CN111544020B

CN111544020B - Geometric correction method and device for X-ray imaging equipment

Info

Publication number: CN111544020B
Application number: CN202010307209.8A
Authority: CN
Inventors: 李洋
Original assignee: Neusoft Medical Systems Co Ltd; Beijing Neusoft Medical Equipment Co Ltd
Current assignee: Neusoft Medical Systems Co Ltd; Beijing Neusoft Medical Equipment Co Ltd
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2023-08-01
Anticipated expiration: 2040-04-17
Also published as: CN111544020A

Abstract

The embodiment of the invention provides a geometric correction method and device of X-ray imaging equipment. According to the embodiment of the invention, the first X-ray image of the correction phantom under the basic angle is acquired by using the X-ray imaging device, the second X-ray image of the correction phantom under the current angle is acquired, the basic mapping parameter value corresponding to the basic angle is acquired according to the first X-ray image, the reference mapping parameter value corresponding to the current angle is determined according to the basic mapping parameter value and the current angle, and the target mapping relation between the three-dimensional data acquired by the X-ray imaging device under the current angle and the two-dimensional projection image is acquired based on the reference mapping parameter value and the second X-ray image, so that the geometric correction of the mapping relation between the three-dimensional data and the two-dimensional projection image under any angle in space can be realized.

Description

Geometric correction method and device for X-ray imaging equipment

Technical Field

The invention relates to the technical field of medical imaging, in particular to a geometric correction method and device of X-ray imaging equipment.

Background

X-rays are attenuated differently by different tissues of the human body, so that structural information of tissues inside the human body can be observed by X-ray imaging (also called X-ray imaging). X-ray imaging devices are widely used in the medical field, including fluoroscopy, large and small C-arms, and the like.

The data acquired by the X-ray imaging device are two-dimensional projection data, which sometimes need to be reconstructed into a three-dimensional image in an application. In order to achieve accurate reconstruction, it is crucial to obtain an accurate mapping of the three-dimensional volume data to the two-dimensional projection image. However, due to the influence of the device installation accuracy, the feedback accuracy, the measurement accuracy and the like, the mapping relationship (for convenience of description, herein simply referred to as mapping relationship) between the three-dimensional volume data and the two-dimensional projection image is inaccurate. Therefore, it is necessary to correct the mapping relationship of the two-dimensional projection data and the three-dimensional image of the X-ray imaging apparatus by geometric correction.

Disclosure of Invention

In order to overcome the problems in the related art, the invention provides a geometric correction method and a geometric correction device of X-ray imaging equipment, which improve the image quality of a heart coronary vessel reconstruction image.

According to a first aspect of an embodiment of the present invention, there is provided a geometric correction method of an X-ray imaging apparatus, including:

acquiring a first X-ray image of a correction phantom at a basic angle by using X-ray imaging equipment, and acquiring a second X-ray image of the correction phantom at a current angle;

acquiring a basic mapping parameter value corresponding to the basic angle according to the first X-ray image; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image;

Determining a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle;

and acquiring the target mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment under the current angle and the two-dimensional projection image based on the reference mapping parameter value and the second X-ray image.

According to a second aspect of an embodiment of the present invention, there is provided a geometric correction method of an X-ray imaging apparatus, including:

acquiring a first X-ray image of a correction phantom under a basic angle by using an X-ray imaging device, and determining the current angle of the X-ray imaging device for acquiring three-dimensional volume data;

and if the difference value between the current angle and the basic angle is smaller than a preset value, obtaining a target mapping relation between the three-dimensional data acquired by the X-ray imaging equipment under the current angle and the two-dimensional projection image according to the reference mapping parameter value.

According to a third aspect of embodiments of the present invention, there is provided a geometry correction device of an X-ray imaging apparatus, comprising:

the acquisition module is used for acquiring a first X-ray image of the correction phantom under the basic angle by using the X-ray imaging equipment and acquiring a second X-ray image of the correction phantom under the current angle;

the parameter value acquisition module is used for acquiring a basic mapping parameter value corresponding to the basic angle according to the first X-ray image; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image;

the determining module is used for determining a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle;

and the relation acquisition module is used for acquiring the target mapping relation between the three-dimensional data acquired by the X-ray imaging device under the current angle and the two-dimensional projection image based on the reference mapping parameter value and the second X-ray image.

According to a fourth aspect of embodiments of the present invention, there is provided a geometry correction device of an X-ray imaging apparatus, comprising:

the acquisition and determination module is used for acquiring a first X-ray image of the correction phantom under a basic angle by using the X-ray imaging equipment and determining the current angle of the three-dimensional volume data acquired by the X-ray imaging equipment;

the parameter value determining module is used for determining a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle;

and the relation acquisition module is used for acquiring a target mapping relation between the three-dimensional data acquired by the X-ray imaging equipment under the current angle and the two-dimensional projection image according to the reference mapping parameter value if the difference value between the current angle and the basic angle is smaller than a preset value.

The technical scheme provided by the embodiment of the invention can have the following beneficial effects:

according to the embodiment of the invention, the first X-ray image of the correction phantom under the basic angle is acquired by using the X-ray imaging device, the second X-ray image of the correction phantom under the current angle is acquired, the basic mapping parameter value corresponding to the basic angle is acquired according to the first X-ray image, the reference mapping parameter value corresponding to the current angle is determined according to the basic mapping parameter value and the current angle, and the target mapping relation between the three-dimensional volume data acquired by the X-ray imaging device under the current angle and the two-dimensional projection image is acquired based on the reference mapping parameter value and the second X-ray image, so that the geometric correction of the mapping relation between the three-dimensional volume data and the two-dimensional projection image under any angle in space can be realized.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the specification and together with the description, serve to explain the principles of the specification.

Fig. 1 is a flowchart illustrating an exemplary method for geometric correction of an X-ray imaging apparatus according to an embodiment of the present invention.

Fig. 2 is an exemplary view of a C-arm and a spatial coordinate system provided by an embodiment of the present invention.

Fig. 3 is an exemplary view of a first X-ray image acquired at a base angle.

Fig. 4 is an exemplary view of a second X-ray image acquired at a current angle.

Fig. 5 is an exemplary diagram of a binarized image.

Fig. 6 is a flowchart illustrating another geometric correction method of an X-ray imaging apparatus according to an embodiment of the present invention.

Fig. 7 is a functional block diagram of a geometry correction device of an X-ray imaging apparatus according to an embodiment of the present invention.

Fig. 8 is another functional block diagram of a geometry correction device of an X-ray imaging apparatus according to an embodiment of the present invention.

Fig. 9 is a hardware configuration diagram of an X-ray imaging apparatus according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects of embodiments of the invention as detailed in the accompanying claims.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting of embodiments of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in embodiments of the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, the first information may also be referred to as second information, and similarly, the second information may also be referred to as first information, without departing from the scope of embodiments of the present invention. The word "if" as used herein may be interpreted as "at … …" or "at … …" or "responsive to a determination", depending on the context.

One application scenario for X-ray imaging devices is image reconstruction techniques. The precondition for image reconstruction is to find the correct mapping of the three-dimensional volume data to the two-dimensional projection image, which is related to the spatial geometry between the source and the detector. However, errors are always introduced into the actual spatial positions of the radiation source and the detector due to installation accuracy, feedback accuracy, measurement accuracy and the like, so that the mapping relationship between the three-dimensional volume data and the two-dimensional projection image is inaccurate, noise and artifacts appear in the reconstructed image, clinical diagnosis is not facilitated, and therefore the mapping relationship needs to be corrected through geometric correction, so that the reconstructed image meets actual clinical requirements.

One application scenario for X-ray imaging devices is three-dimensional path-map technology. The technique of path map is also widely used in medical imaging devices, where in interventional therapy, a contrast-containing filling image is subtracted from a contrast-free perspective image to obtain a contrast-only vessel image. However, for some complex diagnoses and treatments, such as the determination of multiple blood supply arteries, it is difficult for the roadmap technique to provide complete image information. In view of the application of the three-dimensional visualization technology on medical imaging equipment, the three-dimensional visualization technology can display three-dimensional blood vessel images more truly, and if the three-dimensional images are displayed on a path diagram, more direct and convenient image navigation can be provided for interventional therapy, and the accurate mapping relation is needed after geometric correction.

The geometric correction method of the X-ray imaging equipment provided by the embodiment of the invention can realize geometric correction under any angle in space (the geometric position of the detector is a sphere during correction), thereby obtaining the mapping relation between the three-dimensional data and the two-dimensional projection image under any angle. The mapping relation can be used for reconstructing an image and can also be used in a three-dimensional path diagram technology, and a three-dimensional image of two-dimensional projection data under any angle can be obtained through the mapping relation.

The following describes in detail a geometric correction method of the X-ray imaging apparatus by way of examples.

Fig. 1 is a flowchart illustrating an exemplary method for geometric correction of an X-ray imaging apparatus according to an embodiment of the present invention. As shown in fig. 1, in the present embodiment, the geometric correction method of the X-ray imaging apparatus may include:

s101, acquiring a first X-ray image of the correction phantom at a basic angle by using an X-ray imaging device, and acquiring a second X-ray image of the correction phantom at a current angle.

S102, acquiring a basic mapping parameter value corresponding to the basic angle according to the first X-ray image; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image.

S103, determining a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle.

S104, based on the reference mapping parameter value and the second X-ray image, acquiring a target mapping relation between the three-dimensional data acquired by the X-ray imaging device under the current angle and the two-dimensional projection image.

The X-ray imaging device can be a perspective machine, a large-sized C-shaped arm and the like.

In this embodiment, the first X-ray image and the second X-ray image are both original images.

In this embodiment, any suitable calibration phantom may be used.

In this embodiment, in the basic angle, cra=0°, and LAO may be any angle.

In one example, the calibration phantom may be a cylinder with 108 steel balls embedded in the surface of the cylinder to rotate around the cylinder, and the steel balls are random in size. In this example, the X-ray imaging device is a C-arm, see fig. 2. Fig. 2 is an exemplary view of a C-arm and a spatial coordinate system provided by an embodiment of the present invention. In fig. 2, SID denotes the distance from the bulb to the detector, X axe denotes the X-axis, Y axe denotes the Y-axis, and Z axe denotes the Z-axis.

Under basic angles lao=0°, cra=0°, an X-ray image of the cylindrical calibration phantom is acquired, denoted as a first X-ray image I ₁ . First X-ray image I ₁ As shown in fig. 3.

Then under the current angles lao=10°, cra=20°, acquiring the X-ray image of the cylindrical calibration phantom, and recording as a second X-ray image I ₂ . Second X-ray image I ₂ As shown in fig. 4.

Where LAO denotes a C-arm rotating left and right (corresponding to a rotation around the X-axis in the spatial coordinate system), CRA denotes a C-arm rotating back and forth (corresponding to a rotation around the Y-axis in the spatial coordinate system).

Fig. 3 is an exemplary view of a first X-ray image acquired at a base angle (lao=0°, cra=0°). Fig. 4 is an example diagram of a second X-ray image acquired at a current angle (lao=10°, cra=20°). As shown in fig. 3 and 4, the images obtained by X-ray imaging of the same calibration phantom are different at different acquisition angles.

In this embodiment, the mapping relationship between the three-dimensional volume data and the two-dimensional projection image may be represented by a mapping matrix P. When the acquisition angles of the X-ray imaging devices are different, the parameters in the mapping matrix P have different values.

In this embodiment, the parameter value in the mapping matrix P corresponding to the base angle is referred to as a base mapping parameter value.

In an exemplary implementation process, in step S102, obtaining, according to the first X-ray image, a base mapping parameter value corresponding to the base angle may include:

Performing bottom hat transformation on the first X-ray image to obtain a first transformed image;

performing binarization processing on the first transformation image to obtain a first binarized image;

extracting a marker in the correction phantom from the first binarized image to obtain a first actual projection image;

and determining a basic mapping parameter value corresponding to the basic angle according to the first space position of the marker in the correction phantom under the basic angle and the projection position of the marker in the first actual projection image corresponding to the first space position.

For example. For the aforementioned first X-ray image I ₁ The following operations are respectively carried out:

a1, for image I ₁ Performing bottom cap transformation to obtain an image I _S1 。

The bottom hat transformation of image f is defined as the closing operation of f minus f, i.e.: b (B) _hat (f)＝(f·Se)-f。

Wherein symbol "·" represents a closed operation, se represents a structural element.

Then I _S1 ＝B _hat (I ₁ )＝(I ₁ ·Se)-I ₁ 。

The bottom cap transformation can reduce the influence caused by uneven brightness and is used for highlighting dark objects on a bright background. In this example, therefore, the steel balls in the calibration phantom are highlighted by the bottom cap transformation.

a2, for image I _S1 Performing threshold processing to leave only binarized image I containing steel balls _E1 。

Suppose image I _S1 The pixel value corresponding to the pixel point (m, n) in the pixel is I _S1 (m, n), the threshold is set to I _S1 (th), image I _E1 The pixel value corresponding to the middle pixel point (m, n) is I _E1 (m, n), if I _S1 (m, n) is greater than or equal to I _S1 (th), set I _S1 (m, n) =1, otherwise, if I _S1 (m, n) is less than I _S1 (th), set I _S1 (m,n)＝0。

I _S1 (th) is a threshold for distinguishing steel balls, in order to remove noise points in an image, the threshold can be set to be a fixed value, and can be adjusted according to the actual condition of the image, for example, automatic threshold selection is performed by using a method of maximum variance among iterations. Binarized image I _E1 As shown in fig. 5. Fig. 5 is an exemplary diagram of a binarized image.

a3, from image I _E1 Extracting a marker-steel ball from the correction phantom to obtain a first actual projection image I corresponding to the steel ball _M1 。

Because the steel balls on the two sides of the image are overlapped and are not easy to split, the region limitation is adopted in the example, and only the steel balls in the middle part of the image are selected. The area corresponding to the middle part is set according to the position of the overlapped steel balls.

Meanwhile, in order to match the positions on the projection image of the steel balls with the spatial positions of the steel balls, the steel balls are grouped according to a set threshold value, the steel balls are grouped according to coordinates from top to bottom and from left to right in sequence, and if the difference between the horizontal coordinates of adjacent steel balls is smaller than a width threshold value and the difference between the vertical coordinates is smaller than a height threshold value, the steel balls are regarded as the same group.

Because the correction body mold used in the example is a cylinder, 108 steel balls are inlaid on the surface and rotate around the cylinder, the sizes of the steel balls are random, and a plurality of steel balls are required to be simultaneously carried out for matching the projection positions and the space positions of the steel balls, so that the steel balls are required to be grouped in advance.

a4, correcting the actual space position (namely the first space position) of the steel ball in the phantom and the first actual projection image I according to the basic angle _M1 And calculating the parameter value in the mapping matrix P according to the projection position of the steel ball, wherein the parameter value in the corresponding mapping matrix P under the basic angle is called a basic mapping parameter value.

In the example, the space coordinates of steel balls in the correction die body are expressed by x, y and z, and u and v represent an image I _M1 The projection coordinates of the steel balls in the three-dimensional space to two-dimensional plane mapping matrix P can be expressed as:

[wu,wv,w]＝P·[x,y,z,1] ^T

where w represents a scale factor.

The mapping matrix P may be decomposed as follows:

P＝KR[I|-C]

wherein K is an inner parameter matrix, R and C are outer parameter matrices, and I is a feature matrix. Parameters (focal length, pixel size) in the inner parameter matrix are known, then six parameters in the outer parameter matrix: the six parameters of the rotation angle alpha around the X axis, the rotation angle beta around the Y axis, the rotation angle gamma around the Z axis, the offset Ox relative to the X axis, the offset Oy relative to the Y axis and the offset Oz relative to the Z axis in the space coordinate system can be obtained through fitting.

In an exemplary implementation process, in step S103, determining, according to the base mapping parameter value and the current angle, a reference mapping parameter value corresponding to the current angle may include:

determining a rotation angle value around an X axis in a reference mapping parameter value corresponding to the current angle according to the rotation angle value around the X axis in the current angle and a first angle difference corresponding to the X axis;

determining a rotation angle value around the Y axis in a reference mapping parameter value corresponding to the current angle according to the rotation angle value around the Y axis in the current angle and a second angle difference value corresponding to the Y axis;

determining a rotation angle value around a Z axis in the basic angle as a rotation angle value around the Z axis in a reference mapping parameter value corresponding to the current angle;

determining the offset relative to the X axis in the basic mapping parameter value as the offset relative to the X axis in the reference mapping parameter value corresponding to the current angle;

determining the offset relative to the Y axis in the basic mapping parameter value as the offset relative to the Y axis in the reference mapping parameter value corresponding to the current angle;

and determining the offset relative to the Z axis in the basic mapping parameter value as the offset relative to the Z axis in the reference mapping parameter value corresponding to the current angle.

For example.

Assuming that the basic angles lao=0°, cra=0°, the rotation angle value about the X axis is alpha1 (alpha 1≡0°), the rotation angle value about the Y axis is beta1 (beta 1≡0°), the rotation angle about the Z axis is gamma1, the offset amount with respect to the X axis is Ox1, the offset amount with respect to the Y axis is Oy1, and the offset amount with respect to the Z axis is Oz1.

At the current angles lao=10°, cra=20°, the rotation angle value around the X-axis is alpha2 (alpha 2≡10°), the rotation angle value around the Y-axis is beta2 (beta 2≡20°), the rotation angle around the Z-axis is gamma2, the offset amount with respect to the X-axis is Ox2, the offset amount with respect to the Y-axis is Oy2, and the offset amount with respect to the Z-axis is Oz2.

Angle difference of the current angle in the LAO direction compared to the base angleThe angular difference in CRA direction η=20, then +.>beta2＝beta1+η。

The remaining four parameters are equal, namely: gamma2 = gamma1, ox2 = Ox1, oy2 = oy1, oz2 = oz1.

In an exemplary implementation process, in step S104, based on the reference mapping parameter value and the second X-ray image, obtaining a target mapping relationship between the three-dimensional volume data acquired by the X-ray imaging device and the two-dimensional projection image at the current angle may include:

Acquiring a reference projection image corresponding to the current angle according to the reference mapping parameter value;

acquiring a second actual projection image corresponding to the current angle according to the second X-ray image;

matching the reference projection image with the second actual projection image to obtain a matched image;

and determining the target mapping relation between the three-dimensional data acquired by the X-ray imaging device under the current angle and the two-dimensional projection image according to the second spatial position of the marker in the correction phantom under the current angle and the projection position of the marker in the matching image.

The steps in this embodiment will be described in order.

In an exemplary implementation process, according to the reference mapping parameter value, obtaining a reference projection image corresponding to the current angle may include:

determining a reference mapping matrix according to the reference mapping parameter values;

and projecting a second space position of the marker in the correction phantom under the current angle by using the reference mapping matrix to obtain a reference projection image corresponding to the current angle.

For example.

Let the mapping matrix corresponding to the basic angle be P1, and the mapping matrix corresponding to the current angle be P2. In the foregoing example, according to alpha1, beta1, gamma1, ox1, oy1, oz1 in P1, alpha2, beta2, gamma2, ox2, oy2, oz2 in P2 may be determined, alpha2, beta2, gamma2, ox2, oy2, oz2 may be substituted into the mapping matrix, and P2 may be obtained, where P2 is the reference mapping matrix.

Assuming that the second spatial position of the marker (steel ball) in the calibration phantom under the current angle is (x 2, y2, z 2), the scale factor is w2, and the coordinates of the marker in the reference projection image corresponding to the current angle are (u 2, v 2), the reference projection image corresponding to the current angle can be obtained by the following formula:

[w2u2,w2v2,w2]＝P2·[x2,y2,z2,1] ^T

in an exemplary implementation process, according to the second X-ray image, obtaining a second actual projection image corresponding to the current angle may include:

performing bottom hat transformation on the second X-ray image to obtain a second transformed image;

performing binarization processing on the second transformation image to obtain a second binarization image;

and extracting the marker in the correction phantom from the second binarized image to obtain a second actual projection image.

The process of obtaining the second actual projection image according to the second X-ray image is the same as the principle of the process of obtaining the first actual projection image according to the first X-ray image in the foregoing steps a1 to a3, and will not be described herein.

In an exemplary implementation, matching the reference projection image with the second actual projection image to obtain a matched image includes:

for each pixel point in the reference projection image, finding a point closest to the pixel point from the second actual projection image as a matched pixel point corresponding to the pixel point;

Extracting target pixel points from the reference projection image, wherein the target pixel points are pixel points with one-to-one correspondence with the matched pixel points;

and extracting target matching pixel points corresponding to the target pixel points from the second actual projection image to form a target matching point set, wherein an image corresponding to the target matching point set is a matching image.

Assume that the pixel point in the reference projection image is Rp _i The pixel point in the second actual projection image is Rp _j The pixel point Rp can be found by the following formula _i The nearest point, i.e. pixel point Rp _i Corresponding matched pixel points:

min(||Rp _i -Pp _j ||)

under most angles, the situation that steel balls are overlapped in an actual projection image of the steel balls can be caused, so that two overlapped steel balls in the image are identified as one steel ball, and the situation that two pixel points in a reference projection image correspond to the same pixel point in a second actual projection image, namely the situation of a one-to-many correspondence, can occur. In this embodiment, the pixels in the actual projection image related to the case of the one-to-one correspondence are removed, and the pixels with the one-to-one correspondence are reserved, so as to obtain a matching image.

In an exemplary implementation, extracting the marker in the calibration phantom from the first binarized image to obtain a first actual projection image may include:

Taking the pixel of the marker in the first binarized image as a foreground pixel and taking the pixels except the foreground pixel in the first binarized image as background pixels;

initializing a marking matrix, a marking queue and a marking index, wherein the size of the marking matrix is the same as the size of the first binarized image;

the first binarized image is scanned in a left-to-right, top-to-bottom order, and when an unlabeled target foreground pixel is scanned, the following is performed:

increasing the index value of the mark by 1; setting the pixel value of a pixel point corresponding to the target foreground pixel in the marking matrix as a current marking index value; scanning eight neighborhood pixel points of the target foreground pixel, and putting the eight unlabeled neighborhood pixel points into the labeling queue to be marked as seed points;

when the marking queue is not empty, scanning eight neighborhood pixel points of each seed point in sequence, and putting eight neighborhood pixel points of the seed points which are not marked into the marking queue as seed points; and scanning the next pixel point of the target foreground pixel point in the first binarized image according to the sequence until the marking queue is empty. According to the geometrical correction method of the X-ray imaging device, the first X-ray image of the correction phantom under the basic angle is collected by the X-ray imaging device, the second X-ray image of the correction phantom under the current angle is collected, the basic mapping parameter value corresponding to the basic angle is obtained according to the first X-ray image, the reference mapping parameter value corresponding to the current angle is determined according to the basic mapping parameter value and the current angle, and the geometrical correction of the mapping relation between the three-dimensional volume data and the two-dimensional projection image, which are collected by the X-ray imaging device under the current angle, can be achieved under any angle in space.

Fig. 6 is a flowchart illustrating another geometric correction method of an X-ray imaging apparatus according to an embodiment of the present invention. As shown in fig. 6, in the present embodiment, the geometric correction method of the X-ray imaging apparatus may include:

s601, acquiring a first X-ray image of a correction phantom under a basic angle by using an X-ray imaging device, and determining the current angle of the X-ray imaging device for acquiring three-dimensional volume data.

S602, acquiring a basic mapping parameter value corresponding to the basic angle according to the first X-ray image; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image.

S603, determining a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle.

S604, if the difference value between the current angle and the basic angle is smaller than a preset value, obtaining a target mapping relation between the three-dimensional data acquired by the X-ray imaging device under the current angle and the two-dimensional projection image according to the reference mapping parameter value.

In this embodiment, when the difference between the current angle and the base angle is smaller than the preset value, the target mapping relationship under the current angle is directly calculated through the base mapping parameter and the current angle value of the X-ray imaging device, so that the calculated amount can be reduced, and the processing speed can be improved.

The preset value may be set according to experience or actual requirements.

The method of the embodiment can be used for roughly estimating the mapping relation under the current angle, if the angle interval between the current angle and the basic angle is larger, the error is correspondingly increased, and the calculated mapping relation is deviated from the actual mapping relation.

In an exemplary implementation process, in step S604, obtaining, according to the reference mapping parameter value, a target mapping relationship between three-dimensional volume data collected by the X-ray imaging device and a two-dimensional projection image under a current angle may include:

and determining a reference mapping matrix according to the reference mapping parameter value, and taking the reference mapping matrix as a target mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment under the current angle and the two-dimensional projection image.

For example, assume that the expression of the mapping matrix is P, and the reference mapping matrix corresponding to the current angle is P2. Knowing the values of alpha2, beta2, gamma2, ox2, oy2, oz2 in P2, substituting the values of alpha2, beta2, gamma2, ox2, oy2, oz2 into the mapping matrix P, the reference mapping matrix P2 is obtained.

According to the geometrical correction method of the X-ray imaging device, the X-ray imaging device is used for collecting a first X-ray image of a correction phantom under a basic angle, the current angle of the X-ray imaging device for collecting three-dimensional volume data is determined, a basic mapping parameter value corresponding to the basic angle is obtained according to the first X-ray image, a reference mapping parameter value corresponding to the current angle is determined according to the basic mapping parameter value and the current angle, if the difference value between the current angle and the basic angle is smaller than a preset value, a target mapping relation between three-dimensional volume data collected by the X-ray imaging device under the current angle and a two-dimensional projection image is obtained according to the reference mapping parameter value, and geometrical correction of the mapping relation between the three-dimensional volume data and the two-dimensional projection image under the angle with smaller angle interval difference between the three-dimensional volume data and the basic angle in space can be achieved.

Based on the method embodiment, the embodiment of the invention also provides a corresponding device, equipment and storage medium embodiment.

Fig. 7 is a functional block diagram of a geometry correction device of an X-ray imaging apparatus according to an embodiment of the present invention. As shown in fig. 7, in the present embodiment, the geometry correcting means of the X-ray imaging apparatus may include:

the acquisition module 710 is configured to acquire a first X-ray image of the calibration phantom at a basic angle and acquire a second X-ray image of the calibration phantom at a current angle by using an X-ray imaging device;

a parameter value obtaining module 720, configured to obtain a base mapping parameter value corresponding to the base angle according to the first X-ray image; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image;

a determining module 730, configured to determine a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle;

and a relationship obtaining module 740, configured to obtain a target mapping relationship between the three-dimensional volume data collected by the X-ray imaging device and the two-dimensional projection image under the current angle based on the reference mapping parameter value and the second X-ray image.

In an exemplary implementation, the parameter value obtaining module 720 may be specifically configured to:

In an exemplary implementation, the determining module 730 may be specifically configured to:

determining a rotation angle value around the Y axis in a reference mapping parameter value corresponding to the current angle according to the rotation angle value around the Y axis in the current angle and a second angle difference corresponding to the Y axis;

In one exemplary implementation, the relationship acquisition module 740 may be specifically configured to:

In an exemplary implementation process, according to the reference mapping parameter value, obtaining a reference projection image corresponding to the current angle includes:

In an exemplary implementation process, obtaining a second actual projection image corresponding to the current angle according to the second X-ray image includes:

In an exemplary implementation, extracting the marker in the calibration phantom from the first binarized image to obtain a first actual projection image includes:

When the marking queue is not empty, scanning eight neighborhood pixel points of each seed point in sequence, and putting eight neighborhood pixel points of the seed points which are not marked into the marking queue as seed points; and scanning the next pixel point of the target foreground pixel point in the first binarized image according to the sequence until the marking queue is empty.

Fig. 8 is another functional block diagram of a geometry correction device of an X-ray imaging apparatus according to an embodiment of the present invention. As shown in fig. 8, in the present embodiment, the geometry correcting means of the X-ray imaging apparatus may include:

the acquisition and determination module 810 is configured to acquire a first X-ray image of a calibration phantom under a basic angle by using an X-ray imaging device, and determine a current angle at which the X-ray imaging device acquires three-dimensional volume data;

a parameter value obtaining module 820, configured to obtain a basic mapping parameter value corresponding to the basic angle according to the first X-ray image; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image;

a parameter value determining module 830, configured to determine a reference mapping parameter value corresponding to the current angle according to the basic mapping parameter value and the current angle;

And the relation obtaining module 840 is configured to obtain, according to the reference mapping parameter value, a target mapping relation between the three-dimensional volume data acquired by the X-ray imaging device and the two-dimensional projection image at the current angle, if the difference between the current angle and the base angle is smaller than a preset value.

In one exemplary implementation, the relationship acquisition module 840 may be specifically configured to:

The embodiment of the invention also provides an X-ray imaging device. Fig. 9 is a hardware configuration diagram of an X-ray imaging apparatus according to an embodiment of the present invention. As shown in fig. 9, the X-ray imaging apparatus includes: an internal bus 901, and a memory 902, a processor 903, and an external interface 904 connected by the internal bus, wherein:

the memory 902 is configured to store machine readable instructions corresponding to geometric correction logic of the X-ray imaging device;

the processor 903 is configured to read the machine readable instructions on the memory 902 and execute the instructions to implement the following operations:

In an exemplary implementation process, obtaining, according to the first X-ray image, a base mapping parameter value corresponding to the base angle includes:

In an exemplary implementation process, determining, according to the basic mapping parameter value and the current angle, a reference mapping parameter value corresponding to the current angle includes:

In an exemplary implementation process, based on the reference mapping parameter value and the second X-ray image, obtaining a target mapping relationship between three-dimensional volume data acquired by the X-ray imaging device and a two-dimensional projection image under a current angle includes:

The processor 903 is further configured to read machine-readable instructions on the memory 902 and execute the instructions to implement the following operations:

In an exemplary implementation process, according to the reference mapping parameter value, obtaining a target mapping relationship between three-dimensional volume data collected by the X-ray imaging device and a two-dimensional projection image under a current angle includes:

The embodiment of the invention also provides a computer readable storage medium, on which a computer program is stored, wherein the program when executed by a processor realizes the following operations:

For the device and apparatus embodiments, reference is made to the description of the method embodiments for the relevant points, since they essentially correspond to the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the modules illustrated as separate components may or may not be physically separate, and the components shown as modules may or may not be physical, i.e., may be located in one place, or may be distributed over a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purposes of the present description. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

The foregoing describes specific embodiments of the present disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Other embodiments of the present description will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This specification is intended to cover any variations, uses, or adaptations of the specification following, in general, the principles of the specification and including such departures from the present disclosure as come within known or customary practice within the art to which the specification pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the specification being indicated by the following claims.

It is to be understood that the present description is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present description is limited only by the appended claims.

The foregoing description of the preferred embodiments is provided for the purpose of illustration only, and is not intended to limit the scope of the disclosure, since any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the disclosure are intended to be included within the scope of the disclosure.

Claims

1. A method of geometrically correcting an X-ray imaging apparatus, comprising:

determining a basic mapping parameter value corresponding to the basic angle according to a first space position of a marker in the correction phantom under the basic angle and a projection position of the marker in the first actual projection image corresponding to the first space position, wherein the basic angle is that a left-right rotation angle of a C-shaped arm is 0 degrees, and a front-back rotation angle of the C-shaped arm is a set angle;

The mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image;

2. The method of claim 1, wherein determining a reference mapping parameter value corresponding to a current angle from the base mapping parameter value and the current angle comprises:

3. The method according to claim 1, wherein acquiring the target mapping relationship between the three-dimensional volume data acquired by the X-ray imaging device and the two-dimensional projection image at the current angle based on the reference mapping parameter value and the second X-ray image comprises:

4. A method according to claim 3, wherein obtaining a reference projection image corresponding to the current angle according to the reference mapping parameter value comprises:

5. A method according to claim 3, wherein obtaining a second actual projection image corresponding to the current angle from the second X-ray image comprises:

6. A method according to claim 3, wherein matching the reference projection image with the second actual projection image to obtain a matched image comprises:

7. The method of claim 1, wherein extracting the markers in the calibration phantom from the first binarized image yields a first actual projection image, comprising:

8. A method of geometrically correcting an X-ray imaging apparatus, comprising:

9. The method according to claim 8, wherein obtaining the target mapping relationship between the three-dimensional volume data acquired by the X-ray imaging device and the two-dimensional projection image at the current angle according to the reference mapping parameter value comprises:

10. A geometric correction apparatus of an X-ray imaging device, comprising:

The parameter value acquisition module is used for performing bottom hat transformation on the first X-ray image to obtain a first transformation image; performing binarization processing on the first transformation image to obtain a first binarized image; extracting a marker in the correction phantom from the first binarized image to obtain a first actual projection image; determining a basic mapping parameter value corresponding to the basic angle according to a first space position of a marker in the correction phantom under the basic angle and a projection position of the marker in the first actual projection image corresponding to the first space position, wherein the basic angle is that a left-right rotation angle of a C-shaped arm is 0 degrees, and a front-back rotation angle of the C-shaped arm is a set angle; the mapping parameters are parameters in the mapping relation between the three-dimensional volume data acquired by the X-ray imaging equipment and the two-dimensional projection image;

11. A geometric correction apparatus of an X-ray imaging device, comprising: