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RESEARCH PRODUCT

ConformalALU: A Conformal Geometric Algebra Coprocessor for Medical Image Processing

Antonio GentileGiorgio VassalloSilvia FranchiniSalvatore VitabileFilippo Sorbello

subject

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniCoprocessorComputer scienceClifford algebraConformal geometric algebraConformal mapImage processingParallel computingImage segmentationComputational geometryTheoretical Computer ScienceGeometric algebraOperator (computer programming)Computational Theory and MathematicsConformal geometric algebra five-dimensional clifford algebra computational geometry embedded coprocessors systems-on-programmable-chip FPGA-based prototyping medical imaging segmentation 3D modeling Volume registration Growing Neural Gas marching spheres iterative closest point (ICP) thin-plate spline robust point matching (TPS-RPM)Hardware and ArchitectureScalingSoftware

description

Medical imaging involves important computational geometric problems, such as image segmentation and analysis, shape approximation, three-dimensional (3D) modeling, and registration of volumetric data. In the last few years, Conformal Geometric Algebra (CGA), based on five-dimensional (5D) Clifford Algebra, is emerging as a new paradigm that offers simple and universal operators for the representation and solution of complex geometric problems. However, the widespread use of CGA has been so far hindered by its high dimensionality and computational complexity. This paper proposes a simplified formulation of the conformal geometric operations (reflections, rotations, translations, and uniform scaling) aimed at a parallel hardware implementation. A specialized coprocessing architecture (ConformalALU) that offers direct hardware support to the new CGA operators, is also presented. The ConformalALU has been prototyped as a complete System-on-Programmable-Chip (SoPC) on the Xilinx ML507 FPGA board, containing a Virtex-5 FPGA device. Experimental results show average speedups of one order of magnitude for CGA rotations, translations, and dilations with respect to the geometric algebra software library Gaigen running on the general-purpose PowerPC processor embedded in the target FPGA device. A suite of medical imaging applications, including segmentation, 3D modeling and registration of medical data, has been used as testbench to evaluate the coprocessor effectiveness.

https://doi.org/10.1109/tc.2014.2315652