A process for backprojecting a sinogram to a tomographic image includes the steps of subdividing the sinogram into a plurality of subsinograms, preferably in a recursive manner, until each subsinogram represents an image as small as one pixel in size. Each of the final subsinograms is backprojected to produce a plurality of corresponding subimages, and the subimages are aggregated to create the image. Two algorithms can be used in the decomposition process. An exact decomposition algorithm is accurate, but relatively slow. An approximation decomposition algorithm is less accurate, but fast. By switching between the two algorithms, accurate decomposition is realized in a short time, speeding up the backprojection process considerably.
Original languageEnglish (US)
U.S. patent number6282257
StatePublished - Aug 28 2001

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