CN109870471A - A kind of Cone-Beam CT angle sequence scattering acquisition methods of monochromatic light grid detecting - Google Patents
A kind of Cone-Beam CT angle sequence scattering acquisition methods of monochromatic light grid detecting Download PDFInfo
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Abstract
The invention discloses a kind of Cone-Beam CT angle sequences of monochromatic light grid detecting to scatter acquisition methods, the scattered field detected using few amplitude grating of circular scanning, the scattering of different zones is divided according to projection tensor, and is fitted projection-scattering data, obtains scattering model parameters knowledge.The scattering model parameter information under different angle is realized by interpolation, while incorporating influence of the structure to scattering, improves the accuracy that scattering obtains, and then completes correction improving image quality.The Cone-Beam CT angle sequence of monochromatic light grid detecting provided by the invention scatters acquisition methods, the scattering of testee different angle sequence suitable for arbitrarily complicated degree is estimated, reliability, the stability of method are good, sweep object structure can largely be promoted to the accuracy of scatter distributions, the scattered field estimation completed under different angle sequence is detected by few width scattered field, hence it is evident that improve the efficiency that scattering obtains while improving pyramidal CT image quality.
Description
Technical field
The invention belongs to Cone-Beam CTs to apply relevant medical imaging and industrial nondestructive testing field, be related to a kind of monochromatic light grid and detect
The Cone-Beam CT angle sequence of survey scatters acquisition methods.
Background technique
Cone-Beam CT (Cone Beam Computed Tomography, CBCT) is used as a kind of advanced medical imaging and work
Industry non-destructive testing technology, when not destroying object, in the form of two dimension or three-dimensional tomographic image clearly, accurately, intuitively
Show the internal structure of object to be detected, interior of articles defective locations and size are quantitatively provided.
Scattered information and projection information aliasing are an important factor for restricting image quality.The projection information of high-density objects by
Compton scattering influences serious, so that image detail is submerged, marginal information and picture contrast are reduced for scattering, be Cone-Beam CT without
Damage detection defect recognition brings puzzlement.Although scattered information is superimposed in the signal in the form of low frequency component, hardware side can be passed through
Method inhibits it, but whole angular scatter collection efficiency in the case of circular scanning are lower, not can effectively solve interested
Angle position scatters the influence to backprojection reconstruction.
Currently, scattered field acquisition methods generally comprise hardware approach and software approach.Hardware is mainly set with increasing hardware
It is standby, scattered field is obtained by related physical operation, and then complete the correction of scattered field.Hardware approach mainly includes collimator, sky
Air gap, filter line device, scanning slit, radiopaque leads etc..Software approach is using projected image as foundation, at digital picture
Reason method completes image analysis and illuminated object estimation, obtains scatter distributions rule.It include convolution method, warp area method, Meng Te
Monte Carlo Simulation of Ions Inside method etc..In Cone-Beam CT, Huang, Kuidong et al. Chinese Physics C (2016,40 (6):
068202.) article " Robust scatter correction method for cone-beam CT using an
A kind of CBCT scatter correction method based on staggeredly slit is proposed in interlacing-slit plate ", passes through height first
The missing data of this filtering method light filling grid dispersion image, the partial dispersion then obtained to staggeredly slit scan splice.
This method has certain effect, but splices the more difficult assurance of accuracy.Bowen Meng et al. Physica Medica (2013,
40 (1): article " Single-scan patient-specific scatter correction in 011907)
computed tomography using peripheral detection of scatter and compressed
One kind is proposed in sensing scatter retrieval ", scatterplot interpolation method is constituted by mixing scattering model, pass through acquisition
Scatterplot convolution model borderline region on scattering estimated.Yang, Fuqiang et al. are in IEEE Transactions on
Article " the Scattering Estimation for Cone-Beam CT of Nuclear Science (2018, PP (99): 1-1)
A kind of pressure based on measurement is proposed in Using Local Measurement Based on Compressed Sensing "
Contracting perception scattering recovery algorithms, this method are passed through local scatterometry, the estimation of scattered field are completed with Optimized model.
Although above-mentioned distinct methods achieve certain scattering estimation and calibration result, but do not account for object structure
Influence to scattering field distribution.It is past in practical application for the requirement of current Cone-Beam CT medical imaging and industrial nondestructive testing demand
It is insufficient toward accuracy.
Summary of the invention
For the scattering phase not accounted in cone beam computed tomography (CT) scattering estimation method under object structures information and adjacent angular sequence
Closing property problem, the present invention provide a kind of Cone-Beam CT angle sequence scattering acquisition methods of monochromatic light grid detecting.Utilize circular scanning
The scattered field that few amplitude grating is detected divides the scattering of different zones according to projection tensor, and is fitted projection-scattering
Data obtain scattering model parameters knowledge.The scattering model parameter information under different angle is realized by interpolation, while incorporating knot
Influence of the structure to scattering improves the accuracy that scattering obtains, and then completes correction improving image quality.
The technical solution adopted by the present invention to solve the technical problems the following steps are included:
(1) it is scanned, parameter remains unchanged in the process, obtains scanning projection and lacks width；
(2) it is scattered field estimation, completes the detecting of scattering parameter knowledge；
(3) parameter information obtained by detecting obtains the estimation of angle sequence scattered field.
In above-mentioned steps (1), the scanning projection of acquisition includes: single optical grating projection A, project objects B, monochromatic light grid+object
Body projects C, wherein project objects B, monochromatic light grid+project objects C are obtained in a manner of circular scanning.
In above-mentioned steps (2), the specific steps of scattered field estimation include:
1) acquire an amplitude grating projected image A, optical grating projection information is counted, with count in occur higher two
A peak value divides threshold value as raster grid region and slit areas, is denoted as τ1And τ2；
2) grating+testee projection C grid region and slit areas are extracted according to threshold value, numerical value is less than τ1
Region be grid region, numerical value be greater than τ2Region be slit areas, respectively to grid region image and slit areas image
It carries out interpolation and gaussian filtering obtains the grating scattering image (referred to as image C1) of grid region and object+grating of slit areas
Dispersion image (referred to as image C2)；
3) pure projected image, referred to as image D are obtained with image C2 subtracted image C1, with project objects B subtracted image D, obtained
To object scatter field picture E.
In above-mentioned steps (2), the specific steps of scattered field knowledge acquisition include:
1) gradient pixel-by-pixel is carried out to projected image B to calculate, obtain the tensor matrix of two dimensional image, then seek tensor square
The determinant H and characteristic value T of battle array；
2) different zones are obtained according to the difference of determinant and characteristic value, judgment threshold threshold is given, if T ≈
Threshold& | H | ≈ 0, then the region is referred to as flat site, if T > threshold& | H | ≈ 0, the region are referred to as side
Edge region, if T > threshold& | H | > 0, the region are referred to as angle point region.
3) nonlinear model S=ax is selectedbAs fitting function, projection is divided into obtained region and the scattered field acquired
Corresponding region is mapped, and different zones projection-scattering curve is obtained, and obtains the corresponding scattering of different zones under the angle position
Model parameter knowledge, and the scattering parameter knowledge under other angles is obtained in the same way, wherein S indicates scattered field, x table
Show that projection value, a, b indicate scattering model parameter.
In above-mentioned steps (3), the specific steps for obtaining angle sequence scattering parameter knowledge include:
1) building joins the different zones scattering model detected in step (2) using sampling location angle as the grid of variable
Number information carries out interpolation, obtains different angle sequence scattering model parameters knowledge；
2) the corresponding parameter information in region each under equal angular sequence is brought into nonlinear model S=axb, it is calculated not
With the scattered field of regional structure；
3) scattered field that each region parameter information under equal angular sequence obtains is overlapped, and it is flat to carry out Gauss
It is sliding, obtain angle sequence scattered field estimation；
4) different angle sequence is traversed, the scattered field estimation of different angle sequence is completed.
In the above-mentioned methods, in order to carry out region labeling when the purpose of single optical grating projection A sweep, so optical grating projection is only
A width need to be acquired, grid region and the slit areas division that subsequent grating+project objects carry out can be applied directly, without again
It obtains.
The beneficial effects of the present invention are: the Cone-Beam CT angle sequence of monochromatic light grid detecting provided by the invention scatters acquisition side
Method, the scattering estimation of the testee different angle sequence suitable for arbitrarily complicated degree, reliability, the stability of method are good, can
Sweep object structure is largely promoted to the accuracy of scatter distributions, is detected by few width scattered field and completes different angle
Scattered field estimation under sequence, hence it is evident that improve the efficiency that scattering obtains while improving pyramidal CT image quality.
The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments.
Detailed description of the invention
Fig. 1 is inventive algorithm flow chart.
Fig. 2 is optical grating construction schematic diagram.
Fig. 3 is angle sequence scattering estimation compared with the scattering that grating detecting obtains.
Specific embodiment
By existing industrial cone-beam CT equipment, (x-ray source is the MXR-451HP/11 of Comet, and flat panel detector is
The 1621 AN15 ES of XRD of PerkinElmer, and have sweep mechanism, system control and calculating computer), to titanium alloy
Part carries out Projection Sampling, scatters acquisition methods to the Cone-Beam CT angle sequence that monochromatic light grid are detected using the method for the present invention, executes
Following steps:
(1) by multi-power spectrum radiographic source industry cone-beam CT equipment, radiographic source voltage 420kV and electric current 0.18mA is selected, is swept
Retouch geometric parameter are as follows: radiographic source to detector distance 1241.832886mm, radiographic source to rotation center distance
965.323242mm；Rebuild resolution ratio be 512 × 512, circular scanning obtain 0 ° of angle position single optical grating projection A and 0 °,
60 °, 120 °, 180 °, 240 °, the project objects B and monochromatic light grid+project objects C of 300 ° of angle positions.
(2) field estimation is scattered to the sample of acquisition, completes the detecting of scattering parameter knowledge, specific steps include:
1) the optical grating projection image A for selecting 0 ° of angle position, counts optical grating projection information, with what is occurred in statistics
Higher two peak values divide threshold value as raster grid region and slit areas, wherein τ1=3000, τ2=41000；
2) it is mentioned according to grating+testee projection C grid region and slit areas of the threshold value to 0 ° of angle position
It takes, the region of C≤3000 is grid region, and the region of C >=41000 is slit areas, respectively to grid region image and slit
Area image carries out interpolation and gaussian filtering and obtains the grating scattering image (referred to as image C1) and slit areas of grid region
Object+grating scattering image (referred to as image C2)；
3) projected image, referred to as image D are obtained with image C2 subtracted image C1, is subtracted with the project objects B of 0 ° of angle position
Image D is removed, object scatter field picture E is obtained；
4) gradient pixel-by-pixel is carried out to the projected image B of 0 ° of angle position to calculate, obtain the gradient matrix of two dimensional image, so
After seek tensor determinant of a matrix H and characteristic value T；
5) different zones, experimental selection judgment threshold threshold=1.0 are obtained according to the difference of determinant and characteristic value
×10-11If T ≈ threshold& | H | ≈ 0, the region are referred to as flat site, if T > threshold& | H | ≈ 0,
Then the region is referred to as fringe region, if T > threshold& | H | > 0, the region are referred to as angle point region；
6) nonlinear model S=ax is selectedbAs fitting function, projection is divided into obtained region and the scattered field acquired
Corresponding region is mapped, and different zones projection-scattering curve is obtained, and obtains the corresponding scattering of different zones under the angle position
Model parameter knowledge, and the scattering model parameters knowledge under other angles is obtained in the same way, wherein S indicates scattered field,
X indicates that projection value, a, b indicate scattering model parameter.
(3) by above-mentioned 0 °, 60 °, 120 °, 180 °, 240 °, the detecting information of 300 ° of angle positions obtains different angle
The estimation of sequence scattered field, specific steps include:
1) building joins the different zones scattering model detected in step (2) using sampling location angle as the grid of variable
Number information carries out interpolation, obtains different angle sequence scattering model parameters knowledge；
2) the corresponding parameter information in region each under equal angular sequence is brought into nonlinear model S=axb, it is calculated not
With the scattered field of regional structure；
3) scattered field that each region parameter information under equal angular sequence obtains is overlapped, and it is flat to carry out Gauss
It is sliding, obtain angle sequence scattered field estimation；
4) different angle sequence is traversed, the scattered field estimation of different angle sequence is completed.
In the present embodiment, the Cone-Beam CT angle sequence scattering acquisition methods feature based on the detecting of monochromatic light grid is:
(1) combine the gradient of projection to characterize according to the projection information of test object, with the different determinant H of tensor information and
The structural region that characteristic value T is projected；
(2) selection nonlinear scattering model completes projection under different structure region-scattering fitting, obtains different structure area
Domain scattering model parameter；
(3) it detects to have obtained the estimation of angle sequence scattered field with the scattered field knowledge under few width uniform sampling angle, complete
The scatter correction of projection obtains high quality graphic.
Fig. 3 is angle sequence scattering estimation compared with the scattering that grating detecting obtains, it is seen that the method for the present invention is about angle
The scattering field distribution that scattered field estimation under sequence is detected with grating almost coincide, and high can accurately be dissipated using few angle
It penetrates detecting and obtains the scattered field estimation of other angles sequence, and then complete the scatter correction of projection.
Claims (7)
1. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting scatters acquisition methods, it is characterised in that include the following steps:
(1) it is scanned, parameter remains unchanged in the process, obtains scanning projection and lacks width；
(2) it is scattered field estimation, completes the detecting of scattering parameter knowledge；
(3) parameter information obtained by detecting obtains the estimation of angle sequence scattered field.
2. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting according to claim 1 scatters acquisition methods, feature exists
In: in the step (1), the scanning projection of acquisition includes: single optical grating projection A, project objects B, monochromatic light grid+project objects
C, wherein project objects B, monochromatic light grid+project objects C are obtained in a manner of circular scanning.
3. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting according to claim 1 scatters acquisition methods, feature exists
In: in the step (2), the specific steps of scattered field estimation include:
1) an amplitude grating projected image A is acquired, optical grating projection information is counted, with higher two peaks occurred in statistics
Value divides threshold value as raster grid region and slit areas, is denoted as τ1And τ2；
2) grating+testee projection C grid region and slit areas are extracted according to threshold value, numerical value is less than τ1Area
Domain is grid region, and numerical value is greater than τ2Region be slit areas, grid region image and slit areas image are carried out respectively
Interpolation and gaussian filtering obtain the grating scattering image (referred to as image C1) of grid region and object+grating scattering of slit areas
Image (referred to as image C2)；
3) pure projected image, referred to as image D are obtained with image C2 subtracted image C1, with project objects B subtracted image D, obtains object
Volume scattering field picture E.
4. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting according to claim 1 scatters acquisition methods, feature exists
In: in above-mentioned steps (2), the specific steps of scattered field knowledge acquisition include:
1) gradient pixel-by-pixel is carried out to projected image B to calculate, obtain the tensor matrix of two dimensional image, then seek tensor matrix
Determinant H and characteristic value T；
2) different zones are obtained according to the difference of determinant and characteristic value, judgment threshold threshold is given, if T ≈
Threshold& | H | ≈ 0, then the region is referred to as flat site, if T > threshold& | H | ≈ 0, the region are referred to as side
Edge region, if T > threshold& | H | > 0, the region are referred to as angle point region；
3) nonlinear model S=ax is selectedbAs fitting function, it is corresponding with the scattered field acquired that projection is divided to obtained region
Region is mapped, and different zones projection-scattering curve is obtained, and obtains the corresponding scattering model of different zones under the angle position
Parameters knowledge, and the scattering parameter knowledge under other angles is obtained in the same way, wherein S indicates that scattered field, x indicate to throw
Shadow value, a, b indicate scattering model parameter.
5. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting according to claim 1 scatters acquisition methods, feature exists
In: in above-mentioned steps (3), the specific steps for obtaining different angle sequence scattering parameter knowledge include:
1) building believes the different zones scattering model parameter detected in step (2) using sampling location angle as the grid of variable
Breath carries out interpolation, obtains different angle sequence scattering model parameters knowledge；
2) the corresponding parameter information in region each under equal angular sequence is brought into nonlinear model S=axb, not same district is calculated
The scattered field of domain structure；
3) scattered field that each region parameter information under equal angular sequence obtains is overlapped, and carries out Gaussian smoothing,
Obtain angle sequence scattered field estimation；
4) different angle sequence is traversed, the scattered field estimation of different angle sequence is completed.
6. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting according to claim 1 scatters acquisition methods, feature exists
In: in the method, in order to carry out region labeling when the purpose of single optical grating projection A sweep, so optical grating projection need to only be adopted
Collect a width, grid region and the slit areas division that subsequent grating+project objects carry out can be applied directly, without obtaining again
It takes.
7. a kind of Cone-Beam CT angle sequence of monochromatic light grid detecting according to claim 1 scatters acquisition methods, feature exists
In: in the present embodiment, the Cone-Beam CT angle sequence scattering acquisition methods feature based on the detecting of monochromatic light grid is:
(1) gradient of projection is combined to characterize according to the projection information of test object, with the different determinant H and feature of tensor information
The structural region that value T is projected；
(2) selection nonlinear scattering model completes projection under different structure region-scattering fitting, obtains different structure region and dissipates
Penetrate model parameter；
(3) it detects to have obtained the estimation of angle sequence scattered field with the scattered field knowledge under few width uniform sampling angle, completes throwing
The scatter correction of shadow obtains high quality graphic.
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Cited By (2)
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|---|---|---|---|---|
| CN113034636A (en) * | 2021-03-09 | 2021-06-25 | 浙江大学 | Cone beam CT image quality improvement method and device based on cross-scale multi-energy spectrum CT label |
| CN113177991A (en) * | 2021-04-29 | 2021-07-27 | 中国科学技术大学 | Method for correcting scattering artifacts in CBCT (cone beam computed tomography) based on planned CT (computed tomography) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104161536A (en) * | 2014-07-30 | 2014-11-26 | 西北工业大学 | Cone beam CT scatter correction method and device based on complementary gratings |
-
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104161536A (en) * | 2014-07-30 | 2014-11-26 | 西北工业大学 | Cone beam CT scatter correction method and device based on complementary gratings |
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| Title |
|---|
| KUIDONG HUANG等: "Scatter measurement and correction method for cone-beam CT based on single grating scan", 《OPTICAL ENGINEERING》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113034636A (en) * | 2021-03-09 | 2021-06-25 | 浙江大学 | Cone beam CT image quality improvement method and device based on cross-scale multi-energy spectrum CT label |
| CN113034636B (en) * | 2021-03-09 | 2022-04-29 | 浙江大学 | Cone beam CT image quality improvement method and device based on cross-scale multi-energy spectrum CT label |
| CN113177991A (en) * | 2021-04-29 | 2021-07-27 | 中国科学技术大学 | Method for correcting scattering artifacts in CBCT (cone beam computed tomography) based on planned CT (computed tomography) |
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