Surface image velocimetry: Aerial tracer particle distribution system and techniques for reducing environmental noise with coloured tracer particles

A novel aerial tracer particle distribution system has been developed. This is mounted on an unmanned vehicle (UAV) and flown upstream from where surface velocimetry measurements are conducted. Tracer particles can be rapidly deployed across the full channel width distributed in a crescent shape (for larger channels), so that they reach measurement cross section at similar time. enables techniques to applied rivers channels lacking sufficient natural or features. Lack of tracers common problem during low flows, lowland rivers, artificial channels. Techniques for colouring with biodegradable dye have also developed, along methods extracting them Red Green Blue (RGB) imagery Hue Saturation Value (HSV) colour space. The use coloured flow situations sunglint, waves, moving shadows dappled lighting riverbeds interfere corrupt results using techniques. These developments further expand applied, as well improving accuracy results. successfully multiple canals New Zealand enabled were not previously possible due lack tracers.