By using the Hilbert–Huang transform, a novel method is proposed to perform the task of particle sizing and axial locating directly from in-line digital holograms rather than reconstructing the optical field. The intensity distribution of the particle hologram is decomposed into intrinsic mode functions (IMFs) by the empirical mode decomposition. From the Hilbert spectrum of these IMFs, the axial location of the particle can be calculated by fitting the spectrum to a straight line, and the particle size can be derived from the singularities of the spectrum. Our method does not need to predefine any basis function; thus the whole process is fast and efficient. The validity and accuracy of the method are demonstrated by the numerical simulations and experiments. It is expected that this method can be used in on-line particle sizing and 3D tracking.
© 2014 Optical Society of America
Original Manuscript: March 25, 2014
Revised Manuscript: June 15, 2014
Manuscript Accepted: June 24, 2014
Published: July 16, 2014
Danjie Cai, Xiaojuan Zhao, Yuting Cen, Chujun Zheng, and Peng Han, "Holographic particle sizing and locating by using Hilbert–Huang transform," J. Opt. Soc. Am. A 31, 1747-1753 (2014)