JPS63223885A - Stereoscopic image display device - Google Patents

Abstract

PURPOSE:To enable accurate projection even when a complex structure is an object by generating a projection image while putting a view point to be projected in three-dimensional image data. CONSTITUTION:A projection image generation part 2 generates the projection image according to three-dimensional image data stored in a three-dimensional image storage part 1. In this case, an observer sets a view point axis Z and projection distances r1 and r2. Then an imaginary line 9 is drawn from the view point axis Z to a projection surface 8 and voxel data at an object position 6 is ranges of r1 and r2 are integrated radially along the imaginary line 9 to generate the projection image. Then the imaginary line 9 is shifted clockwise by DELTAtheta deg. and similar arithmetic processing is carried out to generate a 2nd projection image. Thus, the line is shifted by DELTAtheta deg. successively to perform the similar processing over the 360 deg. range and projection images are stored in a projection image storage part 3. Then an image to be viewed actually is segmented by a segmenting part 4 and displayed stereoscopically on a display device 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to a three-dimensional image display device that creates and displays an arbitrary projection image based on three-dimensional image data.

(Prior art) There are various known stereoscopic image display methods using I processing, such as the cross-section conversion method, 2-surface display method, multi-frame display method, and reprojection display method. The most suitable method is selected accordingly. Among these, the reprojection method is an effective display method when expressing the internal structure.
A projected image is reconstructed by integrating three-dimensional voxel data obtained from a T-multilayer surface in the direction of the viewer's line of sight.

Such a reprojection method is described in the following literature (1), for example:
, C2).

(1) L, r), Harris, “Dispi
ay and Visualization of Th
ree-Dementiona! Reconstruct
cted AnatomicMorphology;
Experience with the T
horax, Heart and Coronary V
asculaturc of Dogs”, J, Co.
mpt.

As5ist, Tomoraphy, Vol, 3, N
o, 4 (1979) (2) L, ri, 1larri
s, “Identification of th
e Optimal Orientation
of 0blique 5ections dingh
rou-gh Multiple CT! mages
,” J,Compt,As5ist.

Tomography, Vo! ,5. No, 6.
(1981) (Problem to be Solved by the Invention) However, in such conventional reprojection methods, the viewpoint from which the projection is performed to obtain the projected image is placed outside the voxel data, so the image surrounding the heart is There is a problem in that it is difficult to express a structure with a three-dimensionally complex shape such as a coronary vein.

For example, when obtaining an X-ray CT image, if you select an area like the head that is surrounded by substances with high X-ray absorption (bone, etc.), the target area will be accurately projected due to the influence of this substance. There is a possibility that it cannot be done. For this reason, it is necessary to perform projection after recognizing and erasing substances with a high X-ray absorption rate, such as bones, which becomes time-consuming.

The present invention has been made in response to the above-mentioned problems.
It is an object of the present invention to provide a stereoscopic image display device that can perform accurate projection even when a structure having a three-dimensionally complex shape is targeted.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention is characterized in that a projected image is created outward from a viewpoint placed inside three-dimensional image data. It is said that

(Function) Since the projected image is created by placing the projection viewpoint inside the three-dimensional Ryokai data, accurate projection can be performed even when a complex structure is targeted.

(Embodiment) FIG. 1 is a block diagram showing a stereoscopic image display device according to an embodiment of the present invention. 1 is a three-dimensional image storage unit for storing CT multi-sectional images obtained by, for example, an X-ray CT device, an MRI device, etc. as three-dimensional image data, and stores voxels as units from a plurality of CT images. A three-dimensional image is created and stored. 2 is a projection image creation unit that creates a projected image outward from an arbitrary point inside the three-dimensional image data as a viewpoint, and integrates voxel data to create a projected image and viewpoint from the viewpoint to the outside. A projection image is created over a range of 360" with the center at the center. 3 is a projection image storage section for storing the projection image obtained in the above manner. 4 is a display image cutting section for storing the projection image obtained in the above manner. This is for cutting out an image that you actually want to see along an arbitrary viewing direction based on the projection image stored in the image storage unit 3 and displaying it on a display device 5, which will be described later. It consists of a CRT display, etc.

Next, the operation of this embodiment will be explained.

The projection image creation unit 2 creates a projection image by performing arithmetic processing based on the three-dimensional image data stored in the three-dimensional image storage unit 1 using the method shown in FIGS. 2 and 3. First, the observer determines the viewpoint axis Z and the projection distance r1. Give r2. 6
7 shows the projection target part, 7 shows the three-dimensional image data, and 8 shows the projection plane.

Next, a virtual line 9 is drawn from the viewpoint axis Z toward the projection plane 8, and a projection image is created by radially integrating the voxel data of the target region 6 within the range of rl and r2 along this line.

Although the range of the target region 6 can be set arbitrarily, it is effective to set a limited range as in this example in order to avoid substances with a high X-ray absorption rate such as bones.

Subsequently, the virtual line 9 is shifted, for example, by Δθ° in the clockwise direction in FIG. 3, and similar arithmetic processing is performed to similarly create a second projection image. Thereafter, the same arithmetic processing is repeated over a range of 360° by shifting each Δθ° to create a large number of projected images.

Figure 4 shows the arrangement of projection images obtained continuously over 360° at intervals of Δθ°, where the horizontal axis is the angle and the vertical axis is the distance from the viewing axis Z (?1 point axis). (depth direction parallel to the depth direction). Such a projected image is then stored in the projected image storage section 3.

Next, based on the projection image stored in the projection image storage section 3, the display image cutting section 4 cuts out the image that the user actually wants to see using the method shown in FIG. 6, and sends it to the surface water device 5. In other words, if we give the line of sight direction, for example θX, on the projected image like a, then we can cut out the image data of the angle part (θx-n to θx+n) according to the size of the display screen with this angle θX as the center. Display as shown in b. At this time, taking into consideration the curved surface of the projection surface, a corrected display image as shown in C is created so that the screen becomes the same as that projected onto a plane as it moves away from the line-of-sight direction angle.

The display image created in this way is displayed three-dimensionally on the display device 5.

The following two methods can be used for three-dimensional display. One method is to display two images at different angles to the left and right eyes of an observer, and use the left and right parallax angles of the human eyes to create a three-dimensional image. Patent application filed by a person in 1982-
201913).

Another method is to have a display device display an animation of a display screen that gradually changes the line of sight angle, and perform stereoscopic display using motion parallax.

With either of these methods, projection data calculated radially outward from the viewpoint can be displayed as an image with a three-dimensional effect.

FIG. 5 shows another embodiment of the present invention, in which the target region 6
This shows an example in which the range is set to an angle θ of 360° or less. This embodiment is particularly effective when applied when the target region exists in a limited position, and can shorten the calculation processing time.

As another embodiment of the present invention, the projection distance r1. It is possible to make r2 not constant but change for each angle.

This embodiment is particularly effective when applied to target parts with complex shapes.

As described above, according to the embodiment of the present invention, since the projection viewpoint is placed inside the three-dimensional image data, accurate projection can be performed even when a structure with a complicated shape is targeted. Furthermore, since the influence of substances with high X-ray absorption rate can be avoided, projection can be performed without extra effort for this purpose. Therefore, it is a great help for the observer to understand the shape and structure of the projected object.
Diagnostic performance can be improved by applying it to medical equipment.

[Effects of the Invention] As described above, according to the present invention, since a projected image is created from a viewpoint within three-dimensional image data, accurate three-dimensional display can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a three-dimensional image display device according to an embodiment of the present invention, and FIG. 2 is a schematic perspective view illustrating the operation of this embodiment.
3 and 5 are schematic diagrams illustrating the operation of this embodiment,
FIGS. 4 and 6 are data layout diagrams explaining the operation of this embodiment. 2... Projection image creation unit, 3... Projection image storage unit, 4
...Display image cutting section, 6...Target part, 8...
・Projection surface. Agent Patent Attorney Norihiro Chika Ken Zhou Daiko Norifu Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) In a three-dimensional image display device that creates and displays an arbitrary projection image based on three-dimensional image data, there is a three-dimensional image storage unit that stores CT multi-sectional images as three-dimensional image data, and a three-dimensional image storage unit that stores CT multi-sectional images as three-dimensional image data. A stereoscopic image display device comprising: a projection image creation unit that creates a projection image outward from a placed viewpoint; and a projection image storage unit that stores the projection image. (2) The stereoscopic image display device according to claim 1, further comprising a display image cutting section that sequentially cuts out and displays the projected images in the viewing direction. (3) The stereoscopic image display device according to claim 1, wherein the projection image creation section creates the projection image only within a certain limited range of distance from the viewpoint.