The Study Of Fiber-Optic Sensor Signal Denoising Base On Wavelet Transform

An optical fiber strain sensor based on white-light interferometric principle is designed, Compared with common optical fiber strain sensor, it has more advantages, such as low cost, high stability and high anti-interference. It can be manufactured and put into use in many field.There is too much noise in this system. In order to improve the resolution of the system, denoising the output signal is necessary. The denoise technology is summarized in this paper. Applied denoising method is brought forward. In this paper, hardware is designed to deal with the output signal of optical fiber strain sensor. First, the light signal is transform into electrical signal by sending it through CCD. Then, by pass amplifier, filter and A/D transform, the analog signal is transform into digital signal. With the control of SCN, the digital signal is send into computer. The noise lie in the system is analyzed and summarized in this paper. Base on the noise in the system, the idea of denoise with wavelet transform is brought forward. Classical denoising methods such as pure time-domain, pure frequency-domain, FFT, Wigner－Ville are limited. The wavelet transform is a new time-scale and time-frequency analysis method, it begin from the eighth years. It is with fine time and frequency local perfo- rmance, and it is wide used in fact.Several classical denoising methods are analyzed, compared and discuss aim at their application range. The methods of denoise with wavelet transform are summarized. It concludes module max. method, denoise with soft threshold, denoise with wavelet packet and so on. A new wavelet threshold method is brought forward. Theory and experimentation indicate that wavelet transform is precede than classical method.