VOICE RECOGNITION SECURITY SYSTEM

When we think of programmable speech recognition, we think of calling FedEx customer service call center with automated voice recognition response systems. We also think of PC-based speech recognition Dragon NaturallySpeaking. Now we took that a step further. We are talking about speech recognition in a tiny Mega32 microcontroller. We are talking about real-time speech processing which means there is no need to store the samples in an external memory at all. This was made possible by implementing bandpass filters in assembly language with fixed-point format onto the microcontroller. In this filter design, not only the output of the filter is calculated, but its square and accumulation also obtained. Thus much time is saved so that each speech sample can be processed to get its frequency spectrum before next new sample comes. In addition, the analysis of the voice is made using correlation and regression method to compare the voiceprint of different words. These techniques provide stronger ability to recognize the same word. Training procedure is also used to reduce the random changes due to one word is spoken different times. The training procedure can get the more accurate frequency spectrum for one word. The experimental results demonstrate high accuracy for this real-time speech recognition system