JPH0973556A - Picture processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture processor capable of more naturally displaying a surface by properly shadowing a surface generated by cutting an object on displayed picture data as well. SOLUTION: This processor consists of a cutting part 7 cutting a part specified in three-dimensional picture data, a judging part 13 obtaining the position of the surface of the object to judge whether this surface of the object is the original surface of the object or a surface generated by cutting based on three- dimensional picture data after cutting, and a shadowing part 15 shadowing the part judged to be the original surface of the object through the use of a gray level gradient method based on the three-dimensional picture data after cutting but shadowing the part judged to be the surface generated by cutting through the use of a dips gradient method based on the position of the surface of the object.

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 image processing apparatus that appropriately performs surface display processing.

[0002]

2. Description of the Related Art In recent years, various image processing apparatuses have been proposed which three-dimensionally display a subject by performing surface display processing on tomographic image data obtained by an X-ray CT apparatus or the like.

This surface display processing is roughly classified into processing for obtaining an intersection between a viewpoint and an object and shading processing for the surface of the object. The shading process is the Depth gradient method (De
pthGradient Shading method, DG method) and Gray level gradient method (Gray-LebelGradient Shading method, G
G method). This is due to the difference in the method of obtaining the normal vector of the object used for shading. In the Depth gradient method, the normal vector is obtained from the object shape (distance information to the object on the projection surface), and the gray level gradient method is used. Then, the normal vector is obtained from the density gradient of pixel values on the surface of the object.

[0004]

However, although the gray level gradient method performed by the conventional image processing apparatus can obtain a display image with higher image quality than the depth gradient method, it can be displayed on the display image data like a surgical simulation. When a part of an object is cut and the inside of the object is observed, a part that is not originally the surface is regarded as the surface after the object is cut, and thus it may not be possible to appropriately shade the cut part.

The present invention has been made in view of the above problems, and more appropriately performs shading processing on a surface generated by cutting an object on display image data, thereby more naturally displaying the surface. An object of the present invention is to provide an image processing device capable of performing the above.

[0006]

In order to achieve the above object, the present invention according to claim 1 is specified by an operator in three-dimensional image data obtained from image data obtained by a medical image diagnostic apparatus. Based on the cutting means for cutting the part and the three-dimensional image data after the cutting, the position of the object surface for each pixel of an arbitrary projection plane is obtained, and the obtained object surface is the original surface of the object, or The judgment means for judging whether the surface is caused by cutting by the cutting means and the portion judged as the original surface of the object by this judgment means are
Shading is performed using the gray level gradient method based on the three-dimensional image data after cutting by the cutting means,
The part determined to be the surface caused by the cutting, based on the position of the object surface obtained by the determining means, has a shading means for performing shading using the Depth gradient method, To do.

Accordingly, in the image processing apparatus according to the present invention, the cutting means is designated by the operator in the three-dimensional image data obtained from the image data obtained by the medical image diagnostic apparatus. The cut part is cut and the judgment means is
Based on the three-dimensional image data after cutting, the position of the object surface with respect to each pixel of an arbitrary projection plane is obtained, and the obtained object surface is the original surface of the object, or is caused by cutting by the cutting means. Judge whether the surface. Then, the shading means shades the portion judged to be the original surface of the object by the judging means using the gray level gradient method based on the three-dimensional image data after cutting by the cutting means, The portion determined to be the surface caused by the above is shaded by using the depth gradient method based on the position of the object surface obtained by the determination means. As a result, the shading process can be appropriately performed on the surface generated by cutting the object on the display image data, and the surface can be displayed more naturally.

Further, in the image processing apparatus according to claim 2, the determining means according to claim 1 determines whether an object exists based on the three-dimensional image data before being cut by the cutting means. Create binarized voxel data after cutting which is binarized based on whether or not an object exists based on the binarized voxel data before cutting and the three-dimensional image data after being cut by the cutting means. Based on the binary voxel data created by the binary voxel data creation unit, and the cut binary voxel data created by the binary voxel data creation unit, a surface position calculation unit that obtains the position of the object surface with respect to each pixel of an arbitrary projection plane, and If the binary voxel data before cutting just before the object surface obtained by the surface position calculation unit is a value indicating the existence of the object, it is determined that the original surface of the object, surface If the cutting front of the binary voxel data of the previous location calculation unit by the obtained object surface is a value indicative of no object, it is desirable to configure to determine that the a surface generated by cutting.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image processing apparatus according to the present invention. As shown in FIG. 1, the image processing device 1 includes a storage device 3, a three-dimensional image data creation unit 5, a cutting unit 7, a binary voxel data creation unit 9, a surface position calculation unit 11, and a determination unit. 13, a shading unit 15, a memory 17, a keyboard 19, a mouse 121, a display unit 23, and a system bus 25.

The storage device 3 is composed of a magnetic disk device or an optical disk device, and stores tomographic image data and the like obtained by the X-ray CT apparatus. The three-dimensional image data creation unit 5 is composed of a CPU and creates three-dimensional image data based on the tomographic image data obtained by the X-ray CT apparatus. The cutting unit 7 cuts a portion designated by the operator using the mouse 21 in the three-dimensional image data created by the three-dimensional image data creating unit 5. The binary voxel data creation unit 9 binarizes the unexposed binary voxels into “1” for a portion where an object exists and “0” for a portion where an object does not exist based on the three-dimensional image data before cutting. Based on the data and the three-dimensional image data after cutting, binary voxel data after cutting is created by binarizing a portion where an object exists to "1" and a portion where no object exists to "0".

The surface position calculation unit 11 calculates the position of the object surface for each pixel on an arbitrary projection plane based on the cut binary voxel data created by the binary voxel data creating unit 9 by the ray casting method. (Ray tracing method) is used. The determination unit 13 includes the surface position calculation unit 1
If the binary voxel data before cutting immediately before the object surface obtained by 1 is “0”, it is determined that the object is the original surface of the object, and the object surface obtained by the surface position calculation unit 11 When the immediately preceding binary voxel data before cutting is "1", it is determined that the surface is the surface generated by the cutting.

The shading unit 15 shades the portion determined to be the original surface of the object by the determination unit 13 by using the gray level gradient method, and determines the portion determined to be the surface resulting from the cutting. Creates the image data for display by performing shading by using the depth gradient method. The memory 17 includes a RAM and a frame memory, and includes a three-dimensional image data creation unit 5, a cutting unit 7, a binary voxel data creation unit 9, a surface position calculation unit 11, and a determination unit 13.
Also, a program for operating the shading unit 15 is stored. Further, the memory 17 is processed by the three-dimensional image data creation unit 5, the cutting unit 7, the binary voxel data creation unit 9, the surface position calculation unit 11, the determination unit 13, and the shading unit 15 (calculation processing unit). , Tomographic image data, three-dimensional image data, binary voxel data before cutting, and binary voxel data after cutting are temporarily stored. Further memory 17
Temporarily stores the display image data shaded by the shading unit 15.

The keyboard 19 inputs a processing start command or the like to the three-dimensional image data creating section 5 in accordance with a key pressed by the operator. The mouse 21 moves the cursor displayed on the display unit 23 based on the operator's designation. The operator uses the mouse 21 to specify the portion to be removed in the three-dimensional image data. The display unit 23
It is composed of a CRT and displays tomographic image data, three-dimensional image data and display image data.

The system bus 25 includes a storage device 3, a three-dimensional image data creation unit 5, a cutting unit 7, a binary voxel data creation unit 9, a surface position calculation unit 11, a determination unit 13, a shading unit 15, a memory 17, A keyboard 19, a mouse 21, and a display unit 23 are connected to transfer data. The operations of the three-dimensional image data creation unit 5, the cutting unit 7, the binary voxel data creation unit 9, the surface position calculation unit 11, the determination unit 13, and the shading unit 15 may be performed by one CPU or a plurality of CPUs. It may be performed.

Next, the operation of the image processing apparatus 1 of this embodiment will be described with reference to the flowchart of FIG. Note that, here, a case will be described as an example where shading is performed after removing a predetermined portion of the tomographic image data obtained by the X-ray CT apparatus. First, the tomographic image data obtained by the X-ray CT apparatus is stored in the storage device 3. The X-ray CT apparatus is connected to the image processing apparatus 1 via a cable or a network and supplies tomographic image data to the image processing apparatus 1 via the cable or the network. Further, not limited to this, the tomographic image data obtained by the X-ray CT apparatus is stored in an optical disc or the like, the optical disc or the like is carried to the image processing apparatus 1 by hand carry, and read and stored by the storage device 3. You can

Next, the operator presses a predetermined key on the keyboard to input a calculation start command to the three-dimensional image data creating section 5. Accordingly, the three-dimensional image data creation unit 5 creates three-dimensional image data based on the tomographic image data stored in the storage device 3 and stores the three-dimensional image data in the storage device 3 or the memory 17.

When the three-dimensional image data is stored in the storage device 3 or the memory 17, the binary voxel data creation unit 9
Reads the 3D image data and creates binary voxel data before cutting by binarizing the part where the object exists in the 3D image data to "1" and the part where the object does not exist to "0". Then, it is stored in the storage device 3 or the memory 17 (step S1).

Then, the operator uses the mouse 21 to designate the portion to be cut in the three-dimensional image data created by the three-dimensional image data creating section 5. It should be noted that this designation may be made on the three-dimensional image data or on the slice image data obtained from the three-dimensional image data. When the portion to be cut is designated, the cutting unit 7 reads the three-dimensional image data, cuts the three-dimensional image data of the designated portion, and stores the three-dimensional image data after the cutting in the storage device 3.
Alternatively, it is stored in the memory 17.

When the cutting of the three-dimensional image data is performed, the binary voxel data creating unit 9 reads the three-dimensional image data after the cutting, and in the three-dimensional image data, the portion where the object exists is "1". "," The part where no object exists is "0"
Binarized voxel data after cutting which has been binarized is created in the storage device 3 or the memory 17 (step S
3). When the binary voxel data after cutting is created, the surface position calculation unit 11 reads the binary voxel data after cutting and determines the position of the object surface with respect to each pixel of an arbitrary projection plane by the ray casting method (ray.・ Tracing method)
(Step S5). For example, as shown in FIG. 3, a virtual ray L is drawn from one pixel on the projection surface in the direction of the line of sight indicated by an arrow, and binary voxel data after cutting on this ray L is searched, and the value is “ The position of the voxel b1 changed to "1" is set as the surface position.

Then, the judgment unit 13 includes a surface position calculation unit 11
If the binary voxel data before cutting immediately before the object surface obtained by the above is “0”, it is determined to be the original surface of the object, and immediately before the object surface obtained by the surface position calculation unit 11. If the binary voxel data before the cutting is “1”, it is determined that the surface is caused by cutting. For example, as shown in FIG. 4, when the voxel b1 is determined to be the position of the object surface, the value of the binary voxel data before cutting corresponding to the voxel b2 immediately before the voxel b1 is "0". Determines that it is the original surface. When the voxel b3 is determined to be the position of the object surface, the value of the binary voxel data before cutting corresponding to the voxel b4 immediately before the voxel b3 is "1". Judge as the surface.

At this time, the shading unit 15 has the judging unit 13
The pixels on the projection plane corresponding to the voxels judged to be the original surface of the object are shaded using the gray level gradient method (steps S7, S).
9). Further, the shading unit 15 shades the pixels on the projection surface corresponding to the voxels that are determined to be the surface caused by the cutting, by using the Depth gradient method (steps S7 and S11). This process is performed for all pixels on the projection surface to create display image data (step S13). The created display image data is stored in the storage device 3 or the memory 17. Then, the display unit 23 reads the created display image data and displays it on the CRT. Thus, FIG.
As shown in, the original surface of the object is shaded and displayed by the gray level gradient method, and the surface generated by cutting is shaded and displayed by the depth gradient method.

As described above, the image processing apparatus 1 of this embodiment
Then, it is judged whether it is the original surface of the object or the surface caused by cutting the object in the three-dimensional image data, and if it is judged as the original surface of the object, it is shaded by the gray level gradient method. If it is displayed and it is judged that it is the surface caused by cutting the object, it will be displayed with shading by the Depth gradient method,
The shading process can be appropriately performed on the surface generated by cutting the object on the three-dimensional image data,
The surface can be displayed more naturally.

The image processing apparatus 1 according to the present embodiment has been described by way of example in which the image processing apparatus 1 is applied to tomographic image data obtained by an X-ray CT apparatus. However, the present invention is not limited to this and, for example, an MRI apparatus. It can be applied to image data obtained by a medical image diagnostic apparatus such as.

[0024]

As described above, the present invention according to claim 1 cuts a portion designated by the operator in the three-dimensional image data obtained from the image data obtained by the medical image diagnostic apparatus. After that, the position of the object surface in the three-dimensional image data is obtained, and it is determined whether the obtained object surface is the original surface of the object or the surface caused by cutting by the cutting means, and the original surface of the object If it is judged that it is shaded using the gray level gradient method, and if it is judged as the surface caused by cutting the object, it is shaded using the depth gradient method, so the object is cubic It is possible to appropriately perform shading processing even on the surface generated by cutting on the original image data, and to display the surface more naturally.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a general operation flow of the operation of the image processing apparatus shown in FIG.

FIG. 3 is a diagram for explaining how to determine the position of the object surface by the surface position calculation unit shown in FIG.

FIG. 4 is a diagram for explaining a method of determining whether the original surface of the object or the surface generated by cutting is determined by the determination unit shown in FIG.

5 is a diagram showing a display example of an object after cutting, which is shaded by using the image processing apparatus shown in FIG.

[Explanation of Codes] 1 Image processing device 3 Storage device 5 Three-dimensional image data creation unit 7 Cutting unit 9 Binary voxel data creation unit 11 Surface position calculation unit 13 Judgment unit 15 Shading unit 17 Memory 19 Keyboard 21 Mouse 23 Display unit 25 system bus

Claims (2)

[Claims] 1. A cutting means for cutting a portion designated by an operator in the three-dimensional image data obtained from image data obtained by a medical image diagnostic apparatus, and based on the three-dimensional image data after the cutting. A determining means for determining the position of the object surface with respect to each pixel of an arbitrary projection plane, and determining whether the obtained object surface is the original surface of the object or the surface generated by the cutting means. The portion that is determined to be the original surface of the object by the means is a surface generated due to the cutting by performing shading using a gray level gradient method based on the three-dimensional image data after cutting by the cutting means. The determined portion has a shading means for shading using the depth gradient method based on the position of the object surface obtained by the judging means. An image processing device characterized by: 2. The binary voxel data before cutting binarized based on whether or not an object exists based on the three-dimensional image data before being cut by the cutting means,
A binary voxel data creating unit for creating binary voxel data after cutting binarized based on whether or not an object exists based on the three-dimensional image data after being cut by the cutting means, and the binary voxel. Based on the binary voxel data after cutting created by the data creation unit, it has a surface position calculation unit for calculating the position of the object surface for each pixel of an arbitrary projection plane, and is calculated by this surface position calculation unit. When the binary voxel data before cutting immediately before the object surface is a value indicating the presence of an object, it is determined that the object is the original surface, and immediately before the object surface obtained by the surface position calculation unit. The image processing apparatus according to claim 1, wherein when the binary voxel data before the cutting is a value indicating that there is no object, it is determined that the surface is generated by the cutting.