Pixel grouping for filtering cone beam detector data during 3d image

Abstract

A method and apparatus for three dimensional (3D) computerized tomographic (CT) imaging of a region-of-interest (ROI) in an object, wherein image reconstruction processing is applied to a plurality of sets of pixels of 2D image data, each set being acquired on a pixelated 2D detector. The image reconstruction processing comprises filtering each of the acquired 2D image data sets for developing a corresponding plurality of filtered 2D images; and then 3D backprojecting the filtered 2D images into a common 3D space, thereby reconstructing in the 3D space a 3D image of the ROI in the object. In the present invention the filtering step comprises dividing the pixels of each set of the acquired 2D image data sets into first and second groups, and separately filtering the image data of each group to develop for each group it's own contribution to the corresponding filtered 2D image. In accordance with one embodiment of the invention, the first group essentially comprises those pixels that contribute to a given filtered 2D image in a space-invariant manner, and the second group essentially comprises those pixels that contribute to the given filtered 2D image in a space-variant manner. In accordance with another embodiment of the invention, the first group essentially comprises a contiguous portion of the pixels of each set that are entirely internal to the boundaries of a data combination mask that is applied to each set of the acquired 2D image data, and the second group essentially comprises at least one boundary region of contiguous pixels that are on or adjacent to a data combination mask boundary.