紅外線熱影像應用於土石流監測之可行性研究

Infrared Thermal Image Applied on Debris Flow Monitoring

李璟芳(Ching-Fang Lee) ； 張守陽(Shou-Young Chang) ； 林志平(Zin-Ping Lin)

《中華水土保持學報》 35卷3期 (2004/09) Pp. 261-274

https://doi.org/10.29417/JCSWC.200409_35(3).0007

摘要

本研究之目的在於藉由「熱輻射」原理配合熱像儀，用以監測土石流發生流動現象與源頭崩塌地之位移情形，以非接觸式之方法判識坡地災害發生與否，提供土石流與坡地監測之應用參考。
土石流發生與運動可視爲一連續碰撞、滾動與摩擦過程，發生過程將產生熱輻射，又崩塌地之滑動之表面物質與背景環境有某種程度上之差異，二者於理論上可藉由熱影像予以判識。本文利用偵測波長介於8～13μm之紅外線熱像儀作爲研究設備，對現場崩塌地與土石流危險區域進行監測上之可行性研究。
爲了測試惡劣天候下，紅外線熱影像監測用於土石流與坡地災害之適用性，並探討不同渠槽坡度及顆粒粒徑分佈下，土石流發生時是否會因碰撞摩擦而有明顯之溫度變化。本研究進行了現場靜態熱影像分析、室內渠槽模擬土石流動態影像分析與人工降雨能量衰減實驗。實驗結果顯示在相同流量與級配砂石情形下，其流動過程所產生之能量，與水槽坡度大小成正比關係；而同一降雨強度下，能量衰減與雨幕縱深成正比；此外，水槽實驗土石流模擬過程中，由於土石與洪水因不同物質之輻射率，使土石所撞擊能量不易於熱影像呈現，但土石之黯淡熱影像恰可配台影像處理之「紋理特徵值」來加以區別土石流與洪水之差異，其判識率可達100%, 說明以熱像儀擷取熱影像配合機械視覺理論作爲判識土石流之發生，是爲可行之方法。

關鍵字

土石流 ； 熱輻射 ； 紅外線熱影像 ； 監測

並列摘要

The purpose of this study is to construct a ”thermal radiation theory” to determine the process of debris-flow and what collapses of in a landslide. The thermal image process of a camera for monitoring the occurrence of debris flow has the advantages of non-contact. From the analyses of the monitoring system, a judgment can be made to determine whether an alarm should be announced to the public.
The sliding of the crumbled zone and occurrence of debris-flow can be presumed to be a continuous process of collision and rubbingfriction. There is a discrepancy in thermal radiation between the substances in motion and the background; thus, the thermal images can be applied to the monitoring method. This study attempts to use a infrared thermal imaging camera for an image capture device. It has the advantages of a non-light source, monitoring during all-weather; furthermore, the power consumption was much less than machine vision monitoring system.
To examine a feasible estimation on detecting debris-flow under bad weather and explore the effect on the temperature variation under various experimental conditions, a series of experiments have been broadly conducted, including the analyses of field thermal images, the flume experiments of debris flow and the rainfall simulation experiments. The experimental results illustrate that the infrared thermal images can be applied on monitoring the occurrence process of debris-flow. Though the emissivity of water is much greater than that of debris so as to hinder the energy of debris sliding from thermal image, the lower gray level resultinged from debris may easily recognized by 'image texture analysis'.

並列關鍵字

debris-flow ； thermal radiation ； infrared thermal imaging ； monitoring