中文摘要：

系统地综述了河流水面成像测速中可利用的水流示踪物，重点分析了天然漂浮物和天然水面模式的生成机理、适用条件及示踪性能，讨论了人工示踪粒子选择及布撒方式，指出天然水面模式产生的本质原因是明渠紊流，当流速大于一定阈值并且河床满足一定条件时就会发生。天然示踪方式特别适合于高洪期测流，是大尺度粒子图像测速在现场环境下应用推广的发展趋势；在受控条件下开展示踪物的示踪性能分析和精度评定是未来研究的主要工作。

英文摘要：

The available flow tracers for river surface imaging velocimetry were reviewed systematically. Generation mechanism, application conditions, and tracing performance of natural floating objects and natural free-surface patterns were analyzed. The selection and distribution methods of artificial tracer particles is discussed in this paper. It can be concluded that natural free-surface patterns occur because of the turbulent flows in open channels. The natural free-surface pattern occurs when the velocity is greater than a certain threshold, and the river bed meets a certain condition. A natural tracer method that particularly fits flow measurement during high-flood seasons and times is the trend in development of application of large-scale particle image velocimetry （ LSPIV） in the field. Performance analysis and accuracy evaluation of flow tracers under controlled conditions are the main areas of research for the future.