We propose a new digital method for tracking position of particles from in-line holograms by using single wavelet
coefficient. By computing a wavelet transform of the 1-D intensity profile of a hologram, resultant wavelet coefficients
provide space-varying frequency information of an interference pattern. Our study finds that a dilation which is given by
the maximum value of the real wavelet coefficient appeared at the center position of the interference pattern is
determined by a recording distance and a wavelength of a coherent illuminating light. Therefore, this dilation can be used
for extracting the recording distance of particles from the holograms. A feasibility of this method is experimentally
verified by analyzing holograms of a line object.
A new method for sizing particle from in-line Fraunhofer holograms by using absolute values of the wavelet transform is proposed. The method gives zero-crossing points of an envelope function of the hologram which are determined by the particle size. Since the resultant zero-crossing points are functions of the dilation parameter, the frequencies of the fringes at the zero-crossing points are measured. The particle size can be finally calculated from the relationship between the frequencies with the positions of the zero-crossing points. The experimental results agree well with the theory.
A new digital method for measuring size of particle and its position from in-line particle holograms is proposed. In our proposed method, the position of particle is obtained by using a wavelet transform, while its size is retrieved by a reconstruction of envelope function. Usefulness of our proposed method is experimentally verified. The system limitation of the method is discussed.