CN1016836B - Digital subtracting system - Google Patents
Digital subtracting systemInfo
- Publication number
- CN1016836B CN1016836B CN 85101311 CN85101311A CN1016836B CN 1016836 B CN1016836 B CN 1016836B CN 85101311 CN85101311 CN 85101311 CN 85101311 A CN85101311 A CN 85101311A CN 1016836 B CN1016836 B CN 1016836B
- Authority
- CN
- China
- Prior art keywords
- digital
- converter
- video memory
- image signal
- memory
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000015654 memory Effects 0.000 claims abstract description 57
- 239000002872 contrast media Substances 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims description 14
- 230000000007 visual effect Effects 0.000 claims description 7
- 230000009466 transformation Effects 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims 1
- 238000002583 angiography Methods 0.000 abstract 1
- 238000002594 fluoroscopy Methods 0.000 abstract 1
- 210000004204 blood vessel Anatomy 0.000 description 19
- 241000406668 Loxodonta cyclotis Species 0.000 description 6
- 230000003287 optical effect Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 230000017531 blood circulation Effects 0.000 description 2
- 238000002601 radiography Methods 0.000 description 2
- 210000003462 vein Anatomy 0.000 description 2
- 210000001367 artery Anatomy 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000005055 memory storage Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000004304 visual acuity Effects 0.000 description 1
Landscapes
- Apparatus For Radiation Diagnosis (AREA)
Abstract
The present invention relates to a digital subtraction system mainly applied to angiography photography. The digital subtraction system is provided with an analog to digital converter, a first image memory, a second image memory, a comparator and an arithmetic device, wherein a logarithmic converter is arranged in front of the analog to digital converter. Through the reduction of the influence of X-ray quantum noise (quantum pie, dao, chuan), the digital subtraction system not only can obtain difference images (images) by using X ray quantity as small as that of X-ray fluoroscopy, but also can display image repetition displayed in the movement contrast agents on one frame of images in a contrast agent moving track mode.
Description
The present invention relates to digital subtracting method and device, this method and device combine with x-ray television system, and the perspective that x-ray television system is provided resembles carries out the real-time digital image processing.
The digital subtracting method is mainly used in the angiogram photography, the perspective that it can make x-ray television system provide resembles the picture intelligence digitlization, under the form of digital signal, deduct to cover and resemble (マ ス Network picture), depict and cover difference-radiography position of elephant, that is blood vessel resembles, and shown then and observes.
For digital subtracting system, the plotting method of blood vessel picture is diversified: what have arrives that image (cover and resemble) before the target site and the image (looking exactly like-ラ ィ Block picture) behind the arrival target site subtract each other and the time difference of the difference that obtains based on contrast agent; The energy difference that has based on the difference of the X ray elephant of different wave length; Have then obtaining the filter characteristic difference of difference in the different time with two kinds of different filters of characteristic, or the like.
Yet, no matter based on the digital subtracting method of above-mentioned any method, reduce the influence of X ray quantum noise (quantum ノ イ ス), often all must use and directly the photograph roentgen dose X of same degree of X ray, in addition, also will obtain respectively covering and resemble and look exactly like, therefore, the radiation dosage that the subject is subjected to be considerable.
On the other hand, for the angiogram photography, contrast agent is injected by vein usually, along with the blood flow from heart flows into check point, afterwards, is flowed out by check point.
Therefore, the image (hereinafter to be referred as difference) of the check point difference that obtains as the digital subtracting method, what at first show is the coarse motion arteries and veins of close heart, secondly is the thin blood vessel of tip, but when the thin blood vessel of tip occurs, contrast agent in the thick blood vessel flows out, so thick blood vessel disappears, and perhaps disappears, in this case, all can not resemble from thick blood vessel by means of above-mentioned any method and to show, and be observed to thin blood vessel with the track that a frame image flows the radiography mark.
The object of the present invention is to provide a kind of like this digital subtracting method, alleviate the influence of X ray quantum noise (quantum ノ イ ス) by improvement, can not only obtain the second best in quality difference (image) by same few x-ray dose with radioscopy the time, and can be with the form of contrast agent motion track, the image that shows on a frame image contrast agent being moved repeats to show, for example, the image of thick blood vessel to thin blood vessel shown simultaneously, observed.
Digital subtracting method of the present invention and device, it is the digital map picture signals of the perspective elephant that will obtain by x-ray television system, resemble first, second video memory storage of face memory capacity through having a frame respectively, respectively from first, second video memory one by one pixel read, and computing in addition, obtain difference, the signal that digital image signal and described first, second video memory are stored pixel one by one compares respectively, little value on first video memory, big storage simultaneously on second video memory.
Now be illustrated with regard to the example of introducing in the accompanying drawing.With reference to the accompanying drawings, the composition of common x-ray television system has: x-ray source 1, and it is to subject's 2 irradiation X ray; Image intensifier 3, it resembles subject's radioscopy and is transformed into brightness enhanced optical image; Camera tube 4, it is transformed into picture intelligence to the optical image of image intensifier 3 outputs, and camera controller 5 and surveillance television machine 6.
X is the image-processing system that carries out the digital subtracting computing, it by switch 11,11 ', logarithmic converter 12,13, two multiplexers of a-d converter (マ Le チ プ レ Network サ) 14
1, 14
2, two comparators 15
1, 15
2, two frame memories 16 of each pixel of storage digital map picture signals
1, 16
2, read frame memory 16
1, 16
2Memory contents and the subtracter (arithmetic unit) 17 that subtracts each other with regard to each pixel, intensifier circuit 18, D-A converter 19, panel (end illustrates among the figure) and to compositions such as the time-controlled controllers 20 of each several part.
Such as, when a frame resembles mask when 512 * 512 pixels are arranged, frame memory 16
1, 16
2Have 512 * 512 memory block respectively, corresponding with each pixel, and also each district is strict corresponding, for example has 8 bit capacities.
For above-mentioned composition, carrying out the subject when locating needed general perspective, as long as the panel (end illustrates among the figure) of operation control 20, just can connect in the drawings (イ) side to switch 11,11 respectively by controller 20.In this state, x-ray source 1 is ready and to subject's irradiation X ray.Pass subject 2 X line, be transformed into optical image, and brightness strengthens by means of image intensifier 3.The optical image of image intensifier 3 outputs is transformed into picture intelligence by camera tube 4, and this picture intelligence is intactly given surveillance television machine 6, and television set 6 is the same with common x-ray television system, X line perspective is resembled show.
After subject 2 location, as long as touch the image processing start button (not shown) on the panel, control signal that just can be by coming self-controller 20 is switch 11,11 ' receive and illustrate opposite (mouth) side, injects contrast agent with not shown syringe to the subject then.Before contrast agent is about to along with blood flow enter the visual field of image intensifier 3, frame memory 16
1At first whole pixel regions are preset maximum, and frame memory 16
2Whole pixel region preset minimum.Memory 16
1, 16
2Preset, under the control of controller 20, carry out.
Before contrast agent was about to enter image intensifier, for example beginning with contrast-medium injection was that benchmark is through after the certain hour, by means of the control signal of coming self-controller 20, in an image duration, multiplexer 14
1, 14
2Connect, maximum input frame memory 16
1Whole pixel regions, and minimum value input frame memory 16
2Whole pixel regions.At this moment, comparator 15
1, 15
2Under the control of controller 20, do not play relatively effect.
Frame memory 16
1, 16
2Pre-postpone, multiplexer 14
1, 14
2Connect, make the output of a-d converter 13 distinguish device 15 as a comparison
1, 15
2An input, meanwhile, recover the comparing function of comparator.As a result, camera tube 4 is exported the picture intelligence of each frame successively, carries out logarithmic transformation by logarithmic converter 12 then.This is because only get the ratio of target sizes and background signal size, and the absolute value of background signal and picture intelligence size has nothing to do.So can obtain the image clearly of blood vessel etc., and whether overlap irrelevant with bone.Not by logarithmic converter 12 time, switch 11 is transferred to (eight) side.
Through the picture intelligence of logarithmic transformation, realize digitlization by means of a-d converter 13, give comparator 15 then
1, 15
2At comparator 15
1In, with frame memory 16
1Numerical value of reading and a present frame of digital image signal of input compare with regard to same pixel, and less numerical value (dark value) is stored in frame memory 16, pixel region.
Equally, at comparator 15
2In, with frame memory 16
2Numerical value of reading and digital image signal compare with regard to same pixel, choose bigger numerical value (bright value), are stored in frame memory 16
2Respectively this pixel region.These compare and storage operation is at the appointed time, when for example having contrast agent to exist in the visual field of image intensifier, carry out repeatedly, and afterwards, the X line stops irradiation.
As a result, at frame memory 16
1In, store human lens as and resemble animation as the contrast agent image track that obtains successively, and at frame memory 16
2In only store human lens and resemble.After all, frame memory 16
2The image of storage resembles corresponding to covering, and frame memory 16
1The image of storage is corresponding to looking exactly like.
Frame memory 16
1, 16
2Memory contents, carry out subtraction by subtracter 17 with regard to corresponding each pixel, and demonstrate the image of contrast agent, that is contain the picture intelligence of the blood vessel elephant of contrast agent.The digital image signal of subtracter 17 outputs is given intensifier circuit 18, after amplifying through contrast, sends analog picture signal by D-A converter 19 again, and by image-processing system X output, the form with image shows on surveillance television machine 6 then.
Therefore, before contrast agent flows out from the visual field of image intensifier, on surveillance television machine 6, difference builds up in other words on the face of resembling,, along with flowing of contrast agent, for example at first demonstrate thick blood vessel, and thin blood-vessel image replaces thick blood vessel image gradually, thereby the animation that obtains the blood vessel elephant in real time resembles near heart, that is the difference that obtains successively by means of contrast agent flow, the track of contrast agent animation elephant is resembled on the face at a frame show simultaneously.
From the output of image-processing system X, can note by video disk recording equipment 7, also available multiple image imager 18 is recorded on the film with the form of hard copy.
Like this, be stored in frame memory 16
1, 16
2In image, seldom be subjected to the X ray quantum noise and from the The noise of television system, because each pixel mostly is maximum and minimum value in the frame image.The result, not only improved the S/N ratio, and be lower than under the situation of general when perspective X ray intensity in X ray intensity, can obtain the good difference of image quality, can be reduced to 1/10～1/100 of existing digital subtracting method to X ray intensity, and, just can obtain such the covering of existing system without the x x ray irradiation x and resemble.
In the embodiment that is introduced, with the D-A converter digital image signal of subtracter output is transformed into analog picture signal, carry out image with the mechanical, electrical phonographic record tape deck of surveillance television, multiple image imager then and show, and, also can use numeric display unit as image diplay.In this case, can omit that subtracter is provided with later, parameter word picture intelligence is the D-A converter of analog picture signal.
Among the embodiment, use frame memory, but resolving power is not high, when with one be one when resembling face, also can use field memory.
In an embodiment, the output of subtracter also can input to direct display unit, and being situated between is provided with frame memory, in case be stored in this memory, can show the image of storage well.
Utilize digital subtracting method of the present invention and device, not only can significantly reduce the x-ray dose that subject is accepted, and can be simultaneously displayed on the frame image to thin blood vessel from thick blood vessel.In addition, if as embodiment, logarithmic converter is set, then can resembles blood vessel more clearly and show in the front of a-d converter.
In an embodiment, through A/D converter 13 digitized picture intelligences, with frame memory 16
1, 16
2Readout by comparator 15
1, 15
2Compare frame memory 16 respectively
1Store less value, frame memory 16
2Store bigger value, frame memory 16
1Only in the output of A/D converter 13 less than frame memory 16
1Readout and frame memory 16
2Only in the output valve of A/D converter 13 greater than frame memory 16
2Readout the time, frame memory 16
1Or 16
2Storing value rewrite by the output valve of A/D converter.
Upgrade successively if will store the frame memory of maximum in each pixel (bright value), then can describe the TID subtraction that the time changes situation.
If as embodiment, the stipulated time is taken as the time that contrast agent stops in the image intensifier visual field, then can resemble on the face in the contrast agent inflow visual field, being presented at one to the whole states that flow out.
Accompanying drawing is the block diagram of one embodiment of the present of invention.
The 1-x radiographic source; The 2-subject; 3-image intensifier (TI); The 4-camera tube; The 5-camera controller; 6-televimonitor (display unit); 7-video disk recording equipment; 8-multiple image imager; The x-image-processing system; 11,11 '-switch; The 12-logarithmic converter; The 13-A-D converter; 14
1, 14
2-multiplexer; 15
1, 15
2-comparator (comparison means); 16
1, 16
2-frame memory (image storage device); 17-subtracter (arithmetic unit); The 18-intensifier circuit; The 19-D-A converter.
Claims (5)
1, a kind of digital subtracting method, the picture intelligence of the subject that is obtained by x-ray television system wherein becomes through the A/D converter and to be the digital map picture signals; Each pixel for the storage data image signal, first video memory, second video memory have a frame respectively and resemble face memory capacity, read the picture intelligence that first, second memory is stored, with aforementioned digital image signal one by one pixel carry out computing, operation result is shown as picture intelligence; It is characterized in that:
By the resulting digital image signal of described A/D converter conversion, deliver to described first, second video memory simultaneously, two video memories are stored this digital image signal, in specified time limit with the content of having stored in digital image signal and first, second video memory one by one pixel compare respectively, smaller value is stored in first video memory, and bigger value is stored in second video memory.
2,, it is characterized in that the described stipulated time is the residence time of contrast agent in the visual field according to the digital subtracting method of claim 1.
3, a kind of digital subtracting device, having will be by the digitized A/D converter of the picture intelligence that x-ray television system obtains, for the digital image signal after the store transformed respectively has first, second video memory that a frame resembles face memory capacity, and the picture intelligence of two video memories storage read and in addition computing, operation result is shown as picture intelligence, it is characterized in that:
The digital image signal that described A/D converter is obtained, in specified time limit, send simultaneously, respectively the picture intelligence of storing with described first, second video memory one by one pixel compare, less value is stored in first video memory, bigger second video memory that is stored in, and the picture intelligence of described first, second memory is read and pixel carries out computing one by one digital subtracting device.
4,, it is characterized in that being provided with the logarithmic converter that TV image signal is carried out logarithmic transformation in the front of A/D converter according to the digital subtracting device of claim 3.
According to the digital subtracting device of claim 4, it is characterized in that 5, the described stipulated time is the residence time of contrast agent in the visual field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85101311 CN1016836B (en) | 1985-04-01 | 1985-04-01 | Digital subtracting system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85101311 CN1016836B (en) | 1985-04-01 | 1985-04-01 | Digital subtracting system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85101311A CN85101311A (en) | 1987-01-10 |
| CN1016836B true CN1016836B (en) | 1992-05-27 |
Family
ID=4791762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 85101311 Expired CN1016836B (en) | 1985-04-01 | 1985-04-01 | Digital subtracting system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1016836B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100399996C (en) * | 2003-09-19 | 2008-07-09 | 株式会社东芝 | X ray image diagnosing device and image data obtaining method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1100515C (en) * | 1995-05-30 | 2003-02-05 | 岛津制作所株式会社 | Digital angiographic apparatus |
| US7949170B2 (en) | 2003-11-12 | 2011-05-24 | Hitachi Medical Corporation | Image processing method, image processing device, computer aided detection, and method for filtering along the time axis |
-
1985
- 1985-04-01 CN CN 85101311 patent/CN1016836B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100399996C (en) * | 2003-09-19 | 2008-07-09 | 株式会社东芝 | X ray image diagnosing device and image data obtaining method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN85101311A (en) | 1987-01-10 |
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