Forward projection/backprojection processor

摘要

A forward projector/backprojector (30) for a CT scanner includes a VME interface (36) which loads data onto and off of the forward projector/backprojector (30), and a CPU (42) which controls data flow. An array of ASICs (60a-x) is included. Each ASIC has two pipelines along which data is subjected to pipeline operations including one of a forward projection algorithm and a backprojection algorithm. Double-buffered memories for storing data subject to the pipeline operations are arranged on each ASIC (60a-x) such that while data is loaded into one bank of the double-buffered memories data in its opposing bank is subject to pipeline operations. A dual in-line memory module (DIMM) daughtercard (120) holds an output memory (100) with two barks employed during pipeline operations. For consecutive pipeline operations the two output memory barks are alternatingly employed with one of the two output memory barks having previously written results read therefrom for updating by the pipeline operations and the other of the two output memory banks having updated pipeline results written thereto. The DIMM daughtercard (120) also holds an output buffer memory (110) which stores final updated pipeline results after completion of consecutive pipeline operations. A peripheral component interconnect (PCI) bus (50) transfers data between the CPU (42), the VME interface (36), the DIMM daughtercard (120), and the array of ASICs (60a-x).