CN109163708B - Optimization method, device and medium for unmanned aerial vehicle large-scale topographic map house line - Google Patents
Optimization method, device and medium for unmanned aerial vehicle large-scale topographic map house line Download PDFInfo
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Abstract
The invention discloses an optimization method, a device and a medium for a house line of a large-scale topographic map of an unmanned aerial vehicle, wherein the method comprises the following steps: constructing a real-scene three-dimensional model of the specified building according to the multi-view oblique image; selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively, and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface; and connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the outline of the specified building. The method can accurately extract the outline of the building according to the multi-view oblique image, and improves the surveying and mapping precision and efficiency of the building.
Description
Technical Field
The invention relates to the technical field of building surveying and mapping, in particular to an optimization method, device and medium for a building line of a large-scale topographic map of an unmanned aerial vehicle.
Background
A topographic map is an important general map, which is a projection of the location, shape, etc. of land features and landforms on a particular horizontal plane. Specifically, the ground surface is formed by projecting the ground features and the landforms on the ground onto a projection surface along the direction of a plumb line and drawing the ground features and the landforms in a reduced mode according to a certain scale. The house is a key element in various topographic maps as an important feature, and the convenience and accuracy of mapping are important for the topographic maps.
In recent years, unmanned aerial vehicles are adopted to perform 1: 2000 to 1: large scale topographical mapping in the 500 scale range has become a hot issue in the global surveying field. Compared with the traditional topographic map surveying and mapping method, the large-scale unmanned aerial vehicle surveying and mapping method has the advantages of high automation degree, high image resolution, rich visual angles and the like, has remarkable advantages in the aspect of operation efficiency, and greatly reduces field intensity.
The house line in the large-scale topographic map is formed by a projection line of the outer vertical surface of the building on a projection plane, so that the surveying and mapping precision of the house is directly dependent on the determination precision of the outer vertical surface and the side line of the house. However, when a house sideline is manually and directly drawn on a stereoscopic image, a linear target presents a sharp angle in a view and is easy to generate a large collusion deviation; meanwhile, due to the shielding of tree vegetation and other ground objects, the characteristic positions of bases, sidelines, angular points and the like of a large number of houses cannot be directly displayed on the images, and therefore surveying and mapping cannot be performed. The problems lead to insufficient precision and low efficiency of house surveying and mapping, and limit popularization and application of unmanned aerial vehicles to measure large-scale topographic maps to a great extent.
Disclosure of Invention
Based on the method, the device and the storage medium, the invention provides the optimization method, the device and the storage medium for the building line of the large-scale topographic map of the unmanned aerial vehicle, so that the outline of the building can be accurately extracted according to the multi-view oblique image, and the surveying and mapping precision and efficiency of the building are improved.
The embodiment of the invention provides an optimization method of a house line of a large-scale topographic map of an unmanned aerial vehicle, which comprises the following steps:
constructing a real-scene three-dimensional model of the specified building according to the multi-view oblique image;
selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively, and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; the number of points selected in the outer vertical surface is more than 2;
calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface;
and connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the outline of the specified building.
Preferably, the calculating a projection line of the facade and a projection intersection point of the adjacent facades according to the projection points corresponding to the same facade specifically includes:
performing linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line;
calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point;
and connecting two corresponding projection intersection points of the same outer vertical surface to obtain a projection line of the outer vertical surface.
Preferably, before constructing the realistic three-dimensional model of the specified building according to the multi-view oblique image, the method further comprises:
and according to the position data and the attitude data of the multi-view oblique image, performing aerial triangulation, geometric correction, coordinate conversion and image splicing on the multi-view oblique image.
Preferably, the performing linear fitting on a plurality of projection points corresponding to the same facade to obtain a projection straight line specifically includes:
numbering the outer vertical faces of the live-action three-dimensional model according to the adjacent relation of the outer vertical faces of the live-action three-dimensional model;
and according to the numbering sequence of the outer vertical surfaces of the live-action three-dimensional model, sequentially adopting a least square method to perform linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line.
Preferably, the performing linear fitting on a plurality of projection points corresponding to the same facade by using a least square method to obtain a projection straight line specifically includes:
according to the formula
Respectively solving partial derivatives of k and b, taking zero, and calculating two statistical parameters corresponding to a plurality of projection points corresponding to the facade;
wherein n is the number of projection points corresponding to the facade, and n is>2，(xi，yi) The two statistical parameters are respectively the coordinates of the ith projection point:
according to the two statistical parameters and a formula
Calculating linear equation parameters;
wherein, the linear equation parameters are respectively:
and determining a projection straight line corresponding to the outer vertical surface according to the linear equation parameters.
Preferably, the calculating an intersection point of projection straight lines corresponding to the adjacent facade as the projection intersection point specifically includes:
according to the formula
Calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces;
wherein the coordinates of the intersection point are
ki、biLinear equation parameters of a projection straight line corresponding to the ith facade; k is a radical ofi+1、bi+1And the parameters of the linear equation of the projection straight line corresponding to the (i + 1) th facade are obtained, and the (i + 1) th facade is adjacent to the ith facade.
Preferably, the method for optimizing the house line of the unmanned aerial vehicle large-scale topographic map further comprises the following steps:
and establishing a measurement projection plane relative to the real-scene three-dimensional model by adopting an urban plane coordinate system or a Gaussian measurement projection plane coordinate system according to a plane where the local area earth surface in the multi-view oblique image after image splicing is located.
The embodiment of the invention also provides an optimization device for the unmanned aerial vehicle large-scale topographic map house line, which comprises the following steps:
the three-dimensional model building module is used for building a real-scene three-dimensional model of the specified building according to the multi-view oblique image;
the projection module is used for selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; the number of points selected in the outer vertical surface is more than 2;
the projection intersection point calculation module is used for calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface;
and the contour extraction module is used for connecting the projection lines and the projection intersection points according to the topological relation between the projection lines and the projection intersection points to obtain the contour of the specified building.
The embodiment of the invention also provides an optimization device for the unmanned aerial vehicle large-scale topographic map house line, which comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the optimization method for the unmanned aerial vehicle large-scale topographic map house line is realized.
The embodiment of the invention also provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program runs, a device where the computer-readable storage medium is located is controlled to execute the optimization method for the house line of the unmanned aerial vehicle large-scale topographic map.
Compared with the prior art, the optimization method of the unmanned aerial vehicle large-scale topographic map house line provided by the embodiment of the invention has the beneficial effects that: the optimization method of the unmanned aerial vehicle large-scale topographic map house line comprises the following steps: constructing a real-scene three-dimensional model of the specified building according to the multi-view oblique image; selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively, and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface; and connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the outline of the specified building. The method can accurately extract the outline of the building according to the multi-view oblique image, and improves the surveying and mapping precision and efficiency of the building.
Drawings
Fig. 1 is a flowchart of an optimization method for a house line of a large-scale topographic map of an unmanned aerial vehicle according to an embodiment of the present invention;
FIG. 2 is a schematic view of a building facade projection;
FIG. 3 is a schematic view of a projected intersection of a building facade;
fig. 4 is a schematic diagram of an optimization device for a building line of a large-scale topographic map of an unmanned aerial vehicle according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Please refer to fig. 1, which is a flowchart of a method for optimizing a house line of a large-scale topographic map of an unmanned aerial vehicle according to an embodiment of the present invention, where the method for optimizing the house line of the large-scale topographic map of the unmanned aerial vehicle includes:
s100: constructing a real-scene three-dimensional model of the specified building according to the multi-view oblique image;
s200: selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively, and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; the number of points selected in the outer vertical surface is more than 2;
s300: calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface;
s400: and connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the outline of the specified building.
In this embodiment, each point in the facade may be selected according to a feature position in the live-action three-dimensional model, or point coordinates may be directly obtained and input through a design drawing, field measurement, and the like. The principle of selecting two points in the outer vertical surface is that the two points are positioned on the corresponding outer vertical surface, and the outer vertical surface has higher image identification degree and is convenient to click.
And connecting and forming the contour line of the specified building according to the topological relation between the projection lines and the projection intersection points to obtain the contour of the specified building. As shown in fig. 2, the building outline is generally a closed figure, and information such as building attributes and the number of floors can be added to the building outline.
The method directly constructs and projects the outer edge line based on the characteristics of the outer vertical face in the real-scene three-dimensional model corresponding to the specified building, and ensures the accuracy, the tightness and the robustness of the edge line through the constraint of a plurality of faces. The method has strong technical adaptability, and can accurately extract the building characteristic lines which cannot be directly seen on the image due to the problems of shielding, visual angle and the like, so that the contour of the building can be accurately extracted, and the efficiency, convenience and precision of building surveying and mapping are improved. The method has wide application prospect in the related fields of low-altitude aerial survey of unmanned aerial vehicles, ground or aerial oblique photogrammetry, rapid survey and control of large-scale topographic maps and the like.
In an alternative embodiment, as shown in fig. 3, S300: according to a plurality of projection points corresponding to the same outer vertical surface, calculating projection lines of the outer vertical surface and adjacent projection intersection points of the outer vertical surface, and specifically comprising the following steps:
performing linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line;
calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point;
and connecting two corresponding projection intersection points of the same outer vertical surface to obtain a projection line of the outer vertical surface.
Wherein, each point selected on the building facade has certain error due to the view angle, measurement or operation reason. An optimal estimate of the contour can only be obtained if the error is reasonably eliminated. In this embodiment, the distance between each projection point on the measurement projection plane and the fitted projection straight line is calculated, and the calculation formula is as follows:
when the distance diIf the value is greater than a specific threshold value epsilon, the projection point P is indicatediThere is a large error, at this time, the projected point P isiAnd (5) removing. And then, performing straight line fitting on the projection points reserved after the error is eliminated to obtain a projection straight line corresponding to the facade.
In an optional embodiment, the calculating a projection straight line connecting projection points corresponding to the same facade specifically includes:
numbering the outer vertical faces of the live-action three-dimensional model according to the adjacent relation of the outer vertical faces of the live-action three-dimensional model;
and according to the numbering sequence of the outer vertical surfaces of the live-action three-dimensional model, sequentially adopting a least square method to perform linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line.
In an optional embodiment, the performing linear fitting on a plurality of projection points corresponding to the same facade by using a least square method to obtain a projection straight line specifically includes:
according to the formula
Respectively solving partial derivatives of k and b, taking zero, and calculating two statistical parameters corresponding to a plurality of projection points corresponding to the facade;
wherein n is the number of projection points corresponding to the facade, and n is>2，(xi，yi) The coordinates of the ith projection point, the two statisticsThe parameters are respectively:
according to the two statistical parameters and a formula
Calculating linear equation parameters;
wherein, the linear equation parameters are respectively:
and determining a projection straight line corresponding to the outer vertical surface according to the linear equation parameters.
As shown in fig. 3, for example: each point selected by the outer vertical surface is P1(x1，y1)、P2(x2，y2)；P3(x3，y3)、P4(x4，y4)、Pi(xi，yi)…Pn(xn，yn) (ii) a Calculating the statistical parameter t corresponding to the plurality of projection points corresponding to the facade by adopting the formula (2) according to the coordinates of the points selected by the facade1、t2、t3、t4And (2) calculating linear equation parameters k and b by connecting the statistical parameters calculated by the formula (1) with the statistical parameters calculated by the formula (1), and determining that the projection straight line corresponding to the facade is l: y ═ kx + b according to the linear equation parameters k and b.
The outer vertical face side line of the building is a straight line formed by one outer vertical face and two adjacent outer vertical faces. In the embodiment, n points (n >2) on the outer vertical surface are sequentially selected according to the adjacent relation of the outer vertical surface, the projection straight lines of the outer vertical surface are obtained for all the outer vertical surfaces with the contour characteristics of the building by adopting the formula, and the accuracy, the tightness and the robustness of building surveying and mapping can be improved through the constraint of two planes. All the outer facades to be processed are numbered according to the adjacent relation between the outer facades and are sequentially calculated according to the numbering sequence, so that mistakes and omissions can be avoided.
In an alternative embodiment, S400: calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point, and specifically comprising:
according to the formula
Calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces;
wherein the coordinates of the intersection point are
ki、biLinear equation parameters of a projection straight line corresponding to the ith facade; k is a radical ofi+1、bi+1And the parameters of the linear equation of the projection straight line corresponding to the (i + 1) th facade are obtained, and the (i + 1) th facade is adjacent to the ith facade.
In an alternative embodiment, S100: according to the multi-view oblique image, before constructing the real-scene three-dimensional model of the specified building, the method further comprises the following steps:
and according to the position data and the attitude data of the multi-view oblique image, performing aerial triangulation, geometric correction, coordinate conversion and image splicing on the multi-view oblique image.
Because the unmanned aerial vehicle has low flight height and high resolution ratio and is limited by a visual angle, surveying and mapping of large buildings such as houses can be completely covered only by multi-angle image acquisition of a plurality of survey stations, multi-view oblique images of specified buildings need to be acquired, preprocessing such as aerial triangulation, geometric correction, coordinate conversion, image splicing and the like is carried out according to position (GPS) data and attitude (POS) data of the multi-view oblique images by adopting a general method, and image data with the characteristics of large data volume, high overlapping degree and rich visual angles is generated, so that constructed point cloud and live-action three-dimensional models are positioned in the same space rectangular coordinate system with a measured projection plane, and subsequent unified processing is facilitated.
In an optional embodiment, the method for optimizing the house line of the unmanned aerial vehicle large-scale topographic map further includes:
and establishing a measurement projection plane relative to the real-scene three-dimensional model by adopting an urban plane coordinate system or a Gaussian measurement projection plane coordinate system according to a plane where the local area earth surface in the multi-view oblique image after image splicing is located. And the elevation datum plane corresponding to the measurement projection plane is a similar geoid plane.
The coordinate system of the large-scale mapping adopts a form that a plane is separated from an elevation. In this embodiment, the local area earth surface in the multi-view oblique image after image stitching is taken as a plane, and a measurement projection plane corresponding to the live-action three-dimensional model is established by using a plane coordinate, for example, an urban plane coordinate system or a gaussian measurement projection plane coordinate system. And the elevation reference surface of the large-scale mapping can adopt urban elevation reference or national elevation reference. Preferably, in this embodiment, a quasi-geoid is used as the elevation reference surface, and the z-coordinate axis is upward along the direction of the ground plumb line because the building facades are planes that can represent the outline of the building, and the facades are all in line with the plumb line, i.e. parallel to the z-coordinate axis.
Please refer to fig. 4, which is a schematic diagram of an optimization apparatus for a large scale topographic map house line of an unmanned aerial vehicle according to an embodiment of the present invention, the optimization apparatus for a large scale topographic map house line of an unmanned aerial vehicle includes:
the three-dimensional model building module 1 is used for building a real-scene three-dimensional model of the specified building according to the multi-view oblique image;
the projection module 2 is used for selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively and projecting the points onto a preset measurement projection surface to obtain projection points of the plurality of points selected from the adjacent outer vertical surfaces on the measurement projection surface; the number of points selected in the outer vertical surface is more than 2;
the projection intersection point calculation module 3 is used for calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface;
and the contour extraction module 4 is used for connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the contour of the specified building.
In this embodiment, each point in the facade may be selected according to a feature position in the live-action three-dimensional model, or point coordinates may be directly obtained and input through a design drawing, field measurement, and the like. The principle of selecting two points in the outer vertical surface is that the two points are positioned on the corresponding outer vertical surface, and the outer vertical surface has higher image identification degree and is convenient to click.
And connecting and forming the contour line of the specified building according to the topological relation between the projection lines and the projection intersection points to obtain the contour of the specified building. As shown in fig. 2, the building outline is generally a closed figure, and information such as building attributes and the number of floors can be added to the building outline.
The method directly constructs and projects the outer edge line based on the characteristics of the outer vertical face in the real-scene three-dimensional model corresponding to the specified building, and ensures the accuracy, the tightness and the robustness of the edge line through the constraint of a plurality of faces. The method has strong technical adaptability, and can accurately extract the building characteristic lines which cannot be directly seen on the image due to the problems of shielding, visual angle and the like, so that the contour of the building can be accurately extracted, and the efficiency, convenience and precision of building surveying and mapping are improved. The method has wide application prospect in the related fields of low-altitude aerial survey of unmanned aerial vehicles, ground or aerial oblique photogrammetry, rapid survey and control of large-scale topographic maps and the like.
In an alternative embodiment, as shown in fig. 3, the projection intersection calculation module 3 includes:
the projection straight line calculation unit is used for performing straight line fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line;
the projection intersection point calculation unit is used for calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point;
and the projection line connecting unit is used for connecting two projection intersection points corresponding to the same outer vertical surface to obtain the projection line of the outer vertical surface.
Wherein, each point selected on the building facade has certain error due to the view angle, measurement or operation reason. An optimal estimate of the contour can only be obtained if the error is reasonably eliminated. In this embodiment, the distance between each projection point on the measurement projection plane and the fitted projection straight line is calculated, and the calculation formula is as follows:
when the distance diIf the value is greater than a specific threshold value epsilon, the projection point P is indicatediThere is a large error, at this time, the projected point P isiAnd (5) removing. And then, performing straight line fitting on the projection points reserved after the error is eliminated to obtain a projection straight line corresponding to the facade.
In an alternative embodiment, the projection straight line calculating unit includes:
the numbering unit is used for numbering the outer vertical surfaces of the live-action three-dimensional model according to the adjacent relation of the outer vertical surfaces of the live-action three-dimensional model;
and the straight line calculating unit is used for sequentially adopting a least square method to perform straight line fitting on a plurality of projection points corresponding to the same outer vertical surface according to the serial number sequence of the outer vertical surface of the real three-dimensional model to obtain a projection straight line.
In an alternative embodiment, the straight line calculation unit includes:
a statistical parameter calculation unit for calculating a statistical parameter according to a formula
Respectively solving partial derivatives of k and b, taking zero, and calculating two statistical parameters corresponding to a plurality of projection points corresponding to the facade;
wherein n is the number of projection points corresponding to the facade, and n is>2，(xi，yi) Is the coordinate of the ith projection pointThe two statistical parameters are respectively:
a linear equation parameter calculation unit for calculating a linear equation parameter according to the two statistical parameters and the formula
Calculating linear equation parameters;
wherein, the linear equation parameters are respectively:
and the projection straight line determining unit is used for determining the projection straight line corresponding to the outer vertical surface according to the linear equation parameters.
As shown in fig. 3, for example: each point selected by the outer vertical surface is P1(x1，y1)、P2(x2，y2)；P3(x3，y3)、P4(x4，y4)、Pi(xi，yi)…Pn(xn，yn) (ii) a Calculating the statistical parameter t corresponding to the plurality of projection points corresponding to the facade by adopting the formula (2) according to the coordinates of the points selected by the facade1、t2、t3、t4And (2) calculating linear equation parameters k and b by connecting the statistical parameters calculated by the formula (1) with the statistical parameters calculated by the formula (1), and determining that the projection straight line corresponding to the facade is l: y ═ kx + b according to the linear equation parameters k and b.
The outer vertical face side line of the building is a straight line formed by one outer vertical face and two adjacent outer vertical faces. In the embodiment, n points (n >2) on the outer vertical surface are sequentially selected according to the adjacent relation of the outer vertical surface, the projection straight lines of the outer vertical surface are obtained for all the outer vertical surfaces with the contour characteristics of the building by adopting the formula, and the accuracy, the tightness and the robustness of building surveying and mapping can be improved through the constraint of two planes. All the outer facades to be processed are numbered according to the adjacent relation between the outer facades and are sequentially calculated according to the numbering sequence, so that mistakes and omissions can be avoided.
In an alternative embodiment, the projection intersection calculation module 4 is configured to calculate the projection intersection according to a formula
Calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces;
wherein the coordinates of the intersection point are
ki、biLinear equation parameters of a projection straight line corresponding to the ith facade; k is a radical ofi+1、bi+1And the parameters of the linear equation of the projection straight line corresponding to the (i + 1) th facade are obtained, and the (i + 1) th facade is adjacent to the ith facade.
In an optional embodiment, the apparatus for optimizing a house line of a large-scale topographic map of a drone comprises:
and the data preprocessing module is used for carrying out aerial triangulation, geometric correction, coordinate conversion and image splicing on the multi-view oblique image according to the position data and the attitude data of the multi-view oblique image.
Because the unmanned aerial vehicle has low flight height and high resolution ratio and is limited by a visual angle, surveying and mapping of large buildings such as houses can be completely covered only by multi-angle image acquisition of a plurality of survey stations, multi-view oblique images of specified buildings need to be acquired, preprocessing such as aerial triangulation, geometric correction, coordinate conversion, image splicing and the like is carried out according to position (GPS) data and attitude (POS) data of the multi-view oblique images by adopting a general method, and image data with the characteristics of large data volume, high overlapping degree and rich visual angles is generated, so that constructed point cloud and live-action three-dimensional models are positioned in the same space rectangular coordinate system with a measured projection plane, and subsequent unified processing is facilitated.
In an optional embodiment, the apparatus for optimizing a house line of a large-scale topographic map of a drone comprises:
and the projection plane establishing module is used for establishing a measurement projection plane relative to the real-scene three-dimensional model by adopting an urban plane coordinate system or a Gaussian measurement projection plane coordinate system according to a plane where the local area earth surface in the multi-view oblique image after image splicing is located. And the elevation datum plane corresponding to the measurement projection plane is a similar geoid plane.
The coordinate system of the large-scale mapping adopts a form that a plane is separated from an elevation. In this embodiment, the local area earth surface in the multi-view oblique image after image stitching is taken as a plane, and a measurement projection plane corresponding to the live-action three-dimensional model is established by using a plane coordinate, for example, an urban plane coordinate system or a gaussian measurement projection plane coordinate system. And the elevation reference surface of the large-scale mapping can adopt urban elevation reference or national elevation reference. Preferably, in this embodiment, a quasi-geoid is used as the elevation reference surface, and the z-coordinate axis is upward along the direction of the ground plumb line because the building facades are planes that can represent the outline of the building, and the facades are all in line with the plumb line, i.e. parallel to the z-coordinate axis.
The embodiment of the invention also provides an optimization device for the unmanned aerial vehicle large-scale topographic map house line, which comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the optimization method for the unmanned aerial vehicle large-scale topographic map house line is realized.
Illustratively, the computer program may be partitioned into one or more modules/units that are stored in the memory and executed by the processor to implement the invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used for describing the execution process of the computer program in the optimization device of the unmanned aerial vehicle large-scale topographic map house line. For example, the computer program may be divided into functional modules of the optimization apparatus of the unmanned aerial vehicle large scale topographic map house line of fig. 4.
The optimization device of the unmanned aerial vehicle large-scale topographic map house line can be computing equipment such as a mobile phone, a desktop computer, a notebook computer, a palm computer and a cloud server. The optimization device for the unmanned aerial vehicle large-scale topographic map house line can comprise, but is not limited to, a processor and a memory. For example, the optimization device for the unmanned aerial vehicle large-scale topographic map house line can further comprise input and output equipment, network access equipment, a bus and the like.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general processor can be a microprocessor or the processor can be any conventional processor and the like, the processor is a control center of the optimization device of the unmanned aerial vehicle large-scale topographic map house line, and various interfaces and lines are utilized to connect various parts of the optimization device of the whole unmanned aerial vehicle large-scale topographic map house line.
The memory can be used for storing the computer program and/or the module, and the processor realizes various functions of the optimization device of the unmanned aerial vehicle large-scale topographic map house line by running or executing the computer program and/or the module stored in the memory and calling the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
The modules/units integrated by the optimization device of the unmanned aerial vehicle large-scale topographic map house line can be stored in a computer readable storage medium if the modules/units are realized in the form of software functional units and sold or used as independent products. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
The embodiment of the invention also provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program runs, a device where the computer-readable storage medium is located is controlled to execute the optimization method for the house line of the unmanned aerial vehicle large-scale topographic map.
Compared with the prior art, the optimization method of the unmanned aerial vehicle large-scale topographic map house line provided by the embodiment of the invention has the beneficial effects that: the optimization method of the unmanned aerial vehicle large-scale topographic map house line comprises the following steps: constructing a real-scene three-dimensional model of the specified building according to the multi-view oblique image; selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively, and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface; and connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the outline of the specified building. The method can accurately extract the outline of the building according to the multi-view oblique image, and improves the surveying and mapping precision and efficiency of the building.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. In addition, in the drawings of the embodiment of the apparatus provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, and may be specifically implemented as one or more communication buses or signal lines. One of ordinary skill in the art can understand and implement it without inventive effort.
The foregoing is a preferred embodiment of the present invention, and it should be noted that it would be apparent to those skilled in the art that various modifications and enhancements can be made without departing from the principles of the invention, and such modifications and enhancements are also considered to be within the scope of the invention.
Claims (9)
1. An optimization method for a building line of a large-scale topographic map of an unmanned aerial vehicle is characterized by comprising the following steps:
constructing a real-scene three-dimensional model of the specified building according to the multi-view oblique image;
selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively, and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; the number of points selected in the outer vertical surface is more than 2;
calculating projection lines of the outer vertical surfaces and projection intersection points of the adjacent outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface;
connecting the projection lines and the projection intersections according to the topological relation between the projection lines and the projection intersections to obtain the outline of the specified building;
the method comprises the following steps of calculating projection lines of the outer vertical surfaces and adjacent projection intersection points of the outer vertical surfaces according to a plurality of projection points corresponding to the same outer vertical surface, and specifically comprises the following steps:
performing linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line;
calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point;
connecting two corresponding projection intersections of the same outer vertical surface to obtain a projection line of the outer vertical surface;
wherein, carry out straight line fitting to a plurality of projection point that same facade corresponds, obtain the projection straight line, specifically include:
performing straight line fitting on a plurality of projection points corresponding to the same outer vertical surface;
calculating the distance from a plurality of the projection points to the fitted projection straight line by the following formula:
wherein the content of the first and second substances,xiis the abscissa, y, of the ith projection pointiIs the ordinate, k, of the ith projection point1、b1As a parameter of the projected line, diThe distance from the ith projection point to the projection straight line is calculated;
and when the distance corresponding to a projection point is larger than a preset threshold value, the corresponding projection point is removed, and the retained projection point is subjected to straight line fitting again to obtain a projection straight line.
2. The method for optimizing a building line of a large-scale topographic map of an unmanned aerial vehicle as claimed in claim 1, wherein before constructing the realistic three-dimensional model of the designated building based on the multi-view oblique images, the method further comprises:
and according to the position data and the attitude data of the multi-view oblique image, performing aerial triangulation, geometric correction, coordinate conversion and image splicing on the multi-view oblique image.
3. The method for optimizing the house line of the unmanned aerial vehicle large-scale topographic map as claimed in claim 1, wherein the step of performing straight line fitting on the plurality of projection points corresponding to the same facade to obtain a projection straight line specifically comprises the steps of:
numbering the outer vertical faces of the live-action three-dimensional model according to the adjacent relation of the outer vertical faces of the live-action three-dimensional model;
and according to the numbering sequence of the outer vertical surfaces of the live-action three-dimensional model, sequentially adopting a least square method to perform linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line.
4. The method for optimizing the house line of the unmanned aerial vehicle large-scale topographic map as claimed in claim 3, wherein the step of performing straight line fitting on the plurality of projection points corresponding to the same external vertical surface by using a least square method to obtain a projection straight line specifically comprises the steps of:
according to the formula
Respectively solving partial derivatives of k and b, taking zero, and calculating two statistical parameters corresponding to a plurality of projection points corresponding to the facade;
wherein n is the number of projection points corresponding to the facade, and n is>2，(xi，yi) The two statistical parameters are respectively the coordinates of the ith projection point:
according to the two statistical parameters and a formula
Calculating linear equation parameters;
wherein, the linear equation parameters are respectively:
and determining a projection straight line corresponding to the outer vertical surface according to the linear equation parameters.
5. The method for optimizing the house line of the unmanned aerial vehicle large-scale topographic map as claimed in claim 4, wherein the calculating an intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point specifically comprises:
according to the formula
Calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces;
wherein the coordinates of the intersection point are
ki、biLinear equation parameters of a projection straight line corresponding to the ith facade; k is a radical ofi+1、bi+1Is the linear equation parameter of the projection straight line corresponding to the (i + 1) th facade, and the (i + 1) th facade is in phase with the (i) th facadeAnd (4) adjacent.
6. The method for optimizing the house line of the large-scale topographic map of the unmanned aerial vehicle as claimed in claim 2, wherein the method for optimizing the house line of the large-scale topographic map of the unmanned aerial vehicle further comprises:
and establishing a measurement projection plane relative to the real-scene three-dimensional model by adopting an urban plane coordinate system or a Gaussian measurement projection plane coordinate system according to a plane where the local area earth surface in the multi-view oblique image after image splicing is located.
7. The utility model provides an optimization device of unmanned aerial vehicle large-scale topographic map house line which characterized in that includes:
the three-dimensional model building module is used for building a real-scene three-dimensional model of the specified building according to the multi-view oblique image;
the projection module is used for selecting a plurality of points from adjacent outer vertical surfaces in the real three-dimensional model respectively and projecting the points onto a preset measurement projection surface to obtain projection points of the selected points in the adjacent outer vertical surfaces on the measurement projection surface; the number of points selected in the outer vertical surface is more than 2;
the projection intersection point calculation module is used for calculating the projection line of the outer vertical surface and the adjacent projection intersection point of the outer vertical surface according to a plurality of projection points corresponding to the same outer vertical surface, and specifically comprises:
performing linear fitting on a plurality of projection points corresponding to the same outer vertical surface to obtain a projection straight line;
calculating the intersection point of the projection straight lines corresponding to the adjacent outer vertical surfaces as the projection intersection point;
connecting two corresponding projection intersections of the same outer vertical surface to obtain a projection line of the outer vertical surface;
wherein, carry out straight line fitting to a plurality of projection point that same facade corresponds, obtain the projection straight line, specifically include:
performing straight line fitting on a plurality of projection points corresponding to the same outer vertical surface;
calculating the distance from a plurality of the projection points to the fitted projection straight line by the following formula:
wherein x isiIs the abscissa, y, of the ith projection pointiIs the ordinate, k, of the ith projection point1、b1As a parameter of the projected line, diThe distance from the ith projection point to the projection straight line is calculated;
when the distance corresponding to a projection point is larger than a preset threshold value, the corresponding projection point is removed, and straight line fitting is carried out on the reserved projection point again to obtain a projection straight line;
and the contour extraction module is used for connecting the projection lines and the projection intersection points according to the topological relation between the projection lines and the projection intersection points to obtain the contour of the specified building.
8. An apparatus for optimizing a large-scale topographic house line of a drone, comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor when executing the computer program implementing a method of optimizing a large-scale topographic house line of a drone according to any one of claims 1 to 6.
9. A computer-readable storage medium, comprising a stored computer program, wherein the computer program, when executed, controls an apparatus on which the computer-readable storage medium is located to perform the method for optimizing a house line of a large-scale topographic map of unmanned aerial vehicle of any one of claims 1 to 6.
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| CN103198494A (en) * | 2013-04-03 | 2013-07-10 | 武汉海达数云技术有限公司 | Building elevation extraction method based on building outer contour lines and laser-point cloud |
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