INFRASONIC SIGNAL DETECTION VIA THE HOUGH TRANSFORM
D.J. Brown, B.L.N. Kennett, C.Tarlowski.
Research School of Earth Sciences, Australian National University, Canberra 0200
Australia.
email: djb@rses.anu.edu.au
The Hough-Transform is a mathematical device that allows for the retrieval of parametric curve
information from binary-pixelated data in the presence of noise. Originally used by particle-
physicists to retrieve particle track information from cloud-chamber records, the Hough Transform
has found wide use in pattern recognition problems. The Hough Transform maps points in the
image space, S, into straight lines in parameter space, P. It has the very useful property that all
points in S that lie on the same straight line, map to the same number of continuous straight lines in
P with a common intersection point. The problem of extended straight line detection becomes one
of local peak finding, a problem that may be substantially more tractable. It is shown here that the
Hough Transform can be used to reliably detect the points of constant measured backazimuth
associated with propagating acoustic signals in IMS infrasonic array data provided an estimate of
the backazimuth can be made at short regular discrete time intervals. A feature of the detection
algorithm is the ability to accomodate full three-dimensional array geometry.