| Summary: | Having examined a number of common warning signals such a telephone rings, microwave
oven alarms and continuous tone alarms, a software method, eliminating the need for
specialized hardware, was developed for both recognizing known warning signals and learning
new signals. The method, called WARNSIS II was first implemented on a PC-compatible
computer using a Creative Labs signal acquisition board which provided a base for graphical
signal analysis and for the development of algorithms. The algorithms were also implemented
on the Texas Instruments TMS320C30 Evaluation Module (EVM) digital signal processing
board to demonstrate that the algorithms can be easily ported to smaller, more cost effective
platforms.
The WARNSIS II system operates in two modes: learning and recognition. In the learning
mode a template for a signal is constructed by analysing the signal for spectral and temporal
information. The frequency at which the maximum peak in the signal's spectral energy occurs
is determined and this value is saved in a template. The duration of the signal burst, as well as
the interval time between signal bursts for repetitive signals, are determined and are also saved
in the template. In the recognition mode, the spectrum of the incoming real-time signal is
analysed to determine if any of its spectral components match those found in the template. If
a match is found, timing information is then applied to rule out transients which would
generate false alarms
The system has demonstrated the ability to recognize warning signals in high background noise
environments and to correctly identify multiple overlapping warning signals. === Applied Science, Faculty of === Electrical and Computer Engineering, Department of === Graduate
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