Evaluating Image Tracking Approaches for Surface Velocimetry With Thermal Tracers

摘要

In this paper an automatic approach is proposed to measure flow velocity with an uncooled thermal camera. Hot water is used as thermal tracer. The introduced tracking algorithm utilizes the pyramidal Lucas-Kanade method and is especially suitable for thermal image data. The performance of the new tool is compared to traditional image-based tracking tools, that is, PIVlab and PTVlab. Experiments are performed in the laboratory for three different flow velocities and tests are conducted in a small stream to illustrate the suitability of the tool for field measurements. Results of the laboratory experiments as well as of the field experiments show that our tracking algorithm, applied to imagery from a thermal camera, outperforms commonly used tracking methods. Our tool provides velocity fields with very high resolution and is in close agreement with reference measurements, whereas PTVlab and PIVlab tend to overestimate and underestimate flow velocities, respectively.