A Method of Signal Proessing by Wavelet Transform
Yukiyasu Shigeta, S. Hayano, Yutaka Saito · Journal of the Visualization Society of Japan · 2000
We are now exploiting a magnetic sensor, which detects magnetic materials embedded into the ground and concrete walls. Our magnetic sensor is composed of the mechanically vibrating DC magnet having the sensing coils. When there are no metallic materials in the DC vibrating magnetic field, no magnetic field distortion senses no magnetic materials. However, if there is a kind of metallic materials in the DC vibrating magnetic field, then the magnetic field distortion induces a signal at the sensing coils. Analysis of this sensor signal leads to the physical properties of the target metallic material. In the present paper, we propose a method of analysis for magnetic sensor signals. Based on the physical characteristic value such as a time constant of the electric circuit, our methodology tries to work out an equivalent characteristic value reflecting the physical property of the target metallic material. As an initial experiment, we have carried out an evaluation whether the target metallic material is a magnetic or non-magnetic material. As a result, we have succeeded in cognition of the magnetic and non-magnetic materials. Thus, second stage of our smart magnetic sensor developing is reduced into the equivalent characteristic data compression technique employing the discrete wavelet transform. Thus, this paper reports that our characteristic data may be compressed in a quite small data quantity by means of the wavelets.