1. A method of image reconstruction from partial cone beam data comprising: (a) collecting the partial cone beam data in two-dimensional arrays, said collected data corresponding to rays of radiation diverging in two dimensions from a common vertex as the vertex travels along a curve with each element of the data related to line integrals of an object being reconstructed taken along each ray; (b) defining a local coordinate system; (c) pre-weighting the data; (d) computing a one-dimensional convolution of the pre-weighted data in the local coordinate system along a direction which is tangential to the curve along which the vertex travels; (e) weighting the convolved data; and, (f) three-dimensionally backprojecting the weighted convolution.