High-standard farmland DOM (Document Object Model) rapid manufacturing method based on tower top single camera photography

Abstract

The invention discloses a high-standard farmland DOM (Document Object Model) rapid manufacturing method based on tower top single camera photography, and belongs to the technical field of image processing. The method comprises the following steps: acquiring a camera shooting model corresponding to a target camera based on an attitude angle of a target picture shot by the target camera and a geographic position of the target camera; the target camera is a camera mounted on the tower top; obtaining a ground range corresponding to the DOM and a grid size of the DOM based on the elevation of the ground feature in the target range and a camera shooting model; and projecting each grid of the DOM to the target picture based on the camera shooting model with distortion corresponding to the target camera, and obtaining the DOM corresponding to the target picture. According to the high-standard farmland DOM rapid manufacturing method based on tower top single camera shooting, under the condition that high image resolution and certain geometric accuracy are guaranteed, the operation cost is greatly reduced, the operation process is shortened, and the DOM can be efficiently generated at low cost.

Description

Technical Field

[0001] The present application belongs to the field of image processing technology, and in particular relates to a method for quickly producing high-standard farmland DOM based on tower-top single-camera photography. Background Art

[0002] Digital orthophoto map (DOM) is a true reflection of the earth's surface information and has the characteristics of map geometry and image texture. Therefore, DOM is widely used in agriculture, forestry, land resources and environmental monitoring.

[0003] Traditional DOM generation methods are mainly based on satellite images or aerial survey images. The specific steps include field control point measurement, aerial triangulation of satellite images or aerial survey images, digital elevation model (DEM) generation and editing, and digital differential correction to generate DOM.

[0004] In the agricultural sector, there is a demand for more detailed observations of target objects within a local area, as well as for more effective observations of selected crops. These demands necessitate the rapid and efficient generation of DOM images (DOMs) for analyzing objects such as farmland within these areas. However, traditional DOM generation methods utilize low-resolution satellite imagery and aerial surveying, requiring field control measurements, making them unsuitable for these requirements. Therefore, the efficient and cost-effective generation of digital orthophotos of farmland has become a pressing technical challenge in this field. Summary of the Invention

[0005] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a method for quickly producing high-standard farmland DOM based on tower-top single-camera photography, which can generate farmland digital orthophotos at low cost and high efficiency.

[0006] In a first aspect, the present application provides a method for rapidly producing high-standard farmland DOM based on tower-top single-camera photography, the method comprising: Obtaining a camera photography model corresponding to the target camera based on the attitude angle of the target image captured by the target camera and the geographic location of the target camera; the target camera is a camera mounted on top of a tower; the camera photography model is used to indicate the correspondence between homogeneous coordinates of pixels in the target image and coordinates of ground features corresponding to the pixels in a three-dimensional world coordinate system; the target image is obtained by capturing high-standard farmland within a target range with the target camera; Based on the elevation of the objects within the target range and the camera photography model, obtaining a ground range corresponding to the DOM and a grid size of the DOM; the elevation of the objects within the target range is determined based on the height of the target camera from the ground, the maximum height of the objects within the target range, and the height of the target camera in the three-dimensional world coordinate system; Based on the distorted camera photography model corresponding to the target camera, each grid of the DOM is projected onto the target image to obtain the DOM corresponding to the target image; the grid is obtained by dividing the ground range based on the grid size of the DOM.

[0007] According to the high-standard farmland DOM rapid production method based on tower-top single-camera photography of the present application, the camera photography model corresponding to the target camera is obtained based on the attitude angle of the target image taken by the target camera installed on the tower top and the geographical location of the target camera. The ground range corresponding to the DOM and the grid size of the DOM are obtained based on the elevation of the ground objects in the target range and the camera photography model. Based on the distorted camera photography model corresponding to the target camera, each grid of the DOM is projected onto the target image to obtain the DOM corresponding to the target image. The DOM is directly projected and calculated using the camera photography model of the target camera. There is no need to use complex and time-consuming motion recovery structure technology based on multiple images to estimate the camera position and attitude and iteratively adjust it. It can also avoid the problem of distortion caused by features. The method can eliminate the situations such as failure of camera position and posture calculation caused by insufficient points or mismatch, and directly estimate the ground range and grid size of DOM by using the camera photography model of the target camera, and use the elevation to construct the three-dimensional world coordinates of the DOM grid for projection. It does not need to use the complex and time-consuming construction of sparse point cloud or dense point cloud to generate digital elevation model for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the demand for detailed observation of DOM generation for local target features in agricultural applications at a low cost and high efficiency.

[0008] According to one embodiment of the present application, obtaining a camera photography model corresponding to the target camera based on the posture angle of the target camera taking the target image and the geographical location of the target camera includes: Based on the posture angle, obtaining a rotation matrix; Based on the geographic location of the target camera, obtaining the coordinates of the target camera in the three-dimensional world coordinate system; The camera photography model is acquired based on the memory matrix of the target camera, the rotation matrix, and the coordinates of the target camera in the three-dimensional world coordinate system.

[0009] According to one embodiment of the present application, obtaining the ground range corresponding to the DOM and the grid size of the DOM based on the elevation of the ground object within the target range and the camera photography model includes: Based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and the minimum elevation of the ground objects within the target range are calculated to obtain the ground range; The grid size of the DOM is acquired based on the camera photography model, the average elevation of the objects within the target range, and the ground range.

[0010] According to one embodiment of the present application, the step of calculating the homogeneous coordinates of the four corner points of the target image and the maximum elevation and minimum elevation of the objects within the target range based on the camera photography model to obtain the ground range includes: Based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and the minimum elevation of the ground objects within the target range are calculated to obtain the coordinates of the corresponding eight object points in the three-dimensional world coordinate system; Obtaining first target coordinates corresponding to the minimum value of the first coordinate axis coordinate and the minimum value of the second coordinate axis coordinate of the eight object points in the three-dimensional world coordinate system, and second target coordinates corresponding to the maximum value of the first coordinate axis coordinate and the maximum value of the second coordinate axis coordinate; A range on the ground corresponding to a rectangle with the points corresponding to the first target coordinates and the second target coordinates as diagonals is determined as the ground range.

[0011] According to one embodiment of the present application, obtaining the grid size of the DOM based on the camera photography model, the average elevation of the objects within the target range, and the ground range includes: Determine a target object point based on the first target coordinates and the average elevation and based on the second target coordinates and the average elevation respectively; Based on the camera photography model and the coordinates of each target object point in the three-dimensional world coordinate system, obtaining the homogeneous coordinates corresponding to each target object point; A grid size of the DOM is acquired based on the first target coordinates, the second target coordinates, and homogeneous coordinates corresponding to the two target object points.

[0012] According to one embodiment of the present application, obtaining the grid size of the DOM based on the first target coordinates, the second target coordinates, and the homogeneous coordinates corresponding to the two target object points includes: The size of the DOM grid in the direction of the first coordinate axis is obtained based on the minimum value of the first coordinate axis coordinate, the maximum value of the first coordinate axis coordinate, and the coordinates corresponding to the first coordinate axis in the homogeneous coordinates corresponding to the two target object points. The size of the DOM grid in the direction of the second coordinate axis is obtained based on the minimum value of the second coordinate axis coordinate, the maximum value of the second coordinate axis coordinate, and the coordinates corresponding to the second coordinate axis in the homogeneous coordinates corresponding to the two target object points.

[0013] According to one embodiment of the present application, projecting each mesh of the DOM onto the target image based on the distorted camera photography model corresponding to the target camera to obtain the DOM corresponding to the target image includes: Divide the ground range based on the grid size of the DOM, and obtain each grid of the DOM; Based on the distorted camera photography model, project each of the grids onto the target image to obtain floating-point pixel coordinates corresponding to the grid; The floating-point pixel coordinates are interpolated to obtain the color value of each grid of the DOM, thereby obtaining the DOM corresponding to the target image.

[0014] In a second aspect, the present application provides a high-standard farmland DOM rapid production device based on tower-top single-camera photography, the device comprising: A construction module is configured to obtain a camera photography model corresponding to a target camera based on the attitude angle of a target camera in capturing a target image and the geographic location of the target camera; the target camera is a camera mounted on a tower top; the camera photography model is configured to indicate a correspondence between homogeneous coordinates of pixels in the target image and coordinates of ground features corresponding to the pixels in a three-dimensional world coordinate system; the target image is obtained by capturing high-standard farmland within a target range with the target camera; an estimation module, configured to obtain a ground range corresponding to the DOM and a grid size of the DOM based on the elevation of the ground objects within the target range and the camera photography model; the elevation of the ground objects within the target range is determined based on the height of the target camera from the ground, the maximum height of the ground objects within the target range, and the height of the target camera in the three-dimensional world coordinate system; An acquisition module is configured to project each grid of the DOM onto the target image based on a distorted camera photography model corresponding to the target camera, thereby acquiring the DOM corresponding to the target image; the grids are obtained by dividing the ground range based on the grid size of the DOM.

[0015] According to the high-standard farmland DOM rapid production device based on tower-top single-camera photography of the present application, the camera photography model corresponding to the target camera is obtained based on the posture angle of the target image taken by the target camera installed on the tower top and the geographical location of the target camera. The ground range corresponding to the DOM and the grid size of the DOM are obtained based on the elevation of the ground objects in the target range and the camera photography model. Based on the distorted camera photography model corresponding to the target camera, each grid of the DOM is projected onto the target image to obtain the DOM corresponding to the target image. The DOM is directly projected and calculated using the camera photography model of the target camera. There is no need to use complex and time-consuming motion recovery structure technology based on multiple images to estimate the camera position and posture and iteratively adjust it. It can also avoid the problem of distortion caused by features. The method can eliminate the situations such as failure of camera position and posture calculation caused by insufficient points or mismatch, and directly estimate the ground range and grid size of DOM by using the camera photography model of the target camera, and use the elevation to construct the three-dimensional world coordinates of the DOM grid for projection. It does not need to use the complex and time-consuming construction of sparse point cloud or dense point cloud to generate digital elevation model for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the demand for detailed observation of DOM generation for local target features in agricultural applications at a low cost and high efficiency.

[0016] In a third aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for rapidly producing high-standard farmland DOM based on tower-top single-camera photography as described in the first aspect above is implemented.

[0017] In a fourth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for rapidly producing high-standard farmland DOM based on tower-top single-camera photography as described in the first aspect above.

[0018] In a fifth aspect, the present application provides a chip, which includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the high-standard farmland DOM rapid production method based on tower-top single-camera photography as described in the first aspect.

[0019] In a sixth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the method for quickly producing high-standard farmland DOM based on tower-top single-camera photography as described in the first aspect above.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 This is a flow chart of a method for rapidly producing high-standard farmland DOM based on tower-top single-camera photography provided in an embodiment of the present application; Figure 2 This is a schematic diagram of the structure of a high-standard farmland DOM rapid production device based on tower-top single-camera photography provided in an embodiment of the present application; Figure 3 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0023] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0024] Among the related technologies, with the development of the Global Navigation Satellite System (GNSS, also known as the "Global Satellite Navigation System") and the emergence of inertial navigation technology based on the Inertial Measurement Unit (IMU), the DOM production method assisted by the airborne positioning and orientation system (POS) of unmanned aerial vehicles (such as low-altitude drones, etc.) has been widely adopted.

[0025] The aforementioned drone-based, airborne POS-assisted DOM production method may include: extracting feature points from each image captured by the drone's onboard camera and matching feature points between images using at least one of the following algorithms: scale-invariant feature transform (SIFT), speeded up robust features (SURF), and Harris corner extraction; employing structure from motion (SfM) technology and the corresponding POS information of the images to estimate and optimize image extrinsic parameters (which may include position and pose) and construct a sparse 3D point cloud; generating a dense point cloud using multi-view stereo (MVS) methods; generating a digital elevation model (DEM) based on the dense point cloud; and projecting the images using the DEM and the image's extrinsic and extrinsic parameters to generate the DOM. This method requires little or no field control measurement and is therefore widely used for DOM production.

[0026] It should be noted that the intrinsic and extrinsic parameters of an image refer to the intrinsic and extrinsic parameters of the camera that captured the image. The intrinsic and extrinsic parameters of a camera can usually be represented by an intrinsic parameter matrix and an extrinsic parameter matrix, respectively.

[0027] Traditional DOM generation methods, such as those used in agricultural fields for the rapid and efficient generation of small-scale DOM (DOM) for high-standard farmland, are not suitable for the aforementioned needs. The low-resolution satellite and aerial survey images used in these methods require minimal field control measurements, making them unsuitable. While the aforementioned drone-based POS-assisted DOM generation methods produce high-resolution images and require minimal or no field control measurements, they require a large number of images, typically hundreds or even thousands, resulting in a large amount of image data to be processed. Post-processing steps such as feature point extraction and matching, estimation and optimization of image extrinsic parameters, construction of sparse 3D point clouds and dense point clouds, and generation of digital elevation models are complex and time-consuming. Furthermore, the lack of regional crop features can lead to difficulties in feature point extraction and matching, which can lead to DOM generation failures. Furthermore, drone operations are significantly affected by weather conditions (such as wind speed and direction), and controlling the drone's flight still requires a certain amount of cost.

[0028] In summary, the DOM generation methods in related technologies are difficult to meet the demand of quickly and efficiently generating a DOM in a smaller range.

[0029] Below, in conjunction with the accompanying drawings, the high-standard farmland DOM rapid production method based on tower-top single-camera photography, the high-standard farmland DOM rapid production device based on tower-top single-camera photography, the electronic device and the readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0030] Among them, the high-standard farmland DOM rapid production method based on tower-top single-camera photography can be applied to the terminal, and can be specifically executed by the hardware or software in the terminal.

[0031] The terminal includes, but is not limited to, a portable communication device such as a mobile phone or tablet computer having a touch-sensitive surface (e.g., a touch screen display and / or a touch pad). It should also be understood that in some embodiments, the terminal may not be a portable communication device, but rather a desktop computer having a touch-sensitive surface (e.g., a touch screen display and / or a touch pad).

[0032] In the following embodiments, a terminal including a display and a touch-sensitive surface is described. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, a mouse, and a joystick.

[0033] The embodiment of the present application provides a method for quickly producing DOM of high-standard farmland based on tower-top single-camera photography. The execution subject of the method for quickly producing DOM of high-standard farmland based on tower-top single-camera photography can be an electronic device or a functional module or functional entity in the electronic device that can implement the method for quickly producing DOM of high-standard farmland based on tower-top single-camera photography. The electronic devices mentioned in the embodiment of the present application include but are not limited to mobile phones, tablet computers, computers, cameras and wearable devices, etc. The following describes the method for quickly producing DOM of high-standard farmland based on tower-top single-camera photography provided in the embodiment of the present application using electronic devices as an example of the execution subject.

[0034] like Figure 1 As shown, the method for quickly producing high-standard farmland DOM based on tower-top single-camera photography includes: step 110, step 120 and step 130.

[0035] Step 110: Based on the attitude angle of the target camera in taking the target image and the geographical location of the target camera, obtain a camera photography model corresponding to the target camera; the target camera is a camera installed on the top of the tower; the camera photography model is used to indicate the correspondence between the homogeneous coordinates of the pixels in the target image and the coordinates of the ground objects corresponding to the pixels in the three-dimensional world coordinate system; the target image is obtained by photographing high-standard farmland within the target range with the target camera.

[0036] In actual implementation, the embodiment of the present application uses a camera installed on the top of a tower near high-standard farmland to produce a DOM based on the pictures collected by the camera. It should be noted that, under normal circumstances, one picture collected by the camera can produce a corresponding DOM.

[0037] The embodiments of the present application implement a rapid DOM production method based on tower-top single-camera photography. In the field of agricultural applications, it can greatly reduce operating costs and shorten the operation process. While ensuring high image resolution and a certain degree of geometric accuracy, it can simply and efficiently produce high-standard farmland DOM for agricultural analysis and application.

[0038] Well-facilitated farmland refers to arable land that is flat, concentrated and contiguous, has complete facilities, supporting farmland, fertile soil, good ecology, strong disaster resistance, and is compatible with modern agricultural production and management methods, with stable yields in drought and flood, and high yields, and is designated as permanent basic farmland.

[0039] In some embodiments, the camera can be used as part of a data acquisition device. The data acquisition device can be installed on the top of the tower. In addition to the camera, the data acquisition device can also include a pan / tilt platform.

[0040] In some embodiments, the data acquisition device may further include a positioning measurement device. The positioning measurement device may obtain its own geographical location based on GNSS as the geographical location of the camera. In some embodiments, the data acquisition device may include at least one camera.

[0041] It should be noted that the aforementioned high tower may not be limited to tower-type buildings or structures, but may also be other types of buildings or structures with a height greater than the target value.

[0042] It is understandable that the target camera can be a camera installed on the top of the aforementioned tower. In some embodiments, the target camera can be a high-definition camera.

[0043] In some embodiments, before step 110, the target camera may capture the high-standard farmland within the target range to obtain at least one image. Any of the at least one image may be used as the target image. Furthermore, for each image captured by the target camera of the high-standard farmland within the target range, the attitude angle of the target camera when the image was captured may be obtained.

[0044] In some embodiments, the attitude angle of the target camera when taking the image can be obtained based on the angle of the gimbal when the target camera takes the image. In some embodiments, the attitude angle can include yaw, pitch, and roll, etc.

[0045] In some embodiments, the geographic location of the target camera may be acquired before step 110. If the geographic location of the tower top is known in advance, the geographic location of the tower top may be used as the geographic location of the target camera. Alternatively, if the geographic location of the tower top is not known in advance, the geographic location of the positioning measurement device may be acquired using GNSS as the geographic location of the target camera.

[0046] In some embodiments, the above-mentioned geographical location may include longitude L, latitude B and altitude Z. c .

[0047] It should be noted that the target camera is mounted atop a tower, and the present embodiment utilizes only one camera to capture images. This technique for capturing target images can be referred to as tower-based single-camera photography. Tower-based single-camera photography can provide real-time, sustainable image information for monitoring high-standard farmland. For monitoring high-standard farmland, acquiring digital orthophotos from a single-camera system is crucial for effective subsequent farmland monitoring.

[0048] After obtaining the pose angle of the target camera taking the target picture and the geographical location of the target camera, a camera photography model corresponding to the target camera can be constructed based on the pose angle of the target camera taking the target picture and the geographical location of the target camera.

[0049] It should be noted that the correspondence between the homogeneous coordinates of the pixels in the target image and the coordinates of the ground objects corresponding to the pixels in the three-dimensional world coordinate system can be represented by the camera photography model corresponding to the target camera. Based on the posture angle of the target camera taking the target image and the geographical location of the target camera, the camera photography model corresponding to the target camera can be constructed by any existing method. The specific method used to construct the camera photography model corresponding to the target camera is not limited in the embodiments of the present application. The specific three-dimensional world coordinate system used is not limited in the embodiments of the present application. The coordinates in the three-dimensional world coordinate system can be called three-dimensional world coordinates.

[0050] It should be noted that the camera photography model corresponding to the target camera in step 110 is a camera photography model without distortion.

[0051] Step 120: Based on the elevation of the objects within the target range and the camera photography model, obtain the ground range corresponding to the DOM and the grid size of the DOM; the elevation of the objects within the target range is determined based on the height of the target camera from the ground, the maximum height of the objects within the target range, and the height of the target camera in the three-dimensional world coordinate system.

[0052] In actual execution, before step 120 , the height H of the target camera from the ground, the maximum height d of the ground objects within the target range, and the height of the target camera in the three-dimensional world coordinate system may be obtained.

[0053] It is understandable that a reference coordinate system needs to be selected in the environment to describe the position of the camera and objects. This coordinate system is called the world coordinate system. The above-mentioned world coordinate system is a three-dimensional orthogonal coordinate system. The two orthogonal coordinate axes at sea level are the X axis and the Y axis, and the coordinate axis perpendicular to the sea level is the Z axis. The Z axis coordinate represents the altitude. Therefore, the coordinates of the objects in the three-dimensional world coordinate system can be recorded as vectors .

[0054] It is understandable that the height of the target camera in the three-dimensional world coordinate system is generally the altitude Z of the target camera. c , so the height of the target camera in the three-dimensional world coordinate system can also be recorded as Z c .

[0055] In some embodiments, the height H of the target camera from the ground, the maximum height d of the ground objects within the target range, and the height Z of the target camera in the three-dimensional world coordinate system are obtained. c Afterwards, the target camera can be calculated based on its height H from the ground, the maximum height d of the objects within the target range, and the height Z of the target camera in the 3D world coordinate system. c , obtain the elevation of the objects within the target range.

[0056] In some embodiments, the elevation of the features within the target range may include at least one of a minimum elevation, a maximum elevation, and an average elevation.

[0057] It should be noted that based on the height H of the target camera from the ground, the maximum height d of the ground objects within the target range, and the height Z of the target camera in the three-dimensional world coordinate system c , obtaining the elevation of the object within the target range, any existing method can be used. The specific method used to obtain the elevation of the object within the target range is not limited in this embodiment of the application.

[0058] In some embodiments, the minimum elevation of the object within the target range , maximum elevation and average elevation They can be obtained by the following formulas: , , .

[0059] In some embodiments, after obtaining the elevation of the features within the target range, the ground range and grid size of the DOM corresponding to the target image can be estimated based on the elevation of the features within the target range and the camera photography model corresponding to the target camera, thereby obtaining the ground range and grid size of the DOM corresponding to the target image. It will be understood that in order to generate the DOM corresponding to the target image, the ground range corresponding to the DOM corresponding to the target image needs to be divided into multiple grids of the same size. The grid size of the DOM refers to the size of each of the aforementioned divided grids.

[0060] In some embodiments, the homogeneous coordinates of the ground objects within the target range and the coordinates in the three-dimensional world coordinate system can be transformed based on the camera photography model corresponding to the target camera, thereby realizing the transformation from the target range photographed by the target camera under the central projection to the corresponding range in the orthographic projection (that is, the ground range corresponding to the DOM corresponding to the target image), so that the ground range corresponding to the DOM corresponding to the target image can be estimated.

[0061] In some embodiments, based on the transformation between the homogeneous coordinates of the ground objects within the above-mentioned target range and the coordinates in the three-dimensional world coordinate system, it is also possible to determine how large an area in the ground range corresponding to the DOM corresponding to the target image corresponds to each pixel in the DOM corresponding to the target image, and the size of this area is the grid size of the DOM.

[0062] In some embodiments, the ground range of the DOM corresponding to the target image and the grid size of the DOM may be stored in a tfw format file.

[0063] Step 130 : Based on the distorted camera photography model corresponding to the target camera, each grid of the DOM is projected onto the target image to obtain the DOM corresponding to the target image; the grids are obtained by dividing the ground range based on the grid size of the DOM.

[0064] In actual execution, based on the distorted camera photography model corresponding to the target camera, an inverse solution method or other methods can be used for inverse calculation, each grid of the DOM can be projected onto the target image, and the DOM corresponding to the target image can be calculated.

[0065] It should be noted that any commonly used existing method can be used for back calculation using the inverse solution method, etc. The specific steps for back calculation using the inverse solution method, etc. are not limited in the embodiments of the present application.

[0066] In some embodiments, the DOM corresponding to the target image may be in a format such as tif. After obtaining the DOM corresponding to the target image, the DOM corresponding to the target image may be output in the above-mentioned format such as tif.

[0067] According to the method for quickly producing high-standard farmland DOM based on tower-top single-camera photography provided by the embodiment of the present application, the camera photography model corresponding to the target camera is obtained based on the attitude angle of the target image taken by the target camera installed on the tower top and the geographical location of the target camera. The ground range corresponding to the DOM and the grid size of the DOM are obtained based on the elevation of the ground objects within the target range and the camera photography model. Based on the distorted camera photography model corresponding to the target camera, each grid of the DOM is projected onto the target image to obtain the DOM corresponding to the target image. The DOM is directly projected and calculated using the camera photography model of the target camera. There is no need to use complex and time-consuming motion recovery structure technology based on multiple images to estimate the camera position and attitude and iteratively adjust it, and it can also avoid The method can solve the problems such as failure in camera position and posture calculation due to insufficient feature points or mismatch, and directly estimate the ground range and grid size of DOM by using the camera photography model of the target camera, and use the elevation to construct the three-dimensional world coordinates of the DOM grid for projection. It does not need to use the complex and time-consuming construction of sparse point cloud or dense point cloud to generate digital elevation model for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the needs of detailed observation of DOM generation for local target features in agricultural applications at a low cost and high efficiency.

[0068] In some embodiments of the present application, obtaining a camera photography model corresponding to a target camera based on the attitude angle of the target camera taking the target picture and the geographical location of the target camera includes: obtaining a rotation matrix based on the attitude angle.

[0069] In actual execution, the rotation matrix can be obtained by calculation based on the posture angle of the target image taken by the target camera.

[0070] In some embodiments, the target camera can take a picture of the target based on three attitude angles (including the yaw angle , pitch angle and roll angle ), calculate the rotation matrix R.

[0071] In some embodiments, the yaw angle , pitch angle and roll angle The rotation order (i.e. - - The rotation matrix R can be calculated using the following formula: .

[0072] Based on the geographic location of the target camera, obtain the coordinates of the target camera in the 3D world coordinate system.

[0073] In actual implementation, the geographic location of the target camera (generally represented by geographic coordinates using three coordinates, namely longitude, latitude and altitude) can be converted into a three-dimensional world coordinate system to obtain the coordinates of the target camera in the three-dimensional world coordinate system.

[0074] In some embodiments, the 3D world coordinate system may adopt the Universal Transverse Mercator (UTM) projection coordinate system. Convert to UTM projection coordinates .in, is the coordinate mark of the target camera in the three-dimensional world coordinate system, which can be recorded as .

[0075] Get the camera photography model based on the target camera's memory matrix, rotation matrix, and the target camera's coordinates in the 3D world coordinate system.

[0076] In actual implementation, the intrinsic parameter matrix of the target camera can be obtained by pre-calibrating the camera or provided by the manufacturer of the target camera. The intrinsic parameters of the target camera may include focal length and , like the coordinates of the principal point and , and the distortion parameters 、 、 、 and .

[0077] Since the camera photography model corresponding to the target camera in step 110 is not distorted, the intrinsic parameter matrix of the target camera can be expressed as .

[0078] Based on the target camera's memory matrix K, rotation matrix R and the coordinates of the target camera in the three-dimensional world coordinate system , we can construct the camera photography model corresponding to the target camera as shown below: .

[0079] Among them, a represents the homogeneous coordinates of the pixel in the target image ; A represents the coordinate of the object corresponding to the pixel in the three-dimensional world coordinate system .

[0080] According to the high-standard farmland DOM rapid production method based on tower-top single-camera photography provided in the embodiment of the present application, the rotation matrix is obtained based on the posture angle of the target image taken by the target camera, the coordinates of the target camera in the three-dimensional world coordinate system are obtained based on the geographical location of the target camera, and the camera photography model corresponding to the target camera is obtained based on the memory matrix, rotation matrix and coordinates of the target camera in the three-dimensional world coordinate system of the target camera, so that the DOM can be directly projected and calculated using the camera photography model of the target camera, without the need to use complex and time-consuming motion recovery structure technology based on multiple images for camera position and posture estimation and iterative adjustment, and can also avoid camera errors caused by fewer feature points or mismatching. The method can solve the problems such as position and posture calculation failure, and directly estimate the ground range and grid size of DOM by using the camera photography model of the target camera, and use the elevation to construct the three-dimensional world coordinates of the DOM grid for projection. It does not need to use the complex and time-consuming construction of sparse point cloud or dense point cloud to generate digital elevation model for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the demand for detailed observation of DOM generated for local target features in agricultural applications at a low cost and high efficiency.

[0081] In some embodiments of the present application, based on the elevation of the objects within the target range and the camera photography model, the ground range corresponding to the DOM and the grid size of the DOM are obtained, including: based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and the minimum elevation of the objects within the target range are solved to obtain the ground range.

[0082] In actual implementation, the camera photography model corresponding to the target camera can be used to calculate the homogeneous coordinates of the four corner points of the target image and the maximum elevation of the objects within the target range to obtain four coordinates in the 3D world coordinate system. Furthermore, the homogeneous coordinates of the four corner points of the target image and the minimum elevation of the objects within the target range can be calculated to obtain four coordinates in the 3D world coordinate system. Since the four corner points of the target image are the four vertices of the target image, the 8 (4+4) coordinates in the 3D world coordinate system can be used to determine a range on the ground. This range is the ground range corresponding to the DOM corresponding to the target image.

[0083] The grid size of the DOM is obtained based on the camera photography model, the average elevation of the objects within the target range, and the ground range.

[0084] In actual execution, the ground range corresponding to the DOM corresponding to the above-mentioned target image and the average elevation of the ground objects within the target range can be converted into homogeneous coordinates of pixels in the target image through the camera photography model corresponding to the target camera, and based on the converted homogeneous coordinates and the ground range corresponding to the DOM corresponding to the target image, the grid size of the DOM used to divide the ground range corresponding to the DOM corresponding to the target image into grids is determined.

[0085] According to the embodiment of the present application, the method for rapid production of high-standard farmland DOM based on tower-top single-camera photography is provided. The homogeneous coordinates of the four corner points of the target image and the maximum and minimum elevations of the objects within the target range are solved based on the camera photography model corresponding to the target camera to obtain the ground range corresponding to the DOM corresponding to the target image, and the grid size of the DOM is obtained based on the camera photography model corresponding to the target camera, the average elevation of the objects within the target range, and the ground range corresponding to the DOM corresponding to the target image. The method can realize projection of the three-dimensional world coordinates of the DOM grid using the elevation based on the ground range corresponding to the DOM corresponding to the target image and the grid size of the DOM. There is no need to use the complex and time-consuming construction of sparse point clouds or dense point clouds to generate digital elevation models for projection. The method is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural objects at a lower cost, more effectively, and faster. While ensuring high image resolution and a certain geometric accuracy, the operation cost can be greatly reduced and the operation process can be shortened. It can meet the needs of detailed observation of local target objects in agricultural applications by generating DOM at a low cost and high efficiency.

[0086] In some embodiments of the present application, based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and minimum elevation of the ground objects within the target range are solved to obtain the ground range, including: based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and minimum elevation of the ground objects within the target range are solved to obtain the coordinates of the corresponding eight object points in the three-dimensional world coordinate system.

[0087] In actual execution, the homogeneous coordinates of the four corner points of the target image are 、 、 、 .in, 、 Represent the width and height of the target image respectively.

[0088] Using the camera photography model corresponding to the target camera, the homogeneous coordinates of the four corner points of the target image and the maximum elevation of the objects within the target range can be calculated to obtain four coordinates in the 3D world coordinate system. The homogeneous coordinates of the four corner points of the target image and the minimum elevation of the objects within the target range can also be calculated to obtain four coordinates in the 3D world coordinate system. The points corresponding to the 8 (4+4) coordinates in the 3D world coordinate system are all object-space points.

[0089] Obtaining first target coordinates corresponding to the minimum value of the first coordinate axis and the minimum value of the second coordinate axis of the eight object points in the three-dimensional world coordinate system, and second target coordinates corresponding to the maximum value of the first coordinate axis and the maximum value of the second coordinate axis; In actual execution, the minimum and maximum values of the X-axis coordinates and Y-axis coordinates of the eight object coordinates can be obtained respectively. Among them, the X-axis and Y-axis are the first coordinate axis and the second coordinate axis in the three-dimensional world coordinate system respectively; the minimum value of the X-axis coordinate is recorded as , the minimum value of the Y-axis coordinate is recorded as , the maximum value of the X-axis coordinate is recorded as , the maximum value of the Y-axis coordinate is recorded as .

[0090] Get the minimum value of the X-axis coordinate , the minimum value of the Y-axis coordinate , the maximum value of the X-axis coordinate and the maximum value of the Y-axis coordinate After that, we can determine )and( , ) are determined as the first target coordinate and the second target coordinate respectively.

[0091] The range on the ground corresponding to the rectangle with the points corresponding to the first target coordinates and the second target coordinates as diagonals is determined as the ground range.

[0092] In actual implementation, the first target coordinate ( ) and the corresponding point and the second target coordinates ( , ) corresponds to the diagonal rectangular range, which is determined as the ground range corresponding to the DOM corresponding to the target image.

[0093] According to the method for quickly producing DOM of high-standard farmland based on tower-top single-camera photography provided by the embodiment of the present application, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and minimum elevation of the ground objects within the target range are solved based on the camera photography model corresponding to the target camera, and the coordinates of the corresponding eight object points in the three-dimensional world coordinate system are obtained. The first target coordinates corresponding to the minimum value of the first coordinate axis coordinate and the minimum value of the second coordinate axis coordinate in the coordinates of the eight object points in the three-dimensional world coordinate system, as well as the second target coordinates corresponding to the maximum value of the first coordinate axis coordinate and the maximum value of the second coordinate axis coordinate are obtained. The range corresponding to the rectangle on the ground with the points corresponding to the first target coordinate and the second target coordinate as diagonals is determined as the target The ground range corresponding to the DOM corresponding to the target image can be realized by using the ground range corresponding to the DOM corresponding to the target image and the grid size of the DOM, and constructing the three-dimensional world coordinates of the DOM grid using elevation for projection. There is no need to use complex and time-consuming construction of sparse point clouds or dense point clouds to generate digital elevation models for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the needs of detailed observation of DOM generated for local target features in agricultural applications at a low cost and high efficiency.

[0094] In some embodiments of the present application, the grid size of the DOM is obtained based on the camera photography model, the average elevation of the ground objects within the target range, and the ground range, including: determining a target object point based on the first target coordinates and the average elevation and based on the second target coordinates and the average elevation, respectively.

[0095] In actual implementation, the first target coordinates ( ) and mean elevation , determine the coordinates in the three-dimensional world coordinate system as A target object point, and a second target coordinate ( , ) and mean elevation , determine the coordinates in the three-dimensional world coordinate system as Another target object point.

[0096] Based on the camera photography model and the coordinates of each target object point in the three-dimensional world coordinate system, the homogeneous coordinates corresponding to each target object point are obtained.

[0097] In actual implementation, the coordinates of the two target object points can be 、 , respectively substitute the camera photography model corresponding to the target camera, and calculate the homogeneous coordinates of the pixels corresponding to the above two target object points 、 .

[0098] The grid size of the DOM is obtained based on the first target coordinate, the second target coordinate, and the homogeneous coordinates corresponding to the two target object points.

[0099] In actual implementation, we can use the above two homogeneous coordinates 、 And the coordinates of the two target object points 、 The grid size of the DOM corresponding to the target image is estimated, thereby obtaining the grid size of the DOM corresponding to the target image.

[0100] According to the method for rapid production of high-standard farmland DOM based on tower-top single-camera photography provided in an embodiment of the present application, a target object point is determined based on the first target coordinates and the average elevation and based on the second target coordinates and the average elevation, and the grid size of the DOM corresponding to the target image is obtained based on the first target coordinates, the second target coordinates and the homogeneous coordinates corresponding to the two target object points. This method can realize projection of the three-dimensional world coordinates of the DOM grid constructed using the elevation based on the ground range corresponding to the DOM corresponding to the target image and the grid size of the DOM. There is no need to use the complex and time-consuming construction of sparse point clouds or dense point clouds to generate digital elevation models for projection. Data post-processing is simpler and more efficient, and high-resolution DOM of local agricultural objects can be produced at a lower cost, more effectively and faster. While ensuring high image resolution and a certain geometric accuracy, the operation cost can be greatly reduced and the operation process can be shortened. It can meet the needs of detailed observation of DOM generation for local target objects in agricultural applications in a low-cost and efficient manner.

[0101] In some embodiments of the present application, obtaining the grid size of the DOM based on the first target coordinates, the second target coordinates, and the homogeneous coordinates corresponding to the two target object points includes: obtaining the size of the DOM grid in the direction of the first coordinate axis based on the minimum value of the first coordinate axis coordinates, the maximum value of the first coordinate axis coordinates, and the coordinates corresponding to the first coordinate axis in the homogeneous coordinates corresponding to the two target object points; and obtaining the size of the DOM grid in the direction of the second coordinate axis based on the minimum value of the second coordinate axis coordinates, the maximum value of the second coordinate axis coordinates, and the coordinates corresponding to the second coordinate axis in the homogeneous coordinates corresponding to the two target object points.

[0102] In actual execution, the size of the DOM grid in the direction of the first coordinate axis can be obtained based on the minimum value of the first coordinate axis coordinate, the maximum value of the first coordinate axis coordinate and the coordinates corresponding to the first coordinate axis in the homogeneous coordinates corresponding to the two target object points.

[0103] In some embodiments, the maximum value of the first coordinate axis can be obtained The minimum value of the first coordinate axis The difference between the two target points and the coordinates corresponding to the first coordinate axis in the homogeneous coordinates (including the aforementioned and ) is used as the size of the DOM grid corresponding to the target image in the direction of the first coordinate axis. Taking the X axis in the three-dimensional world coordinate system as the first coordinate axis, it can be expressed as the formula .in, Indicates the size of the DOM grid corresponding to the target image in the direction of the first coordinate axis.

[0104] In actual execution, the size of the DOM grid in the second coordinate axis direction can be obtained based on the minimum value of the second coordinate axis coordinate, the maximum value of the second coordinate axis coordinate and the coordinates corresponding to the second coordinate axis in the homogeneous coordinates corresponding to the two target object points.

[0105] In some embodiments, the maximum value of the second coordinate axis can be obtained The minimum value of the first coordinate axis The difference between the two target points and the coordinates corresponding to the second coordinate axis in the homogeneous coordinates (including the aforementioned and ) is used as the size of the DOM grid corresponding to the target image in the direction of the second coordinate axis. Taking the Y axis in the three-dimensional world coordinate system as the second coordinate axis, it can be expressed as the formula .in, Indicates the size of the DOM grid corresponding to the target image in the direction of the second coordinate axis.

[0106] According to the method for rapidly producing a high-standard farmland DOM based on tower-top single-camera photography provided in an embodiment of the present application, the size of the DOM grid in the direction of the first coordinate axis is obtained based on the minimum value of the first coordinate axis coordinate, the maximum value of the first coordinate axis coordinate, and the coordinate corresponding to the first coordinate axis in the homogeneous coordinates corresponding to the two target object points. The size of the DOM grid in the direction of the second coordinate axis is obtained based on the minimum value of the second coordinate axis coordinate, the maximum value of the second coordinate axis coordinate, and the coordinate corresponding to the second coordinate axis in the homogeneous coordinates corresponding to the two target object points. This method can construct the three-dimensional world coordinates of the DOM grid using elevation based on the ground range corresponding to the DOM corresponding to the target image and the DOM grid size, eliminating the need for complex and time-consuming construction of sparse point clouds or dense point clouds to generate digital elevation models for projection. This method simplifies and improves data post-processing, enabling the production of high-resolution DOM of local agricultural features at a lower cost, more effectively, and faster speed. While ensuring high image resolution and a certain level of geometric accuracy, it can significantly reduce operating costs and shorten the operating process, and can cost-effectively and efficiently meet the needs of detailed observation of local target features in agricultural applications by generating DOM.

[0107] In some embodiments of the present application, based on a distorted camera photography model corresponding to a target camera, each grid of the DOM is projected onto a target image to obtain the DOM corresponding to the target image, including: dividing the ground range based on the grid size of the DOM to obtain each grid of the DOM.

[0108] In actual implementation, grid division can be performed based on the ground area of the DOM corresponding to the target image and the grid size of the DOM. The ground area of the DOM corresponding to the target image can be divided into multiple regular grids (typically rectangular grids), each of which serves as a grid of the DOM corresponding to the target image. Each grid of the DOM corresponding to the target image can correspond to a pixel of the DOM. The number of grids, rows, and columns can be denoted as m and n, respectively.

[0109] Based on the distorted camera photography model, each grid is projected onto the target image to obtain the floating-point pixel coordinates corresponding to the grid.

[0110] In actual execution, each of the above grids can be projected onto the target image using the distorted camera photography model corresponding to the target camera to obtain the floating-point pixel coordinates corresponding to the grid.

[0111] In some embodiments, the object coordinates (i.e., 3D world coordinates) of the grid After translation and rotation, Calculation can get the coordinates .make , the distorted camera photography model corresponding to the target camera is specifically expressed as the following equation: ; .

[0112] in, 、 、 、 and is the aforementioned distortion parameter; u and v represent the coordinates of the first coordinate axis and the second coordinate axis in the homogeneous coordinates respectively; and Represent the intermediate results of distortion correction corresponding to u and v respectively.

[0113] Interpolate the floating-point pixel coordinates to obtain the color value of each grid in the DOM, thereby obtaining the DOM corresponding to the target image.

[0114] In actual execution, the floating-point pixel coordinates of each grid of the DOM are interpolated to obtain the interpolated color value, that is, the color value of the pixel corresponding to the grid in the DOM corresponding to the target image. At this point, the DOM corresponding to the target image is completed.

[0115] In some embodiments, the floating-point pixel coordinates of each grid of the DOM are interpolated using any suitable interpolation method, such as bilinear interpolation, etc. The specific interpolation method used is not limited in the embodiments of the present application.

[0116] According to the method for quickly producing high-standard farmland DOM based on tower-top single-camera photography provided by the embodiment of the present application, the ground range is divided by the grid size based on the DOM, each grid of the DOM is obtained, and each grid is projected onto the target image based on the distorted camera photography model corresponding to the target camera, and the floating-point pixel coordinates corresponding to the grid are obtained. The floating-point pixel coordinates are interpolated to obtain the color value of each grid of the DOM, thereby obtaining the DOM corresponding to the target image. The DOM can be directly projected and calculated using the camera photography model of the target camera, without the need to use complex and time-consuming motion recovery structure technology based on multiple images to estimate the camera position and posture and iteratively adjust it, and can also avoid the problem of insufficient feature points or mismatching. The method can avoid situations such as failure in camera position and posture calculation caused by matching, and can directly estimate the ground range and grid size of DOM by using the camera photography model of the target camera, and use the elevation to construct the three-dimensional world coordinates of the DOM grid for projection. It does not need to use the complex and time-consuming construction of sparse point cloud or dense point cloud to generate digital elevation model for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the demand for detailed observation of DOM generated for local target features in agricultural applications at a low cost and high efficiency.

[0117] To facilitate understanding of the above embodiments of the present application, the following describes an implementation process of a method for rapidly producing high-standard farmland DOM based on tower-mounted single-camera photography. In some embodiments, a method for rapidly producing high-standard farmland DOM based on tower-mounted single-camera photography may include the following steps.

[0118] In the first step, the target camera installed on the top of the tower takes a target picture and obtains the attitude angle of the target camera taking the target picture, the geographical location of the target camera, the height of the target camera from the ground, the maximum height of the ground objects within the target range, and the intrinsic parameters of the target camera.

[0119] The second step is to obtain the rotation matrix based on the posture angle of the target image taken by the target camera.

[0120] The third step is to obtain the coordinates of the target camera in the three-dimensional world coordinate system based on the geographic location of the target camera.

[0121] Step 4: Based on the intrinsic parameters of the target camera, obtain the intrinsic parameter matrix of the target camera.

[0122] Step 5. Based on the intrinsic parameter matrix, rotation matrix and coordinates of the target camera in the three-dimensional world coordinate system, obtain the camera photography model corresponding to the target camera.

[0123] Step 6. Obtain the elevation of the objects within the target range (including the maximum elevation, minimum elevation, and average elevation) based on the altitude of the target camera's geographic location, the height of the target camera from the ground, and the maximum height of the objects within the target range.

[0124] Step 7: Based on the elevation of the ground objects within the target range and the camera photography model corresponding to the target camera, obtain the ground range and grid size of the DOM corresponding to the target image. Step 8. Based on the distorted camera photography model corresponding to the target camera, an inverse algorithm is used to calculate the digital orthophoto (DOM) corresponding to the target image.

[0125] The embodiment of the present application provides a method for rapidly producing high-standard farmland DOM based on tower-top single-camera photography. The execution entity may be a device for rapidly producing high-standard farmland DOM based on tower-top single-camera photography. In the embodiment of the present application, the device for rapidly producing high-standard farmland DOM based on tower-top single-camera photography is used as an example to illustrate the method.

[0126] The present application also provides a device for quickly producing high-standard farmland DOM based on tower-top single-camera photography. Figure 2 As shown, the high-standard farmland DOM rapid production device based on tower-top single-camera photography includes: a construction module 210, an estimation module 220 and an acquisition module 230.

[0127] Construction module 210 is configured to obtain a camera photography model corresponding to a target camera based on the attitude angle of the target camera in capturing the target image and the target camera's geographic location; the target camera is a camera mounted on a tower top; the camera photography model indicates the correspondence between homogeneous coordinates of pixels in the target image and coordinates of the corresponding ground features in a three-dimensional world coordinate system; the target image is obtained by capturing high-standard farmland within a target range with the target camera; An estimation module 220 is configured to obtain a ground range corresponding to the DOM and a grid size of the DOM based on the elevation of the objects within the target range and the camera photography model; the elevation of the objects within the target range is determined based on the height of the target camera from the ground, the maximum height of the objects within the target range, and the height of the target camera in the three-dimensional world coordinate system; The acquisition module 230 is used to project each grid of the DOM onto the target image based on the distorted camera photography model corresponding to the target camera, and obtain the DOM corresponding to the target image; the grid is obtained by dividing the ground range based on the grid size of the DOM.

[0128] According to the high-standard farmland DOM rapid production device based on tower-top single-camera photography provided by the embodiment of the present application, the camera photography model corresponding to the target camera is obtained based on the attitude angle of the target image taken by the target camera installed on the tower top and the geographical location of the target camera. The ground range corresponding to the DOM and the grid size of the DOM are obtained based on the elevation of the ground objects in the target range and the camera photography model. Based on the distorted camera photography model corresponding to the target camera, each grid of the DOM is projected onto the target image to obtain the DOM corresponding to the target image. The DOM is directly projected and calculated using the camera photography model of the target camera. There is no need to use complex and time-consuming motion recovery structure technology based on multiple images to estimate and iteratively adjust the camera position and attitude, and it can also avoid The method can solve the problems such as failure in camera position and posture calculation due to insufficient feature points or mismatch, and directly estimate the ground range and grid size of DOM by using the camera photography model of the target camera, and use the elevation to construct the three-dimensional world coordinates of the DOM grid for projection. It does not need to use the complex and time-consuming construction of sparse point cloud or dense point cloud to generate digital elevation model for projection. It is simpler and more efficient in data post-processing, and can produce high-resolution DOM of local agricultural features at a lower cost, more effectively and faster. It can greatly reduce the operation cost and shorten the operation process while ensuring high image resolution and a certain geometric accuracy, and can meet the needs of detailed observation of DOM generation for local target features in agricultural applications at a low cost and high efficiency.

[0129] In some embodiments, the building block 210 may include: A first acquiring unit, configured to acquire a rotation matrix based on a posture angle; A second acquiring unit, configured to acquire the coordinates of the target camera in the three-dimensional world coordinate system based on the geographic location of the target camera; The third acquisition unit is used to acquire a camera photography model based on the memory matrix of the target camera, the rotation matrix and the coordinates of the target camera in the three-dimensional world coordinate system.

[0130] In some embodiments, the estimation module 220 may include: The first estimation unit is used to calculate the homogeneous coordinates of the four corner points of the target image and the maximum and minimum elevations of the objects within the target range based on the camera photography model to obtain the ground range; The second estimation unit is used to obtain the grid size of the DOM based on the camera photography model, the average elevation of the ground objects in the target range, and the ground range.

[0131] In some embodiments, the first estimation unit may be specifically configured to: Based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum and minimum elevations of the objects within the target range are calculated to obtain the coordinates of the corresponding eight object points in the 3D world coordinate system; Obtaining first target coordinates corresponding to the minimum value of the first coordinate axis and the minimum value of the second coordinate axis of the eight object points in the three-dimensional world coordinate system, and second target coordinates corresponding to the maximum value of the first coordinate axis and the maximum value of the second coordinate axis; The range on the ground corresponding to the rectangle with the points corresponding to the first target coordinates and the second target coordinates as diagonals is determined as the ground range.

[0132] In some embodiments, the second estimation unit may include: a determination subunit, configured to determine a target object point based on the first target coordinates and the average elevation and based on the second target coordinates and the average elevation; A first acquisition subunit is configured to acquire homogeneous coordinates corresponding to each target object point based on a camera photography model and the coordinates of each target object point in a three-dimensional world coordinate system; The second acquisition subunit is configured to acquire a grid size of the DOM based on the first target coordinates, the second target coordinates, and the homogeneous coordinates corresponding to the two target object points.

[0133] In some embodiments, the second acquisition subunit may be specifically configured to acquire the size of the DOM grid in the direction of the first coordinate axis based on the minimum value of the first coordinate axis coordinate, the maximum value of the first coordinate axis coordinate, and the coordinates corresponding to the first coordinate axis in the homogeneous coordinates corresponding to the two target object points, and acquire the size of the DOM grid in the direction of the second coordinate axis based on the minimum value of the second coordinate axis coordinate, the maximum value of the second coordinate axis coordinate, and the coordinates corresponding to the second coordinate axis in the homogeneous coordinates corresponding to the two target object points.

[0134] In some embodiments, the acquisition module 230 may be specifically configured to: Divide the ground range based on the grid size of the DOM and obtain each grid of the DOM; Based on the distorted camera photography model, each grid is projected onto the target image to obtain the floating-point pixel coordinates corresponding to the grid; Interpolate the floating-point pixel coordinates to obtain the color value of each grid in the DOM, thereby obtaining the DOM corresponding to the target image.

[0135] The high-standard farmland DOM rapid production device based on tower-top single-camera photography in the embodiment of the present application can be an electronic device or a component in an electronic device, such as an integrated circuit or chip. The electronic device can be a terminal or other device other than a terminal. For example, the electronic device can be a mobile phone, a tablet computer, a laptop computer, a PDA, a car-mounted electronic device, a mobile Internet device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, an ultra-mobile personal computer (UMPC), a netbook or a personal digital assistant (PDA), etc. It can also be a server, a network attached storage (NAS), a personal computer (PC), a television (TV), a teller machine or a self-service machine, etc., and the embodiment of the present application does not specifically limit it.

[0136] The high-standard farmland DOM rapid production device based on tower-mounted single-camera photography in the embodiments of the present application can be a device with an operating system. The operating system can be an Android operating system, an iOS operating system, or other possible operating systems, which are not specifically limited in the embodiments of the present application.

[0137] The high-standard farmland DOM rapid production device based on tower-top single-camera photography provided in the embodiment of the present application can achieve Figure 1 To avoid repetition, the various processes implemented in the method embodiment are not described here.

[0138] In some embodiments, as Figure 3 As shown, an embodiment of the present application also provides an electronic device 300, including a processor 310, a memory 320, and a computer program stored in the memory 320 and executable on the processor 310. When the computer program is executed by the processor 310, each process of the embodiment of the method for rapid production of high-standard farmland DOM based on tower-top single-camera photography is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0139] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0140] An embodiment of the present application also provides a non-transitory computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the various processes of the above-mentioned embodiment of the method for rapid production of high-standard farmland DOM based on tower-top single-camera photography, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0141] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0142] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the above-mentioned method for quickly producing high-standard farmland DOM based on tower-top single-camera photography.

[0143] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0144] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned embodiment of the method for rapid production of high-standard farmland DOM based on tower-top single-camera photography, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0145] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0146] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0147] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of this application.

[0148] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

[0149] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0150] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for quickly producing high-standard farmland DOM based on tower-top single-camera photography, characterized in that: include: Obtaining a camera photography model corresponding to the target camera based on the attitude angle of the target camera in taking the target image and the geographic location of the target camera; the target camera is a camera installed on the top of the tower; the camera photography model is used to indicate the correspondence between the homogeneous coordinates of pixels in the target image and the coordinates of the ground objects corresponding to the pixels in the three-dimensional world coordinate system; The target image is obtained by photographing high-standard farmland within the target range by the target camera; Based on the elevation of the objects within the target range and the camera photography model, obtaining a ground range corresponding to the DOM and a grid size of the DOM; the elevation of the objects within the target range is determined based on the height of the target camera from the ground, the maximum height of the objects within the target range, and the height of the target camera in the three-dimensional world coordinate system; Based on the distorted camera photography model corresponding to the target camera, project each grid of the DOM onto the target image to obtain the DOM corresponding to the target image; The grid is obtained by dividing the ground range based on the grid size of the DOM.

2. The method for rapidly producing high-standard farmland DOM based on tower top single camera photography according to claim 1, wherein: The step of obtaining a camera photography model corresponding to the target camera based on the attitude angle of the target camera taking the target picture and the geographical location of the target camera includes: Based on the posture angle, obtaining a rotation matrix; Based on the geographic location of the target camera, obtaining the coordinates of the target camera in the three-dimensional world coordinate system; The camera photography model is acquired based on the memory matrix of the target camera, the rotation matrix, and the coordinates of the target camera in the three-dimensional world coordinate system.

3. The method for rapidly producing high-standard farmland DOM based on tower top single camera photography according to claim 1, wherein: The obtaining of the ground range corresponding to the DOM and the grid size of the DOM based on the elevation of the ground object within the target range and the camera photography model includes: Based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and the minimum elevation of the ground objects within the target range are calculated to obtain the ground range; The grid size of the DOM is acquired based on the camera photography model, the average elevation of the objects within the target range, and the ground range.

4. The method for rapidly producing high-standard farmland DOM based on tower top single camera photography according to claim 3, characterized in that: The step of calculating the homogeneous coordinates of the four corner points of the target image and the maximum elevation and the minimum elevation of the ground objects within the target range based on the camera photography model to obtain the ground range includes: Based on the camera photography model, the homogeneous coordinates of the four corner points of the target image and the maximum elevation and the minimum elevation of the ground objects within the target range are calculated to obtain the coordinates of the corresponding eight object points in the three-dimensional world coordinate system; Obtaining first target coordinates corresponding to the minimum value of the first coordinate axis coordinate and the minimum value of the second coordinate axis coordinate of the eight object points in the three-dimensional world coordinate system, and second target coordinates corresponding to the maximum value of the first coordinate axis coordinate and the maximum value of the second coordinate axis coordinate; A range on the ground corresponding to a rectangle with the points corresponding to the first target coordinates and the second target coordinates as diagonals is determined as the ground range.

5. The method for rapidly producing high-standard farmland DOM based on tower top single camera photography according to claim 4, characterized in that: The obtaining of the grid size of the DOM based on the camera photography model, the average elevation of the objects within the target range, and the ground range includes: Determine a target object point based on the first target coordinates and the average elevation and based on the second target coordinates and the average elevation respectively; Based on the camera photography model and the coordinates of each target object point in the three-dimensional world coordinate system, obtaining the homogeneous coordinates corresponding to each target object point; A grid size of the DOM is acquired based on the first target coordinates, the second target coordinates, and homogeneous coordinates corresponding to the two target object points.

6. The method for rapidly producing high-standard farmland DOM based on tower top single camera photography according to claim 5, characterized in that: The acquiring the grid size of the DOM based on the first target coordinates, the second target coordinates, and the homogeneous coordinates corresponding to the two target object points includes: The size of the DOM grid in the direction of the first coordinate axis is obtained based on the minimum value of the first coordinate axis coordinate, the maximum value of the first coordinate axis coordinate, and the coordinates corresponding to the first coordinate axis in the homogeneous coordinates corresponding to the two target object points. The size of the DOM grid in the direction of the second coordinate axis is obtained based on the minimum value of the second coordinate axis coordinate, the maximum value of the second coordinate axis coordinate, and the coordinates corresponding to the second coordinate axis in the homogeneous coordinates corresponding to the two target object points.

7. The method for rapidly producing high-standard farmland DOM based on tower-top single-camera photography according to any one of claims 1 to 6, characterized in that: The step of projecting each mesh of the DOM onto the target image based on the distorted camera photography model corresponding to the target camera to obtain the DOM corresponding to the target image includes: Divide the ground range based on the grid size of the DOM, and obtain each grid of the DOM; Based on the distorted camera photography model, project each of the grids onto the target image to obtain floating-point pixel coordinates corresponding to the grid; The floating-point pixel coordinates are interpolated to obtain the color value of each grid of the DOM, thereby obtaining the DOM corresponding to the target image.

8. A high-standard farmland DOM rapid production device based on tower-top single-camera photography, characterized in that: include: A construction module is configured to obtain a camera photography model corresponding to a target camera based on a posture angle of a target image captured by a target camera and a geographic location of the target camera; the target camera is a camera mounted on a tower top; the camera photography model is configured to indicate a correspondence between homogeneous coordinates of pixels in the target image and coordinates of ground features corresponding to the pixels in a three-dimensional world coordinate system; The target image is obtained by photographing high-standard farmland within the target range by the target camera; an estimation module, configured to obtain a ground range corresponding to the DOM and a grid size of the DOM based on the elevation of the ground objects within the target range and the camera photography model; the elevation of the ground objects within the target range is determined based on the height of the target camera from the ground, the maximum height of the ground objects within the target range, and the height of the target camera in the three-dimensional world coordinate system; An acquisition module, configured to project each grid of the DOM onto the target image based on a distorted camera photography model corresponding to the target camera, and acquire the DOM corresponding to the target image; The grid is obtained by dividing the ground range based on the grid size of the DOM.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method for quickly producing high-standard farmland DOM based on tower-top single-camera photography as described in any one of claims 1 to 6 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for quickly producing high-standard farmland DOM based on tower-top single-camera photography as described in any one of claims 1 to 6 is implemented.

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