Application method and system of virtual three-dimensional real scene for air sightseeing tour of civil aviation aircraft
李基伟(中国民航大学 天津300300）(1) Background technology:
This is a new application to improve the flight experience of civil aviation passengers. According to the current analysis of domestic civil aviation passengers' flight experience, passengers are completely in a state of losing contact with the world during the flight. Passengers do not know exactly where they are flying to, and some passengers want to see the scenery below the plane, which is also restricted by factors such as the cruising altitude of the plane and the position of the cockpit. After investigation and analysis, an interesting phenomenon was obtained. During the short period of take-off and landing, most of the passengers will stretch their heads and look at the scenery outside the window, as well as the buildings under the plane and so on. This shows that people generally still want to see the scenery on the ground and see their own life from different angles.
City. In addition, during the flight, in fact, most people are still bored, and only a small number of people watch movies and read books. Even in today's increasingly popular aviation WIFI, there is still a need to see the ground scenery in the air, because even if passengers with WIFI can swipe WeChat and Weibo to watch videos or something, the passengers may have already swiped while waiting at the airport. Almost there. Passengers only have special needs in that specific flight environment, that is, to see the ground scenery from the air, and to know where and which city they are flying to. The invention can realize the virtual sightseeing tour of the three-dimensional real scene in the air, and the viewing angle of the camera can follow the current position of the aircraft, so that the passengers can know their exact position. This application can largely satisfy the desire of passengers to explore the unknown in unfamiliar environments in the air and meet the needs of passengers. If this application is adopted by airlines, it can greatly improve the service quality of airlines and enhance the flight experience of passengers.
If the application is used for commercial charging, the commercial prospect is also huge. According to the inventor's analysis, in 2016, the passenger volume of civil aviation in China was close to 500 million, with an average of 1.4 million passengers a day. Assuming that only 50,000 passengers use it a day, and a charge of 2 yuan is charged for one use of the whole flight, one day is 100,000 income, and a year is 36 million. Income, this use ratio is still only 3.5%, which is equivalent to an average of 3-4 people on a plane carrying more than 100 passengers to achieve such a scale of income.
In addition, according to the analysis of the current state of the existing technology, although foreign Google companies have Google 3D Earth, due to some restrictions, domestic users are basically unable to use them, and they do not provide the function of following passenger flights; domestic Baidu, AutoNavi and Tencent maps are only floor plans. There is no 3D topographic map, nor a 3D map of real buildings. Their so-called street view can only be regarded as 2.5D but not 3D. Moreover, the magnified Baidu Tencent AutoNavi map is not clear enough to achieve the kind of virtual sightseeing tour. Requirements.
(2) Technical content:
l Method description:
l 1. The application for the realization of three-dimensional terrain,
l Step 1: On the basis of the foreign Cesium open source geospatial project, create a Cesium.viewer object with a Cesium container through its underlying code and set it as viewer, set its attribute baseLayerPicker to false, and turn off the small window for manually selecting map layers. Part; Step 2: Create a specific imageryProvider property for the container, set the property value to an object: Cesium.ArcGisMapServerImageryProvider, set the first property url of the object: point to https://services.arcgisonline.com/ArcGIS/rest/ services/World_Imagery/MapServer', the open source geographic layer on the ArcGIS server side
l Loaded into the container, in order to have a good experience of the application, set another property of the object enablePickFeture to false, so that some unnecessary information will not pop up when the user clicks on the layer;
l Step 3: Create a Ceisum.CeisumTerrianProvider object, set the url property of the object to point to https://assets.agi.com/stk-terrain/v1/tilesets/world/tiles, and set a requestWaterMask property for it, the value is true, add a dynamic seawater model to the container. Finally, pass the object to the ceisum container, set a property terrainProvider for the container, and the property value is the object.
l Step 4: Set viewer.scene.globe.depthTestAgainstTerrain
l If it is true, the entities of objects whose actual height is lower than the terrain are hidden.
l 2. The application for the realization of 3D buildings and 3D scenic spots:
l Step 1: The 3D building uses the UAV 3D on-site restoration modeling technology, and uses Pix4Dmapper, or Altizure, Dji's GSPRO and other ground-side software to plan the flight route of the buildings and scenic spots that the UAV needs to collect data. , these applications can set the scheduled flight route of the drone, as well as set the cruising speed and the interval of collecting images. After many personal tests and analysis, the best way to collect data is to use Altizure as the ground terminal, the drone to use DJI 4 Advanced, or DJI 4 Pro, the flight route is set to two different altitudes, and the flight altitude is set to 45m-70m above the tallest building, two different heights are perpendicular to each other, the image acquisition time interval is set to 2s, and the camera tilt angle is set to 45°-60°.
l Step 2: Process the collected image data through Contextcapture 4.4 or later to process computational modeling and reconstruction blocks. After completion, create a reconstruction project, convert the reconstruction project format to Cesium 3d tiles format, and save the model data to a folder. Also generate a JSON file for this project. In order to improve the calculation speed, multiple computer clusters are used for operation, which is divided into task blocks, and finally the subdivided tasks are combined together.
l Step 3: Add the model reconstructed by Contextcapture to the cesium container; create a Cesium.Cesium3DTileset object in the container, set a url attribute value for the object to point to the previous json data file, and load the model data for the container through the json file.
l Step 4: Solve the problem that the 3D model cannot be perfectly matched with the 3D terrain layer after being added to the container; in the json file generated by contextcapture for the reconstructed model, a geometricError attribute needs to be added to the children object to make up for the height error;
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l 3. Obtain the aircraft geographic location, flight altitude, speed, heading, and display it on the main interface;
l Step 1: Realize geolocation by calling the geolocation api of the user's mobile phone or tablet browser to obtain parameters such as altitude, speed, heading, longitude, latitude, etc., and display the speed and altitude on the interface through the HTML DOM method. Heading, latitude and longitude. The aircraft position is determined by the way the passenger's position is determined.
l Step 2: Create a function. The function is to generate an entity object in the container as soon as the position of the browser is obtained. Set it as entity, the shape of the object is displayed as a point, and the value of the position attribute is set to the (latitude) obtained from the browser. , longitude, altitude), the entity is displayed, which is the current aircraft position;
l Step 3: Refresh the aircraft position and create a watchLocation function
l Call the navigator.geolocation.watchPosition function of the geolocation api to monitor the current position change of the browser. Once the change is detected, the obtained position information will be passed into the position attribute of the entity to change the original position.
l 4. Realize that the aerial simulated sightseeing perspective changes with the change of the aircraft position;
l After the entity entity is created, set the value of the container trackedEntity to entity. The purpose is to let the container keep track of entities.
l 5. Realize the camera to follow the aircraft, and the camera to cancel the function of following the aircraft
l In order to facilitate users to explore the scenery around and below the aircraft, set the camera to cancel the following function, create a function viewSide, when calling this function, set the viewer's trackedEntity property value to undefined, that is, the camera will no longer track the entity; create a viewFlight function, call this function when you need to follow the plane, and set the viewer.trackedEntity property value to entity.
l 6. Add function buttons
l Call the built-in Sandcastle.addToolbarMenu function of Sandcastle to create a corresponding function list.
l System drawings
2. The innovation of this project
1. Use an open source Javascript library to display a WebGL-based 3D globe in the browser. WebGL can provide hardware-accelerated 3D accelerated rendering for HTML5 Canvas, which can easily display 3D scenes in the browser with the help of the system graphics card. It can also create complex navigation and data visualization, using the WebGL technology standard to eliminate the trouble of developing special rendering plug-ins for web pages, and it is easier to create website pages with complex 3D structures.
2. UAV 3D on-site rapid restoration modeling is used to collect, process and analyze 3D data of buildings and scenic spots, and generate models that meet the requirements. This set of data collection solutions is a combination of the strengths of each company, integrating the cost of drones, battery life and aerial photography performance factors. The drones use DJI 4 Advanced or DJI 4 Pro drones, with a 20-megapixel aerial camera lens. enough to satisfy
The demand for collecting clear 3D images with a certain degree of overlap, the flight endurance is already very strong among DJI drones, and the prices of these two drones are relatively not too high; the drone ground station uses Hong Kong The Altizure ground station developed by the University of Science and Technology team pre-sets flight tasks for UAV planning routes. After many previous tests, Altizure is the most suitable ground station for setting the task of collecting 3D data for UAVs among the various ground stations on the market. Station, the collection area can be set to be large, and compared with other ground stations, Altizure has the function of reloading the last interrupted mission and following the last unfinished flight plan, which is very helpful for collecting scenic spot data in a large area; digital 3D construction Contexcapture 4.4 is used in the model software, which can better process and analyze the collected data, generate reconstruction projects that meet the requirements of later applications, and the data is in b3dm format, and supports the processing form of large-scale data parallel operation, which improves the operation efficiency. ; Considering that the 3D model of Google Earth is now a 2.5D model instead of a 3D model using satellite and high-flying aerial photography, the effect of the model is not particularly good, and because of the accuracy problem, some important buildings need to pass people If high-precision and non-manual 3D modeling is required, radar scanning needs to be used for modeling, which is costly and difficult to generalize to commercial use. This set of three-dimensional data acquisition, analysis and processing, and final generation of models that meet the requirements of later applications is the result of many experiments, and has the characteristics of simple operation process, high efficiency, low labor cost, and good economy;
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Using the foreign open source Cesium project, the cesium open source project can be used for both commercial and non-commercial use. It is a free and open project. The invention application is further developed on the basis of the Cesium project. Application of passenger experience problems in the civil aviation industry. Develop on the basis of the existing base of predecessors, stand on the shoulders of giants, avoid repeated wheel building, and save a lot of unnecessary development costs;
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Import the data model after the 3D modeling of the UAV into the application and display it on the application. From another point of view, this is also equivalent to a 3D data release platform. Currently, the online 3D model data release on the market The famous display platforms with a large number of users are Sketchfab, Altizure, and wish3D, but the functions that these platforms can provide are only the display of a single 3D model, which is difficult to achieve specific applications and cannot achieve simulated sightseeing tours. effect of tourism. And this application can display the three-dimensional models of multiple architectural scenery in the same container, and comes with many other practical functions, which is practical.
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The route following function is provided. In order to better show passengers the location of the plane they are taking, the app not only displays the plane's latitude, longitude, altitude, speed and other parameters after calling the browser's geolocation API, but also displays the plane's The specific location on the earth is marked out in three-dimensional space. As the position of the aircraft changes, the marked points also change, and the virtual tour perspective will change with the changes of the marked points, and the tour perspective will also move as the aircraft moves. This is actually to give passengers a different perspective than before, to observe the specific position of the plane they are taking, the scenery around the plane, and the scenery on the ground.
- In order to better facilitate passengers to explore other unknown environments and watch the scenery of interest during the simulated sightseeing tour on the plane, in response to this demand, the application has added the functions of following the plane with the camera and canceling the following. Cancelling the following is freedom. The perspective of exploration is convenient for passengers to see the scenery around the aircraft and explore different environments;
In order to avoid finding the position of the aircraft after free exploration, the camera also provides the function of locking the position of the aircraft accordingly.
- New entities can be added to the virtual three-dimensional scenery and buildings, such as labels, and the information bar will be displayed after the label is clicked, so that passengers can understand the information of the place; in addition, billboards can be added on the ground of the virtual earth when appropriate, and a small number of advertisers can be introduced. , bringing new profit points;
8. Open source ceisum project, 3D modeling, UAV, civil aviation, aerial sightseeing, several things that are not related to each other, under the general trend of the gradual opening of aviation WiFi, they can be combined together. The effect of 1+1>2. It can not only improve the flight service quality of airlines, but also improve the flight experience of passengers. In addition, it can bring huge economic value, and the commercial potential should not be underestimated;
3. Beneficial effects of this project
1. Display 3D scenes and 3D models more smoothly in the browser, create complex navigation and data visualization, save the trouble of developing special rendering plug-ins for web pages, and create website pages with complex 3D structures more easily.
2.具有操作流程简单、效率高、人工成本低、经济性好。
3.在前人的已有的底层基础上进行开发，站在巨人肩上，避免了重复轮子，省去了许多不必要的开发成本；
4.达到可以投入实际使用的模拟观光游览旅游效果。
5.更好的给旅客显示他们所乘坐飞机的位置，给旅客一个与众不同的视角，观察自己乘坐的飞机位置，以及飞机周围的环境。
6.提供自由探索的视角，方便旅客看飞机下面对应的三维山水风景；以及更快速的找到并锁定自己的飞机；
7.标注方便旅客了解该地的信息，广告牌引入广告商，带来新的盈利点；
8.该发明集齐各家所长，能够解决用户实际需求，帮助航空公司解决实际问题，为社会带来新的商业价值。4. Specific examples: