Limitation Of Hearing Essay

1. INTRODUCTION

The ability of hearing people talks can only be achieved by deploying acoustic sensors closely around the target individuals. It costs a lot and has a limited sensing and communication range. Further, it has detection delay because the sensor must first record the sound and process it, then transmit it to the receiver. In addition, it cannot be decoded when the surrounding is too noisy. The potential of using Wi-Fi signals to hear people talk and transmit the talking information to the detector at the same time can be achieved.

2. LITERATURE SURVEY

2.1 THE RELATED RESEARCHES

2.1.2 Wireless-based motion detection and tracking:
Wi-Hear builds upon recent research that leverages radio reflections from human bodies to detect, track, and recognize motions. Wi-Vi initializes through-wall motion imaging using MIMO nulling. Wi-Track implemented an FMCW 3D motion tracking system at the granularity of 10 cm. Wi-See recognizes gestures via Doppler shifts. All-See achieves low-power gesture recognition on customized RFID tags. Adopting a similar principle, Wi Hear extracts and interprets reflected signals, yet differs in that Wi-Hear targets at finer-grained motions from lips and tongue. Since the micro motions of the mouth produce negligible Doppler shifts and amplitude fluctuations. It exploits beam forming techniques and

In Wi-Hear, the motion of mouth when pronouncing some syllables shares a lot in common which makes them difficult to be distinguished. By applying discrete wavelet packet transform to the original signals, it can figure out the tiny difference which is beneficial for the classification process. First comes discrete wavelet transform (DWT). As with the Fourier transform, where the signal is decomposed into linear combination of the basis if the signal is in the space spanned by the basis, wavelet decomposition also decomposes a signal to a combination of a series of expansion