| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 101 === Ground penetrating radar (also referred to as GPR) is a nondestructive probing method with improved high-resolution. The principle of this geophysical probing technique uses the penetration and reflection characteristics of electromagnetic waves while propagating through ground layers. Therefore, the nondestructive GPR probing technique may solve problems in a quicker, more economic matter, and improve survey quality. When the GPR electromagnetic waves struck different ground layer boundaries, the specific dielectric constant of each layer result causes the reflective wave differ from the original incident wave. In this study, we applied the GPR technique for an on-site test of flexible pavement subsidence at a section of Gangnan Rd, Taichung LNG Terminal. The investigation used a 400 MHz transducer, which the captured GPR images were then processed by total variation denoising. The final images were used to determine the effectiveness of noise reduction with the road subsidence and tracks when dragging the transducer. Results showed when we used the soft thresholding algorithm for total variation, it enhanced data processing speed; with only around 100 iterations the results were achievable by using the required minimum energy. The method also proved to have effective noise reduction to the noise signals from the hallowed flexible pavement and dragging of the transducer.
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