Atomic number image enhancement by polynomial fitting in dual energy CT

Dual energy CT (DECT) is able to reconstruct the effective atomic number and the electron density from the high and low energy projections of the scanned object. The atomic number image is sensitive to the noise presentation and can easily suffer from severe noises. Here we propose a method which uses the image which is reconstructed directly from the high or low energy projections to enhance the noisy atomic number image. The method uses blocked polynomial fitting to fit the low noise image to the atomic number image. The method preserves the structures of the object and the result has close grey scale values to the atomic number image. The low noise characteristic of the reference image is also preserved. The method has reasonable time and space complexity and parallel computation is possible. Both simulation and real experiment are used to test the method and promising results are shown.