數位相移條紋投影量測系統之設計與實現

Design and implementation of digital phase-shifting fringe projection measurement system

顏子評(Tzu-Ping Yen)

指導教授 ： 劉承揚

淡江大學/工學院/機械與機電工程學系博士班/博士(2018年)

https://doi.org/10.6846/TKU.2018.00483

摘要

本研究建立完整的數位相移條紋投影量測系統來進行物體的三維曲面量測，在演算技術部分，本研究使用多步相位移技術、三種波形條紋、品質導引路徑相位展開技術及參考平面扣除法等。硬體部分，本研究設計了兩套系統，第一套稱為多角度三維複雜曲面量測系統，第二套稱為微米級形貌量測系統。多角度三維複雜曲面量測系統使用DLP投影機投射條紋結構光影像，再藉由CCD相機擷取變形的條紋結構光影像，並利用電控轉盤來控制CCD相機的量測角度，以觀察多步相位移在不同量測角度對物體三維曲面量測的影響。微米級形貌量測系統整合DLP投影機、光學鏡組、立體顯微鏡及CCD相機將條紋結構光縮小並用以量測微米級三維形貌。由實驗結果可知，在量測三維複雜曲面時，七步相位移在量測角度20°可得最佳量測結果，量測直徑50 mm滾珠螺桿之真圓度為0.05mm。在量測特定形狀時，餘弦波條紋對於直徑1 cm內凹半圓形待測物的量測誤差最小為1.27%，方形波條紋對於寬度3 cm長方形待測物的量測誤差最小為5.02%，三角波條紋對於邊長1 cm正三角形待測物的量測誤差最小為10.18%。在量測微米尺寸之形貌時，量測光纖解析度可達3 μm，與共軛焦顯微鏡量測結果比較，本量測系統精度高、架構簡單且操作容易。本系統可應用於生產線上之三維形貌檢測，對於自動化光學檢測領域有相當之助益。

關鍵字

三維曲面量測 ； 數位結構光 ； 相位移技術

並列摘要

The three-dimensional surface imaging system based on the digital phase-shifting fringe projection profilometry is presented in this study. Multi-step phase-shifting technique, three waveforms of fringe patterns, quality-guided phase unwrapping algorithm and reference plane subtraction method are utilized in this study. This study presents the two systems, the first system is the multi-angle three-dimensional complex surface measurement system and the second system is the micro-surface measurement system. In the multi-angle three-dimensional complex surface measurement system, the structured light fringe patterns are projected by the digital light processing (DLP) projector. The deformed fringe patterns are captured by the charge coupled device (CCD) camera. The motorized stage is used to control the detecting angle of the CCD camera. The effects of multi-step phase-shifting technique and the detecting angles are observed and analyzed. In the micro-surface measurement system, a DLP projector, optical lenses, a stereo microscope and a CCD camera are used to gauge the three-dimensional micro-surface. The fringe patterns from the DLP projector pass through the optical lenses to the micro-surface. The optical lenses are used to adjust the size of fringe patterns. According to the experimental results, the seven-step phase-shifting technique for three-dimensional complex surface has the best measurement results. The best detecting angle with lowest phase error is 20 degree. The Roundness value of 50 mm diameter ballscrew for seven-step phase-shifting technique at 20 degree detecting angle is 0.05 mm. In the specific objects measurement, the 1 cm diameter hollow semi-circular object estimated by cosine wave has the least measurement error for 1.27%. The 3 cm width square object estimated by square wave has the least measurement error for 5.02%. The 1 cm length triangular object estimated by triangular wave has the least measurement error for 10.18%. In the micro-surface measurement, the measurement resolution of micro-surface measurement system is about 3 μm. The measurement results of the laser scanning confocal microscopy are compared with the proposed system. The measurement results show that the proposed system has more advantages because of its high resolution, concise system structure and simple operation. Furthermore, the proposed system can be used for three-dimensional inspection in manufacturing process, which is extremely beneficial in the automated optical inspection industry.

並列關鍵字

Three-dimensional surface measurement ； Digital structured light ； phase-shifting technique

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