Experimental Analysis of Terahertz Detection of Polyethylene Thickness
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Jiang Qiang, Yu Yue, Liu Zuoshi, Huao Yuan
In the manufacturing process of polyethylene material pipelines, accurate measurement of pipe thickness is an important technical problem affecting the quality of pipeline production. In the process of terahertz non-metal thickness transmission measurement, the optical path time difference and material refractive index of two transmitted signals are measured. The sample thickness parameter is obtained. In this paper, the thickness error detection calibration of the test sample is firstly carried out, then the stepwise Butterworth bandpass filter is applied to the time domain signal, and the optimal filter interval is determined by the signal to noise ratio calculation formula, and the closest frequency of different samples is selected. The distribution interval is used as a basis for selecting the effective range of the refractive index. The experimental results show that the measurement accuracy is significantly improved, and the measurement error is significantly reduced.
Terahertz, refractive index, measurement error, error calibration