JPS5815842A - Apparatus for extracting image contour - 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 The present invention #i relates to a device for extracting the outline of a target image to be photographed.

For example, in the diagnosis of heart disease, X-ray cine contrast imaging,
In addition to intracardiac pressure, blood flow, and blood acid saturation, information on left ventricular volume and cardiac function are required as extremely important elements. Conventionally,
The left ventricular volume can be measured by tracing and calculating the contrast-enhanced left ventricular wall from an existing cine film.

However, this method has a major drawback in that it takes time to produce calculation results, and today there is a demand in the clinical field for measurement in real time.

By the way, one possible method for measuring ventricular volume or myocardial function (thickness and movement of the myocardium) in real time is to use a video signal obtained by using a television camera. The important point is how to increase the KS ratio (signal-to-noise ratio) to detect the edges of the intraventricular wall and outer wall. Although it is possible to detect a relatively high S/N ratio, there is a problem in that the outer ventricular wall has a low contrast, so detection of its edges is extremely difficult.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a device that can extract contour tubes from images with high accuracy by increasing the 18x ratio.

The tube of the present invention will be specifically explained below using Example f4.

No. 11!5 is a water-substrate diagram of an embodiment in which the apparatus 1 of the present invention is applied to an X-ray image processing system wIK. In the figure, 111 is a subject to be photographed, and is placed on a top plate 2. A medical imaging device 13 and
II pipes 4 are arranged to face each other. 5 controls the exposure' of the xm tube [t2. The Xl1llllJil unit is controlled by the tie 2 pulses TP and sK from the imaging timing pulse generation circuit 8, which will be described later, and is transmitted to Ktk so as to perform X-ray exposure in synchronization with this tie voltage. This is an R-wave trigger pulse generation circuit that generates the electrocardiogram obtained from the 11.7 #i electrocardiograph, which is a rounded electrocardiograph that obtains an electrocardiogram from the specimen.) The period of the trigger pulse matches the period of the heartbeat. 8 is the trigger pulse (also called heartbeat synchronization signal)
Photography tie 2ndabarus T that subdivides TPI at equal intervals
This is a photography pulse generation circuit that generates Th.

9#i is a contrast medium injection stirrup for injecting a contrast medium into the subject 1, and is bent so as to generate a contrast medium injection signal -. 10tiImage data output from the imaging device S■
This is a switching circuit that switches and sends S by the contrast agent injection signal 8@. 11 and 12 are frame memories 111 to 115 and 12 of multiple numbers (eight pages if hooked), respectively.
6 to 12h, and image data for each frame is sequentially transferred to the first page memory 11 by the operation of the switching circuit 10 when the contrast medium injection signal 8I is not generated. is stored, and image data for each frame is sequentially stored in the first and second page memories 12 by the operation of the switching circuit 10 when the contrast agent injection signal 8@ is generated. Reference numeral 15 denotes a subtraction circuit which operates when the contrast agent injection signal & is at a high level and performs subtraction between the data stored in the first page memory 11 and the data stored in the second page memory 12; is a trigger pulse (heartbeat synchronization signal) from the 8-wave syringe generation circuit 7 after the contrast agent injection signal becomes high level.
This is a switching circuit that switches and outputs 1m-order subtraction result data from the subtraction circuit 13 every time TPI occurs.

15 is a page memory group that includes page memories of multiple pages (for example, 8 pages) and 3 types of CfR (B, C); The switching circuit 14 also stores the sequentially sent subtraction result data in each page memo qK.Therefore, in this page memo 9 group 15, the subtraction result data after contrast agent injection is stored in each page memo qK. Nimu, B.
It is stored in an ordered manner like C. 16t
i This is an addition circuit that adds the subtraction result data for each heartbeat stored in the page memo group 15 for each corresponding b page and outputs the summed data for each page. 3
1B is the third page memory 1.
%19 is a device for detecting and processing the outline contour height data from the data for each page, and %19 is a plurality of devices (for example, This is a data memory group having 1 data memory 1 for 8 sheets. 20 is the data memory group 19
This is a contour creation software that creates a contour GL using the respective outline contour data stored in the file as reference data. In addition, each page memory 11.12.17, page memory details 15.
The data memory group 19 etc. are the photographing timing t/g pulse TP.
Write with sK synchronized timing, I! Klk is activated so that extraction or processing is performed. The data I obtained in this manner is displayed on the display device 121 or the like.

Next, the operation of the device will be explained with reference to the time chart of FIG. 2 and the image aspect 8i!I of FIG. 3 (4 to (e)). From the B wave to the R wave of the electrocardiogram, Yr1 heart rate is assumed to be %44 heart ThTs
In addition, the case where a contrast agent is injected at the boundary point between the first heartbeat 5 and the second heartbeat y will be explained. Then, in synchronization with the B wave of the electrocardiogram, an R wave trigger pulse (
Heart rate synchronization signal) TPI is sequentially t@, t*, t*, 1m,
Occurs as at t4, and the photographing pulse TPs Id
A signal a@A4t that is subdivided into 8 equal parts for each heartbeat,
It is assumed that they are output as ha ~ AV, e* ~ eq, and do ~ jv.

First, during the 1st heartbeat and 5th beat, the camera was captured during the 2nd pulse TP.
Since the X-ray controller 5 operates in synchronization with sK and controls the solar radiation of the X-ray tube 4, 1i1i of each exposure from the imaging device 3 to the X-ray tube 4 is
My information vS is sequentially output and sent to the next stage page memory via the first switching circuit 10. At this time, since the contrast medium injection signal is at a low level, the first switching circuit 1
The output from 0 is the first page memo +! 11,
Information on eight frames within one heartbeat 5 is divided into eight frames 11 at the time of the photographing pulse TPtKlj%.
When stored sequentially in g to 11A, it becomes K. The lii* information stored in this page memory 11 is stored as information mainly composed of bones as shown in FIG.
Imaging is performed using the same imaging terminal at heartbeat 'h, but at this time, contrast agent injection is also started, so the contrast agent injection signal 8 becomes high level and the first switching circuit 10 is switched. For.

Image information of the second heartbeat vs. the second page memory 12
The eight memories 12g to 12A are stored sequentially. Then, when all the image information from the second heartbeat is stored and the contrast medium injection signal 8 becomes high level in the 9th stage, the subtraction circuit 13 operates in synchronization with the first page memory 11 and the second page memory 11. Data is subtracted from the page memory 12 for each corresponding phase. When the subtraction result data I is sequentially stored in the first page memory 15 of the next stage page memory 15 by the operation of the second switching circuit 14, it becomes K.

Next, the lii pause information V8d 1-? sent from the imaging device 3 within the period of the third heartbeat Ta? It is introduced into the second page memo 912 via the disconnection circuit 10. This and 11% second
The page memory 12 will be rewritten with new image information, but the first page memo 911 will maintain its previous storage state. The image information IIi in the second page memory 12 includes the stripe 3 image (as in the phrase, the contrast duct of the ventricle).When the storage of the image information of the third heartbeat 5 is completed, both images are transferred as described above. Page memory 11
．． 12 subtraction is performed, and the subtraction result data is sent to the page memory group 15 via the second switching circuit 14. At this time, the second switching circuit 14 is switched to the next output terminal by the heartbeat synchronization signal TPs, so the subtraction result data of the third heartbeat 5 is stored in the 211th page memo 115. Ru. Further, in the same manner, the subtraction result data of the fourth heartbeat 5 is stored in the sixth page memory C in the page memo 115. This sum is stored in the page 741 group 15 and the large data jltj
For example, as shown in FIG. 3(c')K, only the shadow of the ventricle remains, and the other parts are removed.

After obtaining the subtraction result data j+ for the required number of heartbeats (three heartbeats in this case) in the above manner, the adding circuit 16 adds the data for each heartbeat for each corresponding phase. 8 frames in 3 page memory 17 5 memory 171X~
17 Todoroki will be stored sequentially. By such addition processing, the influence of defective two-kissing of the contrast medium can be removed and an image of the left ventricle having uniform density can be obtained.

Next, the data in the third page memory 17 is sequentially retrieved page by page, and a rough contour image is extracted by the contour detection processing device f18. In this case, the known spatial method and 1-hour method are used.

A threshold 111tc or the like is used. The outline contour image data for 98 sheets obtained in this way are stored in the data memo 1 group 19 of the next stage.
The data is sequentially stored in each memory 196 to 19^ in the memory.

Finally, data 141 groups 19 are created using 1 contour image creation device F20.
The contour of the entire contrast image is created using the general contour image data stored in the image data as reference data. III in this case
j,, 114KFor example, if we use the Kukan-koku-seki method.

Within 1 distance from the outline outline 1K outline line
Logic may be used to set the maximum point of the differential value of the data 1c1b as the true contour line.The contour image thus obtained is displayed on the display device 121.

In the above process 71iKk, subtraction is performed between the pre-contrast image and the post-contrast image to remove the influence on images of areas other than the target area, and the 1-subtraction result data are superimposed. An image with uniform density is obtained, excluding the effects of poor mixing, etc. As a result, the 87N ratio can be made extremely high, and a highly accurate contour image can be extracted.

Moreover, in each process K, each phase is matched based on the heartbeat synchronization signal, so that processing that is not influenced by the movement of the heart can be performed.

The present invention is not limited to the embodiments described above, and can be implemented in various modifications.For example, in the embodiments described above, a frame memory (or page memory) was used for storing and reproducing images, but the present invention is not limited to this, and a video disk or the like may also be used. Alternatively, in order to obtain a heart rate signal, in addition to an electrocardiogram, heart sounds, pressure waves, etc. may be used if the animal is kept.

Incidentally, the present invention can be widely applied not only to the X-ray image processing apparatus #i but also to various image processing apparatuses.

According to the present invention as described above, the S ratio is high and the precision <j
It is possible to provide a device that can extract the outline of lm.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one example of feeding in nine cases when the present invention is applied with the X-ray image processing value WK; It is an explanatory diagram. 1--Subject, 3-Imaging device stirrup, 4--X-ray tube, S
- X-ray controller, 6... Electrocardiograph, 7- R wave trigger generation circuit, 8... Imaging timing signal generation circuit. 9-Contrast agent injection device, 10.14-Switching circuit. 11.12.17--page memory, 13-subtraction circuit, 15-page memory group, 16-addition circuit% 1
8-・Contour detection processing installed, 19-Data memory group,
20-Contour production device f% 21-Display device.

Claims (1)

[Claims] a heartbeat synchronization signal generation means for generating a heartbeat synchronization signal based on a specific waveform obtained from a subject; a timing pulse generation means for generating a plurality of imaging pulses included in the heartbeat synchronization signal; a first storage means for storing a plurality of C image data obtained in synchronization with the da pulse for each heartbeat; and a first storage means for storing at least two temporally different types of image data for each heartbeat with equal phases from within the first storage means. A subtraction circuit that performs subtraction for each heartbeat, and a second circuit that stores the subtraction result data obtained from this subtraction circuit for each heartbeat.
a storage means; an addition circuit that sequentially adds the subtraction result data for each heartbeat stored in the second storage means;
An Am image contour extraction device characterized by comprising a contour detection processing means for detecting an approximate contour from the addition result data, and a contour side creation means for creating a contour based on the output of the contour detection processing means.