| Summary: | 碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 107 === A method for measuring the coefficient of thermal expansion using fringe projection technique is proposed. The fringes are projected through the eyepiece of the stereo microscope. The heating object is projected with a sinusoidal fringe pattern. During the exposure time of the CCD camera, the fringes are blurred due to the expansion of the object. In this paper, the information provided by the blurred fringes is used to calculate the amount of expansion of the of the heating object. The coefficient of thermal expansion of the object is calculated by the equation of thermal expansion.
The entire image is divided into several local areas, each of which has its own amount of expansion, whereby the coefficient of thermal expansion of each area of the material can be measured. Unlike most machine visions, this method requires only one-time measurement, so image registration is not required. It is a non-contact measurement method that does not pollute or destroy objects. The full-field approach can also inspect several objects in the same time.
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