JPH0496879A - Picture processor - Google Patents

Abstract

PURPOSE:To emphasize only the concerning site of a perspective transformation picture, and to enable a clear display which is easy to observe by operating a density gradation conversion of various density value data, emphasizing prescribed various density band data, and then operating a perspective transformation. CONSTITUTION:A continuous tomographic image by an X-ray CT device or the like is written in a picture memory 33 of a 3D processing part 3. Then, when a line of sight direction is set, the continuous tomographic picture is extracted through an interpolating part 34 by an interpolation factor corresponding to address integral and decimal parts converted into line of sight coordinates from a line of sight generating part 31, and voxcel data are prepared. The Hans field number of the voxcel data is applied to a designated wind function by a gradation converting part 35 so that the voxcel data whose various density value of the concerning site is large can be prepared, and supplied to a perspective transforming part 36. Then, the perspective transformation picture in the line of sight direction is prepared. Thus, the picture data of the concerning site is always displayed certainly and clearly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention provides a method for determining grayscale value gradation for grayscale value data of three-dimensional image data obtained with an X-ray CT device, an MHI device, etc. The present invention relates to an image processing device that performs conversion to create and display a perspective image viewed from the viewing direction.

(Prior Art) In recent years, with the progress in the development of medical image diagnostic equipment, continuous tomographic images of subjects are taken using X-ray CT equipment, MRI equipment, etc.
Based on this continuous tomographic image, can you create a perspective-transformed image from any viewing direction of the subject? 11 Attempts have been made to do so.

Conventionally, when generating such a perspective transformation image,
Continuous tomographic images of the subject are taken at equal intervals of one inch, and these are written on three-dimensional coordinates. Then, the line of sight is passed through these three-dimensional coordinates from an arbitrary direction (the direction in which a perspective-transformed image is desired), and the line of sight after passing through the subject is mapped onto the line-of-sight plane.

(Problem to be Solved by the Invention) In such a conventional apparatus, the gradation value of the mapping data is determined by the Hounsfield Nankha (CT value) of the subject. Therefore, for example, when passing through an fI section with a large Hansfield Nanpa, the shading value of the pine pink data will be large, and when passing through soft tissue with a small Hansfield Nanpa, the shading value will be small. .

For this reason, it is difficult to emphasize and display only a specific part of the subject with a small gradation value surrounded by an area with a large gradation value. For example, small parts of the Hounsfield pick-up, such as the lungs, may be buried in surrounding data, and the drawback is that the parts of interest cannot be clearly displayed.

This invention was made in order to solve such conventional problems, and its purpose is to create an image that can emphasize and display only parts of a specific gray value in the process of creating a perspective transformation image. The purpose of this invention is to provide a processing device.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention combines fluoroscopic images from any viewing direction based on three-dimensional image data of a subject and displays the image. The image processing apparatus is characterized in that the gradation value data is subjected to density gradation conversion, data in a predetermined gradation value band is emphasized, and then perspective conversion is performed.

(Function) With the above-described configuration, the grayscale value data of continuous tomographic images taken by the tomography apparatus is subjected to grayscale value gradation conversion using a wind function that can emphasize only a predetermined grayscale value band. Therefore, if a window function is set to emphasize the gray value band of the object of interest, three-dimensional image data in which only the gray value of this part is emphasized is generated.

Then, by perspective-transforming this three-dimensional image data from an arbitrary direction, a perspective-transformed image in the line-of-sight direction can be obtained. In this perspective-converted image, only the region of interest for which the gradation value band has been set is emphasized and displayed clearly, making it easier for the operator to observe the image data.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIG. 2 is a block diagram showing a schematic configuration of an image processing apparatus to which the present invention is applied.

As shown in the figure, this image processing device includes a tomographic imaging device 1, such as an X1jlCT device or an MRI device, which can take continuous tomographic images of a subject, and image data taken by this imaging device 1. An interface 2 that outputs to the 3D processing unit 3, and a 3D device that writes the given continuous tomographic images on three-dimensional coordinates and generates a perspective-transformed image from any viewing direction.
It is roughly divided into a processing section 3 and a 2D processing section 4 that subjects the perspective-converted image generated by the 3D processing section 3 to gradation value gradation conversion and window conversion, and then displays the image.

In addition, the 3D processing section 3. An operation section 5 is also provided for setting each setting value in the 2D processing section 4.

FIG. 1 is a block diagram showing the configuration of a 3D processing section 3, which is the main part of the present invention. As shown in the figure, the 3D processing section 3
It is composed of a line of sight generation section 31, a window function generation section 32, an image memory 33, an interpolation section 34, a tone conversion section 35, and a perspective conversion section 36.

The image memory 33 stores continuous tomographic images of the subject obtained via the interface 2.

The line-of-sight generation unit 31 uses the operation unit 5 shown in FIG.
When the direction in which you want to obtain a perspective transformed image is set, the x, y, and z values of the coordinates on the perspective coordinate axes are set from 0 to 51, respectively.
1 and then change it by 1, multiply them by χ·1, perform coordinate transformation using the line of sight angle, and obtain an address on the subject coordinates. At this time, the memory and information provided to the image memory 33 by the line of sight generation unit 3
The address is x, y, which is the coordinate transformation of x, y, z using the line of sight angle.
, use the integer part of z. (By matching x, y to the pixel interval of the subject coordinates and matching Z to the slice interval, the integer parts of x, y, z can be made to correspond to memory addresses.)

Furthermore, the interpolation coefficients given to the line-of-sight generation unit 31 or the interpolation unit 34 are the values below the decimal point of x, y, and z. (These values below the decimal point are used as the interpolation coefficients as the distance ratio between pixels. do).

Furthermore, the line-of-sight generation unit 31 uses the x and y values of the line-of-sight coordinates, which are the basis for calculating the subject coordinates, as memory addresses for the gradation conversion unit 35 to write data into the 2D memory 42 .

The interpolation unit 34 extracts each tomographic image data stored in the image memory 33 and transfers this image data to the line of sight generation unit 31.
Interpolation is performed using the interpolated data obtained from the data to generate voxel data. At this time, in order to calculate data for one point on the line-of-sight coordinates, eight neighboring gradation value data on the subject coordinates are used.

The window function generation section 32 generates a function indicating the relationship between the Hounsfield pick-up and the gray value based on the three-dimensional window value set by the operation section 5 shown in FIG. is supplied to.

The gradation conversion section 35 converts the gradation value by applying the gradation value data of the voxel data generated by the interpolation section 34 to a function given from the window function generation section 32.

The perspective conversion unit 36 causes the line of sight to pass through the image data whose gradation values have been converted by the gradation conversion unit 35 from a set direction,
Initialize 1 addition, repeat writing for the number of pixels,
Mapping the gray value data on the viewing plane. Based on this mapping data, a perspective-transformed image of the subject from the line-of-sight direction is generated.

FIG. 3 is a block diagram showing the detailed configuration of the 2D processing section 4. As shown in FIG. The 2D processing section 4 shown in FIG. 2 is similar to the conventional one, and includes a 2D memory 42 that stores perspective-converted image data from the viewing direction supplied from the 3D processing section 3, and an operation section 5 shown in FIG. Wind function generation unit 4 that generates and outputs a wind function based on the 2D window value set in]
and a gradation converter 43 that converts the grayscale values of the perspective-converted image stored in the 2D memory 42 based on this window function.
, an image display memory 44 that stores the tomographic image after the grayscale values have been converted, and a monitor 45 that displays this.
It consists of

Next, the operation of this embodiment will be explained.

When a tomographic imaging device 1 such as an X-ray CT device or an MRI device captures continuous tomographic images of the subject's head, the continuous tomographic images are supplied to the 3D processing unit 3 via the interface 2 and The image is written to the image memory 33 shown in the figure. When the operator sets the line of sight direction to obtain a tomographic image from the operation unit 5 shown in FIG. 2, the line of sight generation unit 31 shown in FIG. For example, z is changed by 1 from 0 to 51], and coordinate transformation is performed between each coordinate value and the subject coordinates (x, y, z).

At this time, the coordinate values z, y, z of the subject coordinates (x, y, z) corresponding to each line-of-sight coordinate (X, Y, Z) are not necessarily integer values and include decimal values. object coordinates (Xy, z) and line-of-sight coordinates (X, Y,
Z). The decimal value is then supplied to the interpolation unit 34 as an interpolation coefficient.

In this way, the memory address of the tomographic image data written in the image memory 33 is converted from the subject coordinates (x, y2) to the line-of-sight coordinates (X, Y, Z).

Then, the interpolation section 34 extracts the continuous tomographic images written in the image memory 33, performs interpolation processing based on the interpolation coefficient given from the line-of-sight generation section 31, and generates voxel data.

Now, if you want to emphasize and observe a lesion such as a tumor that has come to the head from the photographed image data of the head, the operator 5 shown in FIG. 40'' is set to increase the gradation value in the vicinity. As a result, the window function generation section 32 shown in FIG. 1 generates a wind function as shown in FIG. 4, for example, and supplies this to the gradation conversion section 35.

Then, the gradation conversion unit 35 converts the Hansfield Nancha of the voxel data after the interpolation process has been performed by the interpolation unit 34 to
By applying this window function, the gradation of the four tone values is converted. As a result, voxel data with increased density values of the tumor, which is the site of interest, is generated and supplied to the perspective conversion unit 36.

Thereafter, the perspective transformation unit 36 looks through the line of sight given from the line of sight generation unit 31, initializes the perspective data by pointing at the Z coordinate (Z -0), and converts it to (Z - 0), as shown in FIG. ~
511) is written and the pointing data of (Z-511) is added and mapped onto the viewing plane. Then, such perspective transformation is performed for each pixel, and a perspective transformation image in the line-of-sight direction is generated from the mapping data obtained as a result.

In the perspective transformation image obtained in this way, since the shading value of the tumor, which is the site of interest, has been increased in advance, the image becomes an image in which the tumor portion surrounded by bones and the like having large shading values is emphasized. This perspective-transformed image is then supplied to the 2D processing section 4 and stored in the 2D memory 42. Thereafter, this image data is read out to the gradation conversion section 43, and is subjected to gradation value gradation conversion and window conversion using the window function provided from the window function generation section 41.

After being written into the image memory 44, it is read out and displayed as an image on the monitor 45.

In this way, in this embodiment, a wind function is generated to increase the gray scale value of the object corresponding to a specific Hounsfield pick-up, and the gray scale value gradation conversion of the image data is performed according to this wind function. be done. Therefore, it becomes possible to highlight and display only the region of interest, such as a tumor that has come to the head, in the perspective-transformed image, making it easier for the operator to observe the displayed perspective-transformed image.

Note that the present invention only needs to handle three-dimensional image data of a subject, and is not limited to the imaging apparatus and imaging method described in the above-described embodiments.

[Effects of the Invention] As described above, in the present invention, after emphasizing the data of the grayscale value band of the object of interest, a perspective transformed image from the line-of-sight direction is generated. Therefore, the image data of the region of interest will not be buried in surrounding data, and the image will always be displayed clearly.

As a result, it becomes easier for the operator to observe the image, and the accuracy of image diagnosis is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the internal configuration of a 3D processing unit which is the main part of an embodiment of the present invention, FIG. 2 is a block diagram schematically showing the configuration of an embodiment of the present invention, and FIG. 3 is a 2D FIG. 4 is an explanatory diagram showing an example of a wind function; FIG. 5 is an explanatory diagram schematically showing perspective transformation. 1. Tomographic imaging device 3.. 3D processing section 4.. 2D processing section 31.. Line of sight generation section 33... 3D memory 35.. Gradation conversion section operation section Wind function generation section.. Interpolation section... Perspective conversion section

Claims (1)

[Scope of Claims] An image processing device that synthesizes and displays perspective images from arbitrary line-of-sight directions based on three-dimensional image data of a subject, comprising: An image processing device characterized in that data in a grayscale value band is emphasized and then subjected to perspective transformation.