Camera adjustment method and device in optical positioning site and storage medium

Abstract

The present disclosure relates to a camera adjustment method and device in an optical positioning site and a storage medium. The method comprises: acquiring at least one frame of picture collected by at least one camera for a reference object, the position of the reference object in a world coordinate system being fixed, the at least one camera comprising a target camera, and the at least one frame of picture comprising a first picture collected by the target camera after pose adjustment; and determining camera extrinsics of the target camera when the first picture is collected based on the at least one frame of picture, the camera extrinsics comprising the position and / or pose of the camera. According to the embodiments of the present disclosure, the adjustment time can be greatly saved, and the rework caused by deviation in the adjustment process and the poor optical positioning effect can be avoided. Meanwhile, the camera extrinsics can be determined in real time after the camera adjustment according to the scheme of the embodiments of the present disclosure, and the target camera does not need to keep the pose unchanged in this process, thereby meeting the real-time and efficiency requirements of the optical positioning site.

Description

Technical Field

[0001] This disclosure relates to the field of computer vision technology, and in particular to a camera adjustment method, apparatus and storage medium in an optical positioning field. Background Technology

[0002] In optical positioning environments, several cameras are typically needed to photograph the object to be located within the area. Therefore, the placement and orientation of the cameras are particularly important. The position and orientation of the cameras are generally referred to as camera extrinsic parameters. When the size of the area or the positioning requirements change, it is often necessary to adjust the orientation and position of the cameras accordingly.

[0003] When adjusting a camera in an optical positioning field, the typical approach involves a "field sweep" procedure. Specifically, the camera must maintain its pose after adjustment until its extrinsic parameters are recalibrated to restore normal field positioning functionality. If the camera moves unexpectedly during adjustment, it will cause extrinsic parameter calibration deviations, potentially requiring rework. Furthermore, errors caused by insufficient adjustment precision will also degrade optical positioning performance. This approach cannot meet the real-time requirements of camera adjustment in optical positioning fields, resulting in limitations in efficiency and accuracy. Summary of the Invention

[0004] In view of this, the present disclosure proposes a camera adjustment method, apparatus and storage medium in an optical positioning field.

[0005] According to one aspect of this disclosure, a method for adjusting a camera in an optical positioning field is provided. The method includes:

[0006] Acquire at least one frame of image captured by at least one camera in relation to a reference object, wherein the position of the reference object is fixed in the world coordinate system, the at least one camera includes a target camera, and the at least one frame of image includes the first image captured by the target camera after pose adjustment.

[0007] Based on at least one frame, determine the camera extrinsic parameters of the target camera when capturing the first frame. The camera extrinsic parameters include the camera's position and / or attitude.

[0008] In one possible implementation, based on at least one frame, the camera extrinsic parameters of the target camera are determined when the first frame is captured, including:

[0009] Feature point detection is performed on at least one frame captured by each camera to obtain multiple feature points included in each frame, and the feature points are associated with reference objects.

[0010] Based on the multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined.

[0011] In one possible implementation, based on multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined, including:

[0012] Matching is performed between multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, as well as the position of the target feature points in the world coordinate system;

[0013] Based on the position of the target feature point in the image coordinate system corresponding to the first frame, the position of the target feature point in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame are calculated.

[0014] In one possible implementation, at least one frame also includes images captured by at least two other cameras besides the target camera.

[0015] Matching is performed among multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, and the position of the target feature points in the world coordinate system, including:

[0016] Using binocular stereo vision technology, feature points included in the images captured by at least two other cameras besides the target camera are matched to obtain the target feature points;

[0017] Based on the target feature points, the position of the target feature points in the world coordinate system is obtained.

[0018] In one possible implementation, the preset number is no less than three, and the preset number of target feature points includes no less than three feature points that are asymmetrically distributed; the method further includes:

[0019] If the number of target feature points is less than a preset number, a prompt message will be displayed, indicating that feature point detection should be performed again.

[0020] In one possible implementation, at least one frame also includes a second frame captured by the target camera before pose adjustment. Based on the at least one frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined, including:

[0021] Feature point detection is performed in the first and second frames respectively to obtain the feature points corresponding to the reference objects at the same world coordinate system position;

[0022] Based on the offset of the feature points corresponding to the reference object from the second frame to the first frame, and the camera intrinsic parameters of the target camera, the pose of the target camera when capturing the first frame is calculated.

[0023] In one possible implementation, the reference object includes a preset area in the optical positioning field and / or a rigid body of any fixed size in the optical positioning field;

[0024] In response to the reference object being a predetermined area in the optical positioning field, at least one frame includes an image of the optical positioning field with texture features.

[0025] Since the camera is an infrared camera and the optical positioning site is an outdoor site, the rigid body does not include the rigid body used to emit infrared light.

[0026] In one possible implementation, the target camera is mounted on a stepper motor, and the attitude of the target camera is determined by the control parameters of the stepper motor; or, the target camera is equipped with an attitude positioning module, and the attitude of the target camera is determined based on the measurement parameters of the attitude positioning module.

[0027] In one possible implementation, the method further includes:

[0028] Visualize the camera extrinsic parameters of the target camera when capturing the first frame.

[0029] According to another aspect of this disclosure, a camera adjustment device for optical positioning is provided. The device includes:

[0030] The acquisition module is used to acquire at least one frame of an image captured by at least one camera in relation to a reference object. The reference object is fixed in the world coordinate system. The at least one camera includes a target camera. The at least one frame of an image includes the first image captured by the target camera after pose adjustment.

[0031] The determination module is used to determine the camera extrinsic parameters of the target camera when the first frame is captured, based on at least one frame. The camera extrinsic parameters include the position and / or attitude of the camera.

[0032] In one possible implementation, a module is defined for:

[0033] Feature point detection is performed on at least one frame captured by each camera to obtain multiple feature points included in each frame, and the feature points are associated with reference objects.

[0034] Based on the multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined.

[0035] In one possible implementation, based on multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined, including:

[0036] Matching is performed between multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, as well as the position of the target feature points in the world coordinate system;

[0037] Based on the position of the target feature point in the image coordinate system corresponding to the first frame, the position of the target feature point in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame are calculated.

[0038] In one possible implementation, at least one frame also includes images captured by at least two other cameras besides the target camera.

[0039] Matching is performed among multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, and the position of the target feature points in the world coordinate system, including:

[0040] Using binocular stereo vision technology, feature points included in the images captured by at least two other cameras besides the target camera are matched to obtain the target feature points;

[0041] Based on the target feature points, the position of the target feature points in the world coordinate system is obtained.

[0042] In one possible implementation, the preset number is not less than three, and the preset number of target feature points includes not less than three feature points that are asymmetrically distributed; the device further includes:

[0043] The first display module is used to display a prompt message in response to the number of target feature points being less than a preset number. The prompt message is used to instruct the feature point detection to be performed again.

[0044] In one possible implementation, at least one frame also includes a second frame captured by the target camera before pose adjustment. The determination module is used for:

[0045] Feature point detection is performed in the first and second frames respectively to obtain the feature points corresponding to the reference objects at the same world coordinate system position;

[0046] Based on the offset of the feature points corresponding to the reference object from the second frame to the first frame, and the camera intrinsic parameters of the target camera, the pose of the target camera when capturing the first frame is calculated.

[0047] In one possible implementation, the reference object includes a preset area in the optical positioning field and / or a rigid body of any fixed size in the optical positioning field;

[0048] In response to the reference object being a predetermined area in the optical positioning field, at least one frame includes an image of the optical positioning field with texture features.

[0049] Since the camera is an infrared camera and the optical positioning site is an outdoor site, the rigid body does not include the rigid body used to emit infrared light.

[0050] In one possible implementation, the target camera is mounted on a stepper motor, and the attitude of the target camera is determined by the control parameters of the stepper motor; or, the target camera is equipped with an attitude positioning module, and the attitude of the target camera is determined based on the measurement parameters of the attitude positioning module.

[0051] In one possible implementation, the device further includes:

[0052] The second display module is used to visualize the camera extrinsic parameters of the target camera when capturing the first frame.

[0053] According to another aspect of this disclosure, a camera adjustment device for optical positioning is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to implement the above method when executing the instructions stored in the memory.

[0054] According to another aspect of this disclosure, a non-volatile computer-readable storage medium is provided that stores computer program instructions thereon, wherein the computer program instructions, when executed by a processor, implement the above-described method.

[0055] According to another aspect of this disclosure, a computer program product is provided, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code, wherein when the computer-readable code is run in a processor of an electronic device, the processor in the electronic device performs the above-described method.

[0056] According to embodiments of this disclosure, by acquiring at least one frame of an image captured by at least one camera, including a target camera, of a reference object, wherein the position of the reference object in the world coordinate system is fixed, and the at least one frame of an image includes a first image captured by the target camera after pose adjustment, the camera extrinsic parameters of the target camera at the time of capturing the first image are determined based on the at least one frame of an image. The camera extrinsic parameters include the position and / or attitude of the camera. This allows for accurate determination of camera extrinsic parameters after the camera pose is adjusted, which can greatly save adjustment time and avoid rework and deterioration of optical positioning effect caused by deviations during the adjustment process. At the same time, the solution according to embodiments of this disclosure can realize real-time determination of camera extrinsic parameters after camera adjustment. During this process, the target camera does not need to maintain a constant pose, thereby meeting the requirements of optical positioning sites for real-time performance and efficiency.

[0057] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0058] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this disclosure together with the specification and serve to explain the principles of this disclosure.

[0059] Figure 1 A schematic diagram illustrating an application scenario according to an embodiment of this disclosure is shown.

[0060] Figure 2 A flowchart illustrating a camera adjustment method in an optical positioning field according to an embodiment of the present disclosure is shown.

[0061] Figure 3 A structural diagram of a camera adjustment device in an optical positioning field according to an embodiment of the present disclosure is shown.

[0062] Figure 4 This is a block diagram illustrating a camera adjustment device 1900 for optical positioning in an exemplary embodiment. Detailed Implementation

[0063] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0064] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0065] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0066] In optical positioning environments, several cameras are typically needed to photograph the object to be located within the area. Therefore, the placement and orientation of the cameras are particularly important. The position and orientation of the cameras are generally referred to as camera extrinsic parameters. When the size of the area or the positioning requirements change, it is often necessary to adjust the orientation and position of the cameras accordingly.

[0067] When adjusting a camera in an optical positioning field, the typical approach involves a "field sweep" procedure. Specifically, the camera must maintain its pose after adjustment until its extrinsic parameters are recalibrated to restore normal field positioning functionality. If the camera moves unexpectedly during adjustment, it will cause extrinsic parameter calibration deviations, potentially requiring rework. Furthermore, errors caused by insufficient adjustment precision will also degrade optical positioning performance. This approach cannot meet the real-time requirements of camera adjustment in optical positioning fields, resulting in limitations in efficiency and accuracy.

[0068] In view of this, this disclosure provides a camera adjustment method, apparatus, and storage medium for optical positioning. The method of this disclosure acquires at least one frame of an image captured by at least one camera, including a target camera, targeting a reference object. The position of the reference object in the world coordinate system is fixed, and the at least one frame includes a first image captured by the target camera after pose adjustment. Based on the at least one frame, the camera extrinsic parameters of the target camera at the time of capturing the first image are determined. These extrinsic parameters include the camera's position and / or orientation. This allows for accurate determination of camera extrinsic parameters after camera pose adjustment, significantly saving adjustment time and avoiding rework and deterioration of optical positioning performance due to deviations during adjustment. Furthermore, the solution according to this disclosure allows for real-time determination of camera extrinsic parameters after camera adjustment, without requiring the target camera to maintain a fixed pose, thus meeting the real-time and efficiency requirements of optical positioning.

[0069] Figure 1 The diagram illustrates an application scenario according to an embodiment of the present disclosure. The camera adjustment method of this disclosure can be applied to scenarios involving the positioning of target objects in an optical positioning environment, such as... Figure 1 As shown, an optical positioning field is a physical environment or area where optical technology is used to accurately position an object within a specific space. Multiple cameras (such as cameras 1 to 4, distributed around the perimeter of the optical positioning field) can be arranged within the field to locate the target object. Reference objects can also be placed within the field. In one example, before locating the target object, the cameras must first be moved to a pose that meets the positioning requirements. The extrinsic parameters of cameras 1 to 4 are calibrated using the reference objects. After obtaining the extrinsic parameters of cameras 1 to 4, the optical positioning operation of the target object can be performed using cameras 1 to 4.

[0070] In another example, when the size of the optical positioning field changes or the positioning requirements change (e.g., the target object to be positioned changes or the positioning accuracy needs to be further improved), it is usually necessary to move the position and orientation of the cameras (any one or more of cameras 1 to 4) in the optical positioning field. After that, it is also necessary to use reference objects to recalibrate the camera extrinsic parameters of the moved cameras before the optical positioning function for the target object can continue to be realized.

[0071] In the above example, the position and orientation of the camera may change continuously. However, by using the method of this disclosure embodiment, the changes in camera orientation can be obtained in real time using a reference object, and the updated camera extrinsic parameters can be calculated quickly and accurately without restricting the movement of the camera.

[0072] In one possible implementation, the camera adjustment method of this disclosure embodiment can also be applied to a virtual shooting scene. For example, in a virtual shooting scene for video special effects production, the target object can be a model of a virtual character. In order to make the actor's movements and positions match the model of the virtual character when performing in the optical positioning field, multiple cameras (such as the above-mentioned camera 1 to camera 4) are needed to continuously perform optical positioning on the model of the virtual character during the shooting process.

[0073] Before optically positioning the virtual character model using cameras, the positions and orientations of each camera must first be adjusted to ensure accurate positioning of the virtual character model and reduce blind spots in the camera's field of view, thereby meeting the requirements of the virtual shooting scene. In this process, the method of this disclosure can be used to quickly and accurately determine the camera's extrinsic parameters while adjusting the positions and orientations of each camera in the virtual shooting environment, thus significantly improving adjustment efficiency.

[0074] It should be noted that in a virtual shooting scene, the target object can also be other objects to be located, such as a video recorder used for virtual shooting, and this disclosure does not limit this.

[0075] The camera adjustment method for optical positioning in this disclosure can be used in terminal devices or servers. Terminal devices can be any one or more of the following: mobile phones, foldable electronic devices, tablets, desktop computers, laptops, handheld computers, ultra-mobile personal computers (UMPCs), netbooks, cellular phones, and vehicle-mounted devices. This disclosure does not impose special limitations on the specific type of terminal device; it can have wired or wireless communication capabilities. Servers can be located locally or in the cloud, and can be physical devices or virtual devices, such as virtual machines or containers, with wireless communication capabilities. These wireless communication capabilities can be configured in the server's chip (system) or other components. Wireless communication capabilities can be implemented, for example, through 2G / 3G / 4G / 5G mobile communication technologies, as well as Wi-Fi, Bluetooth, frequency modulation (FM), data radio, satellite communication, etc. Wired connections can also be used for communication to enable interaction with other devices.

[0076] Figure 2 A flowchart illustrating a camera adjustment method in an optical positioning field according to an embodiment of the present disclosure is provided. This method can be used in the aforementioned terminal device or server, such as... Figure 2 As shown, the method may include:

[0077] Step S201: Acquire at least one frame of an image captured by at least one camera in relation to a reference object.

[0078] At least one camera can be a camera positioned in an optically positioned field (e.g., Figure 1 The system includes one or more cameras (cameras 1 to 4), wherein the at least one camera can be positioned at any location in the optical positioning area, as long as it can capture all or part of the image of the reference object. The at least one camera includes a target camera, which can be one or more of the cameras whose extrinsic parameters are to be calibrated. This disclosure does not limit the type of camera described above; it can be an infrared camera, a conventional camera, etc.

[0079] Since the camera adjustment method of this disclosure can be used to adjust the camera in the optical positioning field to a pose that meets the positioning requirements before positioning the target object, step S201 can usually be executed once every preset time interval (e.g., 1 second) within a certain period of time (e.g., 2 minutes or other duration) before fixing the camera pose, that is, to acquire at least one frame of image captured by at least one camera for the reference object and execute the subsequent steps to calibrate the camera extrinsic parameters of the target camera once every preset time interval.

[0080] In one possible implementation, the target camera can be controlled to capture an image every preset time interval (e.g., 1 second). When the image captured by the target camera changes compared to the previous image (e.g., the position of a reference object in the image changes), the pose of the target camera can be considered to have been updated, and step S201 and subsequent steps are executed to calibrate the camera extrinsic parameters of the target camera in real time.

[0081] The reference object can be an object used to calibrate camera extrinsic parameters in the embodiments of this disclosure. Compared to existing "field-scanning" methods for determining camera extrinsic parameters, the position of the reference object in the world coordinate system in the embodiments of this disclosure can be fixed rather than moving, thus eliminating the need for complex adjustments to the reference object's position and simplifying the process of determining camera extrinsic parameters. The reference object can include a preset area in the optical positioning field and / or a rigid body of any fixed size in the optical positioning field. The reference object in the embodiments of this disclosure can be selected as needed, wherein one or more reference objects can be set as needed to meet the requirements of different scenarios and improve adjustment performance and user experience.

[0082] The preset area in the optical positioning field can be set as needed and can be any size area within the optical positioning field. This embodiment does not impose any limitation on this, as long as the camera can obtain an image containing texture features when capturing the preset area. Responding to the reference object being the preset area in the optical positioning field, at least one frame includes an image of the optical positioning field with texture features. Texture features typically refer to unique patterns, shapes, color distributions, or other visual characteristics within the preset area serving as the reference object that can be used for subsequent feature point extraction and matching.

[0083] In optical positioning, any rigid body of a fixed size can also be called an anchor point. For example, it can be a sweeping rod, a marker, an ice hockey puck, etc. When the camera is an infrared camera, the rigid body can also be an object used to emit or reflect infrared light.

[0084] The aforementioned optical positioning site can be an indoor or outdoor site. An indoor site can represent a closed or semi-closed space with stable lighting conditions and less environmental interference, facilitating accurate detection of feature points and thus ensuring more accurate camera extrinsic parameters. An outdoor site can represent an open space with more complex lighting conditions and environmental factors (such as variations in natural light and weather effects). Since the camera is an infrared camera and the optical positioning site is outdoor, the rigid body may not include the rigid body used to emit infrared light. This avoids interference with the infrared signal under complex lighting conditions, which could affect the accuracy of subsequent camera extrinsic parameter calibration.

[0085] The at least one frame captured by the camera for the reference object may include all or part of the frames captured by multiple cameras for the reference object, including at least the first frame captured by the target camera after the pose adjustment.

[0086] The first frame can be one frame or multiple frames, which allows us to determine the camera extrinsic parameters of the target camera when capturing the first frame.

[0087] When the camera only includes the target camera, at least one frame may also include a second frame captured by the target camera before pose adjustment. This second frame may be one frame or multiple frames.

[0088] The camera may also include at least two other cameras positioned in the optical positioning field besides the target camera. At least one frame captured by the camera for the reference object may also include frames captured by at least two other cameras for the reference object, wherein each camera may capture one or more frames, and the camera extrinsic parameters of the other cameras when capturing the frames may be known.

[0089] by Figure 1 For example, if camera 1 is the target camera, in one example, at least one frame captured by the camera for the reference object may include one or more second frames captured by camera 1 for the reference object before pose adjustment, and one or more first frames captured by camera 1 for the reference object after pose adjustment. Thus, the pose of camera 1 when capturing the first frame can be determined subsequently. In another example, at least one frame captured by the camera for the reference object may include one or more first frames captured by camera 1 for the reference object after pose adjustment, and one or more frames captured by any at least two of cameras 2 to 4 for the reference object. Thus, the position and pose of camera 1 when capturing the first frame can be determined subsequently.

[0090] Step S202: Based on at least one frame, determine the camera extrinsic parameters of the target camera when capturing the first frame.

[0091] According to embodiments of this disclosure, by acquiring at least one frame of an image captured by at least one camera, including a target camera, of a reference object, wherein the position of the reference object in the world coordinate system is fixed, and the at least one frame of an image includes a first image captured by the target camera after pose adjustment, the camera extrinsic parameters of the target camera at the time of capturing the first image are determined based on the at least one frame of an image. The camera extrinsic parameters include the position and / or attitude of the camera. This allows for accurate determination of camera extrinsic parameters after the camera pose is adjusted, which can greatly save adjustment time and avoid rework and deterioration of optical positioning effect caused by deviations during the adjustment process. At the same time, the solution according to embodiments of this disclosure can realize real-time determination of camera extrinsic parameters after camera adjustment. During this process, the target camera does not need to maintain a constant pose, thereby meeting the requirements of optical positioning sites for real-time performance and efficiency.

[0092] Camera extrinsic parameters can be used to convert between the world coordinate system and the camera coordinate system. The camera coordinate system can be a three-dimensional coordinate system with the camera's optical center (i.e., the geometric center of the camera lens) as its origin, where the camera's optical axis is the Z-axis, the X-axis is the horizontal axis, and the Y-axis is the vertical axis. The world coordinate system is the coordinate system in real three-dimensional space.

[0093] Camera extrinsic parameters can include the camera's position and / or orientation. The camera's position can be the three-dimensional coordinate position of the camera's optical center in the world coordinate system, which can be represented by a translation vector; the camera's orientation can represent the rotation of the camera coordinate system relative to the world coordinate system, which can be represented by a rotation matrix. By determining the translation vector and rotation matrix, the mapping relationship between the camera coordinate system and the world coordinate system can be described.

[0094] The solution of this disclosure can be used to determine the position and orientation of the target camera when capturing the first image, or to determine only either the position or the orientation.

[0095] In one possible implementation, the camera may include a target camera and at least two other cameras arranged in the optical positioning area besides the target camera. At least one frame captured by the camera for the reference object may include the aforementioned first frame and frames captured by the other at least two cameras for the reference object, thereby enabling real-time calibration of the target camera's attitude using multiple cameras in the optical positioning area. In step S202, the following can be done:

[0096] Feature point detection is performed on at least one frame captured by each camera to obtain multiple feature points included in each frame; based on the multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined.

[0097] By using images captured by multiple cameras to detect feature points for calibrating the target camera's extrinsic parameters, the calibration process can be made faster and more accurate.

[0098] At least one frame may also include images captured by at least two other cameras besides the target camera. These at least two other cameras may be cameras other than the target camera positioned in the optical positioning area.

[0099] The method for feature point detection in each frame can be implemented based on existing technologies, and this disclosure does not impose any limitations on it. The feature points can be associated with a reference object. For example, when the reference object is an anchor point, the detected feature points in the frame can be points corresponding to a certain position on the anchor point, or points corresponding to infrared light emitted or reflected by the anchor point. When the reference object is a preset area in the optical positioning field, the feature points can be points within the preset area associated with a certain texture feature, such as points corresponding to edges, high gradient transformations, or other areas within the preset area. This facilitates subsequent feature point matching and other operations, improving calibration accuracy. The detected feature points can also include points unrelated to the reference object.

[0100] In determining the camera extrinsic parameters of the target camera when capturing the first frame, based on multiple feature points included in each frame, the following can be done:

[0101] Matching is performed between multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, as well as the position of the target feature points in the world coordinate system; based on the position of the target feature points in the image coordinate system corresponding to the first frame, the position of the target feature points in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame are calculated.

[0102] In the process of matching multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, it is possible to: use binocular stereo vision technology to match feature points included in the frames captured by at least two other cameras besides the target camera to obtain target feature points; and based on the target feature points, obtain the position of the target feature points in the world coordinate system.

[0103] Therefore, it is possible to use other cameras in the optical positioning field to assist in the calibration of the target camera's extrinsic parameters, making the calibration results of the target camera's extrinsic parameters more accurate and meeting the needs of optical positioning scenarios.

[0104] This method utilizes at least two frames captured from at least two different cameras. Based on binocular stereo vision technology, feature points in the frames are matched to determine target feature points. Target feature points in different frames corresponding to the same world coordinate system position can be referred to as corresponding points. This disclosure does not limit the implementation method of binocular stereo vision technology; any binocular stereo vision method (such as using a sliding window) can be used. In obtaining the position of the target feature points in the world coordinate system, existing triangulation principles or other methods can be used. This disclosure does not limit this method. In this disclosure, to ensure the calibration accuracy of camera extrinsic parameters, a minimum number of target feature points can be preset as needed, i.e., a preset number. The preset number can be no less than three. The resulting preset number of target feature points includes no less than three asymmetrically distributed feature points, allowing for further determination of the camera extrinsic parameters when capturing the first frame. To improve the accuracy of subsequent determination of camera extrinsic parameters, a higher preset number can be set.

[0105] In one possible implementation, the method may further include:

[0106] If the number of target feature points is less than the preset number, a prompt message will be displayed.

[0107] The system can display prompts in any visual form on the user interface. For example, the user interface can display an image captured by a camera targeting a reference object, and the prompt can be displayed on that image using controls such as a prompt box. The prompt indicates that the number of identified target feature points is insufficient, and can be used to instruct the user to re-detect feature points. Alternatively, based on the prompt, other cameras can be controlled to re-capture images of the reference object to re-detect feature points. This ensures the accuracy of the extrinsic parameters of the subsequently determined target cameras.

[0108] In the process of calculating the extrinsic parameters of the target camera when capturing the first frame, based on the position of the target feature points in the image coordinate system corresponding to the first frame, the position of the target feature points in the world coordinate system, and the camera intrinsic parameters of the target camera, the shape formed by connecting multiple target feature points can be matched with feature points in the first frame. For example, this shape can be combined with feature points in the first frame to obtain a combination of several feature points. The shape obtained by connecting the feature points in the combination of several feature points is compared with the shape formed by connecting multiple target feature points to determine the feature points corresponding to the same or similar shapes in the combination of several feature points as the matched feature points. Through this matching process, the corresponding feature points of multiple target feature points in the first frame are determined, thereby obtaining the positions of these target feature points in the image coordinate system corresponding to the first frame.

[0109] The image coordinate system of the first frame can be represented as a two-dimensional coordinate system in the image captured by the target camera, with any vertex of the image (usually the top left corner) as the origin and directions parallel to the edges of the image as coordinate axes. Based on the position of the target feature points in the image coordinate system corresponding to the first frame, the position of the target feature points in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame can be calculated using related techniques such as the PnP (Perspective-n-Point) algorithm.

[0110] The intrinsic parameters of the target camera can be parameters representing the camera's internal properties, including focal length, principal point (optical center) coordinates, distortion coefficients, etc., and can be predetermined. These intrinsic parameters can be used to perform mutual transformations between the target camera's camera coordinate system and the image coordinate system corresponding to the image captured by the target camera. Therefore, based on the target camera's intrinsic parameters, the position of the target feature point in the image coordinate system corresponding to the first frame can be converted to its position in the target camera's camera coordinate system. Furthermore, by using the correlation between the positions of three or more asymmetrically distributed target feature points in the target camera's camera coordinate system and their positions in the world coordinate system, the PnP algorithm can be used to solve for the translation vector and rotation matrix of the target camera when capturing the first frame, which are then used as the obtained extrinsic parameters of the target camera when capturing the first frame.

[0111] In one possible implementation, if only the change in camera extrinsic parameters needs to be determined, the target camera's attitude when capturing the first image can be determined solely by the first image captured by the target camera after pose adjustment and the second image captured before pose adjustment. In step S202, the following can be done:

[0112] Feature point detection is performed in the first and second frames respectively to obtain the feature points corresponding to the reference object at the same world coordinate system position; based on the offset of the feature points corresponding to the reference object from the second frame to the first frame, and the camera intrinsic parameters of the target camera, the pose of the target camera when acquiring the first frame is calculated.

[0113] This allows for a more flexible and convenient way to determine the pose of the target camera, thus further meeting the diverse needs of users in different scenarios.

[0114] The method for feature point detection in the first and second frames can be the same as described above, implemented based on existing technology. This disclosure does not impose any limitations on this method, as long as at least one feature point is detected in each of the first and second frames. By matching the feature points detected in the first and second frames, the feature points corresponding to the reference object at the same world coordinate system position can be obtained. The matching method can be implemented based on existing technology, as long as at least one feature point can be determined in each of the first and second frames, and these two feature points correspond to the same world coordinate system position. The offset of the feature point corresponding to the reference object from the second frame to the first frame can represent the pixel coordinate offset of the feature point corresponding to the reference object between the image coordinate system of the second frame and the image coordinate system of the first frame. This pixel coordinate offset can be converted into a displacement in the camera coordinate system of the target camera using the camera intrinsic parameters of the target camera. Based on related technologies, the attitude change of the target camera when capturing the first frame relative to when capturing the second frame can be calculated based on the displacement in the camera coordinate system of the target camera. Since the attitude of the target camera when capturing the second frame is known, the attitude of the target camera when capturing the first frame can be calculated.

[0115] In one possible implementation, the position of the target camera can be determined solely through steps S201-S202 described above, while the camera's attitude can be determined separately using measurement or control parameters. This allows for a faster and more accurate determination of the target camera's attitude. Specifically, the target camera can be mounted on a stepper motor, and its attitude can be determined by the stepper motor's control parameters; alternatively, the target camera can be equipped with an attitude positioning module, and its attitude can be determined based on the measurement parameters from the attitude positioning module.

[0116] The stepper motor can be a motor used to precisely control the rotation angle. The control parameters mentioned above can include the rotation angle, the number of rotation steps, etc., so that the attitude of the current target camera can be determined by the control parameters.

[0117] The attitude positioning module can be a sensor, such as a gyroscope, accelerometer, magnetometer, etc. The measurement parameters of the attitude positioning module can represent the parameters measured by the sensor to determine the pose of the target camera in real time.

[0118] To facilitate real-time monitoring of the adjustment process and to determine the effect of camera adjustments in real time, the method may also include: visualizing the camera extrinsic parameters of the target camera when capturing the first frame.

[0119] The visualization method can include one or more of the following: text, charts, and videos. For example, it can be visualized using a heatmap. In one possible implementation, the camera extrinsic parameters of all cameras in the optical positioning field can be visualized on the heatmap. When a camera is adjusting its pose, the adjusted camera extrinsic parameters are determined based on the method of this embodiment and updated in the heatmap. The camera whose pose has been adjusted in real time can be displayed in a darker color (e.g., turn red) in the heatmap, and the real-time determined camera extrinsic parameters are displayed on the corresponding camera.

[0120] Figure 3 This diagram illustrates a structural arrangement of a camera adjustment device for optical positioning in a field according to an embodiment of the present disclosure. This device can be used in servers or terminal devices, such as… Figure 3 As shown, the device may include:

[0121] The acquisition module 301 is used to acquire at least one frame of image captured by at least one camera in relation to a reference object. The position of the reference object in the world coordinate system is fixed. The at least one camera includes a target camera. The at least one frame of image includes the first image captured by the target camera after pose adjustment.

[0122] The determination module 302 is used to determine the camera extrinsic parameters of the target camera when acquiring the first frame based on at least one frame. The camera extrinsic parameters include the position and / or attitude of the camera.

[0123] In one possible implementation, module 302 is configured to:

[0124] Feature point detection is performed on at least one frame captured by each camera to obtain multiple feature points included in each frame, and the feature points are associated with reference objects.

[0125] Based on the multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined.

[0126] In one possible implementation, based on multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined, including:

[0127] Matching is performed between multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, as well as the position of the target feature points in the world coordinate system;

[0128] Based on the position of the target feature point in the image coordinate system corresponding to the first frame, the position of the target feature point in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame are calculated.

[0129] In one possible implementation, at least one frame also includes images captured by at least two other cameras besides the target camera.

[0130] Matching is performed among multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, and the position of the target feature points in the world coordinate system, including:

[0131] Using binocular stereo vision technology, feature points included in the images captured by at least two other cameras besides the target camera are matched to obtain the target feature points;

[0132] Based on the target feature points, the position of the target feature points in the world coordinate system is obtained.

[0133] In one possible implementation, the preset number is not less than three, and the preset number of target feature points includes not less than three feature points that are asymmetrically distributed; the device further includes:

[0134] The first display module is used to display a prompt message in response to the number of target feature points being less than a preset number. The prompt message is used to instruct the feature point detection to be performed again.

[0135] In one possible implementation, at least one frame also includes a second frame captured by the target camera before pose adjustment. The determining module 302 is used for:

[0136] Feature point detection is performed in the first and second frames respectively to obtain the feature points corresponding to the reference objects at the same world coordinate system position;

[0137] Based on the offset of the feature points corresponding to the reference object from the second frame to the first frame, and the camera intrinsic parameters of the target camera, the pose of the target camera when capturing the first frame is calculated.

[0138] In one possible implementation, the reference object includes a preset area in the optical positioning field and / or a rigid body of any fixed size in the optical positioning field;

[0139] In response to the reference object being a predetermined area in the optical positioning field, at least one frame includes an image of the optical positioning field with texture features.

[0140] Since the camera is an infrared camera and the optical positioning site is an outdoor site, the rigid body does not include the rigid body used to emit infrared light.

[0141] In one possible implementation, the target camera is mounted on a stepper motor, and the attitude of the target camera is determined by the control parameters of the stepper motor; or, the target camera is equipped with an attitude positioning module, and the attitude of the target camera is determined based on the measurement parameters of the attitude positioning module.

[0142] In one possible implementation, the device further includes:

[0143] The second display module is used to visualize the camera extrinsic parameters of the target camera when capturing the first frame.

[0144] According to embodiments of this disclosure, by acquiring at least one frame of an image captured by at least one camera, including a target camera, of a reference object, wherein the position of the reference object in the world coordinate system is fixed, and the at least one frame of an image includes a first image captured by the target camera after pose adjustment, the camera extrinsic parameters of the target camera at the time of capturing the first image are determined based on the at least one frame of an image. The camera extrinsic parameters include the position and / or attitude of the camera. This allows for accurate determination of camera extrinsic parameters after the camera pose is adjusted, which can greatly save adjustment time and avoid rework and deterioration of optical positioning effect caused by deviations during the adjustment process. At the same time, the solution according to embodiments of this disclosure can realize real-time determination of camera extrinsic parameters after camera adjustment. During this process, the target camera does not need to maintain a constant pose, thereby meeting the requirements of optical positioning sites for real-time performance and efficiency.

[0145] In some embodiments, the functions or modules of the apparatus provided in this disclosure can be used to perform the methods described in the above method embodiments. The specific implementation can be referred to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0146] This disclosure also proposes a computer-readable storage medium storing computer program instructions that, when executed by a processor, implement the above-described method. The computer-readable storage medium can be volatile or non-volatile.

[0147] This disclosure also proposes a camera adjustment device in an optical positioning field, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to implement the above method when executing the instructions stored in the memory.

[0148] This disclosure also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code, wherein when the computer-readable code is run in a processor of an electronic device, the processor in the electronic device performs the above-described method.

[0149] Figure 4This is a block diagram illustrating an apparatus 1900 for camera adjustment in an optical positioning field, according to an exemplary embodiment. For example, apparatus 1900 may be provided as a server or terminal device. (Refer to...) Figure 4 The apparatus 1900 includes a processing component 1922, which further includes one or more processors, and memory resources represented by memory 1932 for storing instructions, such as application programs, that can be executed by the processing component 1922. The application programs stored in memory 1932 may include one or more modules, each corresponding to a set of instructions. Furthermore, the processing component 1922 is configured to execute instructions to perform the methods described above.

[0150] Device 1900 may also include a power supply component 1926 configured to perform power management of device 1900, a wired or wireless network interface 1950 configured to connect device 1900 to a network, and an input / output interface 1958 (I / O interface). Device 1900 can operate on an operating system, such as Windows Server, stored in memory 1932. TM macOS X TM Unix TM Linux TM FreeBSD TM Or similar.

[0151] In an exemplary embodiment, a non-volatile computer-readable storage medium is also provided, such as a memory 1932 including computer program instructions that can be executed by a processing component 1922 of the device 1900 to perform the above-described method.

[0152] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0153] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0154] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0155] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0156] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0157] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0158] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0159] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0160] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for adjusting a camera in an optical positioning field, characterized in that, The method includes: Acquire at least one frame of image captured by at least one camera for a reference object, the reference object having a fixed position in the world coordinate system, the at least one camera including a target camera, the at least one frame of image including a first image captured by the target camera after pose adjustment, and the at least one frame of image including images captured by at least two other cameras besides the target camera. Based on the at least one frame, determine the camera extrinsic parameters of the target camera when capturing the first frame, the camera extrinsic parameters including the position and / or attitude of the camera; The step of determining the camera extrinsic parameters of the target camera when capturing the first frame based on the at least one frame includes: Feature point detection is performed on at least one frame captured by each camera to obtain multiple feature points included in each frame, and the feature points are associated with the reference object. Based on multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined; The step of determining the camera extrinsic parameters of the target camera when acquiring the first frame based on multiple feature points included in each frame includes: Matching is performed between multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, as well as the position of the target feature points in the world coordinate system; Based on the position of the target feature point in the image coordinate system corresponding to the first frame, the position of the target feature point in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame are calculated. Specifically, feature points included in the images captured by at least two cameras other than the target camera are matched to obtain the target feature points, and the position of the target feature points in the world coordinate system is obtained based on the target feature points.

2. The method according to claim 1, characterized in that, The matching of multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, and the position of the target feature points in the world coordinate system, includes: Using binocular stereo vision technology, feature points included in the images captured by at least two cameras other than the target camera are matched to obtain the target feature points; Based on the target feature point, the position of the target feature point in the world coordinate system is obtained.

3. The method according to claim 1, characterized in that, The preset quantity is not less than three, and the preset quantity of target feature points includes not less than three feature points that are asymmetrically distributed; the method further includes: If the number of target feature points is less than the preset number, a prompt message is displayed, which indicates that feature point detection should be performed again.

4. The method according to claim 1, characterized in that, The at least one frame also includes a second frame captured by the target camera before pose adjustment. Determining the camera extrinsic parameters of the target camera when capturing the first frame, based on the at least one frame, includes: Feature point detection is performed in the first and second frames respectively to obtain the feature points corresponding to the reference objects at the same world coordinate system position; Based on the offset of the feature points corresponding to the reference object from the second frame to the first frame, and the camera intrinsic parameters of the target camera, the pose of the target camera when acquiring the first frame is calculated.

5. The method according to any one of claims 1-4, characterized in that, The reference object includes a preset area in the optical positioning field and / or a rigid body of any fixed size in the optical positioning field; In response to the reference object being a preset area in the optical positioning field, the at least one frame includes an optical positioning field image with texture features; In response to the fact that the camera is an infrared camera and the optical positioning site is an outdoor site, the rigid body does not include a rigid body for emitting infrared light.

6. The method according to claim 1, characterized in that, The target camera is mounted on a stepper motor, and the attitude of the target camera is determined by the control parameters of the stepper motor; or, The target camera is equipped with an attitude positioning module, and the attitude of the target camera is determined based on the measurement parameters of the attitude positioning module.

7. The method according to claim 1, characterized in that, The method further includes: The camera extrinsic parameters of the target camera when capturing the first frame are visualized.

8. A camera adjustment device for optical positioning sites, characterized in that, The device includes: An acquisition module is used to acquire at least one frame of an image captured by at least one camera in relation to a reference object, wherein the position of the reference object in the world coordinate system is fixed, the at least one camera includes a target camera, the at least one frame of an image includes a first image captured by the target camera after pose adjustment, and the at least one frame of an image also includes images captured by at least two other cameras besides the target camera. The determining module is used to determine the camera extrinsic parameters of the target camera when capturing the first frame based on the at least one frame; the camera extrinsic parameters include the position and / or attitude of the camera. The determining module is used for: Feature point detection is performed on at least one frame captured by each camera to obtain multiple feature points included in each frame, and the feature points are associated with the reference object. Based on multiple feature points included in each frame, the camera extrinsic parameters of the target camera when capturing the first frame are determined; The step of determining the camera extrinsic parameters of the target camera when acquiring the first frame based on multiple feature points included in each frame includes: Matching is performed between multiple feature points included in each frame to obtain a preset number of target feature points corresponding to the same world coordinate system position in each frame, as well as the position of the target feature points in the world coordinate system; Based on the position of the target feature point in the image coordinate system corresponding to the first frame, the position of the target feature point in the world coordinate system, and the camera intrinsic parameters of the target camera, the camera extrinsic parameters of the target camera when capturing the first frame are calculated. Specifically, feature points included in the images captured by at least two cameras other than the target camera are matched to obtain the target feature points, and the position of the target feature points in the world coordinate system is obtained based on the target feature points.

9. A camera adjustment device for optical positioning sites, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to implement the method of any one of claims 1 to 7 when executing instructions stored in the memory.

10. A non-volatile computer-readable storage medium storing computer program instructions thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method described in any one of claims 1 to 7.

11. A computer program product comprising computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code, wherein when the computer-readable code is executed in an electronic device, a processor in the electronic device performs the method of any one of claims 1 to 7.

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