CN116421205A - Cone beam CT system correction method - Google Patents
Cone beam CT system correction method Download PDFInfo
- Publication number
- CN116421205A CN116421205A CN202310286446.4A CN202310286446A CN116421205A CN 116421205 A CN116421205 A CN 116421205A CN 202310286446 A CN202310286446 A CN 202310286446A CN 116421205 A CN116421205 A CN 116421205A
- Authority
- CN
- China
- Prior art keywords
- coordinates
- projection
- detector
- determining
- center
- 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.)
- Pending
Links
- 238000012937 correction Methods 0.000 title claims abstract description 98
- 238000000034 method Methods 0.000 title claims abstract description 54
- 239000003550 marker Substances 0.000 claims abstract description 58
- 230000000149 penetrating effect Effects 0.000 claims abstract description 5
- 230000015654 memory Effects 0.000 claims description 15
- 238000003860 storage Methods 0.000 claims description 11
- 238000013461 design Methods 0.000 claims description 3
- 238000004364 calculation method Methods 0.000 description 17
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 238000002591 computed tomography Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/58—Testing, adjusting or calibrating thereof
- A61B6/582—Calibration
- A61B6/585—Calibration of detector units
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
- A61B6/03—Computed tomography [CT]
- A61B6/032—Transmission computed tomography [CT]
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Medical Informatics (AREA)
- Radiology & Medical Imaging (AREA)
- Molecular Biology (AREA)
- Biophysics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Optics & Photonics (AREA)
- Pathology (AREA)
- Physics & Mathematics (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- High Energy & Nuclear Physics (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Pulmonology (AREA)
- Theoretical Computer Science (AREA)
- Apparatus For Radiation Diagnosis (AREA)
Abstract
The invention provides a cone beam CT system correction method, which comprises the following steps: acquiring a projection image sequence of a geometric correction motif; the geometric correction die body is a rotating body, and a marking line penetrating through the rotating body is arranged on the shaft of the rotating body; determining a marker row containing marker lines in each projection image; determining the mark center column coordinates of each mark row in each projection image according to the gray value of each pixel point; determining the rotation axis projection column coordinates of each mark row according to the mark center column coordinates in each projection image; fitting the coordinates of the projection columns of the rotating shafts of the marking rows to determine the coordinates of the projection columns of the central rays and the rotation angles of the detector plane; determining the center offset of the detector according to the center ray projection column coordinates and the detector center column coordinates; the cone beam CT system is calibrated according to the rotation angle in the detector plane and the offset of the center of the detector. The invention can obtain the geometric parameters of the corrected CT system more quickly and accurately.
Description
Technical Field
The invention relates to the technical field of biomedical imaging, in particular to a cone beam CT system correction method.
Background
Cone beam CT refers to X-ray projection detection using a cone beam and a flat panel detector, and finally three-dimensional image reconstruction is performed using collected projection data at multiple angles. Cone beam CT reconstruction generally uses an FDK algorithm, which has stringent requirements on the geometrical relationship between the source, detector, rotation axis center. However, the geometric relationship of the three components cannot completely meet the requirements due to the factors such as machining and mounting precision, and if the geometric parameters are not corrected at this time, the image is generated to be artifact, so that the image quality is affected.
Of the geometrical parameters of the cone beam CT system, the horizontal offset (offset U) of the detector center and the rotation angle (eta) of the detector plane have the most serious influence on the image effect.
In the prior art, when the horizontal offset of the center of the detector and the rotation angle of the detector plane are calculated, a metal ball is used as a geometric correction die body, the rotation axis projection is determined by adopting a mode of extracting the center of the metal ball in each projection after binarization, and then the rotation axis projection is obtained by calculating the average value of the coordinates of the center row so as to calculate the subsequent iteration geometric parameters. According to the method, CT scanning is needed once, the final geometric parameters are calculated by adopting an iterative method, the operation time of the algorithm is far longer than that of other algorithms due to the iterative algorithm, the calculation efficiency is low, an initial value is needed to be designed, and the method is easy to sink into a local optimal solution.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defects of low calculation efficiency and poor accuracy of the calculated set parameters when calculating the geometric parameters in the prior art, thereby providing a cone beam CT system correction method.
The first aspect of the invention provides a cone beam CT system correction method, which comprises the following steps: acquiring a projection image sequence of the geometric correction motif, wherein the projection image sequence comprises a plurality of projection images; the projection image sequence is obtained by scanning the geometric correction die body by the cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle; the geometric correction die body is a rotating body, and a marking line penetrating through the rotating body is arranged on the shaft of the rotating body; determining a marker row containing marker lines in each projection image; in each projection image, determining the mark center column coordinates of each mark row according to the gray value of each pixel point; for each mark row, determining the rotation axis projection column coordinate of each mark row according to the mark center column coordinate in each projection image; fitting the coordinates of the projection columns of the rotating shafts of the marking rows, and determining the coordinates of the projection columns of the central rays and the rotation angles of the detector plane according to fitting results; determining the center offset of the detector according to the center ray projection column coordinates and the detector center column coordinates; the cone beam CT system is calibrated according to the rotation angle in the detector plane and the offset of the center of the detector.
Optionally, in the cone beam CT system correction method provided by the present invention, the step of obtaining the projection image sequence of the geometric correction phantom includes: acquiring bright field correction data and dark field correction data; acquiring an initial projection image sequence of a geometric correction motif, wherein the initial projection image sequence comprises a plurality of initial projection images; the initial projection image sequence is obtained by scanning the geometric correction die body by the cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle; and carrying out bright field correction and dark field correction on each initial projection image according to the bright field correction data and the dark field correction data to obtain a projection image sequence.
Optionally, in the cone beam CT system calibration method provided by the present invention, the coordinates of the marker center column of the marker row are determined by: in a mark row, determining a gray value difference value between each pixel point in the mark row and a pixel point of a distance index column, wherein the index value is determined according to the radius of the mark line and the pixel size of the detector; and determining the column coordinate of the pixel point with the largest gray value difference as the marking center column coordinate of the marking row.
Optionally, in the cone beam CT system correction method provided by the invention,
where r is the radius of the marker line, M is the design value of the magnification of the cone beam CT system to be corrected, and pixelSize is the detector pixel size.
Optionally, in the cone beam CT system correction method provided by the present invention, for a marker row, the projection column coordinates of the rotation axis of the marker row are determined according to the average value of the coordinates of the marker center column corresponding to the marker row in each projection image.
Optionally, in the cone beam CT system correction method provided by the present invention, fitting is performed on coordinates of projection columns of rotation axes of each marker row, and the step of determining coordinates of projection columns of central rays according to a fitting result includes: constructing coordinates of the synthesized points according to the line numbers of the mark lines and the coordinates of the projection columns of the rotating shafts; and fitting the coordinates of each synthesized point, and determining the coordinates of the projection column of the central ray according to the fitting result corresponding to the central line, wherein the central line is a marker line positioned at the central position in each marker line.
Optionally, in the cone beam CT system correction method provided by the present invention, fitting is performed on coordinates of a projection column of a rotation axis of each marker row, and the step of determining the rotation angle in the detector plane according to the fitting result includes: constructing coordinates of the synthesized points according to the line numbers of the mark lines and the coordinates of the projection columns of the rotating shafts; fitting the coordinates of each synthesized point to obtain a fitting straight line; and determining the rotation angle in the plane of the detector according to the slope of the fitting straight line.
Optionally, in the cone beam CT system correction method provided by the present invention, the step of determining the center offset of the detector according to the center ray projection column coordinates and the total column number of the single projection image includes: the detector center offset is determined from the difference between the detector and the detector center column coordinates, which are half the total number of columns of the single projection image.
A second aspect of the present invention provides a computer device comprising: at least one processor; and a memory communicatively coupled to the at least one processor; the memory stores instructions executable by the at least one processor to perform the cone beam CT system calibration method as provided by the first aspect of the invention.
A third aspect of the present invention provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions for causing a computer to execute the cone beam CT system correction method as provided in the first aspect of the present invention.
The technical scheme of the invention has the following advantages:
according to the cone beam CT system correction method provided by the invention, only one geometric correction die body is required to be scanned, the detector in-plane rotation angle and the detector center offset can be calculated according to the scanned image of the geometric correction die body, iterative calculation is not required in the calculation process, the calculation efficiency is high, the calculation process is completed based on the position of the mark line in the projection image, and an initial value is not required in the calculation process, so that the local optimal solution is not involved, the calculated detector in-plane rotation angle and the calculated detector center offset have higher accuracy, in addition, the geometric correction die body used in the method is simple in structure, small in manufacturing difficulty and low in cost, the requirements on the placement of the geometric correction die body in the correction process are not high, and the calculation accuracy is not dependent on the geometric correction die body accuracy, so that the accurate detector in-plane rotation angle and the accurate detector center offset can be obtained more easily by implementing the method.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flowchart of a specific example of a cone beam CT system calibration method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a geometric calibration phantom according to an embodiment of the present invention;
FIG. 3 is a schematic block diagram of a specific example of a cone beam CT system correction apparatus in accordance with an embodiment of the present invention;
fig. 4 is a schematic block diagram of a specific example of a computer device in an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that technical features of different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The embodiment of the invention provides a cone beam CT system correction method, as shown in figure 1, comprising the following steps:
step S11: acquiring a projection image sequence of the geometric correction motif, wherein the projection image sequence comprises a plurality of projection images; the projection image sequence is obtained by scanning the geometric correction die body by the cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle; the geometric correction die body is a rotating body, and a marking line penetrating through the rotating body is arranged on the shaft of the rotating body.
In an embodiment, when the cone beam CT system to be corrected scans the geometric correction mold body, the geometric correction mold body rotates around the axis of the rotating body, and the scanning direction of the cone beam CT system to be corrected is perpendicular to the axis of the rotating body.
In an embodiment, the projection image scanned by the cone beam CT system to be corrected can represent the position of the marker line. The projection image is obtained by scanning the geometric correction module through a detector in the cone beam CT system to be corrected.
In an alternative embodiment, in order to enable the projection image scanned by the cone beam CT system to be corrected to embody the position of the marker line, so as to determine the geometric parameter according to the position of the marker line, in the geometric correction mold body, a transparent material may be adopted except for the marker line, and an exemplary material used in the geometric correction mold body may be acrylic, where the marker line may be copper wire or the like.
In an alternative embodiment, in order to ensure that the geometric parameters calculated by executing the method provided by the embodiment of the present invention can accurately correct the cone beam CT system to be corrected, the diameter of the marker line used should be as small as possible.
In one embodiment, as shown in FIG. 2, the geometric correction mold body is a cylinder with a bottom surface having a diameter of 10cm and a height of 15cm, and the marking lines are copper wires having a diameter of 0.2 mm.
Step S12: a marker row containing marker lines is determined in each projection image.
In an alternative embodiment, after the marker rows are determined, the marker rows may be labeled according to the row numbers of the marker rows from small to large, respectively.
Step S13: in each projection image, the coordinates of the mark center column of each mark row are determined based on the gray value of each pixel.
In an alternative embodiment, in the geometric correction mold body, the mold body and the marking lines are made of different materials, the transparency of the mold body is higher than that of the marking lines, and after the projection image of the geometric correction mold body is obtained by scanning, the gray values of the pixel points where the marking lines are located have larger difference with the gray values of the rest parts, so that the marking center column coordinates of each marking line can be determined according to the gray values of each pixel point.
Step S14: for each marker row, the rotation axis projection column coordinates of each marker row are determined from the marker center column coordinates in each projection image.
For the same marker row, there are corresponding marker center column coordinates in different projection images, and in the embodiment of the invention, the rotation axis projection column coordinates of the marker row are determined according to the marker center column coordinates in each projection image.
Step S15: fitting the coordinates of the projection columns of the rotation shafts of the marker rows, and determining the coordinates of the projection columns of the central rays and the rotation angles of the detector plane according to fitting results.
Step S16: and determining the center offset of the detector according to the center ray projection column coordinates and the detector center column coordinates.
In an alternative embodiment, the detector center column coordinates have a value of half the total column number of a single projection image.
Step S17: the cone beam CT system is calibrated according to the rotation angle in the detector plane and the offset of the center of the detector.
According to the cone beam CT system correction method provided by the embodiment of the invention, only one geometric correction die body is required to be scanned, the internal rotation angle of the detector plane and the center offset of the detector can be calculated according to the scanned image of the geometric correction die body, iterative calculation is not required in the calculation process, the calculation efficiency is high, the calculation process is completed based on the position of the mark line in the projection image, and an initial value is not required to be set in the calculation process, so that the local optimal solution is not involved, the calculated internal rotation angle of the detector plane and the center offset of the detector have higher accuracy, in addition, the geometric correction die body used in the embodiment of the invention has simple structure, small manufacturing difficulty and low cost, the requirement on the placement of the geometric correction die body in the correction process is not high, and the calculation accuracy is independent of the placement accuracy of the geometric correction die body, so that the accurate internal rotation angle of the detector plane and the center offset of the detector can be obtained more easily by implementing the invention.
In an alternative embodiment, the step S11 specifically includes the following steps:
first, bright field correction data and dark field correction data are acquired.
In an alternative embodiment, the dark field correction data is an image acquired by the detector when the light machine does not emit the wire harness; the bright field correction data is the image acquired by the detector when the optical machine emits beams and no object is placed between the optical machine and the detector.
Then, an initial projection image sequence of the geometric correction motif is obtained, wherein the initial projection image sequence comprises a plurality of initial projection images; the initial projection image sequence is obtained by scanning the geometric correction die body by the cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle.
And finally, carrying out bright field correction and dark field correction on each initial projection image according to the bright field correction data and the dark field correction data to obtain a projection image sequence.
In the embodiment of the invention, the purpose of dark field correction is to remove the influence caused by the fact that the detector still has a certain signal output under the condition that no ray beam exists. The purpose of bright field correction is to remove the effect of inconsistent sensitivity of the detector pixels to radiation. Because the projection image sequence is obtained through bright field correction and dark field correction, the rotation angle in the detector plane and the offset of the center of the detector obtained based on the projection image sequence are more accurate.
In an alternative embodiment, in the cone beam CT system calibration method provided in the embodiment of the present invention, with one of the marker rows, the marker center column coordinates of the marker rows are determined by:
first, in a marker line, the gray value difference between each pixel point in the marker line and the pixel point of the distance index column is determined, and the index value is determined according to the radius of the marker line and the detector pixel size.
Then, the column coordinate of the pixel point where the gray value difference is the largest is determined as the mark center column coordinate of the mark row.
In an alternative embodiment, after determining the first pixel, the distance ind from the first pixel is determined e And x one or two second pixel points in the column, calculating the gray value difference value between the first pixel point and the second pixel point, and determining the column coordinate of the first pixel point corresponding to the maximum gray value difference value as the marking center column coordinate of the marking row, wherein if the first pixel point corresponds to two second pixel points, determining the sum of the gray value difference values of the first pixel point and the two second pixel points as the gray value difference value corresponding to the first pixel point.
In an alternative embodiment, the tag center column coordinates are determined by the following formula:
wherein,,
representing column coordinates of the mark line center of the ith mark row in the jth projection image;
the pixel gray value of the z column in the ith mark row of the jth projection image; maxDIff i j Is the maximum difference between adjacent index columns in the ith marker row in the jth projection image.
In an alternative embodiment of the present invention,
where r is the radius of the marker line, M is the design value of the magnification of the cone beam CT system to be corrected, and pixelSize is the detector pixel size.
In an alternative embodiment, in the step S14, for a marker row, the rotation axis projection column coordinates of the marker row are determined according to the average value of the marker center column coordinates corresponding to the marker row in each projection image. For example, the mean value may be determined as the rotation axis projection column coordinates of the marker row:
wherein, center i For the rotation axis projection column coordinate mean of the i-th marker row (i.e., the rotation axis projection of the i-th marker row), viewNum is the number of projection images in the projection image sequence.
In an optional embodiment, in the step S15, the step of fitting the coordinates of the projection column of the rotation axis of each marker row and determining the coordinates of the projection column of the central ray according to the fitting result specifically includes:
first, coordinates of the synthesized points are constructed based on the line number of the marker line and the rotation axis projection column coordinates: (i, center) i ) I e (1, 2,3,., n), where i represents the i-th marker row, center i The rotation axis projection column coordinates of the i-th mark row are indicated.
And then, fitting the coordinates of each synthesized point, and determining the coordinates of the projection column of the central ray according to the fitting result corresponding to the central line, wherein the central line is a marker line positioned at the central position in each marker line of the central line.
In an alternative embodiment, the coordinates of the synthesized points are fitted once by a polynomial to obtain a fitting equation:
Center i ＝a*i+b，i∈(1，2，3，...，n)，
wherein a and b are fitting parameters.
In the central row (i.e
Row) as final central ray projection column coordinates Center, thereby eliminating the effect of individual row axis projection column coordinate calculation bias on the axis projection final result:
in an alternative embodiment, the detector center offset is determined from the difference between the detector and the detector center column coordinates, the detector center column coordinates having a value of half the total column number of a single projection image:
where Cols represents the total number of columns of a single projection image.
In an optional embodiment, in the step S15, the fitting is performed on the coordinates of the projection columns of the rotation axes of each marker row, and the step of determining the rotation angle in the detector plane according to the fitting result specifically includes:
first, coordinates of the synthesized points are constructed based on the line number of the marker line and the rotation axis projection column coordinates: (i, center) i ) I e (1, 2,3,., n), where i represents the i-th marker row, center i The rotation axis projection column coordinates of the i-th mark row are indicated.
And then, fitting the coordinates of each synthesized point to obtain a fitting straight line.
In an alternative embodiment, the coordinates of the synthesized points are fitted once by a polynomial to obtain a fitting equation:
Center i ＝a*i+b，i∈(1，2，3，...，n)，
wherein a and b are fitting parameters.
And finally, determining the rotation angle in the detector plane according to the slope of the fitting straight line.
At fitting Center i In =a×i+b, a represents the slope of the fitting straight line, and the rotation angle η=atan (a) in the detector plane.
An embodiment of the present invention provides a cone beam CT system correction apparatus, as shown in fig. 3, including:
an image acquisition module 21, configured to acquire a projection image sequence of the geometric correction motif, where the projection image sequence includes a plurality of projection images; the projection image sequence is obtained by scanning the geometric correction die body by the cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle; the geometric correction die body is a rotating body, and a marking line penetrating through the rotating body is arranged on the shaft of the rotating body; the details of step S11 are described in the above embodiments, and are not described herein.
The marking line determining module 22 is configured to determine a marking line including a marking line in each projection image, and details of the marking line determining module are described in the above embodiment, and are not repeated herein.
The marking center column coordinate determining module 23 is configured to determine, in each projection image, marking center column coordinates of each marking row according to gray values of each pixel, and details of the marking center column coordinates are described in the above embodiment, and are not described herein.
The rotation axis projection column coordinate determining module 24 is configured to determine, for each of the marker rows, rotation axis projection column coordinates of each of the marker rows according to the marker center column coordinates in each of the projection images, and details of the rotation axis projection column coordinates are described in the above embodiment and are not repeated herein.
The fitting module 25 is configured to fit the coordinates of the projection columns of the rotation axes of each marker row, determine the coordinates of the projection columns of the central ray and the rotation angle in the detector plane according to the fitting result, and details of the fitting module are described in the above embodiment in step S15, which is not repeated herein.
The detector center offset determining module 26 is configured to determine the detector center offset according to the center ray projection column coordinate and the detector center column coordinate, and details of the step S16 are described in the above embodiment, which is not repeated herein.
The correction module 27 is configured to correct the cone beam CT system according to the rotation angle in the detector plane and the offset of the center of the detector, and the details of the correction module are described in the above embodiment in the description of step S17, which is not repeated herein.
The embodiment of the present invention provides a computer device, as shown in fig. 4, which mainly includes one or more processors 31 and a memory 32, and in fig. 4, one processor 31 is taken as an example.
The computer device may further include: an input device 33 and an output device 34.
The processor 31, the memory 32, the input device 33 and the output device 34 may be connected by a bus or otherwise, for example in fig. 4.
The processor 31 may be a central processing unit (Central Processing Unit, CPU). The processor 31 may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination thereof. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The memory 32 may include a storage program area that may store an operating system, at least one application program required for functions, and a storage data area; the storage data area may store data created according to the use of the cone beam CT system correction device, or the like. In addition, the memory 32 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, memory 32 optionally includes memory remotely located relative to processor 31, which may be connected to the cone beam CT system correction device via a network. The input device 33 may receive a user entered calculation request (or other numeric or character information) and generate key signal inputs related to the cone beam CT system calibration device. The output device 34 may include a display device such as a display screen for outputting the calculation result.
Embodiments of the present invention provide a computer readable storage medium storing computer instructions, the computer readable storage medium storing computer executable instructions for performing the cone beam CT system calibration method of any of the above method embodiments. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD), or a Solid State Drive (SSD); the storage medium may also comprise a combination of memories of the kind described above.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (10)
1. A cone beam CT system correction method, comprising the steps of:
acquiring a projection image sequence of a geometric correction motif, wherein the projection image sequence comprises a plurality of projection images; the projection image sequence is obtained by scanning the geometric correction die body by a cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle; the geometric correction die body is a rotating body, and a marking line penetrating through the rotating body is arranged on the shaft of the rotating body;
determining a marker row containing the marker line in each of the projection images;
in each projection image, determining the mark center column coordinates of each mark row according to the gray value of each pixel point;
for each mark row, determining the rotation axis projection column coordinate of each mark row according to the mark center column coordinate in each projection image;
fitting the coordinates of the projection columns of the rotating shafts of the marking rows, and determining the coordinates of the projection columns of the central rays and the rotation angles of the detector plane according to fitting results;
determining the center offset of the detector according to the center ray projection column coordinates and the detector center column coordinates;
and correcting the cone beam CT system according to the rotation in the detector plane and the offset of the center of the detector.
2. The cone beam CT system calibration method of claim 1 wherein the step of acquiring a sequence of projection images of the geometric calibration phantom comprises:
acquiring bright field correction data and dark field correction data;
acquiring an initial projection image sequence of a geometric correction motif, wherein the initial projection image sequence comprises a plurality of initial projection images; the initial projection image sequence is obtained by scanning the geometric correction die body by the cone beam CT system to be corrected in the process of rotating the geometric correction die body for one circle;
and carrying out bright field correction and dark field correction on each initial projection image according to the bright field correction data and the dark field correction data to obtain the projection image sequence.
3. The cone beam CT system calibration method as defined in claim 1 wherein the marker center column coordinates of the marker rows are determined by:
in a marking line, determining gray value difference values between each pixel point in the marking line and pixel points of a distance index column, wherein the index value is determined according to the radius of the marking line and the pixel size of a detector;
and determining the column coordinate of the pixel point with the largest gray value difference as the marking center column coordinate of the marking row.
4. A cone beam CT system calibration method as defined in claim 3, wherein,
wherein r is the radius of the marking line, M is the design value of the magnification factor of the cone beam CT system to be corrected, and pixelSize is the detector pixel size.
5. The method of claim 1, wherein the cone beam CT system calibration method,
and for a mark row, determining the projection column coordinates of the rotating shaft of the mark row according to the average value of the mark center column coordinates corresponding to the mark row in each projection image.
6. The method of correcting a cone beam CT system according to claim 1, wherein the step of fitting the coordinates of the projection columns of the rotation axis of each marker row and determining the coordinates of the projection columns of the central ray based on the fitting result comprises:
constructing coordinates of the synthesized points according to the line numbers of the mark lines and the coordinates of the projection columns of the rotating shafts;
and fitting the coordinates of each synthesized point, and determining the coordinates of the projection column of the central ray according to the fitting result corresponding to the central line, wherein the central line is a marking line positioned at the central position in each marking line of the central line.
7. The method of calibrating a cone beam CT system according to claim 1, wherein the step of fitting the coordinates of the projection columns of the rotation axis of each marker row and determining the rotation angle in the detector plane based on the fitting result comprises:
constructing coordinates of the synthesized points according to the line numbers of the mark lines and the coordinates of the projection columns of the rotating shafts;
fitting the coordinates of each synthesized point to obtain a fitting straight line;
and determining the rotation angle in the detector plane according to the slope of the fitting straight line.
8. The cone beam CT system calibration method of claim 1 or 6 wherein the step of determining the detector center offset from the center ray projection column coordinates and the total column number of individual projection images comprises:
and determining the center offset of the detector according to the difference between the detector and the center column coordinate of the detector, wherein the value of the center column coordinate of the detector is half of the total column number of the single projection image.
9. A computer device, comprising:
at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to perform the cone beam CT system correction method of any one of claims 1-8.
10. A computer-readable storage medium storing computer instructions for causing the computer to perform the cone-beam CT system correction method according to any one of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310286446.4A CN116421205A (en) | 2023-03-22 | 2023-03-22 | Cone beam CT system correction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310286446.4A CN116421205A (en) | 2023-03-22 | 2023-03-22 | Cone beam CT system correction method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116421205A true CN116421205A (en) | 2023-07-14 |
Family
ID=87089934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310286446.4A Pending CN116421205A (en) | 2023-03-22 | 2023-03-22 | Cone beam CT system correction method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116421205A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117237234A (en) * | 2023-11-09 | 2023-12-15 | 杭州睿影科技有限公司 | Image correction method and device applied to X-ray security inspection equipment and electronic equipment |
| CN117770863A (en) * | 2024-02-27 | 2024-03-29 | 赛诺威盛科技(北京)股份有限公司 | Z-direction alignment method and device for CT detector |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103784160A (en) * | 2014-03-06 | 2014-05-14 | 北京锐视康科技发展有限公司 | Correction device and correction method for geometric position of cone beam CT system |
| CN103800032A (en) * | 2014-03-06 | 2014-05-21 | 北京锐视康科技发展有限公司 | Correcting system for correcting geometric position of cone-beam CT system, and correcting method thereof |
| CN104274201A (en) * | 2014-10-10 | 2015-01-14 | 深圳先进技术研究院 | Method, system and equipment for tomography of mammary gland and image acquisition and processing method |
| CN104406989A (en) * | 2014-10-31 | 2015-03-11 | 清华大学 | Double wire model-based CT system structure parameter measuring method and apparatus thereof |
| US20160133031A1 (en) * | 2014-11-07 | 2016-05-12 | Shimadzu Corporation | Radiation ct apparatus |
| CN109549661A (en) * | 2018-12-29 | 2019-04-02 | 北京纳米维景科技有限公司 | A kind of detector geometric correction body mould and bearing calibration |
| CN111449668A (en) * | 2020-04-23 | 2020-07-28 | 深圳市安健科技股份有限公司 | Marking device, method and system for real-time geometric correction in three-dimensional scanning reconstruction |
| CN114494076A (en) * | 2022-02-14 | 2022-05-13 | 深圳康桥软件技术有限公司 | Geometric correction method, image reconstruction method and device |
| CN115105757A (en) * | 2022-05-24 | 2022-09-27 | 沈阳东软智睿放疗技术有限公司 | Medical die body, and equipment precision detection method and system based on medical die body |
-
2023
- 2023-03-22 CN CN202310286446.4A patent/CN116421205A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103784160A (en) * | 2014-03-06 | 2014-05-14 | 北京锐视康科技发展有限公司 | Correction device and correction method for geometric position of cone beam CT system |
| CN103800032A (en) * | 2014-03-06 | 2014-05-21 | 北京锐视康科技发展有限公司 | Correcting system for correcting geometric position of cone-beam CT system, and correcting method thereof |
| CN104274201A (en) * | 2014-10-10 | 2015-01-14 | 深圳先进技术研究院 | Method, system and equipment for tomography of mammary gland and image acquisition and processing method |
| CN104406989A (en) * | 2014-10-31 | 2015-03-11 | 清华大学 | Double wire model-based CT system structure parameter measuring method and apparatus thereof |
| US20160133031A1 (en) * | 2014-11-07 | 2016-05-12 | Shimadzu Corporation | Radiation ct apparatus |
| CN109549661A (en) * | 2018-12-29 | 2019-04-02 | 北京纳米维景科技有限公司 | A kind of detector geometric correction body mould and bearing calibration |
| CN111449668A (en) * | 2020-04-23 | 2020-07-28 | 深圳市安健科技股份有限公司 | Marking device, method and system for real-time geometric correction in three-dimensional scanning reconstruction |
| CN114494076A (en) * | 2022-02-14 | 2022-05-13 | 深圳康桥软件技术有限公司 | Geometric correction method, image reconstruction method and device |
| CN115105757A (en) * | 2022-05-24 | 2022-09-27 | 沈阳东软智睿放疗技术有限公司 | Medical die body, and equipment precision detection method and system based on medical die body |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117237234A (en) * | 2023-11-09 | 2023-12-15 | 杭州睿影科技有限公司 | Image correction method and device applied to X-ray security inspection equipment and electronic equipment |
| CN117237234B (en) * | 2023-11-09 | 2024-01-30 | 杭州睿影科技有限公司 | Image correction method and device applied to X-ray security inspection equipment and electronic equipment |
| CN117770863A (en) * | 2024-02-27 | 2024-03-29 | 赛诺威盛科技(北京)股份有限公司 | Z-direction alignment method and device for CT detector |
| CN117770863B (en) * | 2024-02-27 | 2024-05-28 | 赛诺威盛科技(北京)股份有限公司 | Z-direction alignment method and device for CT detector |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN116421205A (en) | Cone beam CT system correction method | |
| US7953265B2 (en) | Method and system for automatic algorithm selection for segmenting lesions on pet images | |
| CN103969269B (en) | Method and apparatus for geometric calibration CT scanner | |
| CN101489486B (en) | X-ray detector gain calibration depending on the fraction of scattered radiation | |
| CN106994023B (en) | The geometric parameter of Conebeam computed tomography imaging system determines method | |
| US8452064B2 (en) | Apparatus and methods for geometric calibration of positron emission tomography systems | |
| CN106667512B (en) | Geometric correction method of X-ray imaging device and breast tomography device | |
| US9993217B2 (en) | Producing panoramic radiograph | |
| CN110555834B (en) | CT bad channel real-time detection and reconstruction method based on deep learning network | |
| CN110353713A (en) | The determination method and apparatus of geometric correction die body, reconstruction image geometric parameter | |
| WO2020118896A1 (en) | Image repair method, image repair system, and flat panel detector | |
| CN110264421B (en) | CT bad channel correction method | |
| JP4195029B2 (en) | Image correction apparatus, pattern inspection apparatus, image correction method, and pattern defect inspection method | |
| CN103479379A (en) | Image reconstruction method and device by oblique spiral scanning | |
| CN112509060B (en) | CT secondary scanning positioning method and system based on image depth learning | |
| CN111223159B (en) | Cone beam imaging method, apparatus, computer device and storage medium | |
| KR101653861B1 (en) | Drawing data generating method, drawing method, drawing data generating apparatus and drawing apparatus | |
| CN109148433B (en) | Method and apparatus for determining dimensions of an integrated circuit device | |
| US7111985B2 (en) | Method and system for measuring table sag | |
| CN109875589B (en) | Method and device for measuring centering error of vascular machine system | |
| CN111696047B (en) | Imaging quality determining method and system of medical imaging equipment | |
| JP4395581B2 (en) | Wire detection program and wire inspection apparatus | |
| CN113940692A (en) | Multi-field-of-view X-ray imaging splicing method | |
| CN113749680B (en) | Scanning positioning method, scanning positioning device, storage medium and computer equipment | |
| JP2007121259A (en) | Image processor, image processing program, display controller, and display control program |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20230714 |