Abstract: A calculation for reconstructing tomographic images involves the decomposition of two-dimensional sets of projections of this image by a wavelet decomposition method, in which the set of projections is separated into thumbnail images expressing the whole and the higher frequency details of the projections, respectively. The reconstruction is carried out separately on the thumbnail images before making a combination. Certain properties of this decomposition, notably in the Fourier frequency domain, provide substantial reduction of the amount of calculations.

Abstract: Sets of projections of measurements through an object (1) the image of which is to be represented, undergo Fourier transforms before being broken down into blocks according to cutoff frequencies. The blocks are separately reconstructed in order to form a series of thumbnail images of the object, which are then combined in order to reconstruct the final image. The reconstruction calculations on the thumbnail images are rapid and often a large portion of the blocks will be discarded, notably those which are at high frequencies, whereby their contribution may frequently be neglected as well as the noise effects which accumulate therein. The invention is applied to medical or industrial tomography methods and is of larger interest for mobile objects, the movement of which may be estimated and compensated.

Abstract: Sets of projections of measurements through an object (1) the image of which is to be represented, undergo Fourier transforms before being broken down into blocks according to cutoff frequencies. The blocks are separately reconstructed in order to form a series of thumbnail images of the object, which are then combined in order to reconstruct the final image. The reconstruction calculations on the thumbnail images are rapid and often a large portion of the blocks will be discarded, notably those which are at high frequencies, whereby their contribution may frequently be neglected as well as the noise effects which accumulate therein.