Design of an ASIP architecture for low-level visual
elaborations.

Luigi Raffo
DIEE - University of Cagliari, Piazza d'Armi, 09123 Cagliari, ITALY
Silvio P. Sabatini , Mauro Mantelli, Alessandro De Gloria, and Giacomo M. Bisio
DIBE - University of Genoa, Via Opera Pia 11a, 16145 Genova, ITALY

We consider the design process of VLSI systems dedicated to the real-time
implementation of cooperative algorithms whose functionalities can be
characterized by multi-layer ensembles of simple elements which interact
locally. These algorithms are related, even though not exclusively, to the
implementation of various tasks in low-level machine vision. The starting
point in the design process is the formulation of the sequential algorithm
that computes the behavior of the system. Algorithmic transformations are
performed to expose the parallelism originally present in the task.
Given the description in terms of parallel loops, we partition the system and
organize it as a set of processing units. The architectural structure of these
units takes properly into account the algorithmic constraints on precision both
in data representation and computation. The program flow implemented by
our programmable architectural solution (ASIP) is an iterative sequence of
multiply-and-accumulate operations performed in parallel.
The programmability concerns both the structure/coefficients of the
algorithm - depending on the specific application - and its computational
parameters. The architecture's main blocks are described in VHDL and
synthesized as a semi-custom chip, using standard tools.
Following this procedure, we designed an ASIP core for performing real-time
texture-based image segregation.