JPH03219377A - Three-dimensional image processor - Google Patents

Abstract

PURPOSE:To obtain effective stereographic information by fast processing by preparing mask data in addition to voxel data, and processing a three- dimensional image without working the voxel data. CONSTITUTION:A voxel data generating part 2 generates the voxel data by performing the binarization processing of three-dimensional data stored in a three-dimensional storage part 1 by using a thresh-old value, etc. A mask data generating part 5 generates the voxel data for masking according to cutting shape designated by an operator. Then, the voxel data for masking representing the cutting shape in addition to the voxel data is prepared, and respective distance image can be generated by performing the beam tracing processing of the voxel data and the mask data. Working is performed by executing the arithmetic processing of both distance images of the voxel data and the mask data, and the change of shape to be worked is performed by changing only the mask data without working the voxel data. In such a way, the fast processing can be realized, and the effective stereographic information can be obtained.

Description

[Detailed description of the invention] [Objective of the invention] (Industrial application field) The present invention performs surface display by performing processing such as drilling and cutting data at high speed without changing three-dimensional data. The present invention relates to a three-dimensional image processing device.

(Prior Art) In the surface display method, when three-dimensional cutting or other processing is performed, a method has conventionally been used to create a surface image by processing the three-dimensional data itself that generates the surface image. Fig. 12 is an explanatory diagram of this conventional method, in which the three-dimensional data of A is cut at arbitrary positions as shown in B, and the three-dimensional data of the cut shape is created as shown in C, and then the MPR image is obtained as shown in D. are generated and synthesized as shown in E, and then displayed as a surface display image as shown in H. F and G are surface display images corresponding to A and B, respectively.

In this case, a storage medium is required to store the processed voxel data as well as the original voxel data (stereoscopic data). Furthermore, since the data is changed three-dimensionally, the amount of calculation becomes enormous each time the shape and direction of cutting is changed, resulting in a considerable amount of processing time being unavoidably consumed.

(Problems to be Solved by the Invention) In this way, with conventional three-dimensional image processing devices, the processing time becomes long, which reduces diagnostic efficiency, and the processing direction is restricted to be orthogonal to the projection plane, so it is difficult to There is a problem that it is not possible to observe the situation. In other words, since effective three-dimensional information cannot be obtained, the accuracy of diagnosis and treatment decreases.

The present invention has been made in response to the above-mentioned problems.
It is an object of the present invention to provide a three-dimensional image processing device that can perform high-speed processing and obtain effective three-dimensional information.

[Configuration of the Invention (Means for Solving the Problems)] In order to achieve the above object, the present invention provides means for generating voxel data reflecting three-dimensional data obtained by an arbitrary diagnostic device, and an operator means for generating mask data in accordance with the line of sight direction and cutting direction specified by; means for generating a distance image of a voxel by ray tracing the voxel data; and means for generating a distance image of the mask by ray tracing the mask data. means for generating a surface display image by performing shading processing on a voxel distance image; means for cutting out and generating an image of a cut surface based on three-dimensional data; and a means for generating a surface display image and a cut surface image. The present invention is characterized by comprising means for synthesizing and displaying the images.

(Function) In addition to voxel data, voxel data for a mask (mask data) indicating the cutting shape is prepared, and each distance image is generated by performing ray tracing processing on the voxel data and mask data. Processing is performed by processing both distance images of voxel data and mask data,
The processing shape is changed by changing only the mask data without processing the voxel data at all. Further, the processing direction is changed by changing the direction of ray tracing without changing the mask data. After performing shading processing on the voxel distance image to generate a surface display image and a cut surface image, the surface display image and the cut surface image are combined and displayed on a display. As a result, not only the surface display image but also the cut surface image can be displayed, so that the inside of the cut can be observed and effective three-dimensional information can be obtained. Further, since the voxel data is not processed in any way, there is no need for a storage medium to store the processed voxel data, and as a result, the amount of calculations is reduced and the processing time is shortened.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the three-dimensional image processing apparatus of the present invention, in which numeral 1 denotes a three-dimensional data storage unit, for example, an X-ray CT
Three-dimensional data (or multi-slice data) obtained by a medical image diagnostic apparatus such as an MR device or an MR device is stored. 2 is a voxel data generation unit for generating voxel data by binarizing the three-dimensional data stored in the three-dimensional data storage unit 1 using a threshold value or the like. 3 is a first ray tracing processing unit for performing ray tracing processing on voxel data according to the line of sight direction specified by the operator; 4 is a distance image generation unit for generating a distance image of voxels according to the first ray tracing processing; It is for generating.

5 is a mask data generation unit for generating mask voxel data (mask data) according to the cutting shape specified by the operator.

6 is a second ray tracing processing unit for performing ray tracing processing on the mask data according to the viewing direction and cutting direction designated by the operator; 7 is a mask distance image generation unit for performing ray tracing processing on the mask data according to the second ray tracing processing This is for generating a distance image of a mask.

The ray tracing process can be performed by a well-known method as shown in FIGS. 7(a) and 7(b), in which voxel data and mask data are traced from the projection planes Fv and FM using ray vectors, respectively. By checking the presence or absence of a distance image, a distance image can be generated. Figure 7 (
The position of the projection plane F7 in a) is determined by the direction from which the operator views the voxel data Dv.

On the other hand, the position of the projection plane FM in FIG. 7(b) is determined by the direction in which the operator cuts (digs) the mask data DM.

Here, a ray ■ is extended from a certain point (X, Y) on the projection plane F9 toward the voxel data Dv, and similarly, a certain point (X, Y) is extended from a certain point (X, Y) on the projection plane F9.

The light ray VM is extended from Y) toward the mask data D4. V for the entire projection plane Fv and FM, respectively.
, VM is extended and according to the flowchart shown in FIG. (corresponding to 4' in FIG. 2) and a distance image of the inner surface of the mask data (representing the depth of drilling and corresponding to 7' in FIG. 2) of the inner surface of the mask data.

8 is a shading processing unit which generates a shading image by determining the brightness value when light is applied to the voxel data Dv from the distance image on the surface of the voxel data Dv. Furthermore, pixel values inside the cut surface are determined from the distance image of the inner surface of the mask data. Reference numeral 9 denotes a three-dimensional data cutting unit for cutting out an image of the cut surface based on the three-dimensional data stored in the three-dimensional data storage unit 1 by a well-known method as shown in FIG. 8, for example. be.

Cutting (drilling) with reference to Figures 8 (a) to (C) below.
How to obtain pixel values inside a plane will be explained.

In the mask distance image of FIG. 8(a), distance values are included only in the area where a hole is to be made, and values that do not represent distance values (for example, -1) are included in other areas. Figure 8(b)
What position is the projection plane Fv (which has no meaning in FM) of the voxel data set for the voxel data, and the point FM (X, Y) on the mask distance image is three-dimensional as follows? It can be converted to the data coordinate system (X-Y-Z).

FM (X, Y) →p (x, y, z)
p in FIG. 8(C) indicates an image cut out from the three-dimensional data, and the pixel values inside this cut (hole-drilled) surface can be determined by the flowchart shown in FIG. 9.

In addition, to create a shaded image from a distance image as shown in Fig. 10, for example, use PhongShadin as shown in Fig. 11.
g can be used. Here, the brightness value ■ of a certain point is determined by the following equation.

I=IbRb+IdRd cosθ/ (r+k)
+■d-R8(CO8θ)''/(r+k) However, ■b=
Strength of environmental light Rb: Reflection coefficient of environmental light d: Strength of light source Rd: Diffuse reflection coefficient on object surface R8: Specular reflection coefficient of object surface r: Distance from viewpoint to object surface θ: Light ray and surface Angle α between the normal line: An angle between the reflected ray and the line of sight. Here, r can be determined from the distance image value, θ can be determined from the amount of change in the distance image value, and α can be determined from θ.

Reference numeral 10 denotes an image synthesis section, and the shading is for displaying a composite image of the surface display image generated by the processing section 8 and the cut surface image cut out by the three-dimensional data cutting section 9. is displayed on an image display unit 11 such as a CRT display as shown in FIG.

FIG. 2 shows an example in which the apparatus of this embodiment shown in FIG. 1 is specifically applied to drilling processing, and parts corresponding to those in FIG. 1 are indicated with the same numbers and suffixes.

The operation of the drilling process shown in FIG. 2 will be described below with reference to the flowchart shown in FIG. 3.

First, in step A, the light rays of the voxel data Dv and mask data DM are advanced by one pitch, and then in step B, the voxel data Dv and the region R where the voxel exists are compared.

If Dv > R, the flow jumps to step J and D
If v≦R, the flow proceeds to step C. In step C, it is determined whether there is data at the coordinates where the Dv ray has advanced, and if there is no data, the flow returns to step A again.
If so, flow proceeds to step D. In step D, it is determined whether or not there is data at the coordinates advanced by the D ray. If there is no data, the flow jumps to step ■, and if there is, the flow advances to step E, where the DM ray is advanced by one pitch. . Next, in step F, a comparison is made between Dl,l and R, and if I)t>R, the flow jumps to step J, and if Dl,I≦R, the flow advances to step G. In step G, it is determined whether or not there is data at the coordinates where the DM ray has advanced. If there is, the flow returns to step E; if not, the flow advances to step H. In step H, based on the background value XX, D
A distance image Fv(X, Y) of v is generated, and D
A distance image FM (X, Y) of DM is generated based on M. In step (2), Fv (X, Y) is generated based on Dv, and F, (X, Y) are generated based on XX. In step J, Fv (X, Y) is generated based on XX, and FM (X, Y) is generated based on XX.

As a result, a composite image as shown by 10' is displayed on the image display section 11.

FIG. 4 shows an example in which the apparatus of this embodiment shown in FIG. 1 is specifically applied to excavation processing, and parts corresponding to those in FIG. 1 are indicated with the same numbers and ``'. There is.

Below, the effect when performing the digging process shown in Figure 4 is shown in Figure 5.
This will be explained with reference to the flowchart shown in the figure.

First, in step A, the rays of Dv and DM are advanced by one pitch, and then in step B, a comparison is made between Dv and R. If Dv > R, the flow jumps to step J, and if Dv≦R, the flow jumps. Proceed to step C. In step C, it is determined whether or not there is data at the coordinates that the Dv ray has advanced. If there is no data, the flow returns to step A again, and if there is, the flow proceeds to step D. In step D, it is determined whether or not there is data at the coordinates that the DM ray has advanced, and if there is no data, the flow advances to step E and the DM
The ray is advanced by one pitch, and if there is, the flow is a step ■
Jump to. Next, in step F, DM and R are compared, and if DM > R, the flow jumps to step J, and if DM≦R, the flow advances to step G. In step G, it is determined whether or not there is data at the coordinates advanced by the DM ray. If there is, the flow proceeds to step H; if not, the flow returns to step E. In step H, Fv (X, Y) is generated based on XX, and FM (X, Y) is generated based on DM. In step (2), Fv (x, y) is generated based on Dv, and FM (X, Y) is generated based on XX. In step J, Fv (X, Y) is generated based on XX, and F, (X, Y) are generated based on XX.

As a result, a composite image as indicated by 10'' is displayed on the image display section 11.

According to this embodiment, an image of three-dimensional data cut out according to the cutting shape and cutting direction specified by the operator and an image of the internal shape of the cut out part are displayed on the same screen as shown in FIG. can be displayed on top. This makes it possible to observe not only the surface display image but also the internal state of the cut, making it possible to obtain effective three-dimensional information.
diagnosis.

The accuracy of treatment can be improved. In addition, since such display can be performed without processing the voxel data Dv, there is no need for a storage medium to store the processed Dv, which reduces the amount of calculations and reduces processing time, resulting in faster processing. becomes possible.

To change the machining shape, you only need to change the mask data.
Further, the processing direction can be changed by changing the direction of ray tracing without changing the mask data.

[Effects of the Invention] As described above, according to the present invention, not only voxel data but also mask data are prepared and three-dimensional images are processed without processing the voxel data, so high-speed processing is possible. At the same time, effective 3D information can be obtained.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing an embodiment of the three-dimensional image processing device of the present invention, Fig. 2 is an explanatory diagram when drilling is performed by the device of this embodiment, and Fig. 3 is a block diagram showing an embodiment of the three-dimensional image processing device of the present invention. 2 is a flowchart explaining the operation, FIG. 4 is an explanatory diagram when the excavation process is performed by the apparatus of this embodiment, FIG. 5 is a flowchart explaining the operation of FIG. 4, and FIG. 6 is the embodiment 7(a) and (b) are schematic explanatory diagrams of the ray tracing method. FIGS. 8(a) to (C) are schematic explanatory diagrams of the three-dimensional data extraction method. The figure is a flowchart showing a method for determining pixel values inside the cutting surface, Figure 10 is a schematic diagram of a distance image and a shadow image, Figure 11 is an explanatory diagram of one method for determining a shadow surface image from a distance image, and Figure 12 is an illustration of a method for determining a shadow surface image from a distance image. FIG. 2 is an explanatory diagram of a processing method using a conventional device. 1... Three-dimensional data storage unit, 2... Voxel data generation unit, 3.6... Ray tracing processing unit, 4.7... Distance image generation unit, 5... Mask data generation unit, 8... Shadow material processing section, 9... Three-dimensional data cutting section, 10... Image composition section, 11... Image display section. Fig. 9 Kageme fi Banki) Fv (X + Y) Fig. (b) Fig. 0 Fig. Light / Fig. ■ Fig. Q

Claims (1)

[Claims] A means for generating voxel data reflecting three-dimensional data obtained by an arbitrary diagnostic device, a means for generating mask data according to the viewing direction and cutting direction specified by the operator, and a means for ray tracing the voxel data. means for generating a distance image of a voxel by ray tracing the mask data; means for generating a surface display image by performing shading processing on the voxel distance image; A three-dimensional image processing device comprising means for cutting out and generating an image of a cut surface based on original data, and means for synthesizing and displaying a surface display image and a cut surface image.