摘要
构建了基于双高速摄像机的立体摄影测量与大范围PIV测量系统,实现了对高坝泄洪的水面曲面和流速场的原型观测。摄影测量系统将相机内外参数分开标定,既保证了相机标定精度,又减少了布置标定点的工作量;使用SIFT关键点标识法提取不同照片中水流表面流动纹理的特征点。大范围PIV系统中,使用灰度标准化、背景移除、中值滤波等方法提取水流表面流动纹理作为PIV计算的示踪物,解决了原型观测中释放示踪物的难题。根据重构出的水面曲面形态对大范围PIV所得流场进行尺度换算与水面贴合,得到真实的表面流场。在向家坝消力池运用实例表明,本方法的计算结果合理。
Large-scale flood flows discharged from high-dam reservoirs are extremely difficult to measure due to the presence of fast developing,highly fluctuating flow surfaces. This study presents a novel in-situ method suitable to monitor surface topography as well as velocity fields of such complex flows. The new method combines stereo photogrammetry and large-scale particle image velocimetry（ PIV）. The two-camera stereo photogrammetry adopts the SIFT approach for spotting and matching distinct points,and to enhance measurement accuracy and efficiency the internal and external camera parameters are calibrated separately. The large-scale PIV system traces texture of the surface flow through image acquisition,grey standardization,background removing,and median filtering. Real surface velocity field is constructed from velocity field and surface topography measured by two cameras simultaneously. Application of the new method to Xiangjiaba project has been successful.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2015年第6期829-836,共8页
Advances in Water Science
基金
国家自然科学基金资助项目(51279081)
"十二五"国家科技支撑计划资助项目(2012BAB04B01)~~
关键词
高坝泄洪
水面流场
水面曲面
特征点
三维重构
flood flow discharged from high dams
surface velocity field
surface topography
feature point
three-dimensional reconstruction
