February 29, 1996
Abstract -
A real-time high speed pulse-echo imaging system capable of parallel
processing multiple image lines is presented. The system uses
transmitter arrays with coded-excitation. Mathematically, it can be
formulated into a discretized linear image equation via a newly
introduced discrete spatio-temporal model of the received sampled
echo data. The implementation of the system is realized by a
transversal filter bank with each filter designed for processing
echoes from a specific direction in the region of interest.
The filter coefficients are derived from a pseudo-inverse image
operator obtained from the image equation. Preliminary results
show that, in addition to being well-suited for real-time
parallel processing implementation, the transversal filters
are capable of decoupling echoes from different directions
before performing matched filtering. Thus, the proposed approach
eliminates a major drawback of conventional coded-excitation
systems designed based only on matched filtering. Without
complicating the transducer array, our results also show that
the new system offers high spatial resolution which may exceed the
conventional diffraction limit. Since the system complexity
is primarily in the filter bank which can be implemented by
using VLSI technology, the proposed approach allow us for
implementing very high speed pulse-echo imaging systems with
much lower hardware costs. This leads to a possible solution
to the currently unsolved real-time 3D imaging problem. The method
may also find many applications in SONAR, NDE, and biomedical
imaging areas.