ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

In order to improve the speed and accuracy of terrain measurement in farmland leveling operation, a method of farmland leveling terrain measurement was proposed based on UAV LiDAR. Firstly, high-precision farmland terrain point cloud data was obtained by using LiDAR measurement system equipped with UAV. After preprocessing the collected point cloud data, a large number of noise points along the z-axis were removed by direct filtering. Then, the progressive morphological filtering algorithm was used to segment farmland surface points and non surface points. Finally, on the basis of retaining the main farmland terrain information features, the farmland terrain point cloud reduction method based on VoxelGrid filter was used to simplify the farmland terrain point cloud data. The results showed that compared with the flatness of GNSS, the accuracy was 94.681%, 91.364%, 90.588% and 90.287% respectively; compared with the maximum elevation difference of GNSS, the accuracy was 99.391%, 98.167%, 97.025% and 98.776% respectively. Compared with the height difference distribution of GNSS, the accuracy was 99.307%, 97.914%, 98.673% and 95.110% respectively. The farmland terrain measurement method proposed based on UAV LiDAR can quickly and accurately measure the farmland terrain information, and provide data support for the next farmland leveling operation.