CN111915494B

CN111915494B - Calibration method, device and system

Info

Publication number: CN111915494B
Application number: CN202010705843.7A
Authority: CN
Inventors: 刘月; 赵烁; 邹达; 韩冬
Original assignee: Neusoft Medical Systems Co Ltd
Current assignee: Neusoft Medical Systems Co Ltd
Priority date: 2020-07-21
Filing date: 2020-07-21
Publication date: 2024-05-28
Anticipated expiration: 2040-07-21
Also published as: CN111915494A

Abstract

The embodiment of the invention provides a calibration method, a device and a system. According to the embodiment of the invention, the first video data of the calibration plate on the movable scanning bed of the medical imaging equipment in the target space range acquired by the image acquisition device is acquired, the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed, at least one target image frame is extracted from the first video data, the first coordinates of a plurality of first reference points in a pixel coordinate system are acquired from the at least one target image frame, the second coordinates of the plurality of first reference points in a world coordinate system are acquired, and the coordinate conversion relation between the pixel coordinate system and the world coordinate system is determined according to the first coordinates and the second coordinates, so that the standardized and automatic calibration which is universally applicable is realized, and the calibration efficiency is improved.

Description

Calibration method, device and system

Technical Field

The present invention relates to the field of image collector calibration technologies, and in particular, to a calibration method, device, and system.

Background

Currently, medical imaging examinations have become routine examinations in clinical examinations. In medical image examination, the patient registration, positioning and positioning process of workflow scanning is easy to cause misoperation due to the tedious operation process. In the conventional workflow of medical image examination, a doctor is required to enter a scanning room to adjust the bed height and the bed code of a scanning bed of a medical imaging device by means of manual control keys so as to determine the scanning starting range, and then return to the operating room to start scanning by means of a console device, which is time-consuming and requires direct contact with a patient.

In recent years, a method of performing remote positioning based on natural images is increasingly used. The technology replaces the manual control of the keys of the medical imaging equipment with the operation of the real-time natural image, and can realize the compartment operation. An important aspect is that the pixel coordinates of the natural image acquired by the image collector and the spatial coordinates of the world coordinate system are mutually converted, and the precondition of the conversion is calibration, namely, the coordinate conversion relationship between the pixel coordinate system and the world coordinate system is acquired.

Disclosure of Invention

In order to overcome the problems in the related art, the invention provides a calibration method, a device and a system.

According to a first aspect of an embodiment of the present invention, there is provided a calibration method, applied to a calibration apparatus, including:

Acquiring first video data of a movable scanning bed on-board calibration plate of medical imaging equipment in a target space range acquired by an image acquisition device, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed;

Extracting at least one target image frame from the first video data, and acquiring first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame;

acquiring second coordinates of the plurality of first reference points in a world coordinate system;

and determining a coordinate conversion relation between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate.

According to a second aspect of embodiments of the present invention, there is provided a calibration device applied to a calibration apparatus, comprising:

the video data acquisition module is used for acquiring first video data of a movable scanning bed upper calibration plate of the medical imaging equipment in a target space range acquired by the image acquisition device, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed;

A first target coordinate acquisition module, configured to extract at least one target image frame from the first video data, and acquire first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame;

The second coordinate acquisition module is used for acquiring second coordinates of the plurality of first reference points in a world coordinate system;

and the conversion relation determining module is used for determining the coordinate conversion relation between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate.

According to a third aspect of embodiments of the present invention, there is provided a calibration method applied to a calibration system including an image collector, a medical imaging device and a calibration device, comprising:

the method comprises the steps that an image collector collects first video data of a movable scanning bed on-board calibration plate of medical imaging equipment in a target space range, and sends the first video data to the calibration equipment, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed;

the calibration device extracts at least one target image frame from the first video data, and acquires first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame;

the calibration equipment acquires second coordinates of the plurality of first datum points in a world coordinate system;

And the calibration equipment determines the coordinate conversion relation between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate.

According to a fourth aspect of embodiments of the present invention, there is provided a calibration system comprising:

a medical imaging device comprising a scanning bed on which a movable calibration plate is mounted;

The image acquisition device is used for acquiring first video data of a movable scanning bed calibrating plate of the medical imaging device in a target space range and transmitting the first video data to the calibrating device, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions;

A calibration device for extracting at least one target image frame from the first video data and acquiring first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame; acquiring second coordinates of the plurality of first reference points in a world coordinate system; and determining a coordinate conversion relation between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate.

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 video data of the calibration plate on the movable scanning bed of the medical imaging equipment in the target space range acquired by the image acquisition device is acquired, the target space range comprises a plurality of horizontal positions and a plurality of vertical positions, at least one target image frame is extracted from the first video data, the first coordinates of a plurality of first reference points in a pixel coordinate system are acquired from the at least one target image frame, the second coordinates of the plurality of first reference points in a world coordinate system are acquired, and the coordinate conversion relation between the pixel coordinate system and the world coordinate system is determined according to the first coordinates and the second coordinates, so that the standardized and automatic calibration which is universally applicable is realized, and the calibration efficiency is improved.

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 an exemplary diagram of an application scenario of a calibration method according to an embodiment of the present invention.

Fig. 2 is an exemplary diagram of another application scenario of the calibration method according to the embodiment of the present invention.

Fig. 3 is an exemplary diagram of another application scenario of the calibration method according to the embodiment of the present invention.

Fig. 4 is a flowchart illustrating a calibration method according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of the positional relationship between a camera and a scanning bed of a medical imaging device.

FIG. 6 is a functional block diagram of a calibration apparatus according to an embodiment of the present invention.

Fig. 7 is a hardware configuration diagram of a calibration device 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 "in response to a determination" depending on the context.

Fig. 1 is an exemplary diagram of an application scenario of a calibration method according to an embodiment of the present invention. As shown in fig. 1, the medical imaging device and the image acquisition device are placed in a scan room and the console device is placed in an operation room adjacent to the scan room at the time of installation of the related devices for medical image examination. Wherein the medical imaging apparatus comprises a scanning couch (which may also be referred to herein as an examination couch), over which the image acquisition apparatus may be mounted by a fixture. The console device is in communication connection with the medical imaging device and the image collector, respectively, and is capable of receiving data transmitted by the medical imaging device and the image collector and transmitting related instructions to the medical imaging device and the image collector. The console device may obtain the coordinate conversion relationship between the pixel coordinate system and the world coordinate system by executing the calibration method at the calibration device side of the present invention, and store the coordinate conversion relationship in the console device, that is, in this embodiment, the console device includes the calibration device or the console device as the calibration device.

When medical image examination is carried out, the image collector collects natural images of a part to be scanned of a subject on a scanning bed, the natural images are sent to the console device, the console device displays the natural images of the subject including the part to be scanned through the display, and receives operation information of the natural images, which is input by an operator through input devices (such as a keyboard and a mouse) of the console device, the operation information of the natural images is converted into operation information of the medical imaging device according to a coordinate conversion relation between a stored pixel coordinate system and a world coordinate system and is sent to the medical imaging device, so that the medical imaging device is controlled to execute corresponding operation, and compartment operation is achieved.

Fig. 2 is an exemplary diagram of another application scenario of the calibration method according to the embodiment of the present invention. As shown in fig. 2, in comparison with fig. 1, the present embodiment further includes a calibration device connected to the console device. The calibration device may communicate with the image acquisition device via the console device to obtain the natural image acquired by the image acquisition device. In this embodiment, the calibration device executes the calibration method of the calibration device side of the present invention, and the coordinate conversion relationship between the obtained pixel coordinate system and the world coordinate system is stored in the calibration device, or is transmitted to the console device, and is stored by the console device.

It should be noted that, although the calibration device is shown in fig. 2 as being located in the operation room, in other embodiments, the calibration device may be a remotely located cloud service device, such as a cloud server, capable of communicating with the console device.

When medical image examination is performed, the image collector firstly collects natural images of a subject on a scanning bed, and sends the natural images to the console device, the console device displays natural images of a part to be scanned through a display, and operation information of the natural images, which is input by an operator through input equipment (such as a keyboard and a mouse) of the console device, is received.

When the coordinate conversion relation between the pixel coordinate system and the world coordinate system is stored in the console device, the console device converts the operation information into the operation information of the keys of the medical imaging device according to the coordinate conversion relation between the locally stored pixel coordinate system and the world coordinate system and sends the operation information to the medical imaging device so as to control the medical imaging device to execute corresponding operation, and thus compartment operation is achieved.

When the coordinate conversion relation between the pixel coordinate system and the world coordinate system is not stored in the console device, the console device can read the coordinate conversion relation between the pixel coordinate system and the world coordinate system from the calibration device which is in communication connection with the console device, convert the operation information into the operation information of the keys of the medical imaging device according to the coordinate conversion relation and send the operation information to the medical imaging device so as to control the medical imaging device to execute corresponding operation, and realize compartment operation; or the console device can send the operation information to the calibration device, the calibration device converts the operation information into the operation information of the keys of the medical imaging device according to the coordinate conversion relation between the locally stored pixel coordinate system and the world coordinate system and sends the operation information to the console device, and the console device forwards the operation information of the keys of the medical imaging device to the medical imaging device so as to control the medical imaging device to execute corresponding operation, thereby realizing compartment operation; or the console device can send the position information in the operation information to the calibration device, the calibration device converts the position information in the operation information into the spatial position information of the world coordinate system according to the coordinate conversion relation between the locally stored pixel coordinate system and the world coordinate system and sends the spatial position information to the console device, the console device converts the operation information into the operation information of the keys of the medical imaging device according to the converted spatial position information and sends the operation information to the console device, and the console device forwards the operation information of the keys of the medical imaging device to the medical imaging device so as to control the medical imaging device to execute corresponding operations, thereby realizing compartment operation.

Although the above is an example in which the coordinate conversion relationship between the pixel coordinate system and the world coordinate system is applied to convert the coordinates of the pixel coordinate system into the coordinates of the world coordinate system, it is to be understood that the coordinate conversion relationship between the pixel coordinate system and the world coordinate system may be applied to convert the coordinates of the world coordinate system into the coordinates of the pixel coordinate system.

Fig. 3 is an exemplary diagram of another application scenario of the calibration method according to the embodiment of the present invention. As shown in fig. 3, compared with fig. 1, the present embodiment further includes a calibration device, and the calibration device is disposed in the image collector. The operation performed by the calibration device in this embodiment may be the same as the operation performed by the calibration device in the embodiment shown in fig. 2, and will not be described here again.

Wherein the image collector may be a camera.

The calibration method is described in detail by way of examples.

Fig. 4 is a flowchart illustrating a calibration method according to an embodiment of the present invention. As shown in fig. 4, in this embodiment, the calibration method may include:

s401, acquiring first video data of a movable scanning bed calibration plate of the medical imaging device in a target space range acquired by an image acquisition unit, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed.

S402, at least one target image frame is extracted from the first video data, and first coordinates of a plurality of first reference points in a pixel coordinate system are obtained from the at least one target image frame.

S403, obtaining second coordinates of the plurality of first datum points in a world coordinate system.

S404, determining a coordinate conversion relation between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate.

In this embodiment, the image collector may be a 3D (three-dimensional) camera. The 3D camera may acquire an RGB image (i.e., a color image) and a depth map of a target object (e.g., a subject). Where the pixel values of the pixels in the depth map represent the distance (depth) from the image collector (e.g., camera) to the points in the scene.

In this embodiment, the target spatial range may be a spatial range determined by the scanning bed range and the bed height range.

Fig. 5 is a schematic diagram of the positional relationship between a camera and a scanning bed of a medical imaging device. As shown in fig. 5, the camera is preferably located directly above the scanning bed (i.e., the examination bed in fig. 5) so as to be able to (as much as possible) include the initial position of the scanning bed.

In this embodiment, the first video data may be acquired through the following procedure:

a, aligning a calibration plate to a datum point position of a movable scanning bed, wherein the calibration plate has accurate standard thickness and a plurality of mark lines distributed at known distances, and is fixed on the scanning bed by a locking device;

b, setting the initial bed height and the bed depth of the scanning bed;

c, shooting a calibration plate on the examination bed by using a 3D camera (or other image collectors with an image acquisition function and a depth information acquisition function);

d, keeping the bed height of the scanning bed unchanged, changing the depth of the bed, and shifting the calibration plate along with the horizontal bed feeding direction by a fixed step length;

e, repeating the steps c and d until the image data of each position of the calibration plate meeting the inspection requirement in the vertical direction of the horizontal plane of the image field scanning bed is obtained;

f, changing the height of the calibration plate by adjusting the height of the scanning bed;

g, repeating the steps c to f until the image data of each position of the calibration plate meeting the inspection requirement in the vertical direction of the image field is acquired.

In this embodiment, the first video data may also be obtained by the following procedure:

The 3D camera is arranged at the position above the scanning bed, and the 3D camera is additionally provided with a moving device with adjustable placing height and a vertical position on a plane parallel to the scanning bed, so that the 3D camera can move along the horizontal direction and the vertical direction. In the shooting process, the position of the calibration plate and the position of the scanning bed are kept unchanged, the 3D camera is moved to different horizontal positions and vertical positions through the moving device, and the calibration plate on the scanning bed is shot by the 3D camera. In the shooting process, the mobile device can move the 3D camera in a fixed frequency fixed sequence, and perform multiple acquisition after the same position is stable until the image data of each position of the calibration plate meeting the inspection requirement in the horizontal direction of the horizontal plane of the scanning bed in the image view field are acquired.

For example, assuming that the entire image field of view of the scanning bed is divided into n areas equally according to the travelling direction of the scanning bed, respectively denoted as L1 and L2 … … Ln, and the width occupied by each area is equal to the width of the calibration plate, that is, the calibration plate can completely cover each area, the height of the scanning bed is set to m gear positions, respectively denoted as H1 and H2 … … Hm, then the image of the calibration plate can be taken when the calibration plate is in the following positions:

the height of the scanning bed is H1, and the calibration plates are respectively positioned at L1 and L2 … … Ln;

the height of the scanning bed is H2, and the calibration plates are respectively positioned at L1 and L2 … … Ln;

……

the height of the scanning bed is Hm, and the calibration plates are respectively positioned at L1 and L2 … … Ln.

Wherein the first video data is a sequence of image frames. There may be multiple image frames for each position of the calibration plate. For each location, at least one image frame meeting the preset calibration requirements may be extracted as a target image frame.

In the present embodiment, the pixel coordinate system is a 2D (two-dimensional) coordinate system, i.e., a planar coordinate system. The point in the upper left corner of the image may typically be taken as the origin of the pixel coordinate system.

The world coordinate system is a 3D (three-dimensional) coordinate system, i.e. a spatial coordinate system. The origin of the world coordinate system can be set manually.

Assuming that the first coordinate is (u, v) and the corresponding second coordinate is (x, y, z), the coordinate conversion relationship between the pixel coordinate system and the world coordinate system can be expressed as: x=f (u, v), y=g (u, v).

F (u, v), G (u, v) may be a multivariate function fitted from a known set of pairs of coordinates consisting of a first coordinate and a second coordinate. The polynomials herein may include, but are not limited to, polynomial functions, trigonometric functions, and the like.

In an exemplary implementation, determining a coordinate transformation relationship between a pixel coordinate system and a world coordinate system according to the first coordinate and the second coordinate may include:

dividing the first coordinate and the second coordinate into a plurality of coordinate pairs, wherein each coordinate pair comprises a first coordinate and a second coordinate, and the first coordinate and the second coordinate in each coordinate pair belong to the same first datum point;

Substituting the first coordinate and the second coordinate of each coordinate pair into a preset objective function, wherein the objective function is a multi-element equation set with unknown parameters, and a plurality of equations corresponding to the coordinate pairs are obtained;

Determining parameter values of the system of polynary equations from the plurality of equations;

substituting the parameter value into the multi-element equation set to obtain an objective function;

the objective function is determined as a coordinate conversion relationship between a pixel coordinate system and a world coordinate system.

In the present embodiment, the parameter of the multivariate function relationship is taken as an unknown number, and the value of the unknown number (parameter of the polynomial function) is obtained by solving the equation set composed of a plurality of equations.

In an exemplary implementation, before determining the objective function as the coordinate conversion relationship between the pixel coordinate system and the world coordinate system, the method may further include:

Acquiring first coordinates of a plurality of second reference points in a pixel coordinate system from the at least one target image frame;

Acquiring second coordinates of the plurality of second reference points in a world coordinate system;

substituting the first coordinates of the plurality of second datum points into the objective function respectively to obtain a plurality of estimated function values, wherein each estimated function value corresponds to one second datum point;

For each estimated function value, acquiring an absolute value of a difference value between the estimated function value and a second coordinate of a corresponding second reference point, and taking the absolute value as an error value corresponding to the function value;

and determining that the maximum value of the error values corresponding to the estimated function values is smaller than or equal to a preset error threshold value.

In this embodiment, the coordinate pair of the second reference point with known pixel coordinates and spatial coordinates is used to verify the objective function, so that the obtained coordinate conversion relationship between the pixel coordinate system and the world coordinate system (i.e. the coordinate calibration result between the natural image and the medical imaging device) meets the preset precision requirement.

If error values larger than a preset error threshold exist in the error values corresponding to the plurality of estimated function values, the current objective function is not up to a preset precision requirement, more first datum points can be taken at the moment, or the expression form of the objective function can be predicted and replaced according to the first coordinates and the second coordinates of the first datum points, and the calibration method of the embodiment of the invention is adopted for carrying out the calibration again.

The embodiment of the invention can ensure that the calibration result reaches the preset precision requirement.

In an exemplary implementation process, after step S404, the method may further include:

and performing coordinate conversion based on the coordinate conversion relation between the pixel coordinate system and the world coordinate system.

In this embodiment, the coordinate conversion may be to convert the coordinates of the pixel coordinate system into the coordinates of the world coordinate system, or may be to convert the coordinates of the world coordinate system into the coordinates of the pixel coordinate system.

In an exemplary implementation, performing coordinate transformation based on the coordinate transformation relationship between the pixel coordinate system and the world coordinate system may include:

acquiring second video data of a subject on a scanning bed in a target space range acquired by an image acquisition device and distance information between the image acquisition device and the subject;

Determining a natural image frame from the second video data;

receiving first operation information of a first target coordinate in the natural image frame;

and converting the first target coordinate into a second target coordinate in the world coordinate system according to the coordinate conversion relation between the pixel coordinate system and the world coordinate system, the pixel coordinate system coordinate corresponding to the first target coordinate and the distance information.

On this basis, in an exemplary implementation, after converting the first target coordinate into the second target coordinate in the world coordinate system, the method may further include:

Generating second operation information aiming at the second target coordinates according to the first operation information;

and transmitting the second operation information to the medical imaging device.

The second operation information is a control object for instructing the medical imaging apparatus to perform the corresponding operation, the medical imaging apparatus being the second operation information.

In one embodiment, the calibration device may be a console device.

In another embodiment, the calibration device may also be a device connected to the console device. The calibration device being connected to the console device means that the calibration device is communicatively connected to the console device. In this case, the calibration device may be a stand-alone device connected to the console device, or may be a cloud service device capable of communicating with the console device via a network.

Such as a stand-alone device connected to the console device or a remote cloud service device connected to the console device.

Acquiring second video data of a subject on a scanning bed in a target space range acquired by an image acquisition device and depth information between the image acquisition device and the subject;

Determining a natural image frame from the second video data;

And converting the first target coordinate into a second target coordinate in the world coordinate system according to the locally stored coordinate conversion relation between the pixel coordinate system and the world coordinate system, the pixel coordinate system coordinate corresponding to the first target coordinate and the depth information.

With the present embodiment, coordinates in the world coordinate system corresponding to coordinates in the pixel coordinate system can be determined, thereby providing a basis for operating an object in physical space (e.g., a key on a medical imaging device) based on a natural image.

In an exemplary implementation, after converting the first target coordinate to the second target coordinate in the world coordinate system, the method may further include:

Generating second operation information aiming at the second target coordinates according to the first operation information, and sending the second operation information to medical imaging equipment.

According to the embodiment, the operation on the natural image can be converted into the control operation on the appointed operation mechanism (such as a key) of the medical imaging device by using the calibration result (namely, the coordinate conversion relation between the pixel coordinate system and the world coordinate system), so that an operator responsible for medical image inspection can operate the medical imaging device without entering a scanning room, the operation is convenient, quick and time-consuming, the image inspection efficiency is improved, the compartment operation is realized, the direct contact between the operator and a subject is avoided, and the safety is improved.

In an exemplary implementation, when the calibration device is a device connected to the console device, performing coordinate transformation based on the coordinate transformation relationship between the pixel coordinate system and the world coordinate system may include:

Receiving first operation information and depth information between the image collector and the subject, which are sent by a console device, wherein the first operation information is operation information of the console device for receiving first target coordinates in a natural image frame after the second video data are determined from the second video data, wherein the second video data and the depth information of the subject on a scanning bed are acquired within a target space range acquired by the image collector;

according to the locally stored coordinate conversion relation, the pixel coordinate system coordinate corresponding to the first target coordinate and the depth information, converting the first target coordinate into a second target coordinate in a world coordinate system;

and transmitting the second operation information to the console device so that the console device transmits the second operation information to the medical imaging device.

The present embodiment is another way of implementing the operation of the compartments, in which the conversion of the operation information is implemented by the calibration device, reducing the burden on the console device.

Receiving first target coordinates and distance information between the image collector and the subject, which are sent by a console device, wherein the first target coordinates are coordinates in first operation information of the received natural image frames after the console device scans second video data of the subject on a bed in a target space range acquired by the image collector and the distance information, and the natural image frames are determined from the second video data;

And sending the second target coordinates to the console device, so that the console device generates second operation information aiming at the second target coordinates according to the first operation information, and sends the second operation information to the medical imaging device.

The present embodiment is another way of implementing the compartment operation, in which the conversion of the position information is implemented by the calibration device, reducing the burden on the console device.

determining a natural image frame from the second video data and determining a third target coordinate from the natural image frame;

Converting the third target coordinate into a fourth target coordinate in the world coordinate system according to the coordinate conversion relation between the pixel coordinate system and the world coordinate system, the pixel coordinate system coordinate corresponding to the third target coordinate and the distance information;

Receiving displacement information aiming at the fourth target coordinate, and determining a fifth target coordinate in a world coordinate system obtained after the fourth target coordinate moves according to the displacement information;

and converting the fifth target coordinate into a sixth target coordinate in the pixel coordinate system according to the coordinate conversion relation between the pixel coordinate system and the world coordinate system, and displaying the position corresponding to the sixth target coordinate in the natural image frame.

By the embodiment, the coordinates of the pixel coordinate system corresponding to the position after the physical position of the world coordinate system is shifted can be displayed in the natural image. For example, the operator identifies a location M0 (which may be a set of one or more coordinates in the natural image) on the natural image of the heart, where the location M0 corresponds to an actual physical location N0, and in use, it is necessary to determine a location N1 where the location N0 has moved down by 2 cm. With the present embodiment, the position M1 on the natural image corresponding to the physical position N1 can be displayed on the natural image based on the position M0 and the displacement information shifted down by 2 cm.

In an exemplary implementation, when the calibration device is a device connected to a console device, the method may further include:

and sending the coordinate conversion relation between the pixel coordinate system and the world coordinate system to the console device.

In this embodiment, when the calibration device and the console device are not the same device, the calibration result (the coordinate conversion relationship between the pixel coordinate system and the world coordinate system) can be sent to the console device, so that the console device can implement the compartment operation of the medical imaging device according to the locally stored coordinate conversion relationship.

In an embodiment of the present invention, the medical imaging device may be a CT (Computed Tomography, electronic computer tomography) device, an MRI (Magnetic Resonance Imaging ) device, or the like.

The calibration method provided by the embodiment of the invention is an automatic calibration flow, does not need personnel with professional calibration experience to calibrate, and reduces the professional technical requirements on the calibration personnel. Compared with manual calibration, the calibration method provided by the embodiment of the invention has the advantages of short time consumption and high efficiency in the use scene of the medical imaging equipment based on remote image operation. Furthermore, the calibration method provided by the embodiment of the invention is a commonly applicable standardized calibration flow, different calibration processes can achieve the same calibration precision, and the result consistency is good.

According to the calibration method provided by the embodiment of the invention, the first video data of the calibration plate on the movable scanning bed of the medical imaging equipment in the target space range acquired by the image acquisition device is acquired, the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed, at least one target image frame is extracted from the first video data, the first coordinates of a plurality of first reference points in a pixel coordinate system are acquired from the at least one target image frame, the second coordinates of the plurality of first reference points in a world coordinate system are acquired, the coordinate conversion relation between the pixel coordinate system and the world coordinate system is determined according to the first coordinates and the second coordinates, so that the universal standardized and automatic calibration is realized, and the calibration efficiency is improved.

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

FIG. 6 is a functional block diagram of a calibration apparatus according to an embodiment of the present invention. As shown in fig. 6, in the present embodiment, the calibration device is applied to the calibration apparatus, and the calibration device may include:

A video data acquisition module 610, configured to acquire first video data of a movable on-couch calibration plate of a medical imaging apparatus within a target spatial range acquired by an image acquisition unit, where the target spatial range includes a plurality of horizontal positions and a plurality of vertical positions of the couch;

A first coordinate acquiring module 620, configured to extract at least one target image frame from the first video data, and acquire first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame;

A second coordinate acquiring module 630, configured to acquire second coordinates of the plurality of first reference points in a world coordinate system;

The conversion relation determining module 640 is configured to determine a coordinate conversion relation between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate.

In one exemplary implementation, the conversion relationship determination module 640 may be specifically configured to:

In an exemplary implementation, the method further includes:

A third coordinate obtaining module, configured to obtain first coordinates of a plurality of second reference points in a pixel coordinate system from the at least one target image frame;

a fourth coordinate obtaining module, configured to obtain second coordinates of the plurality of second reference points in a world coordinate system;

The substituting module is used for substituting the first coordinates of the plurality of second datum points into the objective function respectively to obtain a plurality of estimated function values, and each estimated function value corresponds to one second datum point;

The error value acquisition module is used for acquiring the absolute value of the difference value between the estimated function value and the second coordinate of the corresponding second reference point as an error value corresponding to the estimated function value for each estimated function value;

and the determining module is used for determining that the maximum value of the error values corresponding to the estimated function values is smaller than or equal to a preset error threshold value.

In an exemplary implementation, the apparatus may further include:

and the calibration module is used for carrying out coordinate conversion based on the coordinate conversion relation between the pixel coordinate system and the world coordinate system.

In one exemplary implementation, the calibration module may be specifically configured to:

Determining a natural image frame from the second video data;

In an exemplary implementation, the calibration module may be further specifically configured to:

Coordinate conversion relation between pixel coordinate system and world coordinate system

In an exemplary implementation, when the calibration device is a device connected to a console device, the apparatus may further include:

And the sending module is used for sending the coordinate conversion relation between the pixel coordinate system and the world coordinate system to the console equipment.

The embodiment of the invention also provides calibration equipment. Fig. 7 is a hardware configuration diagram of a calibration device according to an embodiment of the present invention. As shown in fig. 7, the calibration apparatus includes: an internal bus 701, and a memory 702, a processor 703 and an external interface 704 connected by the internal bus, wherein,

The memory 702 is configured to store machine-readable instructions corresponding to the calibration logic;

The processor 703 is configured to read the machine readable instructions on the memory 702 and execute the instructions to implement the following operations:

The calibration device of the embodiment of the present invention can execute any one of the calibration methods of the foregoing embodiments, and will not be described herein.

The embodiment of the invention also provides a calibration system, which comprises:

The image acquisition device is used for acquiring first video data of a calibration plate on a scanning bed of the medical imaging device in a target space range and transmitting the first video data to the calibration device, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed;

Wherein, the calibration plate is movable and lockable in a fixed position of the scanning bed.

In one exemplary implementation, the calibration device is a console device.

In an exemplary implementation, the calibration device is a device coupled to a console device, and the system further includes the console device.

The embodiment of the invention also provides a calibration method which is applied to a calibration system comprising an image collector, medical imaging equipment and calibration equipment, and comprises the following steps:

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:

In an exemplary implementation, determining a coordinate transformation relationship between a pixel coordinate system and a world coordinate system according to the first coordinate and the second coordinate includes:

In an exemplary implementation, before determining the objective function as a coordinate transformation relationship between the pixel coordinate system and the world coordinate system, the method further includes:

For each estimated function value, acquiring an absolute value of a difference value between the estimated function value and a second coordinate of a corresponding second reference point, and taking the absolute value as an error value corresponding to the estimated function value;

In an exemplary implementation, after determining the coordinate conversion relationship between the pixel coordinate system and the world coordinate system according to the first coordinate and the second coordinate, the method may further include:

In an exemplary implementation, performing coordinate transformation based on a coordinate transformation relationship between the pixel coordinate system and the world coordinate system includes:

Determining a natural image frame from the second video data;

In an exemplary implementation, after converting the first target coordinate to a second target coordinate in the world coordinate system, the method further includes:

In an exemplary implementation, when the calibration device is a device connected to a console device, the method further comprises:

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 calibration method, applied to a calibration device, comprising:

acquiring first video data of a calibration plate on a movable scanning bed of medical imaging equipment in a target space range acquired by an image acquisition device, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed, and the calibration plate has standard thickness and at least one mark line;

Extracting at least one target image frame from the first video data, and acquiring first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame, wherein the at least one target image frame comprises target image frames corresponding to the plurality of horizontal positions and target image frames corresponding to the plurality of vertical positions;

determining a coordinate conversion relation between a pixel coordinate system and a world coordinate system according to the first coordinate and the second coordinate;

Wherein the first video data is acquired based on the following process:

under the condition that the calibration plate is aligned to the datum point position of the scanning bed, and the bed height and the bed depth of the scanning bed reach the preset initial bed height and the initial bed depth, shooting the calibration plate on the scanning bed based on an image collector with an image acquisition function and a depth information acquisition function;

The bed height of the scanning bed is kept unchanged, the bed depth of the scanning bed is circularly changed by a first step length, so that the calibration plate moves along with the scanning bed in the horizontal depth direction by the first step length until the image data of each position of the calibration plate meeting the inspection requirement in the parallel direction of the horizontal plane where the scanning bed is positioned is acquired;

The depth of the bed of the scanning bed is kept unchanged, the bed height of the scanning bed is circularly changed by a second step length, so that the calibration plate moves along with the scanning bed along the direction of the horizontal plane where the scanning bed is located by the second step length until the image data of all positions of the calibration plate meeting the inspection requirement in the vertical direction of the horizontal plane where the scanning bed is located are acquired.

2. The method of claim 1, wherein determining a coordinate conversion relationship between a pixel coordinate system and a world coordinate system from the first coordinate and the second coordinate comprises:

3. The method of claim 2, wherein prior to determining the objective function as a coordinate transformation relationship between a pixel coordinate system and a world coordinate system, further comprising:

4. The method of claim 1, further comprising, after determining a coordinate conversion relationship between a pixel coordinate system and a world coordinate system based on the first coordinate and the second coordinate:

5. The method of claim 4, wherein performing coordinate conversion based on a coordinate conversion relationship between the pixel coordinate system and a world coordinate system comprises:

Determining a natural image frame from the second video data;

6. The method of claim 5, further comprising, after converting the first target coordinate to a second target coordinate in a world coordinate system:

7. The method of claim 4, wherein performing coordinate conversion based on a coordinate conversion relationship between the pixel coordinate system and a world coordinate system comprises:

8. A calibration device, characterized by being applied to a calibration apparatus, comprising:

The system comprises a video data acquisition module, a video data acquisition module and a display module, wherein the video data acquisition module is used for acquiring first video data of a calibration plate on a movable scanning bed of medical imaging equipment in a target space range acquired by an image acquisition device, the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed, and the calibration plate has standard thickness and at least one mark line;

A first coordinate acquisition module, configured to extract at least one target image frame from the first video data, and acquire first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame, where the at least one target image frame includes target image frames corresponding to the plurality of horizontal positions and target image frames corresponding to the plurality of vertical positions;

The conversion relation determining module is used for determining a coordinate conversion relation between a pixel coordinate system and a world coordinate system according to the first coordinate and the second coordinate;

Wherein the first video data is acquired based on the following process:

9. A calibration method for use in a calibration system comprising an image acquisition device, a medical imaging device and a calibration device, comprising:

the method comprises the steps that an image collector collects first video data of a calibration plate on a movable scanning bed of medical imaging equipment in a target space range, the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed, and the calibration plate has standard thickness and at least one mark line;

The calibration equipment extracts at least one target image frame from the first video data, and acquires first coordinates of a plurality of first datum points in a pixel coordinate system from the at least one target image frame, wherein the at least one target image frame comprises target image frames corresponding to the plurality of horizontal positions and target image frames corresponding to the plurality of vertical positions;

the calibration equipment determines a coordinate conversion relation between a pixel coordinate system and a world coordinate system according to the first coordinate and the second coordinate;

Wherein the first video data is acquired based on the following process:

10. The method of claim 9, wherein the calibration device is a console device;

the method further comprises the steps of:

11. The method of claim 9, wherein the calibration device is a device connected to a console device;

Transmitting the first video data to a calibration device, comprising:

The image collector transmits the first video data to the console device so that the console device forwards the first video data to the calibration device.

12. A calibration system, comprising:

the medical imaging device comprises a scanning bed, wherein a calibration plate is installed on the scanning bed, and the calibration plate has standard thickness and at least one mark line;

The image acquisition device is used for acquiring first video data of a movable scanning bed on-board calibration plate of the medical imaging device in a target space range, and sending the first video data to the calibration device, wherein the target space range comprises a plurality of horizontal positions and a plurality of vertical positions of the scanning bed;

A calibration device, configured to extract at least one target image frame from the first video data, and acquire first coordinates of a plurality of first reference points in a pixel coordinate system from the at least one target image frame, where the at least one target image frame includes target image frames corresponding to the plurality of horizontal positions and target image frames corresponding to the plurality of vertical positions; acquiring second coordinates of the plurality of first reference points in a world coordinate system; determining a coordinate conversion relation between a pixel coordinate system and a world coordinate system according to the first coordinate and the second coordinate;

Wherein the first video data is acquired based on the following process: