Three-dimensional particle position using continuous wavelet and circle Hough transforms

Abstract

An alternative method to determine particle position in 3D is herewith proposed. The procedure to be followed is simple since it avoids a complicated experimental set-up and several computation steps to obtain the final particle position. In order to compute the position and radius of a particle image, the continuous wavelet and Hough transforms are employed: the proposed method is based on the size and position calculation for a particle diffraction image central spot size. The size and centroid of the central spot size render the z and x-y position of a particle image, respectively. This approach has been applied to simulated and experimental particle images. Simulated particle images have been obtained using the near field Lorenz-Mie theory, and show between the actual and calculated central spot size. An average relative error of 0.4% and 1.7% for x-y and z directions, respectively, was found in the analysis. The extraction of the 3D particle position was done with experimental particle images obtained from particle motion provoked by heated water inside a channel. The quality of the particle images determines the accuracy of the calculation of its central spot size.