利用HSI色彩梯形相移模型發展一種創新式高速三維形貌量測技術

Innovative High Speed 3-D Surface Profilometry using HSI Color Model and Trapezoidal Phase-shifting Method

許耀升(Yao-Sheng Shu)

指導教授 ： 陳亮嘉

國立臺北科技大學/機電學院/自動化科技研究所/碩士(2008年)

https://doi.org/10.6841/NTUT.2008.00369

摘要

在三維形貌重建方面，為因應自動化光學檢測業界之需求，國內外研究主要鎖定於三維偵測之精度與速度兩方面。目前三維形貌重建以主動式光學量測為主流。又以線上即時量測或動態量測為未來研究發展之趨勢。本研究主要使用數位投影機(DLP)所投影之彩色梯形條紋結構光，並利用色彩梯形相移模型，發展一種高速動態全域三維形貌重建技術。相較於傳統相移法必須擷取三張相移強度影像；本方法所使用之單張結構光同時包含了傳統三步相移之相位資訊，不僅單張取像即可執行梯形相移及相位還原，省略傳統相位封裝及尤拉轉換之過程，並具有執行速度快及對均勻光強依賴性較小等優點。
本研究所採用之彩色梯形結構光，其彩色頻譜分布均勻且色彩飽和度高，但因DLP投影之色彩具有偏移的現象，本研究使用查表法(LUTs, Lookup Tables)對色彩作校正及補償，量測系統依量測應用之需求產生不同週期校正後之梯形結構光，並投影至待測物。而為了減少色彩對光的依賴性，降低量測誤差，吾人將3色CCD擷取之彩色影像轉換至色相飽和強度(HSI)色彩座標之色相域，即利用色彩梯形相移模型對結構光影像作相位封裝，並透過相位還原重建物體三維形貌。本研究之實驗利用標準塊來驗證系統量測準確度(accuracy)，並分析不同的環境振動頻率對量測結果之影響。同時，本研究亦採取以實際量測實例，以驗證本研發技術之實用性。

關鍵字

自動化光學檢測(AOI) ； 動態量測 ； 相移法 ； 相位封裝 ； 尤拉轉換 ； HSI

並列摘要

The importance of high-speed micro 3-D surface profilometry has been greatly highlighted by many in-field applications of modern metrology technology all over the world. A considerable amount of research and development work has been performed to increase the performance of 3-D measurement systems by using automatic optical inspection (AOI) techniques. The active method has been prevailing due to its high accuracy and reliability for on-line real time measurement or dynamic measurement.
In this research, a novel surface profilometry approach using HSI color model and trapezoidal phase-shifting method is developed for achieving fast 3-D surface reconstruction with high spatial resolution. Most importantly, the developed method can perform one shot image for high-speed full field 3-D surface profilometry.
To obtain a continuous and linear phase in the projected fringe pattern, it is important that the hue component after being transformed from its trapezoidal RGB pattern to the HSI model is linear. With the structured fringe pattern being projected on to the measured surface, the color image captured from the CCD camera is then transformed into the HSI model, where the hue component is extracted as the phase quantity in phase-shifting method. Following that, the hue component is further compensated by a mapping process using LUTs. To evaluate the feasibility of the development, the surface of a standard step height was measured for 30 times to evaluate the measurement accuracy and precision of the developed system and techniques. Some of industrial measurement examples were also employed to test the measurement performance of the developed system.

並列關鍵字

Automatic optical inspection (AOI) ； surface reconstruction ； HSI color model ； full field ； surface profilometry

參考文獻

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