to say each of the radiation detectors produces an output signal which is proportional to the intensity of received radiation optionally a reference detector may detect radiation which has not traversed the examination region 14 a difference between the magnitude of radiation received by the reference detector and each active radiation detector 40 provides an indication of the amount of radiation attenuation along a corresponding ray of sampled radiation in detector view geometry each view or two dimensional array of data represents a cone of rays having its vertex at one of the radiation detectors 40 collected over a short period of time as the source 20 rotates behind the examination region 14 from the detectors in source view geometry each view or two dimensional array of data represents a cone of rays having a vertex at the source 20 collected by a concurrent sampling of detectors a gantry acquisition memory board 42 receives sampled data from the radiation detectors 40 the gantry acquisition memory board 42 optionally shuffles the data to transform it from a detector cone geometry to a source cone geometry or vice versa and performs a ripple filtering operation before passing the data to an image processor 50 the image processor 50 processes the view data from the gantry acquisition board 42 and three dimensionally backprojects it into an image memory 60 the image processor 50 performs mathematical manipulations which convolve each view with an appropriate filter or convolution function for the view format more specifically a first data processor 52 pre weights the data a convolver 54 then performs a one dimensional convolution after a.