Tomographic Image Reconstrution in Experimental Fluid Dynamics: Synopsis and Problems

Particle Image Velocimetry (PIV) denotes a prevailing technique for imaging turbulent fluids with high-speed cameras. Corresponding image sequences provide the basis for estimating such flows and related flow patterns through image processing. While so far this technique has been applied in two dimensions (2D) in terms of an illuminated plane intersecting the volume, recent research focuses on imaging fluids directly in 3D. This paper provides a synopsis of the state-of-the-art and its connections to previous research work on image restoration. We address the basic problems involved and point out promising research directions for reconstructing scalar-valued particle functions from few tomographical measurements. Solutions to these problems will provide an essential processing step prior to the estimation of 3D flows from reconstructed volume functions