土壤侵蚀形态演化数字摄影观测系统设计与实验

为解决目前在连续降雨条件下尚无有效的观测技术与手段从时空两个维度对土壤侵蚀过程进行观测的问题,设计了一种基于无线组网技术的数字近景摄影观测系统。该系统通过对连续降雨条件下不同时间节点的土壤侵蚀坡面进行数字影像的瞬时采集、雨滴噪声去除、点云匹配、三维重建等手段,实现对土壤侵蚀坡面形态演化过程的动态监测。该系统的测量精度可达到亚毫米级,最小测量误差为0. 006 2 mm;凹槽尺寸测量值与实测值之间最大相对误差为-2. 968 3%。土壤侵蚀坡面观测实证表明,土壤流失量估算平均相对误差为-1. 73%,单次观测精度最高可达99. 26%,时间观测分辨率可达到分钟级别,空间分辨率达到2 mm。该系统能够准确获取土壤侵蚀坡面形态变化的精细信息,可为土壤侵蚀过程研究提供新的方法和技术手段。

Digital Close Range Photogrammetry System for Soil Erosion

Observing soil erosion process at fine spatial and temporal scale is of great significance to the study of soil erosion mechanism. A digital close range photogrammetric observation system based on wireless networking technique was explored and established. The evolution of soil surface topography was dynamically monitored by instantaneous image acquisition at different time intervals during ongoing rainfall. Noises on the images such as raindrops was removed by K-means clustering, digital point clouds were calculated and digital elevation model (DEM) was then generated. The results showed that the measurement precision of the established system could reach a sub-millimeter level, and the minimum measurement error was 0.0062mm. The maximum relative error between the measured value and the actual value was -2.9683%. According to the experimental observations, the average relative error of soil loss was -1.73%, and the accuracy of single observation was up to 99.26%. The established digital photogrammetric observation system could accurately calculate the digital point cloud from the underlying surface with 1min time interval and 2mm spatial resolution. The observation methods explored provided a reliable way to monitor soil erosion processes, especially under rainfall conditions, which was of great importance in understanding soil erosion mechanisms.