In the present work, a new multilevel backprojection procedure for both parallel and fan beam geometries based on 1D MRA wavelet is derived and analyzed. It is based on the characterization property of orthonormal wavelets via their autocorrelation functions. The algorithm does not involve any wavelet-based decomposition in the normal sense, yet it uses a multiresolution formula as a crucial element in a CBP type procedure valid for both the parallel and complex fan beam geometries. The algorithm can be used for wavelet based image analysis. © World Scientific Publishing Company.