We present a method for the trajectory and the velocity measurement of a particle in spray by digital holography. Based on multiple exposure digital in-line holography, a sequence of digital holograms of a dynamic spray particle field at different times are recorded with a CW laser and a high-speed CCD. The time evolution of the serial positions of particles, i.e., the motion trajectories of the particles, is obtained by numerically reconstructing the synthetic hologram of a sequence of digital holograms. The center coordinate (x,y) of each particle image can be extracted using a Hough transform and subpixel precision computing, and the velocity of an individual particle can also be obtained, which is then applied to measuring the velocity of diesel spray and alcohol spray. The research shows that the method presented in this paper for measuring spray field is feasible.
© 2009 Optical Society of America
Original Manuscript: June 19, 2009
Revised Manuscript: November 17, 2009
Manuscript Accepted: November 17, 2009
Published: December 18, 2009
Qieni Lü, Yiliang Chen, Rui Yuan, Baozhen Ge, Yan Gao, and Yimo Zhang, "Trajectory and velocity measurement of a particle in spray by digital holography," Appl. Opt. 48, 7000-7007 (2009)