本論文以發展低成本Moiré 偏折技術用以量測在自然對流中測試物之 二維溫度分佈。實驗架設使用一個紅色單色光之LED 燈當作燈源，其燈源光 譜約為625-635 nm。在實驗過程中，單色LED 燈經過球透鏡，然而利用球透鏡 將LED 燈發散光源聚焦成一個點光源，並將此點光源放置在一直徑406 mm 及 f/4.5 之拋物面鏡的焦點上產生一平行光。最後此平行光經過測試區以及兩個 由雷射印表機列印頻率皆為254 lpi 之光柵。在光柵後方有一台CCD 用來抓取 變動之條紋，根據Moiré 理論得知，變動之條紋的移動量代表著其溫度的高低。 本研究成功地量測2 維熱流在自然對流下的溫度分布，使用Moiré 偏折技術以 及熱電偶可以得到最小誤差為5%。

This article develops low cost moiré deflectometry for two-dimensional temperature measurement in free boundary environment. Experimental setup uses a red monochrome LED lamp with a wavelength range of 625-635 nm as light source. In the process, the light first runs through the convex lens and then propagates to the parabolic mirror with diameter of 406 mm and f/4.5 for generating the parallel light. The parallel light further propagates to test object and through two gratings with both pitch 254 lpi, which are printed by laser printer. Behind the two gratings, a CCD camera is applied to capture the image, the distorted fringes. Based on the Moiré deflectometry theory, the two-dimensional temperature distribution in free boundary environment can be determined in terms of the captured fringe shift analysis. This work has successfully measured the two-dimensional temperature distribution in free boundary environment with heat source models of 40-95C vertical wall. The measured temperature deviations between Moiré deflectometry and thermocouple thermometer are all less than 5%.