Unmanned aerial vehicle field surveying and mapping method
Technical Field
The invention relates to the technical field of unmanned aerial vehicle surveying and mapping, in particular to a method for field surveying and mapping of an unmanned aerial vehicle.
Background
The aerial photogrammetry is an important technical means for rapidly acquiring geographic information, is a way for measuring and updating a national topographic map and establishing a geographic information database, plays an irreplaceable role in the acquisition and updating processes of spatial information, and particularly ensures that the acquisition and updating of large-area and large-medium-scale data are independent of the aerial photogrammetry.
At present, most of aerial photogrammetry adopts small civil aircrafts, but after once surveying and mapping, more cost is generated, a flight scheme needs to be formulated and an airspace needs to be applied during flight, the weather condition needs to be determined, and the small civil aircrafts are inconvenient to steer for many times and measure for many times during flight.
Disclosure of Invention
The invention aims to solve the problems that more cost is generated, a flight scheme and an applied airspace need to be formulated during flying, the weather condition needs to be determined, and the small civil aircraft can not be conveniently used for multiple steering and multiple measurement during flying, and provides a method for field surveying and mapping of the unmanned aerial vehicle.
In order to achieve the purpose, the technical scheme of the invention is as follows: a method for field mapping of unmanned aerial vehicles comprises the following steps:
the method comprises the following steps: carrying out unmanned plane test flight in the operation area, and primarily observing the operation area;
step two: laying image control points according to the condition of the operation area, and measuring coordinate values of the image control points;
step three: importing aerial shooting image data and POS data of the unmanned aerial vehicle and measured image control point coordinate values into surveying and mapping special software to carry out aerial three-dimensional encryption, point cloud generation and live-action three-dimensional model calculation;
step four: and (5) performing tone painting and supplementary measurement by comparing the live-action three-dimensional model with the live-action, and recording.
Preferably, in step one, the unmanned aerial vehicle need collect the operation district data before trying to fly, look over local weather condition, customization unmanned aerial vehicle flies technical scheme and inspection equipment.
Preferably, in the step one, during test flight, the unmanned aerial vehicle firstly flies for a circle around the edge of the operation area, and flies linearly in the opposite area and records the flight.
Preferably, in the second step, three or more image control points are arranged in each square kilometer of the working area, and the image control points identify marks easy to identify.
Preferably, in the second step, the PTK measuring instrument is used for measuring the coordinate value of the image control point, the PTK measuring instrument is initialized, the number of measured epochs is not less than 20, the sampling interval is generally 2 s-4 s, and the PTK measuring instrument cannot be used for measuring by using a total station.
Preferably, in the third step, the heading of the unmanned aerial vehicle should exceed the two baselines in the range of the operation area, the lateral exceeding range is not less than 40% of the image fortune, the overlapping of the heading of the image is not less than 60%, the overlapping of the lateral direction is not less than 60%, and the rotation deviation angle is 5-20 °.
Preferably, in the third step, the aerial images are preprocessed, the number of POS terminals is checked to be consistent with and corresponding to the number of images, and the distorted images are removed by performing checking analysis by combining inertial navigation data.
Preferably, the connecting points are firstly thinned to 500 after initial net building, accurate matching and gray point optimization, then free net adjustment is carried out, parameters are set, points with large residual errors are deleted, and after the free net is stable, thorn control points are added for carrying out air-to-three adjustment.
Preferably, in the third step, the aerial photography image is firstly subjected to light and color homogenizing treatment, then multiple times of editing modification and digital differential correction are carried out, the color tone treatment is carried out, so that the color tone close to consistency is achieved, no obvious splicing seam exists, and the live-action three-dimensional model is formed through mapping software.
Preferably, in the fourth step, the live-action three-dimensional model is compared with the live-action, the error region is corrected, the image is subjected to gray processing, and the edge is subjected to enhancement processing.
Compared with the prior art, the invention has the following beneficial effects:
1. the unmanned aerial vehicle is used for aerial photography, the operation is convenient, the working cost is low, the working efficiency is high in use, the operation is flexible, the measurement can be carried out for multiple times, the unmanned aerial vehicle is suitable for multiple working environments, the influence by weather conditions is small, the flight safety of pilots is not required to be considered when aerial photography images are obtained, the requirements on geographic airspace and weather conditions when data are obtained are low, and the problem that the regional monitoring function cannot be achieved by manual detection can be solved;
2. the final generated image of the aerial photography image of the unmanned aerial vehicle is clear in imaging, real and uniform in color, and capable of measuring local areas for multiple times and convenient to modify.
Drawings
Fig. 1 is a flow chart of a method for field surveying and mapping of an unmanned aerial vehicle according to the present invention.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.
Referring to fig. 1, a method for field mapping of an unmanned aerial vehicle includes the following steps:
the method comprises the following steps: carrying out unmanned plane test flight in the operation area, and primarily observing the operation area; in step one, the unmanned aerial vehicle needs to collect data of an operation area before test flight, check the local weather condition, customize the unmanned aerial vehicle flight technical scheme and check equipment. In the first step, during test flight, the unmanned aerial vehicle firstly flies for a circle around the edge of the operation area, and then linearly flies in the operation area and records the operation area. Before test flight, firstly, survey area data are collected, local weather conditions are checked, the survey area data comprise control point achievements, coordinate systems, elevation datum parameters, existing topographic map achievements, place name data and the like, an unmanned aerial vehicle flight technical scheme is formulated, an airspace is applied, and the problems of sensors, ground resolution, image overlapping degree, flight high-altitude flight time, image shooting intervals and the like carried by the unmanned aerial vehicle are determined. It is desirable to have an impression of the work area that was initially photographed, and to record marked areas and buildings, and to record problems encountered during the initial flight and initial photographing.
Step two: laying image control points according to the condition of the operation area, and measuring coordinate values of the image control points; in the second step, more than three image control points are distributed in each square kilometer in the operation area, and the image control points mark marks which are easy to identify. And in the second step, measuring the coordinate value of the image control point by using the PTK measuring instrument, initializing the PTK measuring instrument, wherein the number of measured epochs is not less than 20, the sampling interval is generally 2 s-4 s, and the PTK measuring instrument cannot be used for measuring by using a total station. The field working personnel lay the image control point according to taking or survey the district area by area, lay the image control point more than three every square kilometer, then according to technical scheme's arrangement, carry on multisensor with unmanned aerial vehicle and gather the topographic data from different angles such as a perpendicular, a plurality of slopes, the flexible high-efficient characteristics of full play unmanned aerial vehicle oblique photogrammetry technique, the working duration uses hour as the unit, different in the past large scale topographic map field work survey is calculated according to the number of days, shorten the project cycle, the surveying personnel only need unmanned aerial vehicle flight hand and a small amount of operator, compare with the field working personnel of a certain proportion of traditional mapping method according to survey the district area, personnel's quantity is reduced, save cost
Step three: importing aerial shooting image data and POS data of the unmanned aerial vehicle and measured image control point coordinate values into surveying and mapping special software to carry out aerial three-dimensional encryption, point cloud generation and live-action three-dimensional model calculation; in the third step, the course of the unmanned aerial vehicle should exceed the two baselines in the range of the operation area, the side direction exceeding range is not less than 40% of the image-like fortune, the course overlap of the image-like pictures is not less than 60%, the side direction overlap is not less than 60%, and the rotation deflection angle is 5-20 °. And in the third step, preprocessing the aerial images, checking that the number of POS (point of sale) is consistent with and corresponds to the number of the images, and performing checking analysis by combining inertial navigation data to remove distorted images. The method comprises the steps of firstly thinning connection points to 500 degrees after initial net building, accurate matching and gray point optimization, then performing free net adjustment, setting parameters, deleting points with large residual errors, and adding thorn control points to perform empty three-dimensional adjustment after the free net is stable. In the third step, the aerial photography image is firstly subjected to dodging and color homogenizing treatment, then is subjected to multiple editing modification and digital differential correction, and is subjected to color tone treatment, so that nearly consistent color tones are achieved without obvious splicing seams, and a real-scene three-dimensional model is formed through mapping software. The operations of interior space-air triple encryption, point cloud generation, real-scene three-dimensional model establishment and the like can be automatically solved by software after the digital oblique image is imported into the software, the oblique image area network adjustment and multi-view image dense matching technology is carried out through the multi-view image combined adjustment technology to obtain high-precision high-density point cloud data, and the data processing time can be shortened by adopting online operation. The process of drawing the map needs to be manually finished by an operator, and the speed is greatly improved by taking the three-dimensional model and the point cloud as reference.
Step four: and (5) performing tone painting and supplementary measurement by comparing the live-action three-dimensional model with the live-action, and recording. And in the fourth step, comparing the live-action three-dimensional model with the live-action, correcting the error area, carrying out gray level processing on the image, and carrying out enhancement processing on the edge. After finishing the works of framing and decorating the large-scale topographic map and the like, submitting the works to a quality inspection department to check whether the mathematical precision, the attribute precision, the geographic precision, the accessory quality and the like of the results meet the standard requirements of the large-scale topographic map, and storing and using the products after passing acceptance.
According to the method for field surveying and mapping of the unmanned aerial vehicle, the unmanned aerial vehicle usually flies at low altitude, the airspace application is convenient, and the influence of the climatic conditions is small. The flight safety of pilots does not need to be considered when the aerial images are acquired, the requirements on the geographic airspace and meteorological conditions when data are acquired are low, the problem that the area monitoring function cannot be achieved by manual detection can be solved, and the aerial image acquisition system is simple to operate and convenient to transport. The ground surface information can be rapidly acquired through equipment such as a digital camera and a digital color aerial camera which are carried by an unmanned aerial vehicle system, ultrahigh-resolution digital images and high-precision positioning data are acquired, two-dimensional and three-dimensional visual data such as a DEM (digital elevation model), a three-dimensional orthophoto map, a three-dimensional landscape model and a three-dimensional ground surface model are generated, and development and application of an application system in various environments are facilitated.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.