應用非線性擴散於非同質性紋路之ITO導電玻璃表面檢測

Defect detection in inhomogeneous textures of ITO glass using nonlinear diffusion

趙新民(Shin-Min Chao)

指導教授 ： 蔡篤銘

元智大學/工程學院/工業工程與管理學系/碩士(2003年)

摘要

本研究是利用機器視覺的技術自動檢測ITO（Indium Tin Oxide）導電玻璃表面之瑕疵，ITO導電玻璃為觸控面板（Touch panel）及液晶顯示器（LCD）之重要基礎零件，其製程需將可導電的化學物質濺鍍（Sputtering）至玻璃基板上以產生導電之特性，而經濺鍍後之ITO導電玻璃表面不具同質性（Homogeneous）之紋路特徵，由於非同質性（Inhomogeneous）紋路在空間分佈上不具備高度之規律性，因此使用傳統的紋路分析方法並不能夠有效地檢測出瑕疵。
本研究採用非線性擴散（Nonlinear diffusion）的方法對ITO導電玻璃表面進行瑕疵檢測，此方法之特性是利用灰階梯度（Gradient）之資訊對影像中不同梯度的部份進行不同程度之擴散處理，所謂擴散處理是對影像中梯度較低之背景紋路進行平滑，而對梯度較高之瑕疵邊緣抑制平滑，所以此方法運用在ITO導電玻璃表面之檢測上，可以有效地將背景紋路濾除並同時保留住瑕疵原有之輪廓。
非線性擴散在處理的效果上會受到擴散函數及擴散參數的影響，因此本研究主要針對這兩項因素進行探討，並找出適合用於ITO導電玻璃表面檢測之參數，在選定適當的參數下，實驗結果皆能正確地將背景紋路濾除並凸顯瑕疵，驗證了此方法對於具非同質性紋路之ITO導電玻璃表面有良好的檢測效果。

關鍵字

機器視覺 ； 瑕疵檢測 ； ITO導電玻璃 ； 濺鍍玻璃基板 ； 非同質性紋路 ； 非線性擴散

並列摘要

The purpose of this study is to discuss the use of machine vision in automatic defects inspection in inhomogeneous textures. These inhomogeneous textures include materials such as sputtered glass substrates of touch panels. These textures have similarities in some regions while not in the whole image. Therefore, good processing effect cannot be achieved on these textures by using traditional processing methods.
The proposed method is based on the nonlinear diffusion, in which the edge preserving smoothing filter is dependent on image gradient. This method can smooth the edges in textured regions and, in the meantime, preserve the borders between regions. After the nonlinear diffusion process being done, the inhomogeneous region in the original image will have an approximate uniform gray level, and yet the shape of defective region will be distinctly preserved.
The factors that we found affecting diffusion process result include diffusivity function, diffusivity parameter and iteration times. In this paper, we have analyzed the effects of these factors in order to obtain the best effectiveness. Experiments are performed on sputtered glass substrates of touch panels which lead to our conclusion. The experimental results have shown that our proposed method will have promising results for detecting defects in inhomogeneous textures.

並列關鍵字

Machine vision ； Defect detection ； Inhomogeneous textures ； Nonlinear diffusion ； Sputtered glass substrates

參考文獻

郭志嘉，2002年，「應用三維傅立葉分析於非同質性隨機紋路表面之瑕疵檢測」，碩士論文，私立元智大學工業工程與管理研究所。

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