Study on the Digital Camera Measuring System based on Digital Camera and PTV Technology

摘要

The Digital Camera Measuring System based on digital camera and Particle Tracking Velocimetry (PTV) technique is introduced in this paper. It is applied to measure a wide range of surface velocity distribution of steady or unsteady flow in real time. The powerful post-processing analysis module in the system makes users analyze measure data efficiently and conveniently. The seeding Particles are scattered in the Hydraulic model, and the system will control cameras to capture images continuously. The system uses image processing technique to recognize particles, and the error is within 0. 5 pixels. The particles are matched by the PTV technique, thereby the system can be used to measure wide range distribution of velocity. The velocity noise can be identified by automatic filtering, and the error vectors of the calculated velocity distribution could be excluded by the method. The velocity vector is interpolated by combining moving least squares method with inverse distance weighted method, so the system can generate the velocity distribution with uniform grid. The system can sustain 16 cameras to collect images in real time. And a study on the collecting image mode improves the synchronization of multicamera collecting image greatly. In order to measure wider range distribution of velocity, the system is extended by using Local Area Network (LAN) technology. The system is widely applied to measure the velocity distribution in hydraulic, river and harbor model experiment.