Development of holographic particle field data reduction by Fourier analysis

The purpose of this work is to establish the feasibility of using a Fourier transform analysis to automatically extract size distribution from particle field off-axis holograms. Both experimental and theoretical studies were conducted to show that this technique is feasible. A holographic system was designed and built compatible for use with a commercially available Fourier transform analyzer and software. Holograms of a standard particle field were obtained, and scattered light of both the particle field and its hologram were Fourier transform analyzed. The Sauter mean diameter determined by the two methods agreed to within 5%. The experimental and theoretical studies show that the prediction of the size distribution could be improved by increasing the diffraction efficiency of the hologram. This can be accomplished by producing phase holograms. Spray holograms were also Fourier transform analyzed at various locations of the spray. Photographs of the spray are provided for comparison. The results of this phase show that this method will yield very fast analysis of large amounts of holographic data.