JPS61253042A - Stereoscopic x-ray tv fluoroscopic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to improvements in stereo X-ray TV fluoroscopy equipment.

Conventional technology Using an X-ray tube with left and right focal points, X-rays are emitted from the left focal point to obtain the left image, X-rays are emitted from the right focal point to obtain the right image, and these left and right images are divided into left and right images. By arranging the objects in the same direction and observing them with a stereo synthesizer such as a stereoscope, a stereo image of the object viewed three-dimensionally using X-rays can be obtained.

Problems to be Solved by the Invention When performing stereo X-ray fluoroscopy using a stereo X-ray TV fluoroscopy device, it is certainly possible to grasp images of blood vessels etc. in three dimensions, but the three-dimensional observation is limited to the observer. It is a sensory thing that can be seen by the eyes, and the distance in the depth direction is
It is difficult to measure (depth) accurately.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved stereo X@TV fluoroscopy device that can accurately measure depth by displaying an index in the depth direction.

Means for Solving the Problems According to the present invention, for each of the left and right images displayed in a stereo X-ray TV fluoroscope, the right screen and the left screen differ by a predetermined distance in the left-right direction. means for displaying an index located at.

Function When the right screen and the left screen display indicators located at points that differ by a predetermined distance in the horizontal direction, these can be displayed as
If the images are synthesized using a stereo synthesis means and observed, the above-mentioned indicators are synthesized and appear as an indicator representing the depth corresponding to the above-mentioned distance. Therefore, by adjusting the above distance so that this index overlaps the target region in the depth direction, it becomes possible to calculate the depth of the target region from this distance.

Embodiment In FIG. 1, a stereo X-ray tube 1 has left and right focal points, and X-rays are alternately emitted from these focal points toward a subject 2.

The X-rays transmitted through the subject 2 enter an image intensifier 3, where the X-ray image is converted into an optical image, and further converted into a video signal by an image pickup tube 4. The image obtained by irradiating X-rays from the left focus is the left image, and the image obtained from the right focus is the left image. These video signals pass through the video processor 5 and undergo processing such as digital subtraction, and images of blood vessels and other objects created by the contrast agent are extracted from the background image, and the left CR
The signals are sent to T6 and right CRT7 and displayed.

By observing these left and right images through a stereoscope 8, a three-dimensional subject image 9 can be observed.

Pulses from the depth index display circuit 10 are added to the video signals sent to the left and right CRTs 6.7. In the depth index display circuit 1O, a pulse is generated from the pulse generation circuit 11 in synchronization with the horizontal synchronizing signal of the TV and delayed by a predetermined time, and this is shifted as the right pulse (pulse applied to the right CRT 7). The signal is sent to the circuit 13, and on the other hand, it is input to the shift circuit 13 as a left pulse delayed by a predetermined time T from the right pulse via the delay circuit 12. The shift circuit 13 transfers these right pulses and left pulses for each vertical synchronization signal, that is, for each frame of an image.
Shift the left and right pulses by the same amount little by little.

Here, suppose that images of blood vessels as shown in FIGS. 2(a) and 2(b) are displayed on the CRT 6.7. In these left and right images, vertical bright lines 92 and 93 appear due to the pulses from the depth index display circuit 10. If we take out the signals of horizontal scanning lines 94 and 96, we get (c) and (d). That is, in the right image, pulse 97 is superimposed at a position delayed by TR from the horizontal synchronization signal, and in the left image, pulse 97 is superimposed at a position delayed by time T from this right pulse 97, and delayed by time T from the horizontal synchronization signal. A pulse 95 is superimposed at the position (TL=TR+T). Since this pulse 95.97 is applied to all horizontal scanning lines, it appears as a vertical bright line 92.93. This bright line 92.9
The horizontal position of 3 is xL in the left image, XR in the left image,
The two are different, and the distance between them is X (=Xi−XL
) corresponds to the time difference T.

Then, the shift circuit 13 changes T, TL little by little frame by frame while maintaining this time difference T, so that the bright line 92.93 is Gradually move from left to right (or right to left).

Left and right bright lines 92.93 with such a parallax
When viewed through the stereoscope 8, an image of a certain depth (
depth index).

The depth corresponds to the parallax X. Therefore, this depth index moves left and right on the constant depth plane 91 at a specific depth. If the image overlaps the blood vessel image in the depth direction and left/right direction, the overlapping blood vessel image becomes invisible. Therefore, by superimposing this depth index on the target part, the depth of the target part can be known.

That is, while observing the stereo image with the stereoscope 8, the delay time T of the delay circuit 12 is adjusted to adjust the parallax X, thereby determining the depth direction position of the depth index to be the same as the target region. Then, the delay time T at this time
information is sent to the depth display circuit 20, and the calculation circuit 21 calculates parameters such as the focal length W and the distance between the focal point and the incident surface of the image intensifier 3 (
(These are entered in advance using a keyboard, etc.)
Depth (depth from reference surface; mm) by using
is calculated, and based on the result, the character display circuit 22 displays the depth in mm (numerals) on the screen.

Operating principles Next, we will explain the operating principles described in the following section in more detail.

The principle behind the reproduction of stereo images is that, in general, when a three-dimensional object is viewed from two different points and left and right images (including transmitted images such as X-ray images) are obtained, a certain three-dimensional position in both images can be reproduced. There is always a corresponding point representing the image.Conversely, if the corresponding point is found in the left and right images, the three-dimensional position can be uniquely determined.

As shown in FIG. 3, it is assumed that a point P in the subject 2 is projected onto points IL and IR on the entrance plane of the image intensifier 3 by X-ray stereo exposure. Corresponding to this IL, mark a point cL on the left CRT 6.1. Corresponding to the right CRT7
When the points cR are respectively displayed above and observed with the stereoscope 8, a point P' is imaged in the space.

Therefore, the point existing at a certain distance from the focal point is CRT6.7
Think about how it will be displayed.

Now, as shown in Fig. 4, focal length: W, distance between focal point and projection plane (incident plane of image intensifier 3) @
, D, the points PI, P2, P that are d away from the focal point
The projection points from the left and right focal points of 3 are respectively (XL 1, X 1)
, (XL 2, XR2), (XL 3, XR3). To simplify the explanation, CR is the same size as the projection surface.
Suppose that it is displayed on T. Then, the parallax between the left and right images or Xi, X2, x3 becomes W:X1=d :D-d W:X2=d:D-d W:X3='d:D-d, As a result, X1=X2=X3. In other words, it can be seen that the parallax between the left and right images obtained for any point on a plane parallel to the sparrow shadow plane (equal depth plane) at a certain distance from the X-ray focal point is constant.

Then, for example, let e=D”d be the coordinates of point PI (x
, e) is e/D= (x-xH1)/(-12W-XR' 1)
e/D= (x-XL 1)/(34W-xtl)
It can be obtained by solving . This gives x = W (
XR1+XL 1)/2(W+XR1-XI: 1)e
=D (XR1-XL 1)/(W+xi+ 1-
XL1), and the position X in the left-right direction and the position e in the depth direction are obtained. Regarding e, XR1-Xl, 1=X1, so e=D ・X1/ (W+X1).

Modified example Display a small cursor (in other words, the line is very short in the vertical direction) instead of the vertical bright line as shown above,
Place this cursor on each of the two desired points, and
It is also possible to calculate the distance between two points in dimensional space. Furthermore, this cursor is moved along a specific blood vessel, and the three-dimensional coordinate information of the cursor is calculated while it is moving.
Using this 3D coordinate information, a 3D map (computer graphics) of blood vessels is created using a microcomputer, etc.
You can also make

Effects of the Invention According to this invention, xti reproduced as a stereo image
The three-dimensional position of a stereoscopic image of a perspective image can be accurately measured. It is also possible to determine the absolute depth from the reference plane or the depth from one part to another. It can also be extended to calculating the distance between two different points.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 (a) and (b) are diagrams representing left and right images, respectively, and Fig. 2 (c) and (d) are signals on the l horizontal scanning line. FIG. 3 is a schematic diagram for explaining the principle of stereo X-ray fluoroscopy, and FIG. 4 is a schematic diagram for explaining the principle of determining depth from parallax. ■... Stereo X-ray tube 2... Subject 3... Image intensifier 4... Image pickup tube 5... Video processor 6.7... CRT 8... Stereoscope 9... Subject image 10...Depth index display circuit 20...Depth display circuit

Claims (1)

[Claims] (1) Stereo X-ray generation means having left and right focal points, imaging means for converting X-ray images into video signals, left image display means and right image display means for displaying left and right X-ray images, respectively;
stereo synthesis means for synthesizing these displayed left and right images so that they can be observed as a stereo image;
In each of the left and right images, the left image and right image are
A stereo X-ray TV fluoroscopy device comprising means for displaying indicators located at points that differ by a predetermined distance in the left and right direction.