JPH11206768A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare stereoscopic images for making an observer able to recognize the stereoscopic effect of an object. SOLUTION: A filter processing part 6 removes the prescribed high frequency components of Doppler images 4 and obtains processed images by executing a filter processing to the Doppler images 4. In the case of performing the filter processing, in both of the Doppler images of respective slices and MIP images (pseudo three-dimensional images) obtained by MIP reconstituting the Doppler images, the peak part of a profile is rounded. Thus, the roundness of the thick part of a blood vessel is appropriately displayed and the stereoscopic effect of the blood vessel is obtained. Also, even at the part where the blood vessels are crossed or adjacent to each other, both are discriminated and recognized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing for obtaining an image in which an observer can grasp the stereoscopic effect of a subject, and more specifically, for example, a tomographic image obtained by an image diagnostic apparatus such as an ultrasonic diagnostic apparatus. The image processing when reconstructing into a stereoscopic image.

[0002]

2. Description of the Related Art For example, in a diagnosis for finding a tumor in an organ such as a kidney, a doctor takes a tomogram of blood flow (blood flow power value) in the kidney by Doppler imaging using an ultrasonic diagnostic apparatus. Looking at the image, she remembered the three-dimensional appearance of the kidney. Also, a pseudo three-dimensional image obtained by performing a reconstruction process such as MIP (Maximum Intensity Projection) on the Doppler image is observed and diagnosed.

[0003] Conventionally, Doppler imaging according to the image density of peripheral blood vessels has also been performed in order to observe the state of a tumor located near the periphery (plasma) of the blood vessels. The dynamic range is reduced according to the image density.

Here, the conventional example has the following problems. That is, in Doppler radiography performed conventionally, the state of peripheral blood vessels is often observed,
For this reason, if the dynamic range is reduced in accordance with the image density of the peripheral blood vessel, an overrange occurs in a thick blood vessel. Therefore, the pixel density at the top of the blood flow becomes the same value, and so-called clipping occurs.

To observe only Doppler images,
An image with clipping is sufficient. However, when pseudo three-dimensional display is performed by maximum intensity projection (MIP) or the like, since a change in the gray level of a pixel represents the shape of a subject, the MIP is performed using a clipped image.
When the reconstruction is performed, there is a problem in that the three-dimensional appearance of the blood vessel in a thick blood vessel part is lost. Further, there is another problem that it is not possible to distinguish and recognize each blood vessel in a portion where blood vessels cross or are adjacent to each other.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image processing apparatus for creating a three-dimensional image in which an observer can grasp the three-dimensional effect of a subject. Is to do.

More specifically, even when the dynamic range is lowered in accordance with the pixel density of peripheral blood vessels, a three-dimensional effect of a thick blood vessel can be obtained.
It is an object of the present invention to provide an image processing apparatus capable of obtaining a blood vessel image in which blood vessels can intersect or be adjacent to each other and can be recognized separately.

[0008]

In order to solve the above problems and achieve the object, an image processing apparatus according to the present invention is configured as follows. (1) An image processing apparatus according to the present invention includes an input unit for inputting an image of a subject, and a density shape of a specific target object in the subject is pseudo-displayed on the image input by the input unit. Filtering processing means for performing a filtering process for performing the filtering.

According to this configuration, by performing the above-described filtering process on the input image of the subject, it is possible to simulate the density shape of the specific object in the subject. (2) The image processing apparatus of the present invention is the apparatus according to (1), wherein the image is a Doppler tomographic image, and the object is a blood flow in the subject. I do.

According to this configuration, by performing the above filter processing, even if clipping occurs in the thick blood flow (blood vessel) in the density direction, the roundness of the blood flow (blood vessel) is reproduced in a pseudo manner. Doppler tomographic images can be obtained. (3) The image processing apparatus according to the present invention, wherein (1) or (2)
And a reconstructing means for reconstructing a predetermined three-dimensional image based on the image on which the filtering process has been performed by the filtering means.

Here, the reconstructing means obtains a three-dimensional image (MIP image) by performing, for example, a reconstruction process including a maximum value projection operation using the Doppler image on which the filtering process has been performed. it can.

According to the MIP image, a three-dimensional effect of a specific object in the subject can be reproduced in a pseudo manner. (4) The image processing apparatus according to the present invention includes the above (1) to (3)
And the filter processing means is a real space filter, which has a small effect on a blood flow image of a peripheral blood vessel in the subject, and also displays the pseudo display object. The concentration shape of the object is characterized by a blood vessel that is thicker than the peripheral blood vessel.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of a three-dimensional image reconstruction system according to an embodiment of the image processing apparatus according to the present invention. The present embodiment is a system for reconstructing and displaying one MIP image (three-dimensional image) from a plurality of Doppler images (tomographic images).

As shown in FIG. 1, the three-dimensional image reconstruction system according to the present embodiment includes an ultrasonic diagnostic apparatus 1, a data acquisition unit 2, a data storage unit 3, and a subject geometry setting unit 5.
Is provided.

The ultrasonic diagnostic apparatus 1 is for taking a Doppler image of a subject. The data collection unit 2 collects the imaging result of the Doppler image by the ultrasonic diagnostic apparatus 1 and sends the imaging result to the data storage unit 3. The data collection unit 2 is, for example, an interface device for a direct connection in the present embodiment. It should be noted that the imaging result obtained by the ultrasonic diagnostic apparatus 1 is transmitted to a network or FD or M
The data can be supplied to the data storage unit 3 via D, OD, and other external storage media (both not shown).

The data storage unit 3 stores image data of a Doppler image 4 composed of a plurality of slice tomographic images and information on the image data (imaging matrix, image type, etc.).
In addition to this, storage of shooting geometric information and the like when shooting in three dimensions is performed. The photographing geometric information is set by the subject geometry setting unit 5, and the interpolation unit 8 and the projection unit 1
1 provides information on the position, angle, size, etc. of the slice.

The three-dimensional image reconstruction system of the present embodiment includes a filter processing unit 6, a filter setting unit 7, an interpolation unit 8, and an interpolation type / interpolation number setting unit 9. The filter processing unit 6 applies a predetermined filter set by the filter setting unit 7 to the Doppler image 4. This filter is, for example, a real space filter for removing high frequency components of the Doppler image 4 in the present embodiment. The filter setting unit 7 sets the size and type of the filter.

The interpolating section 8 applies linear interpolation, spline interpolation, and other interpolation algorithms to each slice data of the Doppler image 4 to generate non-existing data between slices by interpolation. In this case, a desired interpolation type and interpolation number can be set by the interpolation type / interpolation number setting unit 9.

The three-dimensional image reconstruction system according to the present embodiment includes a projection unit 11, a line-of-sight angle operation unit 13, and a line-of-sight plane memory 16, and the projection unit 11 includes a plurality of Doppler images 4.
A pseudo three-dimensional image is created by performing MIP reconstruction on.

The projection unit 11 creates a rotation matrix from vertical and horizontal rotation angles with respect to the angle of the currently displayed image in accordance with an operation from the line-of-sight angle operation unit 13. Next, the projection unit 11 rotates the image data to the coordinate system of the line-of-sight plane using the created rotation matrix, and performs a projection operation on the projection plane.

In the present embodiment, a plurality of data along the line of sight (this data is obtained from a plurality of Doppler images) are sequentially compared with data on the projection plane, and data having a large value is projected. By leaving the data of the maximum value on the line of sight on the projection plane.
An IP image (pseudo three-dimensional image) is created. The created image is stored and held in the line-of-sight plane memory 16.

As described above, in the present embodiment, one MIP image is reconstructed as a three-dimensional image from a plurality of Doppler images (tomographic images). However, the present invention is limited to a specific three-dimensional display. Instead, a three-dimensional display different from the MIP display may be performed. For example, when performing surface display, the projection unit 11
Creates a depth map and calculates shading of the subject using the depth map.

Further, the three-dimensional image reconstruction system according to the present embodiment comprises a gradation value gradation conversion unit 14, a WW / WL setting unit 1
5, a display memory 17, an image display unit 18, and a monitor 19. The WW / WL setting unit 15 sets a window width and a window level of an image. The gradation value gradation conversion unit 14 performs image processing of gradation value gradation conversion generally performed in the medical image diagnostic apparatus according to the setting contents of the WW / WL setting unit 15.

The display memory 17 stores and holds the image obtained as a result of the gradation value gradation conversion, and the image display section 18 reads out the image stored in the display memory 17,
It is displayed on the monitor 19.

FIG. 2 is a diagram showing the concept of the filter processing by the filter processing section 6. As described above, the filter processing unit 6 performs the filter processing on the Doppler image. That is, as shown in the figure, the original image 30 of the Doppler blood flow tomographic image
, A predetermined high-frequency component of the original image 30 is removed, and a processed image 32 is obtained.

The filter 31 is a filter function as shown in FIGS. 3A and 3B.
For example, it is represented by a 9 × 9 matrix as shown in FIG. 7A, and has a frequency-gain characteristic as shown in FIG.

By performing the filter processing of the present invention by the filter processing section 6, the following operation can be obtained. FIG. 4 is a diagram showing the profile of the gray value of the Doppler image and the MIP image of each slice when the filtering process of the present invention is not performed and when the filtering process is performed. FIG. It is a schematic diagram which expands and shows a part of MIP image.

First, when the filtering process of the present invention is not performed, the above-described clipping occurs, and the top of the profile becomes flat as shown in FIG. As a result, as shown in FIG. 5A, for example, the roundness of a thick portion of a blood vessel may be lost.

On the other hand, when the filtering process of the present invention is performed, as shown in FIG. 4B, the Doppler images of the individual slices and the MIP images (pseudo three-dimensional Image), the top of the profile is rounded. As a result, FIG.
As shown in (b), the roundness of the thick part of the blood vessel is appropriately displayed, and the three-dimensional appearance of the blood vessel can be obtained. Further, even in a portion where blood vessels intersect or are adjacent to each other, both can be distinguished and recognized.

Here, a plurality of tomographic images of the blood flow in the kidney (blood flow power value) are photographed by Doppler imaging using an ultrasonic diagnostic apparatus, and an image obtained by MIP reconstruction of these tomographic images is obtained. This is specifically shown.

First, FIG. 6 shows a Doppler tomographic image and a profile curve at a specific position when the present invention is not applied, and FIG. 7 shows a case where the present invention is applied. 6 and 7
As is clear from the comparison with the above, when the present invention is not applied, the top of the profile curve (right center on the paper) is flattened by clipping, while when the present invention is applied, the top of the profile is rounded. ing.

Next, the MIP obtained by performing MIP reconstruction as it is using the Doppler image when the present invention is not applied.
FIG. 8 shows an IP image (pseudo three-dimensional image) and a profile curve at a specific position. FIG. 8 shows a MIP image and a profile at a specific position obtained by performing MIP reconstruction using the Doppler image subjected to the filtering process according to the present invention. The curve is shown in FIG.

As is apparent from a comparison between FIG. 8 and FIG. 9, the top of the profile is rounded, and the roundness of the thick part of the blood vessel is appropriately displayed. Thereby, a three-dimensional effect of a thick blood vessel can be obtained. Further, even in a portion where blood vessels cross or are adjacent to each other, both can be distinguished and recognized.

As described above, according to the present embodiment,
For example, even if clipping occurs as a result of reducing the dynamic range in order to observe a thin blood vessel and the image density of a thick blood vessel is overranged, the original shape (roundness) of the blood vessel can be obtained by performing the above-described filtering.
Can be reproduced in a pseudo manner.

Accordingly, the three-dimensional appearance of the blood vessels is not impaired, and each blood vessel can be distinguished and recognized at a portion where the blood vessels cross or are adjacent to each other. Thereby, the diagnostic ability of a doctor or the like can be improved. The present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

[0036]

As described above, according to the present invention, it is possible to provide an image processing apparatus for creating a three-dimensional image from which a viewer can grasp the three-dimensional effect of a subject. In addition, even when the dynamic range is lowered according to the pixel density of the peripheral blood vessel, a three-dimensional effect of a thick blood vessel can be obtained,
In addition, it is possible to provide an image processing apparatus capable of obtaining a blood vessel image in which blood vessels can intersect or be adjacent to each other and can be recognized separately.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a concept of a filtering process on a Doppler blood flow tomographic image.

FIG. 3 is a diagram showing a filter function.

FIGS. 4A and 4B are graphs showing profiles of grayscale values of Doppler images and MIP images of individual slices when filter processing is not performed and when the filter processing is performed.

FIG. 5 is a schematic diagram showing an enlarged part of a MIP image in a case where a filtering process is not performed and in a case where the filtering process is performed.

FIG. 6 is a photograph showing a halftone image of a profile curve at a specific position and a Doppler tomographic image when the present invention is not applied, which is displayed on a display.

FIG. 7 is a photograph showing a Doppler tomographic image and a halftone image of a profile curve at a specific position when the present invention is applied, which is displayed on a display.

FIG. 8 shows a middle point between a MIP image (pseudo three-dimensional image) obtained by directly performing MIP reconstruction using a Doppler image to which the present invention is not applied and a profile curve at a specific position. A photograph representing a toned image.

FIG. 9 is a photograph showing a MIP image obtained by performing MIP reconstruction using a filtered Doppler image according to the present invention and a halftone image of a profile curve at a specific position, which are displayed on a display.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ultrasonic diagnostic apparatus 2 ... Data collection part 3 ... Data storage part 4 ... Doppler image 5 ... Subject geometry setting part 6 ... Filter processing part 7 ... Filter setting part 8 ... Interpolation part 9 ... Interpolation kind and number of interpolation setting part 10 ... interpolated slices 11 ... projection unit 12 ... projection type setting unit 13 ... viewing angle operation unit 14 ... shade value gradation conversion unit 15 ... WW / WL setting unit 16 ... viewing plane memory 17 ... display memory 18 ... image display unit 19 …monitor

Claims (4)

[Claims] 1. An input unit for inputting an image of a subject, and a filter process for pseudo-displaying a density shape of a specific object in the subject on the image input by the input unit. An image processing apparatus, comprising: 2. The image processing apparatus according to claim 1, wherein the image is a Doppler tomographic image, and the object is a blood flow in the subject. 3. The image according to claim 1, further comprising a reconstructing unit configured to reconstruct a predetermined three-dimensional image based on the image on which the filtering process has been performed by the filtering unit. Processing equipment. 4. The filter processing means is a real space filter, which has a small effect on a blood flow image of a peripheral blood vessel in the subject, and the density shape of the object to be simulated displayed is The image processing apparatus according to claim 1, wherein the blood vessel is rounder than a peripheral blood vessel.