基于FTP的三維輪廓測量方法及實驗

摘 要:為了快速、高精確度地得到物體的三維輪廓信息，在此利用傅里葉變換輪廓術，將被測物體置于光柵投影下，采集變形光柵圖像，根據被測物體表面的高度與相位差之間的映射關系，通過在計算機中與參考光柵原像的比較分析，以獲得被測物體的三維輪廓信息。實驗中搭建了由LCD投影儀、CCD攝像機、圖像采集卡和光學導軌等組成的光柵投影測量系統的硬件平臺，提出了用1臺計算機同時控制投影和采集處理光柵圖像，根據映射關系在多次實驗中不斷修改優化測量參數，做到既不影響視場范圍，又保證較高的測量精度，并給出了由計算機重建后較好的三維輪廓圖像精度及其實驗的測量誤差分析。

關鍵詞:FTP; 三維輪廓測量; 光柵投影法; 三維重構

中圖分類號:TP391 文獻標識碼:A

文章編號:1004-373X(2010)12-0111-03

Method of 3-D Profile Measurement and Experiment Based on FTP

JIANG Lei

(Nedong County Fire Brigade， Tibet General Fire Brigade， Shannan 856000， China)

Abstract:In order to obtain the high-precision 3-D profile information of an object at high speed， based on Fourier transform profilometry (FTP)， the images of the object′s reference grating and deformation grating are collected. According to the mapping relation between height of the object surface and phase difference， after being analyzed and prepared with the original image by computer， 3D profile information of the object is obtained. A grating project measurement platform proposed of LCD projector， CCD camera， image grabbing card， optical guides and so on was established in the experiment. Both the image projection and acquisition were implemented by one computer. On the basis of the mapping relation， the measurement parameters are modified and optimized in the experiments， which promises the measuring accuracy and an enough field range. The object′s 3-D profile image reconstructed by a computer and the measurement error analysis according to the experiment are given.

Keywords:FTP; 3-D profile measurement; grating projection method; 3-D reconstruction

0 引 言

傅里葉變換輪廓術(Fourier transform profilometry，FTP)是結構照明型三維傳感領域中運用較為廣泛的一種方法，FTP以Ronchi光柵(或正弦光柵)產生的結構光投影到待測量的三維物體表面，獲取被測物體面形調制的變形條紋光場，成像系統將該變形光場成像于CCD探測器上，通過在計算機上與參考光柵原像的比較分析處理，以獲得物體的三維輪廓信息[1-4]。用該種方法獲取的數據具有速度快，系統結構簡單，精度較高，適合計算機快速處理等特點。本文簡要介紹了利用傅里葉變換輪廓術測量物體三維輪廓信息的基本原理，并在實驗室搭建了由LCD投影儀、CCD攝像機、圖像采集卡和光學導軌等組成的光柵投影測量系統的硬件平臺，給出了由計算機重構后具有較好精度的三維輪廓圖像及其實驗的測量誤差分析。……