CN106780395A - The method and device of motion blur in removal CBCT Systems Projection images - Google Patents
The method and device of motion blur in removal CBCT Systems Projection images Download PDFInfo
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Abstract
The invention discloses the method for motion blur, device and CBCT systems in a kind of removal CBCT Systems Projection images, the method of motion blur includes determining the region N shared in the projected image of voxel in the removal CBCT Systems Projection images, and the size of the region N is associated with time for exposure T, the Pixel Dimensions L of imaging unit and frame pivot of angular speed W, CBCT system of gantry motion in CBCT systems to imaging unit plane apart from D；To be not less thanFrame rate gather the first projected image, (FR × T) first projected image will synthesize the projected image that motion blur is eliminated to generate per INT.Projected image after being synthesized using the method for the present invention eliminates the motion blur that detector motion is caused, and can significantly improve the spatial resolution and signal to noise ratio of projected image.
Description
Technical field
The present invention relates to a kind of method of motion blur in image procossing, more particularly to removal CBCT Systems Projection images,
Device and CBCT systems.
Background technology
It is the technology that fault image is recombinated using cone-beam projections computer that pencil-beam computerized tomography rebuilds (CBCT), its
Principle is that x-ray generator is annular DR (digital radiation exposure) with relatively low quantity of X-rays X target volume, then will be around target
Data set after body multiexposure, multiple exposure rebuilds three-dimensional data in a computer, and CBCT mainly exists relative to traditional spiral CT difference
On detector, conventional helical CT uses area array sensor, spiral CT to use quasi- one-dimensional data weight using line array sensor and CBCT
The slice of data of two dimension is built out, three-dimensional data is set up by each two dimensional slice data, and CBCT directly uses two-dimensional projection data
Three-dimensional data is reconstructed, therefore CBCT significantly improves the utilization rate of x-ray relative to spiral CT.
CBCT is because z-axis coverage rate is big, spatial resolution is high and is easy to mutually be tied with other clinical events (as intervention is performed the operation)
Its advantage closed, in medical C-arm system, it has also become important technological trend.
The main application of of CBCT is the 3-D view for obtaining patient's blood vessel.For 3D blood vessel imagings, in order that blood vessel
It is high-visible, in CBCT sweep phases, the contrast agent of certain high-contrast need to be injected in the blood vessel of patient.The vascular scan phase
Between, contrast agent should fully be full of blood vessel, it is therefore desirable to inject substantial amounts of contrast agent.
However, the health of the possible injure patient of the contrast agent of high-contrast, so to control the dosage of contrast agent.Required
Radiography dosage is related to blood flowing speed and CBCT sweep times.Generally, the speed of blood flow is the nature of patient
Attribute, it is difficult to control.Therefore, the sweep speed that CBCT is improved in this case is most important.One of CBCT potentially should
With being 3D cardiac imagings, under this application scenarios, due to heart of patient beat rate quickly, therefore sweep speed becomes more
It is crucial.Sum it up, the CBCT systems of sweep speed high have very big advantage in clinical practice.
It is well known that there are two kinds of scan modes in CBCT：
1. step-by-step movement：X-ray bulb (hereinafter referred to as bulb) and detector motion are exposed to stopping behind target location
Light, bulb and detector motion are to the next position after end exposure.
2. continous way：Bulb and detector are continuously moved, continual to be exposed and integrate.
Based on above-mentioned scan mode, in order to the CBCT systems for obtaining sweep speed high have following two solutions：
1. under continuous scan pattern, C-arm gantry rotation rate is improved.
Generally, this scheme is using the mono-tank of fixed focal spot or the X-ray bulb of fixed focal spot.When frame with compared with
When speed high rotates, the motion blur that detector and focal spot cause may be introduced in image.Fig. 1 shows that focal spot draws
The schematic diagram of the motion blur for rising, illustrates the motion mould that focal spot causes by taking the projected image of central X-ray beam as an example in Fig. 1
Paste.As seen from Figure 1, when frame rotates at a high speed, X-ray beam can pass through the shadow region for treating a corpse or other object for laboratory examination and chemical testing shown in Fig. 1, through the moon
The pixel value that the X-ray beam Hui Dui centers X-ray beam in shadow zone domain is formed on the detector has been contributed, therefore reduces acquisition
The quality of image, is especially reduction of the spatial resolution of image.In order to overcome the motion blur caused by focal spot, current one
The mode of kind is to increase the power of X-ray tube and reduce the time for exposure, but can so cause cost to be significantly increased, and due to detector
The smaller effect on driving birds is not good of Pixel Dimensions, namely motion blur is still present.Another way is to use some correcting algorithms, including repeatedly
Generation reconstruction, blind deconvolution or non-blind deconvolution.But Deconvolution Method also can only partly solve motion blur, and iterative reconstruction
Then can significantly increase the calculating time.
Therefore, the spatial resolution of the image that the CBCT system photographs of the sweep speed high for being obtained using aforesaid way are obtained
Still it is relatively low.
2. under step-by-step movement scan pattern, using the detector and multi-source X-ray tube of large area.
If using traditional X-ray tube and detector in the step-by-step movement scan mode of sweep speed high, system can be very
It is unstable, because the acceleration of each step of frame and the very strong power of needs of slowing down.
However, for using multiple light courcess X-ray tube, can be by switching the light source of each position come instead of the rotation of frame
Turn, so, sweep speed can will not very high and also introduce motion blur, but this solution depends on high cost
With limited tube current.
Therefore, this scheme is seldom applied in clinic.
In sum, the existing scheme for obtaining sweep speed high is with picture quality and calculating time as cost, even
There is motion blur in the image that the CBCT systems of the sweep speed high under continuous scan pattern are obtained, the quality of image does not meet reality
Clinical demand.Therefore, obtained in the CBCT systems of sweep speed high and meet the high quality graphic of actual clinical demand and turn into
Current problem demanding prompt solution.
The content of the invention
In order to solve the above-mentioned technical problem, the invention provides motion blur in a kind of removal CBCT Systems Projection images
Method, including：
Determine the shared region N in the projected image of voxel, the size of the region N is associated with machine in CBCT systems
Frame motion the time for exposure T of angular speed W, CBCT system, the Pixel Dimensions L of imaging unit and frame pivot into
As unit plane is apart from D；
To be not less thanFrame rate gather the first projected image, will (FR × T) first projected image conjunction per INT
Into the projected image that motion blur is eliminated to generate, wherein, INT (N) is that the region N is rounded, and FR is frame rate.
Further, the region N is obtained by equation below：
Further,
It is described (FR × T) first projected image to synthesize the projected image bag that motion blur is eliminated to generate per INT
Include：
I-th the first projected image is chosen in INT (FR × T) the first projected image as the perspective view of benchmark first
Picture；On the basis of the projected image of the benchmark first, by jth the first projected image translationSo that
Picture of the same voxel in the projected image of benchmark first is obtained to overlap, wherein, i ∈ [1, INT (FR × T)], j ∈ [1, INT (FR ×
T)]。
Further, the span of the N is：(1,10].
Further, the method for motion blur also includes in the removal CBCT Systems Projection images：
The focal spot of x-ray source is moved along the direction opposite with the direction of motion of the x-ray source in control CBCT systems,
To cause the focal spot of the x-ray source static relative to earth axes.
Present invention also offers a kind of device of motion blur in removal CBCT Systems Projection images, including：
Area determination module, the region N shared in the projected image for determining voxel, the size of the region N
Be associated with the time for exposure T of angular speed W, CBCT system of gantry motion in CBCT systems, the Pixel Dimensions L of imaging unit, with
And frame pivot to imaging unit plane apart from D；
Image capture module, for being not less thanFrame rate gather the first projected image, wherein, INT (N) is
The region N is rounded；
Image synthesis unit, for per INT (FR × T) the first projected image synthesis motion blur will to be eliminated to generate
Projected image, wherein, FR is frame rate.
Further, the region N is obtained by equation below：
Further, described image synthesis module includes：
Benchmark image chooses unit, for choosing i-th the first perspective view in INT (FR × T) the first projected image
As the projected image of benchmark first；
Synthesis unit, on the basis of the projected image of the benchmark first, by jth the first projected image translationTo cause that picture of the same voxel in the projected image of benchmark first overlaps, wherein, i ∈ [1, INT (FR
×T)],j∈[1,INT(FR×T)]。
Further, the device of motion blur also includes in the removal CBCT Systems Projection images：
Control module, for controlling the focal spot of x-ray source in CBCT systems along the direction of motion phase with the x-ray source
Anti- direction motion, to cause the focal spot of the x-ray source static relative to earth axes.
The present invention also provides a kind of CBCT systems, including in above-mentioned removal CBCT Systems Projection images motion blur dress
Put.
Compared with prior art, technical solution of the present invention has advantages below：
The region N shared in the projected image by first determining voxel, the size of the region N is associated with CBCT systems
During the time for exposure T of angular speed W, CBCT system of gantry motion, the Pixel Dimensions L of imaging unit and frame rotate in system
The heart is to imaging unit plane apart from D；Then being not less thanFrame rate gather the first projected image；Finally will be every
INT (FR × T) the first projected image synthesis eliminates the projected image of motion blur to generate.Due to being not less than
High frame rate gather the first projected image, and every INT (FR × T) the first projected image synthesized and then can be gone
Except motion blur caused by detector motion in the CBCT systems of sweep speed high, the spatial resolution and letter of image are improve
Make an uproar and compare, and then improve the quality of image, obtain and meet actual clinical demand image.
Further, because the focal spot by controlling x-ray source in CBCT systems is along the motion side with the x-ray source
Move in the opposite direction so that the focal spot of the x-ray source is static relative to earth axes, and then CBCT systems can be removed
Due to the motion blur that focal spot causes in system, the spatial resolution and picture quality of image are further improve so that final
The image of acquisition more conforms to actual clinical demand.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art and advantage, below will be to implementing
Example or the accompanying drawing to be used needed for description of the prior art are briefly described, it should be apparent that, drawings in the following description are only
Only it is some embodiments of the present invention, for those of ordinary skill in the art, on the premise of not paying creative work,
Other accompanying drawings can also be obtained according to these accompanying drawings.
Fig. 1 is the schematic diagram of the motion blur that focal spot causes；
Fig. 2 is the schematic diagram of the motion blur that detector causes；
Fig. 3 is the schematic diagram of the projected image after obscuring；
Fig. 4 be the embodiment of the present invention 1 removal CBCT Systems Projection images in motion blur method flow chart；
Fig. 5 is the flow chart of step 103；
Fig. 6 is the schematic diagram of composograph；
Fig. 7 be the embodiment of the present invention 2 removal CBCT Systems Projection images in motion blur method flow chart；
Fig. 8 is the schematic diagram of X-ray tube；
Fig. 9 is the schematic diagram of the focal spot movement direction with gantry motion direction of the embodiment of the present invention 2；
Figure 10 be the embodiment of the present invention 3 removal CBCT Systems Projection images in motion blur device structured flowchart.
Specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art obtained on the premise of creative work is not made it is all its
His embodiment, belongs to the scope of protection of the invention.
Just as described in the background art, when existing CBCT systems are scanned using step-by-step movement, if wanting with relatively low dosage
To realize high-velocity scanning, high cost and limited tube current are depended on, therefore seldom by step-type CBCT systems come real
Existing high-velocity scanning.And for the CBCT systems that sweep speed high is realized using continuous scan pattern, using existing method
The image of acquisition still fails to remove the motion blur in projected image, causes the resolution ratio of the image of final acquisition low, image matter
Amount does not meet actual clinical demand.Therefore, inventor is from the root for causing projected image fuzzy, from by detector motion
The motion blur for causing sets out come the spatial resolution and noise for removing the motion blur in projected image to improve projected image
Than acquisition meets the image of clinical demand.Further, cause from the motion blur and focal spot caused by detector motion
Two aspects of motion blur set out to remove the motion blur in projected image, further improve the spatial discrimination of projected image
Rate and signal to noise ratio, largely improve the quality of the projected image of acquisition.
Embodiment 1：
The method that the present embodiment provides motion blur in a kind of removal CBCT Systems Projection images.With described in the present embodiment
The frame of CBCT systems is that C-shaped, imaging unit are illustrated for detector, but technical scheme is not limited this.
CBCT systems in the present embodiment include the frame of C-shaped, x-ray source and detector, and the frame can be around the central axis of frame
Rotation, the x-ray source and detector are separately positioned on the relative two ends of frame.In CBCT system work process, person under inspection
Or be located between x-ray source and detector by inspection position, the ray that x-ray source sends is projected on the detector, generates perspective view
Picture.
Fig. 2 is the schematic diagram of the motion blur that detector causes, as shown in Fig. 2 the process of the frame high-speed rotation in C-shaped
In, due to that can not keep absolute geo-stationary between x-ray source and detector, therefore detector has phase relative to x-ray source
To motion, now, central X-ray beam shown in Fig. 2 can inswept detector certain area, and then cause to go out in projected image
Now obscure.
Fig. 3 is the schematic diagram of the projected image after obscuring, in figure, the signal that black portions are detected for detector, due to
The motion of detector, the signal distributions that should be obtained by a pixel cell cause projected image to go out in multiple pixel cells
Now obscure, the signal to noise ratio of image is also reduced while reducing image spatial resolution.Inventor proposes, first passes through and put forward high frame rate
The mode acquired projections image of rate, then synthesizes to the projected image for collecting, to remove because detector motion is brought
It is fuzzy.Illustrated accordingly below by way of specific embodiment.
As shown in figure 4, Fig. 4 be the embodiment of the present invention 1 removal CBCT Systems Projection images in motion blur method
Flow chart, methods described includes：
Step 101, determines the shared region N in the projected image of voxel, and the size of the region N is associated with CBCT
The time for exposure T of angular speed W, CBCT system of gantry motion, the Pixel Dimensions L of imaging unit and frame rotate in system
Center is to imaging unit plane apart from D.
In a kind of optional implementation method, the region N is obtained by equation below：
Step 102, to be not less thanFrame rate gather the first projected image, wherein, INT (N) is to the area
Domain N is rounded.
The time for exposure of CBCT systems is T in a step 101, therefore the frame rate of detector is 1/T, performs step 102,
To be not less thanFrame rate gather the first projected image, enter again equivalent to the INT (N) more than or equal to former frame rate
Row IMAQ, can realize the collection to the first projected image by the detector using high frame rate in this step.
Step 103, (FR × T) first projected image will synthesize the perspective view that motion blur is eliminated to generate per INT
Picture, wherein, FR is frame rate.
As a kind of optional implementation method, as shown in figure 5, in step 103 (FR × T) the first perspective view will be opened per INT
The projected image of motion blur is eliminated to generate as synthesis, including：
Step 1030, chooses i-th the first projected image as benchmark the in INT (FR × T) the first projected images
One projected image；Wherein, i ∈ [1, INT (FR × T)].
Specifically, perform step 1030 before, also including being grouped to the first projected image for collecting the step of：
(FR × T) first projected image will be divided into one group per INT successively.Every group of first projected image is same voxel
Projected image.
Specifically, can according to the acquisition time of the first projected image or collection the first projected image when corresponding machine
Frame angle, (FR × T) first projected image will be divided into one group per INT.
In every group of first projected image, wherein one is chosen as the projected image of benchmark first.
It should be noted that the above method is directed to the projected image collected under a certain projection angle being processed
's.It it is 5 degree with projection angle, as a example by INT (FR × T)=3, three the first projected images may respectively correspond to projection angle and be
5 degree, 5.1 degree, 5.2 degree.Specifically using the first projected image under which projection angle as the projected image of benchmark first, can basis
Actual demand is selected, and the present invention is not specifically limited to this, simply on the basis of the first projected image under different projection angles
First projected image, and other first projected images are translated on the basis of the projected image of benchmark first synthesis acquisition eliminate fortune
After the projected image of dynamic model paste, when subsequently being rebuild with the projected image, it is necessary to as the projected image pair of benchmark first
Geometrical relationship (how being mapped to three-dimensional space from two-dimensional projection image) under the projection angle answered is rebuild.
Step 1031, on the basis of the projected image of the benchmark first, by jth the first projected image translationTo cause that picture of the same voxel in the projected image of benchmark first overlaps, wherein, i ∈ [1, INT
(FR × T)], j ∈ [1, INT (FR × T)].Work as i<During j, translated with a direction, work as i>During j, the direction of translation and i<D during j
Translation direction is opposite；It is exactly the projected image of benchmark first during i=j, any translation is not done.
After the first projected image of benchmark has been chosen, then can be according to other first projected images of the group and benchmark first
Relative position relation between projected image carries out the translation of horizontal direction to it, to cause that same voxel is projected in benchmark first
Picture in image overlaps, and specific translational movement is
Below by taking Fig. 6 as an example, the method to the present embodiment is described in detail.
By taking INT (N)=3 as an example, shared pixel after the projected image with a voxel on the detector is blurred in other words
Unit is for as a example by 3, the projected image of the first row is the projected image gathered with the frame rate of 1/T in Fig. 6, is entered with the frame rate
During the collection of row projected image, due to there is relative motion between detector and x-ray source, therefore can produce by detector motion
Caused motion blur.The projected image of same voxel is distributed in 3 pixel cells in Fig. 6 as described above.
Three projected images of the second row are to be exactly equal in Fig. 6Frame rate collection the first perspective view
Picture, that is, be acquired with the frame rate of 3 times of collection the first row projected images, due to INT (FR × T)=INT (N)=3,
One group, the projected image of the same voxel not photographed in the same time respectively are constituted with every 3 pictures.
In the present embodiment, if choosing the first projected image on the basis of first the first projected image in the second row, i.e. i
=1, then by second the first projected image (correspondence j=2) and the 3rd the first projected image (correspondingly j=3) translated with
So that picture of the same voxel in the projected image of benchmark first overlaps.
For second translational movement of projected image, by i=1, j=2 substitutes into following formula and calculates：
For the 3rd translational movement of projected image, by i=1, j=3 substitutes into following formula and calculates：
Corresponding in Fig. 6, during translation, only second the first projected image need to integrally be arranged to left one, the 3rd the
As soon as projected image is integrally arranged to left two, can cause that picture of the same voxel in three the first projected images overlaps.
The third line is that, by second schematic diagram of the first projected image translation, fourth line is by the 3rd first throwing in Fig. 6
The schematic diagram of shadow image translation.
Finally, three the first projected images are synthesized to generate the projection for eliminating motion blur under the projection angle
Image.Specifically, exactly by translation after three the first projected images to be overlapped and eliminate motion blur synthesizing one
Projected image afterwards.Last column is the projected image after synthesis in Fig. 6.Projected image after synthesis effectively removes motion
It is fuzzy, and the spatial resolution of the projected image after synthesis is higher, signal to noise ratio is every signal to noise ratio of the first projected imageTimes.
Certainly, in specific application scenarios, frame rate FR can be more thanFor example, work as INT (FR × T)=5,
During INT (N)=3, one group, the projected image of the same voxel not photographed in the same time respectively are constituted with every 5 pictures.If choosing
Take the first projected image on the basis of first the first projected image, i.e. i=1, then by second the first projected image (correspondence j=
2), the 3rd the first projected image (correspondence j=3), the 4th the first projected image (correspondence j=4) and the 5th first projection
Image (correspondence j=5) is translated：To cause same voxel in the projected image of benchmark first
As overlapping.Finally, by translation after the synthesis of 5 the first projected images eliminate motion blur under the projection angle generating
Projected image.If image on the basis of choosing the 3rd, then the one the second should move to right, and the four or five should move to left.This
The method of motion blur in the removal CBCT Systems Projection images that inventive embodiments 1 are provided, by first determining voxel in the throwing
Shared region N after being blurred in shadow image, then again being not less thanFrame rate gather the first projected image, pass through
The INT (FR × T) that high frame rate is collected first projected images synthesized after translation transformation and then generated removal
The projected image of motion blur.The projected image obtained using the method for the present embodiment is eliminated because caused by detector motion
Motion blur, improves the spatial resolution of the projected image for collecting while also considerably improving the noise of projected image
Than.
Embodiment 2
The difference of the present embodiment and embodiment 1 is except in view of the fortune caused due to detector motion in the present embodiment
Dynamic model paste is outer, it is also contemplated that the motion blur caused by focal spot, namely draws in terms of eliminating detector and focal spot two in this implementations
The motion blur for rising.
As shown in fig. 7, Fig. 7 be the embodiment of the present invention 2 removal CBCT Systems Projection images in motion blur method
Flow chart, methods described includes：
Step 101, determines the shared region N in the projected image of voxel, and the size of the region N is associated with CBCT
The time for exposure T of angular speed W, CBCT system of gantry motion, the Pixel Dimensions L of imaging unit and frame rotate in system
Center is to imaging unit plane apart from D.
Step 102, to be not less thanFrame rate gather the first projected image, wherein, INT (N) is to the area
Domain N is rounded.
Step 103, (FR × T) first projected image will synthesize the perspective view that motion blur is eliminated to generate per INT
Picture, wherein, FR is frame rate.
Step 104, the focal spot of x-ray source is along opposite with the direction of motion of the x-ray source in control CBCT systems
Direction is moved, to cause the focal spot of the x-ray source static relative to earth axes.
Step 101-103 is similar with embodiment 1 in the present embodiment, and here is omitted.
In CBCT systems, for x-ray source, it can not be preferable into spot light, but has effigurate
Focal spot, and during frame high-speed motion, also in motion, the inswept region necessarily within the time for exposure please for focal spot
With continued reference to Fig. 1, as shown in figure 1, when x-ray source rotates at a high speed with frame, X-ray beam can pass through treating shown in Fig. 1
The shadow region of a corpse or other object for laboratory examination and chemical testing, the pixel value that the X-ray beam Ye Huidui centers X-ray beam through shadow region is formed on the detector has
Contributed, focal spot movement is caused through treating that it is fuzzy that projected image that the central X-ray beam of a corpse or other object for laboratory examination and chemical testing is generated on the detector is generated,
In order to remove the fuzzy of the projected image caused by focal spot movement, by controlling x-ray source in CBCT systems in the present embodiment
Focal spot is moved along the direction opposite with the direction of motion of the x-ray source, to cause the focal spot of the x-ray source relative to ground
Areal coordinate system is static.Additionally, being illustrated so that the x-ray source is as X-ray tube as an example in the present embodiment, those skilled in the art
Know, x-ray source can also be accelerating tube etc., not limit herein.Fig. 8 is the schematic diagram of X-ray tube, as shown in figure 8, X is penetrated
Spool includes：Anode 1, plate target 2 and cathode filament 4, between plate target 2 and cathode filament 4 after applied voltage, negative electrode meeting
There is electronics 3 to be moved to plate target 2, high-velocity electrons 3 bombard plate target 2 and then produce X-ray.
Fig. 9 is the schematic diagram of the focal spot movement direction with gantry motion direction of the embodiment of the present invention 2, as shown in figure 9, Fig. 9
In moved right with frame and illustrated, during frame high-speed motion, control the focal spot of X-ray tube to be illustrated by Fig. 9
The position of right side square frame moved along the direction opposite with gantry motion, i.e., direction shown in dotted lines in Figure 9 is moved in Fig. 9
The position of shown left side square frame.Annulus in Fig. 9 schematically represents the anode of X-ray tube, in the focal spot of control X-ray tube
When being moved along the direction in opposite direction moved with X-ray tube, equivalent to so that the focal spot of X-ray tube is relative to X-ray tube
The motion of anode coordinate system, it is and static relative to earth axes.During frame rotates at a high speed, by controlling X-ray
The focal spot of pipe is moved along the direction in opposite direction with gantry motion, can remove the motion blur that focal spot movement causes, and then
The spatial resolution and signal to noise ratio of the projected image for collecting can also be improved.
Be could be aware that by Fig. 8, the bombardment plate target 2 of electronics 3 that negative electrode is produced in X-ray tube forms focal spot, therefore this implementation
In example, the focal spot of X-ray tube is controlled during frame high-speed motion along opposite with the direction of motion of the X-ray tube
Direction motion, specifically can by between plate target 2 and cathode filament 4 increase a magnetic field, under the magnetic fields produce
Raw Lorentz force can cause that the direction of motion of electronics is in opposite direction with gantry motion.And then realize control CBCT systems in
The focal spot of x-ray source is moved along the direction opposite with the direction of motion of the x-ray source, and move distance and movement velocity with
The move distance of the x-ray source is identical with movement velocity, so as to realize the focal spot of the x-ray source relative to earth axes
It is static.Moved along the direction opposite with the direction of motion of the x-ray source by controlling the focal spot of x-ray source, the fortune of focal spot
The dynamic motion that can compensate x-ray source so that interior during acquired projections image, effective focal spot is looked and existed relative to detector
The position in space is fixed, and then can remove the fuzzy of the projected image that focal spot movement causes.
It should be noted that for foregoing each method embodiment, in order to be briefly described, therefore it is all expressed as a series of
Combination of actions, but those skilled in the art should know, the present invention not by described by sequence of movement limited because
According to the present invention, some steps can sequentially or simultaneously be carried out using other.Secondly, those skilled in the art should also know
Know, embodiment described in this description belongs to preferred embodiment, involved action and module is not necessarily of the invention
It is necessary.
The method of motion blur in the removal CBCT Systems Projection images of the present embodiment, in the removal detector fortune of embodiment 1
On the basis of the dynamic projected image for causing is fuzzy, be further advanced by the focal spot of control x-ray source along with X-ray source movement
Direction motion in opposite direction, effectively eliminates the fuzzy of the projected image that focal spot movement causes, and further increasing throwing
The spatial resolution and signal to noise ratio of shadow image, largely improve the quality of projected image so that the final throwing for obtaining
Shadow image more meets actual clinical demand.
Embodiment 3
As shown in Figure 10, Figure 10 be the embodiment of the present invention 3 removal CBCT Systems Projection images in motion blur device
Structured flowchart, as shown in Figure 10, the device of motion blur includes in the removal CBCT Systems Projection images：
Area determination module, the region N shared in the projected image for determining voxel, the size of the region N
Be associated with the time for exposure T of angular speed W, CBCT system of gantry motion in CBCT systems, the Pixel Dimensions L of imaging unit, with
And frame pivot to imaging unit plane apart from D；
Image capture module, for being not less thanFrame rate gather the first projected image, wherein, INT (N) is
The region N is rounded；
Image synthesis unit, for per INT (FR × T) the first projected image synthesis motion blur will to be eliminated to generate
Projected image, FR is frame rate.
Used as a kind of optional embodiment, the region N is obtained by equation below：
Used as a kind of optional embodiment, described image synthesis module includes：
Benchmark image chooses unit, for choosing i-th the first perspective view in INT (FR × T) the first projected image
As the projected image of benchmark first；
Synthesis unit, on the basis of the projected image of the benchmark first, by jth the first projected image translationTo cause that picture of the same voxel in the projected image of benchmark first overlaps, wherein, i ∈ [1, INT (FR
×T)],j∈[1,INT(FR×T)].As a kind of optional embodiment, in the removal CBCT Systems Projection images of the present embodiment
The device of motion blur also includes：
Control module, for controlling the focal spot of x-ray source in CBCT systems along the direction of motion phase with the x-ray source
Anti- direction motion, to cause the focal spot of the x-ray source static relative to earth axes.
The specific implementation of the device of motion blur can be found in removal in the removal CBCT Systems Projection images of the present embodiment
The implementation of the method for motion blur in CBCT Systems Projection images, here is omitted.
The present embodiment also provides a kind of CBCT systems, including motion blur in above-mentioned removal CBCT Systems Projection images
Device.
If the integrated unit or module in above-described embodiment are using realization in the form of SFU software functional unit and as independently
Production marketing or when using, can store in the storage medium of embodied on computer readable.It is of the invention based on such understanding
Part that technical scheme substantially contributes to prior art in other words or all or part of the technical scheme can be with
The form of software product is embodied, the computer software product store in storage medium, including some instructions be used to so that
One or more computer equipment (can be personal computer, server or network equipment etc.) performs each embodiment of the invention
The all or part of step of methods described.
In addition, during each functional unit or module in each embodiment of the invention can be integrated in a processing unit,
Can also be that unit is individually physically present, it is also possible to which two or more units are integrated in a unit.Above-mentioned collection
Into unit can both be realized in the form of hardware, it would however also be possible to employ the form of SFU software functional unit is realized.
The above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications also should
It is considered as protection scope of the present invention.
Claims (10)
1. in a kind of removal CBCT Systems Projection images motion blur method, it is characterised in that including：
Determine that the size of voxel shared region N in the projected image, the region N is associated with frame fortune in CBCT systems
The dynamic time for exposure T of angular speed W, CBCT system, the Pixel Dimensions L of imaging unit and frame pivot is single to imaging
First plane apart from D；
To be not less thanFrame rate gather the first projected image, will per INT (FR × T) first projected image synthesize with
Generation eliminates the projected image of motion blur, wherein, INT (N) is that the region N is rounded, and FR is frame rate.
2. the method for removing motion blur in CBCT Systems Projection images as claimed in claim 1, it is characterised in that the area
Domain N is obtained by equation below：
3. the method for removing motion blur in CBCT Systems Projection images as claimed in claim 1, it is characterised in that described to incite somebody to action
The projected image that every INT (FR × T) the first projected image synthesis eliminates motion blur to generate includes：
I-th the first projected image is chosen in INT (FR × T) the first projected image as the projected image of benchmark first；
On the basis of the projected image of the benchmark first, by jth the first projected image translationSo that
Picture of the same voxel in the projected image of benchmark first is obtained to overlap, wherein, i ∈ [1, INT (FR × T)], j ∈ [1, INT (FR ×
T)]。
4. the method for removing motion blur in CBCT Systems Projection images as claimed in claim 1, it is characterised in that the N
Span be：(1,10].
5. the method for removing motion blur in CBCT Systems Projection images as claimed in claim 1, it is characterised in that also wrap
Include：
The focal spot of x-ray source is moved along the direction opposite with the direction of motion of the x-ray source in control CBCT systems, so that
The focal spot for obtaining the x-ray source is static relative to earth axes.
6. in a kind of removal CBCT Systems Projection images motion blur device, it is characterised in that including：
Area determination module, the size association of the region N shared in the projected image for determining voxel, the region N
The time for exposure T of angular speed W, CBCT system of gantry motion, Pixel Dimensions L, Yi Jiji of imaging unit in CBCT systems
Frame pivot is to imaging unit plane apart from D；
Image capture module, for being not less thanFrame rate gather the first projected image, wherein, INT (N) is to institute
Region N is stated to round；
Image synthesis unit, for per INT (FR × T) first projected image the throwing that motion blur is eliminated to generate will to be synthesized
Shadow image, wherein FR are frame rate.
7. the device of motion blur in CBCT Systems Projection images is removed as claimed in claim 6, it is characterised in that the area
Domain N is obtained by equation below：
8. the device of motion blur in CBCT Systems Projection images is removed as claimed in claim 6, it is characterised in that the figure
As synthesis module includes：
Benchmark image chooses unit, makees for choosing i-th the first projected image in INT (FR × T) the first projected image
On the basis of the first projected image；
Synthesis unit, on the basis of the projected image of the benchmark first, by jth the first projected image translationTo cause that picture of the same voxel in the projected image of benchmark first overlaps, wherein, i ∈ [1, INT (FR
×T)],j∈[1,INT(FR×T)]。
9. the device of motion blur in CBCT Systems Projection images is removed as claimed in claim 6, it is characterised in that also wrapped
Include：
Control module, for controlling the focal spot of x-ray source in CBCT systems along opposite with the direction of motion of the x-ray source
Direction is moved, to cause the focal spot of the x-ray source static relative to earth axes.
10. a kind of CBCT systems, it is characterised in that thrown including the removal CBCT systems described in any one in claim 6-9
The device of motion blur in shadow image.
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Address after: 201807 Shanghai City, north of the city of Jiading District Road No. 2258 Patentee after: Shanghai Lianying Medical Technology Co., Ltd Address before: 201807 no.2258, Chengbei Road, Jiading District, Shanghai Patentee before: SHANGHAI UNITED IMAGING HEALTHCARE Co.,Ltd. |