direction.

The volume model position calculation unit 14 reads the two-dimensional position from the line-of-sight direction position calculation unit 13, performs coordinate conversion of this position, and through the projection plane of the projection processing unit 15, the three-dimensional position corresponding to the position. The position is obtained, and this three-dimensional position is sent to the projection processing unit 15 as the three-dimensional position of the volume model of the designated point of the volume rendering image. That is, the three-dimensional position corresponding to the two-dimensional position from the line-of-sight direction position calculation unit 13 is set as the three-dimensional position of the volume model.

Then, the projection processing unit 15 projects the volume model on the projection surface (screen space) based on the three-dimensional position from the volume model position calculation unit 14 and the line-of-sight direction from the line-of-sight direction position calculation unit 13. The volume rendering image of the projection surface is displayed on the screen. Thus, in the volume rendering image, the accurate volume image at the designated position can be displayed on the screen.

(Characteristic Configuration of this Embodiment) Here, the feature of this embodiment, that is, the principle for calculating the CT value by the weighting coefficient will be described with reference to FIGS.

In the present embodiment, the CT as shown in FIG.
A case will be described in which a three-dimensional image G of the head is displayed using an image captured using the above. For the sake of explanation, the image size is 512 × 512, and the number of images is 512.
The number of pixels is the same, and the pixel size (pixel size in the xy plane) and the slice pitch (pixel size in the z direction) are the same. Further, it is assumed that the coordinate system is as shown in FIG. 4 and that the weighting function is set in advance by the weighting function setting unit 31a in the display unit 31.

In the present embodiment, the user clicks one point on a desired portion (region of interest) he / she wants to see, so that the clicked coordinate value (x, y,
By changing the transparency of each pixel (voxel value or CT value) as it is separated from z) toward the viewpoint position side, the region of interest is displayed darker, and as it is separated from the region of interest, it is displayed lighter. By doing so, the region of interest can be clearly seen, and the structure around the region of interest, for example, the running condition of a blood vessel or the like can be displayed relatively relatively. For example, as shown in FIG. 5, when the area of the tumor ai is clicked using the operation unit 32, the tumor ai becomes visible as much as possible. If the clicked point is the center of the tumor ai (region of interest), the viewpoint position side of the tumor ai (region of interest) may be displayed slightly thin with respect to the center point.

Specifically, first, the user of the apparatus displays the display unit 3
In the volume rendering image, which is a three-dimensional image displayed on the first display screen, a portion to be noticed (specific area) to be noticed is specified by clicking using the operation unit 32.

The designated position of the designated point in the designated specific area is converted by the volume model position calculation unit 14 into a position (point A shown in FIG. 3) on the volume model M corresponding to the designated position. At this time, it is assumed that the directions of the projection plane and the volume model M are determined by the line-of-sight direction V and the like.

Specified position on volume model M (point A)
And the viewpoint position (point C) on the volume model based on the line-of-sight direction, the distance (AC) between the designated position (point A) and the viewpoint position (point C) on the projection line L is calculated as the line-of-sight direction distance. The calculation is performed by the unit 16.

Here, in the voxel space (VO) on the viewpoint position side from the specified position (point A) in the volume model M, an object (distribution region having a high CT value or voxel value) B is located on the projection line L. If it exists, the voxel position extraction unit 22 extracts the position of the center position of the object B on the volume model M. That is, in the display unit 31, if any object B exists on the front side of the object A in the specified designated area, the three-dimensional position of the object B is extracted.

In addition, the line-of-sight direction distance calculation unit 16
The distance (AB) between the designated position (point A) and the position B, the distance (BC) between the position B and the position C, and the like are also calculated.

Then, the weighting factor calculator 21 uses the preset weighting function to weight the weighting factor (first weighting factor) corresponding to the designated position (point A) and the weighting factor corresponding to the position (point B). (Second weighting coefficient) is calculated. Here, it is preferable that the weighting function is, for example, a function having a characteristic that the weight of the designated portion is increased and the weight becomes smaller as the distance from the designated portion increases.

For example, assuming that the transparency is changed by the weighting coefficient and the light (voxel data or CT value) at the point C is 200 when viewed from the line-of-sight direction,
The light becomes 100 at the point B where the blood vessel bi exists, and the light becomes 50 at the point A where the tumor ai exists at the double distance. Here, since the weight coefficient is a weight proportional to the distance, the blood vessel b
At point B with i, 0.5, at point A with tumor ai,
It is 1. In this example, the tumor ai and the blood vessel bi
Although the distance between and is equal to the distance from the blood vessel bi to the point C, if they are not equal, if the distance changes, the weight also changes according to the distance.

When various data conditions such as the weighting coefficient / voxel value (CT value) at the specified position (point A) on the volume model M and the weighting coefficient / voxel value (CT value) at the position (point B) are met. , C based on the data
The T value calculation unit 23, for example, ((first weighting coefficient) (first voxel value) + (second weighting coefficient) (second voxel value)) /
The CT value corresponding to the pixel on the projection line is calculated by a calculation formula such as ((first weighting coefficient) + (second weighting coefficient)).

In the above example, the CT value used to display the points on the straight line L is {(weighting coefficient of point A) ×
(Point A light) + (Point B weighting factor) × (Point B light)} /
{(Weighting factor of point A) + (weighting factor of point B)} = 66.
Therefore, the value (CT value in the case of CT) used for displaying the points on the straight line L is 66.7. Where C
The T value is within an allowable range of 100, 200 and the like.

In this way, when the CT value is calculated for one pixel on the projection plane, the CT value corresponding to each pixel on the projection plane is calculated in the same manner as described above, that is, the plane H in FIG. The same processing is performed over the whole.

Here, if the distance between the tumor A and the blood vessel B is extremely short, there is no difference in the CT values at each point. In such a case, for example, by squaring the weighting coefficient, the difference becomes clearer.

As a weight function for calculating the weight coefficient, there are various function setting methods. For example, if the weight is taken on the vertical axis and the distance is taken on the horizontal axis, and the weight is set to 1, and the distance is to some extent, for example, the size of the tumor is about 2 cm, it is straight up to about 2 cm and has a certain length. The nonlinear function shown in FIG. 10A may be used so that the weight is reduced when the value exceeds.

As described above, when the weighting coefficient is thinned from the designated point, an example of the weighting function that defines the weighting coefficient may be the linear function or the curvilinear (2 A second-order curve, a hyperbola, or the like) or a non-linear function may be used.

Compared to the case where the weights are changed linearly and uniformly according to the distance, the lightness becomes weaker when the weighting coefficient is obtained by squaring the weights. , The image of the indicated point is displayed more clearly. When the tumor ai is small, the weighting factor is 2
It is better to use a value that has been multiplied, but when the tumor ai is large, it is preferable to use a value that does not square as a weighting factor. After all, it is preferable to change the method of multiplying the weighting factors according to the size of the tumor. Furthermore, it is preferable to change the method of calculating the weighting factor depending on the size and positional relationship between the blood vessel bi and the tumor ai, that is, how much the blood vessel bi has reached the tip of the tumor ai.

When the method of calculating the weighting coefficient is changed, it is preferable that the function can be changed in various ways. Here, for changing the function, for example, various functions may be registered in advance so that the function can be selected from a plurality of selection units displayed on the display screen.

As shown in FIGS. 10A and 10B,
The weighting function F1 is configured to be changeable by performing an operation such as pinching the line portion of the function displayed in a graph with the pointer P or the like. FIG. 10 (A)
In the example of (B), when the horizontal axis is the distance and the vertical axis is the weighting factor, for example, the weighting function F1 as shown in FIG.
By changing and setting F2 to F5, the transparency is changed by the weighting coefficient.

Further, the weighting function is not limited to the above example, but a dedicated function is provided in advance, and a curve as shown in FIGS. 10A and 10B is drawn on the screen by manual operation. May be configured so that As a result, the function curve can be extended by grasping it with the operation unit (mouse), or can be newly created, and can be freely set.

Further, for example, function keys for selecting a plurality of respective functions are prepared (a plurality of functions are registered in the function keys), and the optimum function may be selected while referring to the screen. . In this case, if you press any one of the function keys,
A screen of a function registered in advance is called, and the function displayed on the screen can be finely adjusted and set and registered.
Alternatively, a function key in which a function is newly registered may be generated.

By doing so, it is possible to provide a plurality of function keys dedicated to the preferences of a plurality of users (doctors). With this, it is possible to configure a plurality of ways of changing the transparency, and for example, the transparency can be changed by a function depending on the size of the tumor, and can be freely changed according to the purpose for viewing a specific region. In the X-ray CT apparatus, for example, a function key for tumor, a function for blood vessel, etc. may be configured.

(Regarding Processing Procedure) Next, in the image processing apparatus having the above-described configuration, more detailed calculation steps for calculating the CT value in consideration of the weighting coefficient will be described with reference to FIG. . It should be noted that in the present embodiment, the stereo model generation unit 12 uses the CT device or the MRI.
A three-dimensional object based on the slice image obtained by the method etc. is generated in the object space by voxels.

First, the processing for setting the weighting function will be described. Using the weighting function setting unit 31a, the device user sets and inputs parameters such as distances and weighting factors for determining the gradient of the weighting function with reference to the designated position (point A) designated in the tumor ai. I do. At this time, for example, in the default setting, the weighting function F1 as shown in FIG. 10 (A) is displayed, and the pointer P is used as necessary to
As shown in FIG. 10B, it is possible to change to various characteristics. When setting input is performed, a corresponding weighting function is generated, and the weighting function setting unit 31 stores the characteristics of the weighting function in the image storage unit 11 in a table format.

By setting the weighting function in advance and performing the processing described below, the object in the specific area of the volume rendering image is clearly displayed.

Next, in order to form a volume rendering image on the display screen of the display unit 31, first, a stereo model is generated based on the slice image obtained by the CT device or MRI and stored in the image storage unit 11. The unit 12 generates a voxel space (coordinate system) having a three-dimensional structure (step, hereinafter "S" 101), and generates a volume model in which color information corresponding to the CT value is assigned to each voxel (S102).

When this volume model is generated and an image is displayed, for example, a volume rendering image as shown in FIG. 5 is created from the three-dimensional image shown in FIG. Here, for simplification, as shown in FIG.
And the blood vessel bi are set to remain.

Further, the projection processing unit 15 performs projection processing from a predetermined viewpoint position and line-of-sight direction (V) onto a three-dimensional object (object) defined by voxels in the object space,
A volume rendering image including the tumor ai, the blood vessel bi, etc. is generated, and the image processing unit 17 displays the image viewed from the line-of-sight direction V on the display unit 31 (S103). Here, in the projection processing, when the projection processing unit 15 performs ray tracing on the three-dimensional object from the pixels on the projection surface, the pixel coordinates ki thereof are read.

Here, when the display is performed by the conventional method, the light incident from the direction V shown in FIG. 5 is blocked by the blood vessel bi, and as shown in FIG. 7, the tumor ai becomes the blood vessel bi.
Hide in.

On the other hand, in this example, as shown in FIG.
The position of the tumor ai is designated by the pointer P using the operation unit 32 with a three-dimensional cursor, a mouse or the like. At this time,
As shown in, the position A of the designated tumor ai is assumed to be the center (255, 255, 255) of the volume image. Further, on the straight line L connecting the points A and C, the position A (255, 255, 255) of the tumor ai and the position B of the blood vessel bi are located.
(255, 383, 255), point C (255, 511,
255), and the position B is between the positions A and C. Furthermore, when light enters from the direction of point C, the tumor ai is attenuated more than the blood vessel bi, and the attenuation is
It is assumed to be inversely proportional to the distance. For example, if the incident light is 200, it is 200 at point C, 100 at blood vessel bi, and tumor ai.
Now let's say 50. At this time, for example, the weighting function in FIG. 10A is used as the weighting function.

When the pointer P or the like is designated by the user of the apparatus at the designated position of the specific region (tumor ai shown in FIG. 7) on the volume rendering image, the volume model position calculation unit 14 determines that the designated position is the volume model. Calculate what position it is above. That is, when the pointer P is designated at the position of the tumor ai by the operation of the operation unit 12, the coordinates of the position (tumor ai) designated by the pointer are extracted (S104). When there is an image (blood vessel bi) between ACs, the voxel position extraction unit 22 extracts the coordinates of a point (for example, blood vessel bi) on the straight line L connecting ACs (S105). If the pixel coordinates ki on the projection surface do not include an object such as a blood vessel bi, the weighting function is not calculated.

Then, the distance between AC and the distance between BC are calculated (S106). Next, the weighting factors in A and B are calculated from the weighting function representing the designated or selected "weight" (S107). Specifically, the weight coefficient calculation unit 20 calculates the weight coefficient at the point A, the weight coefficient at the point B, the weight coefficient at the point C, and the like from the distance between the weight function and AB, the distance between BC, and the like.

On the other hand, when the incident light enters at the point C, the CT value calculation section 23 determines the voxel value (CT value) at the point C.
Where v is a predetermined value, each voxel value of points A and B (C
(T value) is extracted (S108), the weighting factors of the points A and B,
The CT value of the point C on L is calculated based on the CT values of the points A and B and the distance between the points A, B, and C (S109).
Then, for all the points on the plane H, the above S109
Is calculated and each CT value is calculated (S110). In this way, the transparency of the voxel information is determined using this weighting function, and the image obtained by integrating the transparency based on the weighting function and the brightness at the voxel is projected onto the pixel on the projection surface.
Then, the transparency of the information of the voxel of the three-dimensional object is determined by using the weighting function, and the image obtained by integrating the transparency and the brightness at the voxel is projected on the pixel on the projection surface. For example, when the head is a voxel and is defined in the object space as a three-dimensional object, and the weighting function is set,
Projection is performed on pixels on the projection surface using this weight function. At this time, the projection processing unit 15 determines whether or not the projection has been completed for all pixels on the projection surface, and if it is determined that the projection has not been completed, the projection processing unit 15 updates the pixel on the projection surface to the pixel at the next coordinate. Then, the contour of the tumor ai is displayed on the display unit 31 (S111).

In the conventional display, since the light incident from the point C is blocked by the blood vessel bi, the CT value for displaying is displayed using 100, which is described above. As shown, the tumor ai is blocked by the blood vessel bi.

In this embodiment, the designated point (tumor ai)
To the plane H shown in FIG. 7 by weighting. For example, when the weight function is set to the weight function F1, the weight coefficient is set to “1” when the CT value is 50, and the weight coefficient is set to “0” when the CT value is “200”. Since the curve has a gradient, the weight of the tumor ai is 1 and the weight of the blood vessel bi is 0.5, as shown in FIG. Then, the value of the point on L to be displayed is
The calculated value is 66.7. If this is performed for all points on the plane H, the blood vessel bi that blocks the tumor ai will become semitransparent and disappear, and the tumor ai will be clearly visible.
As shown in FIG. 8, the contour of the tumor ai hidden under the blood vessel bi can be seen.

In this way, by designating one point in the image photographed in three dimensions and changing the transparency according to the distance from the designated point, the tumor is displayed as shown in FIG. When you want to see etc., blood vessels, which are obstructive structures, become translucent. Therefore, the shape of the tumor or the like can be recognized from any direction, and the surrounding structure can be grasped.

As described above, according to the present embodiment, as the distance from the desired portion of the tumor or the like is increased, the weight is lightened so that the portion other than the desired portion becomes semi-transparent, and the desired portion of the tumor or the peripheral portion is seen. The structure of the tumor can be easily seen, and in particular, the state of the tumor can be clearly understood while observing the relationship between the tumor and the blood vessel.

In the present embodiment, the case where there is one designated position designated by the operation unit has been exemplified, but the present invention is not limited to such a case, and when a plurality of other designated places are designated, for example, 2 It may be applied when specifying a location or the like. Further, in the present embodiment, as an example of the weight function, the case where the reciprocal number based on the designated point is used as the weight is illustrated, but the example of the weight function is not limited to this, and is inversely proportional to the square of the distance, for example. It may be a case where various other methods such as the method are used.

Further, in the above embodiment, the processing in the case where only the tumor, the blood vessel and the like are displayed and designated in the volume rendering image has been described. However, other structures of the head, such as other tumors and The same applies when other various organs and the like are designated in a displayed state. Of course, even when a tumor (region of interest), a blood vessel, or the like is extracted by using each function relating to a predetermined transparency, it can be easily realized by further performing the correction calculation of the CT value by the weighting function.

Furthermore, when the size of the tumor is large,
A region of interest including a designated point in a tumor (region of interest) is processed by a dedicated weighting function (different from the opacity curve when extracting the region of interest) different from the weighting function. You may. In this case, when the device user sets a region of interest on the volume rendering image, the region of interest calculating unit 19 recognizes the region and allocates the region of interest to the projection plane, and pixel coordinates in the region of interest are calculated. When the pixel coordinates Pi corresponding to ki are set in the image storage unit 11, a code indicating the region of interest is added to each pixel coordinate Pi in the region of interest on the projection surface and stored in the image storage unit 11. Therefore, the weighting function calculation unit may use the weighting function of the region of interest when the code is detected, and may use the weighting function when the code is not detected. With such a volume rendering display, regions other than the tumor ai are displayed with the weighting function F1 transparency, and the tumor ai is displayed with the weighting function F.
By displaying with a weighting function different from 1, for example, the tumor is clearly visible in the tumor ai, the blood vessels bi in regions other than the tumor ai are thinly visible, and the tumor ai itself is semitransparent, or Conversely, it can be emphasized.

Furthermore, the image processing as exemplified in this embodiment has been described with respect to the three-dimensional image generated by the volume rendering image, but the three-dimensional image generated by various other display methods is designated. It does not matter if you do. Here, various display methods include volume rendering method, surface rendering method,
It refers to various other image display methods such as the MIP method, the MinIP method, and the X-ray projection method.

[Second Embodiment] Next, a second embodiment according to the present invention will be described with reference to FIGS. Note that, in the following, description of substantially the same configuration as that of the first embodiment will be omitted, and only different portions will be described. FIG. 10 is a functional block diagram showing an example of the configuration of the medical image diagnostic system of this embodiment.

The medical image diagnostic system 1 of this embodiment is
As shown in FIG. 11, an X-ray CT apparatus, an X-ray diagnostic apparatus, M
Various modalities 201 (medical image diagnostic apparatus) such as RI apparatus, ultrasonic diagnostic apparatus, and SPECT apparatus, and various image processing is performed on the image information acquired by the modality 201 to generate, for example, a three-dimensional image. And a displayable image processing device 200a.

The image processing apparatus 200a has the modality 20.
1. An image storage unit 202 for storing the image information acquired in 1 and an MIP image creation processing unit 203 for creating a MIP image based on the image information in the image storage unit 202.
A MIP number setting processing unit 204 for processing the set number of MIPs, a display unit 205 for displaying these various image information, MIP images, etc., and a display mode displayed on the display unit 205 (for example, MIP Image display mode, <M
Display mode switching unit 206 for switching between non-IP> tomographic image display mode and 3D image display mode, operation unit 207 for performing various operations on the display screen, transfer of image information in image storage unit 202, etc. An image transfer unit 208 for performing processing, and a control unit 209 for controlling these units
And are included. In addition, M of the present embodiment
The IP image creation processing unit and the control unit constitute the “image creation unit” according to the present invention, and the MIP number setting processing unit and the display setting unit described later according to the present invention include the “setting unit” according to the present invention. Can be configured.

The image processing apparatus 2 having the above-mentioned configuration
A case where a three-dimensional image of the head is displayed at 00a using an image captured by, for example, an X-ray CT apparatus will be described. Here, for explanation, the image size is 512 ×
At 512, it is assumed that the number of images (slice images) is 300, for example. The coordinate system is assumed to be as shown in FIG.

As shown in FIG. 12, in the first place, the MIP process is a projection image obtained by projecting the three-dimensional original image onto a plane from a predetermined direction based on a three-dimensional original image formed by stacking a plurality of original tomographic images. Is an image processing for displaying. That is, with respect to all the original images to be processed, the maximum value is extracted for all the pixels in each observation direction to generate a projected image. The value to be extracted here is not limited to the maximum value, and may be a specific value. For example, the second largest value, the smallest value,
It may be an average value or the like. In this way, the lesion area is visualized by contrast imaging.

When the MIP processing is performed in the image processing apparatus 200a having the above structure,
As shown in FIG. 11, the MIP image creation processing unit 203
Using several tens of pieces of image data accumulated in the image storage unit 202, several areas are defined for each image with a small change,
Image data is read from the image storage unit 202 for each area, and MIP processing of the maximum value, the minimum value, the average value, the specific value, etc. is performed for each area. As a result, MIP processed data is generated for each of the divided areas. Image data for division processing is generated for each area divided by the MIP processing unit with reference to the MIP processing data obtained in this way.

Then, by using the obtained image data for the division processing, the MIP image creation processing unit 203 uses the image storage unit 2
02, the MIP processing is executed for each of the divided areas of the image data composed of a series of image groups, and the MIP-processed image data is again processed by the image storage unit 20.
Return to 2. In this case, the MIP processing is performed for each area, so that the efficiency is high and the MIP processing time can be shortened. Also in this case, the region of interest can be accurately extracted.

Then, the M stored in the image storage unit 202
The control unit 209 performs desired image processing on the IP-processed image data and displays it on the display unit 205. In this case, since the image storage unit 202 stores a group of image data that has already been subjected to MIP processing, the image processing in the control unit 209 can be any image processing. That is, a desired image can be easily observed even by MIP processing or 3D processing at an arbitrary angle.

(Display Setting Section) Here, an example of a display setting section capable of setting various setting items in the above-mentioned “MIP processing” will be described with reference to FIG. Figure 14
It is explanatory drawing which shows an example of the display screen of a display setting part at the time of performing the said MIP process.

As shown in the figure, in the display setting section 300, an image number display section 301 displaying the number of images to be MIPed according to the number of slice images, and a delimiter for setting a delimiting method for MIP. Method setting unit 302,
A first division number setting unit 303 that sets the division number when the number of divisions is equal, and a second division number setting unit that sets the number of divisions when the number of divisions is not uniform
A division number setting unit 304, a division direction setting unit 305 for setting the division direction, and the like are formed.

In the delimitation method setting unit 302, for example, various processing forms such as MIP processing by maximum value, processing by minimum value, processing by arithmetic mean value, or processing by various other specific values can be selected and set. It has become.

The first division number setting section 303 is a setting item for evenly dividing, for example, 0 to 300 images, and in the example of the figure, it is "10", so This means that the sheet is divided into 10 sheets, the 10 sheets are subjected to MIP processing into one image, and the total number of images after the MIP processing is 30 sheets.

The second division number setting unit 304 is a setting item when, for example, 0 to 300 images are divided unevenly, and in the example of the figure, the first of the 0 to 300 images is set. The 40 sheets and the last 40 sheets are set to 20 sheets each, and the central portion is set to 10 sheets, for example. As described above, in the case of uneven setting, it is possible to arbitrarily set according to the place.

The first division number setting unit 303 and the second division number setting unit 304 can set equality or unequality, for example, by using check boxes.

The delimiter direction setting unit 305 is a setting item for setting the delimiter direction in a reconstructed image of a multi-slice image in which a plurality of slice images are superposed, and in the example of the figure, an axial direction along the body axis is set. (AX)
It means the case of dividing by. In addition to this, it is also possible to set in a sagittal direction (SA), a coronal direction (CO), an oblique direction (OB), or the like.

In this way, by using the display setting unit 300, various settings in the MIP processing are performed, and the setting is registered by pressing the OK button or the like, and the MIP processing start button or the like (not shown) is used. The MIP process is performed according to the setting condition set by the setting item. When the MIP processing is performed, these setting conditions are stored in the image storage unit 202 together with the image data.
For example, it is stored as a file of supplementary information.

(Processing Procedure) Next, a specific processing procedure for generating a MIP image using the image processing apparatus having the above-described configuration will be described. CT in the image storage unit 202
Alternatively, a large number of image data obtained by MR are accumulated. For example, it is assumed that image data including a series of image groups of dozens of tomographic images in the body axis direction of the chest and abdomen obtained by the helical scan is accumulated.

As a more detailed calculation step, in the image processing apparatus having the above-described configuration, first, by using the display setting unit 300 as shown in FIG. 14, per group divided when performing MIP processing. Number of sheets (in the present embodiment, for example, every 10 sheets). As a result, the MIP number setting processing unit 204 performs a process of dividing each slice image into each predetermined group. And FIG.
As shown in FIG. 5, the MIP number information is extracted and the coordinate values (x, y, 9), (x, y, 19), (x, y, 19) to be classified are (x, y,
29) ... Is calculated (S201).

Next, the MIP image creation processing unit 203
For example, MIP based on up to 10 slice images
Processing for creating an image is performed (S202). Here first
The process (S210) of generating "MIP image 1" will be described. In the following, the coordinate value of the reference voxel is (x, y, z) = (0, 0, 0), and for example, x = 0
The row is originally the “first row”.

Then, the coordinates (x, y, z) = (0, 0,
A process of setting the maximum pixel value among the pixel values of 0) to (0, 0, 9) as the pixel value of the coordinates (X, Y) = (0, 0) of the MIP image is performed (S211 (1, 1)). Nochi, Figure 1
As shown in FIG. 2, a straight line M (x and y are the same but z is different,
The first pixel value of "MIP image 1" is determined from 10 points on the (pixels along the z-axis direction). Here, it is assumed that the xy coordinate system of the three-dimensional image and the xy coordinate system of the MIP image are the same. Then, as to how to determine the pixel value of "MIP image 1", as shown in FIGS. 12 and 13, when the pixel values of 10 points on the straight line M are seen, the maximum value is set to the first pixel of "MIP image 1". The value. For example, assuming that the pixel values of 10 pixels along the z-axis direction shown in FIG. 12 are as shown in FIG.
Since the maximum value of the pixel values is "9", the pixel value "9" is set as the pixel value of the corresponding position of the "MIP image 1".

Similarly, coordinates (x, y, z) = (0,
A process of setting the maximum pixel value among the pixel values of (1,0) to (0,1,9) as the pixel value of the coordinates (X, Y) = (0,1) of the MIP image is performed (S211 ( 2, 1)). Then, the second pixel value of the "MIP image 1" is determined from 10 points on the straight line N adjacent to the straight line M. Also at this time, "MIP
To determine the pixel value of "Image 1", as shown in FIGS. 12 and 13, the maximum pixel value of the pixel values at 10 points on the straight line N is set as the next pixel value of "MIP image 1". For example, in FIG.
Each pixel value of 10 pixels along the z-axis direction shown in FIG.
If the value is 2, the maximum value of the pixel values is “7”, and thus the pixel value “7” is set as the pixel value of the corresponding position of the “MIP image 1”.

In this way, the y coordinate is "0" to "5".
The same processing is performed until it becomes "11". Finally, coordinates (x, y, z) = (0, 511, 0) to (0, 51)
The maximum pixel value among the pixel values of (1, 9) is set as the pixel value of the coordinates (X, Y) = (0, 511) of the MIP image (S211 (512, 1)). by this,
The generation of the image value of the X = 0th column in the XY coordinate system of “MIP image 1” is completed.

Next, the coordinates (x, y, z) = (1, 0,
A process of setting the maximum pixel value among the pixel values of 0) to (1, 0, 9) as the pixel value of the coordinates (X, Y) = (1, 0) of the MIP image is performed (S211 (1, 2)). Similarly, coordinates (x, y, z) = (1,1,0) to (1,1,
The process of setting the maximum pixel value among the pixel values of 9) as the pixel value of the coordinates (X, Y) = (1, 1) of the MIP image is performed (S211 (2, 2)). In this way, similar processing is performed until the y coordinate becomes "0" to "511". Finally, coordinates (x, y, z) = (1,511,0)
The process of setting the maximum pixel value among the pixel values of (1, 511, 9) to the pixel value of the coordinates (X, Y) = (1, 511) of the MIP image is performed (S211 (512, 2)). ). As a result, X in the XY coordinate system of "MIP image 1"
= The generation of the image value in the first column is completed.

In this way, similar processing is performed up to the X = 511th column. In the X = 511th column, first, the coordinates (x, y, z) = (511, 0, 0) to (511, 0,
The process of setting the maximum pixel value among the pixel values of 9) as the pixel value of the coordinates (X, Y) = (511, 0) of the MIP image is performed (S211 (1, 512)). Similarly, coordinates (x, y, z) = (511, 1, 0) to (511, 1,)
The process of setting the maximum pixel value among the pixel values of 9) as the pixel value of the coordinates (X, Y) = (511, 1) of the MIP image is performed (S211 (2, 512)). In this way, similar processing is performed until the y coordinate becomes "0" to "511". Finally, coordinates (x, y, z) = (511, 5)
The maximum pixel value among the pixel values of (11, 0) to (511, 511, 9) is the coordinate (X, Y) = (51
1, 511) as the pixel value (S211 (5
12, 512)). In this way, when the process of assigning the maximum pixel value among the pixel values along the z-axis direction for all positions on the xy plane is performed, X = 511 column in the XY coordinate system of “MIP image 1” Is generated, and the creation of “MIP image 1” is completed.

When the process for generating the "MIP image 1" is completed as described above, the process for generating the "MIP image 2" is performed in the same manner as the "MIP image 1" (S21).
2). In the process of generating this “MIP image 2”, “MIP image 2” is generated.
The start coordinates in the “IP image 1” are (x, y, z) = (0, 0,
0) to (0, 0, 9) is (x, y, z) =
It may be set to (0,0,10) to (0,0,19). In this way, the "MIP image 2" is created by performing the above process for the next 10 slice images.

In the present embodiment, the number of slice images along the z direction is 300. Therefore, the above process is repeated and "MIP image 3" ...
A total of 30 "MIP images 30" will be created. In this way, when the processes up to the “MIP image 30” have been performed (S288), the MIP image creation process ends. Furthermore, 30 MIP images can be displayed by performing MIP image display processing (S290).

As described above, according to the present embodiment, a large number of images photographed with a volume are subjected to MIP processing for several images, and the images are divided into several images for MIP display. For example,
In the case of evenly dividing by 10, for example, the maximum value in the divided portion is added, and some divided portions are displayed. As a result, the image interpretation time can be shortened, an image that is easy to see can be provided, and the entire image can be easily grasped.

In the present embodiment, 10 sheets are MIPed at equal intervals, but the number of MIPs is not limited to the above, and other numbers, for example, as shown in FIG.
The number of sheets may be 15, and every 5 sheets in the central portion (K1). For example, when an image of the head is collected, there is little information in the end area. Therefore, when the MIP processing is performed, the edge region is set to about 15 sheets, the central region is set to about 5 sheets, and it is possible to make only the desired portion such as the blood vessel of the head easy to see. Since there is a large amount of information in the central area, it is preferable to make the number of divisions dense (fine division).

Further, in the present embodiment, the MIP
However, the present invention is not limited to MIP (calculating the maximum value). For example, the average value may be used, the second highest value instead of the maximum value may be used, and the average value of five out of ten may be used. Alternatively, as another processing form, a process of adding half the pixel value having the higher luminance value and taking the average thereof may be performed. In short, a predetermined pixel may be extracted by performing a predetermined process from the plurality of pixels. Alternatively, the 10 sheets at the edge have the second largest value, but the maximum value may be set toward the center. Of these various types, in the case of MIP treatment, blood vessels, tumors, etc. are particularly emphasized and displayed.
The processing is preferable because the characteristic points can be easily found.

The apparatus and processing procedure according to the present invention are as follows.
Although described according to some specific embodiments thereof, various modifications can be made to the embodiments described in the text of the present invention without departing from the spirit and scope of the present invention. For example, in the above-described first embodiment, an example in which an X-ray CT apparatus is used as a modality has been described, but the present invention is not limited to this, and other modalities such as an MRI (nuclear magnetic resonance imaging) apparatus, SPECT or PET, X Line imager,
As an ultrasonic diagnostic apparatus and further an X-ray imaging apparatus,
"Fluoroscopic imaging device", "Multipurpose X-ray diagnostic imaging device", IV
It may be an R-CT device or the like.

In the first embodiment, the case where the specific region (region of interest) is designated by the operating means has been described as an example, but the present invention is not limited to this, and a specific region registered in advance may be used. Further, in the above-described first embodiment, the case where the designation is made in the volume rendering image by volume rendering has been illustrated, but the designation may be made in the three-dimensional image displayed by various other methods. Furthermore, in the first embodiment, the method of changing the weighting function and the transparency may be selected from several types or may be registered by oneself.

Furthermore, in the second embodiment,
Divide many images taken in 3D into several images
Although the “MIP” process for displaying the IP or the like has been described, the process is not limited to such a process, and may be a process for simply superimposing the tomographic images. At this time, the number of MIPs and the number of overlappings can be changed. Further, in the second embodiment described above, the case where the “MIP” direction is the axial direction has been described, but the present invention is not limited to this, and the sagittal direction, the coronal direction, the oblique direction, etc.
It goes without saying that "MIP" processing in any direction is possible.

Furthermore, in the second embodiment,
For example, when the image is reconstructed by the modality, the MIP process may be divided into the original tomographic images, and the reconstruction process may be performed on the MIP-processed data. In this case, MIP processing is performed on each tomographic image of the subject for each predetermined number of slices, and image creating means for creating a plurality of MIP processed data of the subject, and data subjected to MIP processing by the image creating means. It is preferable to have a reconstructing unit that performs a reconstructing process and creates a tomographic image after the MIP process, and a display unit that displays a plurality of tomographic images obtained by the reconstructing unit.

Further, as the medical image diagnostic system of the above-mentioned embodiment, one or a plurality of medical image storage devices (image server) connected to a modality via a network, one or a plurality of image reference terminals (image viewer). Three
(Including a D workstation, etc.) may be configured. At that time, if the terminal has a 3D display function, the program for the processing described in each of the embodiments may be installed in the terminal.
Furthermore, the processing program processed in the medical image diagnostic system, the described processing, the whole data or each part may be recorded in an information recording medium. As the information recording medium, an optical disc, a magneto-optical disc, a magnetic recording medium or the like may be used, and further, a CD-RO.
M, hard disk, CD-R, CD-RW, DVDR
It may be recorded in an AM, a DVDROM, an MO, a ROM, a RAM, a non-volatile memory card, or the like to be configured and used.

By using this information recording medium in a system or apparatus other than the system according to each of the above-mentioned embodiments and reading the program code stored in this storage medium and executing it, the above-mentioned each of the above The function equivalent to that of the embodiment can be realized, and the same effect can be obtained.

Further, the above embodiment includes various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Moreover, it goes without saying that examples including the above-described respective embodiments or a combination of any of them with any of the modifications are included. Further, some constituent elements may be deleted from all the constituent elements shown in the embodiment.

[0127]

As described above, according to the present invention, one point is designated by the operating means in the three-dimensional image displayed on the display screen, and the distance from the designated point to the viewpoint position side. Corresponding weighting factors corresponding to each voxel value are correlated and displayed with varying transparency, which makes the obstructive structure, etc., of the object other than the specific area to be seen semi-transparent, and allows the specific area, such as a tumor, to be seen from all directions. It is possible to recognize the shapes such as, and also grasp the surrounding structure.

Further, according to another aspect of the present invention, a plurality of stacked images are divided into a plurality of groups to form a plurality of groups, and one group of pixels in the stacking direction of each image is used. By extracting a specific value with respect to the pixel value of, a projection image is created, and this image is displayed, even if the number of images is increased, the image can be read in a short time.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an example of a schematic configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing an example of the configuration of an X-ray CT apparatus including the image processing apparatus of FIG.

3 is an external view showing an example of the image processing apparatus of FIG.

FIG. 4 is an explanatory diagram showing a display example of a three-dimensional image of the head displayed on the display unit of the image processing apparatus of FIG.

FIG. 5 is an explanatory diagram for explaining a volume rendering.

6 is an explanatory diagram for explaining a rendering process in the image processing apparatus of FIG. 1. FIG.

FIG. 7 is an explanatory diagram for explaining image display after conventional volume rendering.

8 is an explanatory diagram for describing image display after volume rendering in the image processing apparatus of FIG. 1. FIG.

9 is a flowchart showing an example of a processing procedure in the image processing apparatus of FIG.

10A and 10B are explanatory diagrams showing an example of a weighting function.

FIG. 11 is a functional block diagram showing an example of a schematic configuration of an image processing apparatus according to an embodiment of the present invention.

12 is an explanatory diagram for explaining the principle of MIP processing in the image processing apparatus of FIG.

13 is an explanatory diagram for explaining the principle of MIP processing in the image processing apparatus of FIG.

14 is an explanatory diagram showing an example of a setting screen for MIP processing in the image processing apparatus of FIG.

FIG. 15 is a flowchart showing an example of a processing procedure when performing MIP processing under a certain condition.

FIG. 16 is an explanatory diagram for explaining the principle of performing MIP processing under other conditions.

FIG. 17 is an explanatory diagram for explaining image display after conventional volume rendering.

[Explanation of symbols]

1 Medical diagnostic imaging system 10 Image processing device 11 Image storage 17 Image processing section 21 Weighting factor calculator 23 CT value calculator 31 Display 31a Weighting function setting unit 32 Operation part 34 Control unit 200 medical diagnostic imaging system 200a image processing apparatus 202 image storage unit 203 MIP image creation processing unit 204 MIP number setting unit 205 display 206 Operation unit 209 Control unit 300 Display setting section

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01R 33/32 G01N 24/02 520Y F term (reference) 4C093 AA22 AA26 CA23 FF43 FG04 4C096 AB50 AD14 AD15 DC36 DC40 DD08 5B050 AA02 BA03 BA09 BA15 CA07 DA02 EA07 EA27 EA29 FA02 FA06 5B057 AA09 BA24 CA08 CA13 CB08 CB13 CB16 CH01 CH11 DA16 5B080 AA17 BA07 FA17 GA26

Claims (5)

[Claims] 1. A volume model obtained by dividing into voxels is generated, the volume model is projected from a predetermined viewpoint position, information of each voxel is projected onto a projection surface, and a volume rendering image of the projection surface is displayed. An image processing device for performing display processing on a display screen, comprising: operating means for designating a designated point with respect to a specific area on the volume rendering image displayed on the display screen; and the viewpoint from the designated point specified. For each voxel value in the voxel space on the position side, at least the weight of the designated point becomes large and the weight of each voxel value in the voxel space becomes small. A calculation unit that performs calculation processing, and image information based on the corrected voxel value calculated by the calculation unit is projected on each pixel of the projection surface to An image processing device, comprising: an image processing unit that displays the volume rendering image having a changed brightness on the display screen. 2. The calculating means includes weighting coefficient calculating means for calculating each weighting coefficient of each corresponding voxel based on a weighting function indicating a weighting coefficient according to a distance from a designated designated point. The image processing apparatus according to claim 1, which is characterized in that. 3. A weighting function setting means for arbitrarily setting the weighting function on the display screen, wherein the weighting coefficient calculating means calculates each weighting coefficient of each corresponding voxel based on the weighting function. The image processing apparatus according to claim 1, which is calculated. 4. An image processing apparatus for performing image processing for displaying a projection image obtained by projecting the three-dimensional original image from a predetermined direction on a projection surface based on the three-dimensional original image, wherein the plurality of original tomographic images Setting means for making a setting for dividing a predetermined number of sheets into a plurality of groups in the stacking direction, and for each of the plurality of groups set by the setting means,
For each of the original tomographic images forming one group, a projection image in a predetermined direction is created by performing a predetermined process on pixel values of pixels for one group in the stacking direction of the original tomographic images. An image processing device comprising: 5. The image creating means performs a process of extracting a specific value from pixel values of pixels in at least one group in the stacking direction.
The image processing device according to item 1.