Target positioning method and device based on medical perspective

Abstract

The invention provides a target positioning method and device based on a medical perspective. The method is applied to medical image processing. The method comprises the following steps: selecting a two-dimensional medical perspective image under any two visual angles, and obtaining two-dimensional pixel coordinates and image parameters of a target point on the perspective image; a target coordinate conversion matrix is calculated according to the image parameters, the target coordinate conversion matrix is used for converting two-dimensional pixel coordinates of the target point into three-dimensional world coordinates, and the target coordinate conversion matrix is composed of conversion parameters of a two-dimensional pixel coordinate system, a two-dimensional image coordinate system, a three-dimensional camera coordinate system and a three-dimensional world coordinate system; substituting the two-dimensional pixel coordinates of the target points of the double viewing angles into the target coordinate conversion matrix, and calculating to obtain the three-dimensional world coordinates of the initial target points of the double viewing angles; and processing and calculating according to the dual-view initial target point and the three-dimensional world coordinate to obtain the three-dimensional world coordinate of the target point. According to the invention, the target point can be quickly and accurately positioned.

Description

Technical Field

[0001] The present invention relates to the field of medical image processing, and in particular to a target positioning method and device based on medical perspective images. Background Art

[0002] Surgical robots are widely used in minimally invasive surgery, puncture, and ablation due to their precision, safety, fewer needle insertions, and fewer complications. They do not rely on the doctor's experience and techniques, and effectively solve clinical pain points. Perspective images are black-and-white images produced by X-ray perspective technology. With the help of the differences in X-ray absorption by different tissues of the human body, image data with different brightness are formed. Common applications include CBCT images and DSA images. In surgical robot technology, perspective images generated by CBCT images can be used to reorganize into high-resolution three-dimensional slice data through special algorithms, which can accurately locate the center of the target lesion or other target positions. After obtaining the target image coordinates, the optical navigation module is used to guide the robotic arm to perform subsequent operations, improve the success rate of one-time needle insertion, reduce operation time, and reduce patient pain. The entire process requires precise image guidance and is an important part of the surgical process.

[0003] However, perspective images have limitations in target positioning tasks because they ignore the distance information from the target to the light source, or depth information. In target positioning tasks, if the target deviates from the position of the rotation center plane, the distance from the light source to the target plane and the pixel spacing become unknown, and directly using DICOM tag values ​​will lead to significant errors. Moreover, obtaining the three-dimensional coordinates of the target in the CBCT tomographic image requires the device to complete more than 200 degrees of shooting and reconstruction algorithm processing, as well as subsequent segmentation or modeling. The entire process is complicated and time-consuming. Therefore, in the case of inaccurate label values ​​of two-dimensional perspective images, it is impossible to quickly and accurately determine the three-dimensional coordinates, and it involves a lot of calculations and the process is cumbersome. Summary of the invention

[0004] In view of this, the present invention provides a target positioning method based on medical perspective images, comprising:

[0005] Selecting a two-dimensional medical perspective image under any dual viewing angles, and obtaining the two-dimensional pixel coordinates and image parameters of a target point on the perspective image, wherein the image parameters are basic properties of the medical perspective image and geometric parameters of an imaging system;

[0006] Calculating a target coordinate conversion matrix according to the image parameters, the target coordinate conversion matrix is ​​used to convert the two-dimensional pixel coordinates of the target point into three-dimensional world coordinates, wherein the target coordinate conversion matrix is ​​composed of conversion parameters of a two-dimensional pixel coordinate system, a two-dimensional image coordinate system, a three-dimensional camera coordinate system, and a three-dimensional world coordinate system;

[0007] Substituting the two-dimensional pixel coordinates of the target point of the dual-view into the target coordinate conversion matrix, and calculating the three-dimensional world coordinates of the initial target point of the dual-view;

[0008] Processing and calculation are performed based on the initial target point and the three-dimensional world coordinates of the dual-viewing angles to obtain the three-dimensional world coordinates of the target point.

[0009] Optionally, the image parameters include image resolution of the medical fluoroscopic image, pixel spacing, the distance from the light source point to the patient in the imaging system, the distance from the light source point to the detection plate in the imaging system, the first angle, the second angle, the first angle increment, and the second angle increment.

[0010] Optionally, the target coordinate transformation matrix is ​​calculated as follows:

[0011]

[0012] Among them, (X W ,Y W ,Z W ) represents the three-dimensional world coordinates, (u, v) represents the two-dimensional pixel coordinates, row represents the number of pixels of the perspective image in the vertical direction, cols represents the number of pixels of the perspective image in the horizontal direction, spacing represents the pixel spacing, SOD represents the distance from the light source to the patient, SID represents the distance from the light source to the detection board, R is the rotation matrix, and T represents the offset vector.

[0013] Optionally, the target coordinate transformation matrix is ​​calculated as follows:

[0014]

[0015] Wherein, (u, v) represents the two-dimensional pixel coordinates, (X W ,Y W ,Z W ) represents the three-dimensional world coordinates, row represents the number of pixels of the perspective image in the vertical direction, cols represents the number of pixels of the perspective image in the horizontal direction, spacing represents the pixel spacing, SOD represents the distance from the light source to the patient, SID represents the distance from the light source to the detection board, R is the rotation matrix, and T represents the offset vector.

[0016] Optionally, processing is performed according to the initial target point and the three-dimensional world coordinates of the dual-view to obtain the three-dimensional world coordinates of the target point, including:

[0017] Using the target coordinate transformation matrix, the three-dimensional world coordinates of the light source point of the dual-viewing angle are calculated;

[0018] Connecting the light source point of the first viewing angle with the corresponding initial target point to obtain a first connecting line, and connecting the light source point of the second viewing angle with the corresponding initial target point to obtain a second connecting line;

[0019] Selecting a point on the first connecting line and the second connecting line respectively, so that the midpoint of the connecting line between the two selected points is closest to the first connecting line and the second connecting line;

[0020] The midpoint is used as a target point, and the three-dimensional world coordinates of the target point are obtained.

[0021] Optionally, a point is selected on the first connecting line and the second connecting line respectively in the following manner:

[0022]

[0023] Among them, l1 represents the line equation of the first line, l2 represents the line equation of the second line, A represents the three-dimensional world coordinates of the light source point on the first line, B represents the three-dimensional world coordinates of the initial target point on the first line, C represents the three-dimensional world coordinates of the light source point on the second line, D represents the three-dimensional world coordinates of the initial target point on the second line, i represents the parameter on the first line, and j represents the parameter on the second line.

[0024] Optionally,

[0025]

[0026] in,

[0027]

[0028] Among them, (A x ,A y ,A z ) is the 3D world coordinate of the light source point on the first line, (B x ,B y ,B z ) is the 3D world coordinate of the initial target point on the first line, (C x ,C y ,C z ) is the 3D world coordinate of the light source point on the second line, (D x ,D y ,D z ) is the 3D world coordinate of the initial target point on the second line.

[0029] Optionally, an included angle between the first viewing angle and the second viewing angle is between 30° and 150°.

[0030] A second aspect of the present invention provides a target positioning device based on medical perspective images, the device comprising: a processor and a memory connected to the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor executes the above-mentioned target positioning method based on medical perspective images.

[0031] The present invention selects a two-dimensional medical perspective image under any dual viewing angle, obtains the two-dimensional pixel coordinates of the target point on the perspective image, establishes a target coordinate conversion matrix according to known perspective geometric parameters, and converts the two-dimensional pixel coordinates into three-dimensional world coordinates. Compared with the traditional multi-view shooting and reconstruction algorithm, the present method only needs to select the perspective image under any dual viewing angle, which greatly reduces the shooting time and the amount of calculation of the reconstruction algorithm. In addition, the present method has low requirements for the acquisition of perspective data, is suitable for medical perspective image processing in various environments, does not require additional in vitro markers or pre-calibration, and reduces the complexity of operation and preparation. Specifically, by selecting dual viewing angles to obtain perspective images, the loss of single-view information is avoided, and the processing amount and calculation cost are reduced. Since the image parameters may be inaccurate, the method also performs reprocessing to improve the accuracy of coordinate conversion. The method can quickly and accurately locate the center of the tumor lesion, the body surface marker, the needle tip of the in vivo puncture needle or ablation needle, etc., and is suitable for a variety of clinical application scenarios, such as registration and navigation systems, lesion confirmation and ablation treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 is a flow chart of a target positioning method based on medical perspective images in an embodiment of the present invention;

[0034] Figure 2 It is a projection schematic diagram in an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of calculating target points in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a target positioning method based on a medical perspective image, which is executed by an electronic device such as a computer or a server, and specifically includes:

[0041] S1, select a two-dimensional medical perspective image under any dual-viewing angle, and obtain the two-dimensional pixel coordinates and image parameters of the target point on the perspective image, where the image parameters are the basic attributes of the medical perspective image and the geometric parameters of the imaging system.

[0042] The imaging system is a C-arm X-ray machine, including a light source system, which includes a transmitter and a receiver. The transmitter and the receiver are respectively located on both sides of the medical bed. X-rays are mainly emitted through the transmitter. After these rays penetrate the human body, they are attenuated. The receiver receives these attenuated signals to obtain perspective images. Among them, X-rays are not "light" in the traditional sense. The present invention can be broadly understood as the rays required for imaging. Then the transmitter (i.e., X-ray source) can be regarded as a part of the light source system, and the light source point mentioned below refers to the transmitter. At the same time, the C-arm can rotate around the patient to obtain more comprehensive perspective images from different angles. The C-arm X-ray machine is used to rotate at a predetermined angle to obtain a number of perspective images, and perspective images of any multiple perspectives (the number is much less than the total number of perspective images) are selected, preferably dual perspectives, such as the C-arm X-ray machine rotates half a circle 180° to obtain 180 frames of perspective images, and perspective images of two frames of two perspectives are selected. Selecting perspective images from multiple perspectives can avoid the loss of information from a single perspective and reduce the time for acquiring images and algorithm calculations. Perspective images from too many perspectives will increase the computing cost. Therefore, two or more perspectives can provide complementary information, reduce the amount of processing, and quickly obtain accurate information.

[0043] Perspective images are two-dimensional pixel images, black-and-white images obtained through X-ray perspective technology, which use the different absorption of X-rays by different tissues of the human body to form data of different brightness. Common ones include CBCT images and DSA images. The target point can be the center of a tumor lesion, a body surface positioning marker, or the tip of a puncture needle or ablation needle in the body. The acquisition method is not limited to manual selection or extraction by traditional methods or machine learning methods to obtain the two-dimensional pixel coordinates (u, v) of the target point with the pixel image as the coordinate system. The image parameters are built-in default values, which can be read from the standard format image of the DICOM image, or can be obtained by technicians or doctors based on actual environment self-test.

[0044] S2, calculate the target coordinate transformation matrix according to the image parameters, the target coordinate transformation matrix is ​​used to transform the two-dimensional pixel coordinates of the target point into three-dimensional world coordinates, wherein the target coordinate transformation matrix is ​​composed of transformation parameters of the two-dimensional pixel coordinate system, the two-dimensional image coordinate system, the three-dimensional camera coordinate system and the three-dimensional world coordinate system.

[0045] The transformation matrix among the 2D pixel coordinate system, 2D image coordinate system, 3D camera coordinate system and 3D world coordinate system is calculated according to the image parameters to transform the 2D pixel coordinates of the target point into 3D world coordinates. All coordinate systems satisfy the right-hand coordinate system.

[0046] S3, bringing the two-dimensional pixel coordinates of the target point of the dual-view into the target coordinate transformation matrix, and calculating the three-dimensional world coordinates of the initial target point of the dual-view.

[0047] S4, processing and calculating according to the initial target point and the three-dimensional world coordinates of the dual-viewing angles to obtain the three-dimensional world coordinates of the target point.

[0048] Since the image parameters may be inaccurate, the world coordinates obtained by the target coordinate transformation matrix may be inaccurate, so reprocessing is required to obtain the accurate three-dimensional world coordinates of the target point.

[0049] This embodiment selects a two-dimensional medical perspective image under any dual perspective, obtains the two-dimensional pixel coordinates of the target point on the perspective image, establishes a target coordinate conversion matrix according to known perspective geometric parameters, and converts the two-dimensional pixel coordinates into three-dimensional world coordinates. Compared with the traditional multi-perspective shooting and reconstruction algorithm, this method only needs to select the perspective image under any dual perspective, which greatly reduces the shooting time and the amount of calculation of the reconstruction algorithm. In addition, this method has low requirements for the acquisition of perspective data, is suitable for medical perspective image processing in various environments, does not require additional in vitro markers or pre-calibration, and reduces the complexity of operation and preparation. Specifically, by selecting dual perspectives to obtain perspective images, the loss of single perspective information is avoided, and the processing volume and computing cost are reduced. Since the image parameters may be inaccurate, the method also performs reprocessing to improve the accuracy of coordinate conversion. The method can quickly and accurately locate the center of the tumor lesion, the surface marker, the needle tip of the in vivo puncture needle or ablation needle, etc., and is suitable for a variety of clinical application scenarios, such as registration and navigation systems, lesion confirmation and ablation treatment.

[0050] Preferably, when selecting the perspective image, the included angle between the first viewing angle and the second viewing angle is controlled to be between 30° and 150°.

[0051] The angle between the perspective images of the two perspectives is controlled within the preset angle range, which can ensure that there is a certain parallax (depth and distance of the object) between the two perspective images, which is helpful for subsequent 3D reconstruction or target point positioning. If the angle is too small, it may lead to insufficient parallax, thus affecting the accuracy of 3D reconstruction. On the contrary, if the angle is too large, although the parallax will increase, it may also lead to a reduction in the overlap between the images, increasing the difficulty of subsequent processing.

[0052] The image parameters obtained in step S1 are basic properties of the medical fluoroscopic image and geometric parameters of the imaging system, wherein the image parameters include the image resolution row, cols, pixel spacing Spacing, the distance SOD from the light source point to the patient in the imaging system, the distance SID from the light source point to the detection board in the imaging system, the first angle θ1, the second angle θ2, the first angle increment Δθ1, and the second angle increment Δθ2.

[0053] Among them, the distance from the light source point to the detection plate in the imaging system is the distance from the transmitting end to the receiving end of the C-arm X-ray machine; the first angle and the second angle are the initial angles of the two selected frames of perspective images, and the first angle increment and the second angle increment correspond to the angle of the frame image rotation. For example, the angle of the 90th frame is the corresponding initial angle plus the angle increment, that is, the angle of the corresponding viewing angle. The following description takes the dual viewing angles of 0° and 90° as an example. In one embodiment, the target coordinate conversion matrix is ​​calculated according to the image parameters, and the target coordinate conversion matrix is ​​obtained by the conversion matrix between the two-dimensional pixel coordinate system and the two-dimensional image coordinate system, the conversion matrix between the two-dimensional image coordinate system and the three-dimensional camera coordinate system, and the conversion matrix between the three-dimensional camera coordinate system and the three-dimensional world coordinate system. Among them, the conversion matrix between the two-dimensional pixel coordinate system and the two-dimensional image coordinate system is calculated by the image resolution and the pixel spacing, the conversion matrix between the two-dimensional image coordinate system and the three-dimensional camera coordinate system is obtained by the distance from the light source point to the patient, and the conversion matrix between the three-dimensional camera coordinate system and the three-dimensional world coordinate system is calculated by the first angle, the second angle, the first angle increment, and the second angle increment.

[0054] According to the two-dimensional pixel coordinates (u, v), the canvas center pixel coordinates (row / 2, col / 2), and the two-dimensional image coordinates (x, y), the transformation matrix between the two-dimensional pixel coordinate system and the two-dimensional image coordinate system is as follows:

[0055]

[0056] According to the coordinates (Xc, Yc, Zc) in the 3D camera coordinate system, the transformation matrix between the 2D image coordinate system and the 3D camera coordinate system is as follows:

[0057]

[0058] The current perspective image rotates around the Z axis at an angle of (θ1+Δθ1), and around the X axis at an angle of (θ2+Δθ2). The coordinates in the 3D world coordinate system are (Xw, Yw, Zw). The transformation matrix between the 3D camera coordinate system and the 3D world coordinate system is as follows:

[0059]

[0060] Finally, the target coordinate transformation matrix is ​​calculated:

[0061]

[0062] Among them, (X W ,Y W ,Z W) represents the three-dimensional world coordinate, (u,v) represents the two-dimensional pixel coordinate, row represents the number of pixels of the fluoroscopic image in the vertical direction, cols represents the number of pixels of the fluoroscopic image in the horizontal direction, spacing represents the pixel spacing, SOD represents the distance from the light source to the patient, SID represents the distance from the light source to the detection board, R represents the rotation matrix, and T represents the offset vector.

[0063] In another embodiment, there is another way to calculate the target coordinate transformation matrix as follows:

[0064] According to the two-dimensional pixel coordinates (u, v), the canvas center pixel coordinates (row / 2, col / 2), and the two-dimensional image coordinates (x, y), the transformation matrix between the two-dimensional pixel coordinate system and the two-dimensional image coordinate system is as follows:

[0065]

[0066] According to the coordinates (Xc, Yc, Zc) in the 3D camera coordinate system, the transformation matrix between the 2D image coordinate system and the 3D camera coordinate system is as follows:

[0067]

[0068] The current perspective image rotates around the Z axis at an angle of (θ1+Δθ1), and around the X axis at an angle of (θ2+Δθ2). The coordinates in the 3D world coordinate system are (Xw, Yw, Zw). The transformation matrix between the 3D camera coordinate system and the 3D world coordinate system is as follows:

[0069]

[0070]

[0071] Among them, (u, v) represents the two-dimensional pixel coordinates, (X W ,Y W ,Z W ) represents the three-dimensional world coordinate, row represents the number of pixels of the perspective image in the vertical direction, cols represents the number of pixels of the perspective image in the horizontal direction, spacing represents the pixel spacing, SOD represents the distance from the light source to the patient, SID represents the distance from the light source to the detection board, R represents the rotation matrix, and T represents the offset vector.

[0072] In one embodiment, step S4 processes the initial target point and the three-dimensional world coordinates of the dual-view to obtain the three-dimensional world coordinates of the target point, including:

[0073] S41, using the target coordinate conversion matrix, calculating the three-dimensional world coordinates of the light source point in dual perspectives;

[0074] S42, connecting the light source point of the first viewing angle with the corresponding initial target point to obtain a first connecting line, and connecting the light source point of the second viewing angle with the corresponding initial target point to obtain a second connecting line;

[0075] S43, selecting a point on the first connecting line and the second connecting line respectively, so that the midpoint of the connecting line between the two selected points is closest to the first connecting line and the second connecting line;

[0076] S44, taking the midpoint as a target point, and obtaining the three-dimensional world coordinates of the target point.

[0077] like Figure 2 As shown in the figure, the light source point of the first viewing angle (0°) is A, the light source point of the second viewing angle (90°) is C, the cube represents the patient, point B is the two-dimensional pixel target point obtained from the first viewing angle (corresponding to a point on the receiving end detection plate of the C-arm X-ray machine), and point D is the two-dimensional pixel target point obtained from the second viewing angle. Since the distance from the light source point to the patient in the image parameters is only the distance from the light source point to the patient, not the distance to the tumor in the body, after the light source (such as X-ray) penetrates the human body, the image formed on the receiving end (such as the detection plate of the C-arm X-ray machine) can often only reflect the projection position on the skin surface, rather than the real position of the lesion in the body. Therefore, the two-dimensional pixel target points (such as point B and point D) directly obtained from the image are often only the projection of the lesion on the skin surface, rather than the lesion itself. The initial target point obtained from the first viewing angle is E, and the initial target point obtained from the second viewing angle is F, that is, the initial target points E and F are also just points on the skin surface, and the real target is located on the line segment or extension line between the light source and the initial target point. Therefore, the initial target point E and point F need to be processed again. Point A and point E need to be connected to obtain the first connection line, and point C and point F need to be connected to obtain the second connection line.

[0078] Furthermore, since point B and point D are the target points of the pixel image obtained by projecting X-rays emitted by the light source point through the human body to the detection board at the receiving end, point B is on the extension line of the first connecting line, and point D is on the extension line of the second connecting line. Then, the equations of the first connecting line and the second connecting line are as follows:

[0079]

[0080] Among them, l1 represents the line equation of the first line, l2 represents the line equation of the second line, A represents the three-dimensional world coordinates of the light source point on the first line, B represents the three-dimensional world coordinates of the initial target point on the first line, C represents the three-dimensional world coordinates of the light source point on the second line, D represents the three-dimensional world coordinates of the initial target point on the second line, i represents the parameter on the first line, and j represents the parameter on the second line.

[0081] in,

[0082]

[0083] The equation construction matrix is ​​as follows:

[0084]

[0085] Solve the basic form of PX=Q by the lowest square method and get:

[0086]

[0087] in,

[0088]

[0089] Among them, (A x ,A y ,A z ) is the 3D world coordinate of the light source point on the first line, (B x ,B y ,B z ) is the 3D world coordinate of the initial target point on the first line, (C x ,C y ,C z ) is the 3D world coordinate of the light source point on the second line, (D x ,D y ,D z ) is the 3D world coordinate of the initial target point on the second line.

[0090] After solving i and j according to the above formula, we can substitute them into the two equations of l1 and l2 to get the points on the two connecting lines. Figure 3 As shown, the midpoint of the two points is the spatial point closest to the two connecting lines, corresponding to Figure 2 In the above figure, point G is the target point, and its coordinates will be used as the three-dimensional world coordinates of the target point.

[0091] Since the lesion is located in the body, it must be located at a certain position of these two lines or their extension lines. In order to find an estimated position closer to the lesion, the present embodiment adopts a method of taking the midpoint of the same distance point on the two lines as the target point. This method is based on the assumption that the distance between the lesion and the two lines is equal (or at least very close). By constructing the line equation and solving it by the least square method, a pair of points (respectively located on the two lines) can be found, and their distances to the midpoint are equal (or closest to being equal). This midpoint is the target point we are looking for, and it is closer to the true position of the lesion. This method not only takes into account the distance from the light source point to the patient, but also solves by the intersection of the lines, further improving the accuracy of the target point positioning.

[0092] The three-dimensional world coordinates of the target point have important application value in medical scenarios. For example, in tumor treatment, the three-dimensional coordinates of the target point can be used to accurately navigate surgical instruments, such as puncture needles and ablation needles, to ensure that they can accurately reach the tumor lesions and improve the accuracy and safety of the operation. In addition, this method can also be used for registration and navigation systems to accurately align the patient's actual anatomical structure with medical images, providing doctors with more accurate surgical guidance.

[0093] In general, the method of the present embodiment provides an accurate and reliable method for calculating the three-dimensional coordinates of a target point, which provides powerful support for applications such as navigation and treatment in the medical field. It should be understood by those skilled in the art that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0094] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0095] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0096] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0097] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A target positioning method based on medical perspective images, characterized in that: include: Selecting a two-dimensional medical perspective image under any dual viewing angles, and obtaining the two-dimensional pixel coordinates and image parameters of a target point on the perspective image, wherein the image parameters are basic properties of the medical perspective image and geometric parameters of an imaging system; Calculating a target coordinate conversion matrix according to the image parameters, the target coordinate conversion matrix is ​​used to convert the two-dimensional pixel coordinates of the target point into three-dimensional world coordinates, wherein the target coordinate conversion matrix is ​​composed of conversion parameters of a two-dimensional pixel coordinate system, a two-dimensional image coordinate system, a three-dimensional camera coordinate system, and a three-dimensional world coordinate system; Substituting the two-dimensional pixel coordinates of the target point of the dual-view into the target coordinate conversion matrix, and calculating the three-dimensional world coordinates of the initial target point of the dual-view; Processing and calculation are performed based on the initial target point and the three-dimensional world coordinates of the dual-viewing angles to obtain the three-dimensional world coordinates of the target point.

2. The method according to claim 1, characterized in that The image parameters include image resolution of the medical fluoroscopic image, pixel spacing, distance from the light source point to the patient in the imaging system, distance from the light source point to the detection plate in the imaging system, first angle, second angle, first angle increment, and second angle increment.

3. The method according to claim 1, characterized in that The target coordinate transformation matrix is ​​calculated as follows: Among them, (X W ,Y W ,Z W ) represents the three-dimensional world coordinates, (u, v) represents the two-dimensional pixel coordinates, row represents the number of pixels of the perspective image in the vertical direction, cols represents the number of pixels of the perspective image in the horizontal direction, spacing represents the pixel spacing, SOD represents the distance from the light source to the patient, SID represents the distance from the light source to the detection board, R is the rotation matrix, and T represents the offset vector.

4. The method according to claim 1, characterized in that The target coordinate transformation matrix is ​​calculated as follows: Wherein, (u, v) represents the two-dimensional pixel coordinates, (X W ,Y W ,Z W ) represents the three-dimensional world coordinates, row represents the number of pixels of the perspective image in the vertical direction, cols represents the number of pixels of the perspective image in the horizontal direction, spacing represents the pixel spacing, SOD represents the distance from the light source to the patient, SID represents the distance from the light source to the detection board, R is the rotation matrix, and T represents the offset vector.

5. The method according to claim 1, characterized in that Processing is performed according to the initial target point and the three-dimensional world coordinates of the dual-view to obtain the three-dimensional world coordinates of the target point, including: Using the target coordinate transformation matrix, the three-dimensional world coordinates of the light source point of the dual-viewing angle are calculated; Connecting the light source point of the first viewing angle with the corresponding initial target point to obtain a first connecting line, and connecting the light source point of the second viewing angle with the corresponding initial target point to obtain a second connecting line; Selecting a point on the first connecting line and the second connecting line respectively, so that the midpoint of the connecting line between the two selected points is closest to the first connecting line and the second connecting line; The midpoint is used as a target point, and the three-dimensional world coordinates of the target point are obtained.

6. The method according to claim 5, characterized in that Select a point on the first connecting line and the second connecting line respectively in the following manner: Among them, l1 represents the line equation of the first line, l2 represents the line equation of the second line, A represents the three-dimensional world coordinates of the light source point on the first line, B represents the three-dimensional world coordinates of the initial target point on the first line, C represents the three-dimensional world coordinates of the light source point on the second line, D represents the three-dimensional world coordinates of the initial target point on the second line, i represents the parameter on the first line, and j represents the parameter on the second line.

7. The method according to claim 6, characterized in that in, Among them, (A x ,A y ,A z ) is the 3D world coordinate of the light source point on the first line, (B x ,B y ,B z ) is the 3D world coordinate of the initial target point on the first line, (C x ,C y ,C z ) is the 3D world coordinate of the light source point on the second line, (D x ,D y ,D z ) is the 3D world coordinate of the initial target point on the second line.

8. The method according to claim 1, characterized in that The included angle between the first viewing angle and the second viewing angle is between 30° and 150°.

9. A target positioning device based on medical perspective images, characterized in that: include: A processor and a memory connected to the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor executes the target positioning method based on medical fluoroscopic images as described in any one of claims 1-8.

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