複合結構光式動態三維形貌精密量測技術

Dynamic Three Dimensional Surface Profile Measurement Using Composite Structure Light Projection

陳亮嘉(Liang-Chia Chen) ； 翁明軒(Ming-Xuan Weng)

《科儀新知》 194期 (2013/06) Pp. 6-18

摘要

本研究提出一個複合結構光式動態三維形貌精密量測方法，乃結合傅立葉輪廓術（Fourier transform profilometry, FTP）與相移輪廓術（phase shifting profilometry, PSP）兩種演算法，所發展出一種具即時量測能力之創新性複合式條紋輪廓術（composite fringe profilometry, CFP），其量測精密度可媲美PSP，且可同時達到動態三維形貌量測之創新動態形貌量測技術。將不同相位的正弦條紋進行色彩編碼，以組合形成一種具獨特性的結構圖案並且投影至物體表面上，利用高速影像單元取像並且由所發展的帶通濾波器（bandpass filter）進行處理。本技術能夠以最高取像速度進行三維影像之重建能力（目前可達數百Hz以上），主要原理乃利用FTP萃取出的彩色結構光（紅藍綠，RGB）結構條紋，並同步進行三步之相位重建。在初步的驗證階段，本方法將可以達到接近於傳統相移術的量測精度與重複度，並且可即時獲得三維影像資訊的能力。針對標準階高量測所產生之最大誤差，可控制在全高量測範圍的1.231%以內。

並列摘要

In the article, a novel composite fringe profilometry (CFP) method based on both of Fourier Transform Profilometry (FTP) and phase shifting principle (PSP) is newly proposed to achieve the measuring accuracy closely reaching to the approximately same level by PSP, as well as one-shot imaging capability for achieving high-speed 3-D profile measurement. Multi sinusoidal colour fringe patterns are encoded to form a unique composite colour pattern for projecting onto the object's surface, and its reflected deformed fringe image is taken by use of a triple-colour CCD camera and rapidly processed by the developed CFP method employing an innovative band-pass filter. To reconstruct a 3-D profile of an object, a new strategy is developed to wrap three FTP-derived phases by using the PSP method, in which surface reconstruction can be performed robustly for production of high-quality profile information. By measuring standard step heights in a repeatability test, it is confirmed that a maximum measured error can be controlled less than 1.231% of the overall measuring depth range.