Separation of left and right skull bones from low angle x-ray projections

This study shows how two layers which are superposed in two low angle x-ray projections can be reconstructed separately without having any a priori knowledge of their shape. Similar to stereoscopic imaging, the projections of the two layers appear at different positions in the two superposition images. Matching one of the layers allows its elimination by subtraction. The resulting difference signal is the so-called 'movement artefact' of the second, mismatched layer. A filter method is developed to reconstruct this layer from the spectrum of its artefact within the Fourier domain. The second layer is reconstructed in an analogous way. So, for example, the bones of the left and the right side of the human skull can be imaged separately. This is used to reduce image artefacts caused by patient movements in subtraction angiography and tumourfluoroscopy of the brain.