Abstract: A method of reconstructing data acquired on a fan beam CT system first rebins the data to parallel beam format using limited angle weighting that fold-over redundant data by adding corner rays of one scan to the center rays of another scan. For each view, now parallel beam data are filtered with a parallel beam kernel, and transformed. The transform is replicated, and multiplied by an interpolation filter. Next, the replicated, multiplied transform is convolved with the gridding function, and added into the Fourier image at an angle corresponding to the view angle. In the case of an n-scan cone beam correction a two-dimensional weighting function is calculated for each view giving the view's contribution to each pixel in the image. Multiplication by this weighting function is accomplished by convolution of the transform of the weighting function with the above transformed view. These steps are repeated for all views, whereafter the two-dimensional inverse Fourier transform is taken to get a preliminary image.

Abstract: A pneumatic cleaning and degreasing system that draws power from a single source of compressed air and provides agitation, active draining of solvent, drying, odor-control and optional recirculation features. The preferred configuration of the invention provides for the use of two solvents, each in a separate chamber. Agitation, drainage and, if desired, solvent recirculation are accomplished by means of a pair of pneumatic pumps. An air venturi withdraws solvent vapors from the plenum into which the solvent chambers open, thereby creating a vapor gradient that facilitates rapid drying. When the device is inactive, a smaller flow through the air venturi removes solvent fumes to reduce or eliminate perceptible odors.