Three dimensional velocity measurement of moving particles by image rotating method

A new approach to the measurement of three-dimensional movement of particles is introduced. A single TV camera with apparatus to rotate the image enables recording of the three-dimensional movement of particles as spiral streaks on a single image. Every shape of the spiral streak on the image plane is related to the position and the velocity of the individual particle. Information on the three dimensional movement of particles is extracted from the image using an image processing technique. The authors applied this technique to the measurement of a three-dimensional water flow field and obtained satisfactory results.