Li Dong, Liu Chunyang, Tian Jindong
Opt Express. 2014 Dec 29;22(26):31826-35. doi: 10.1364/OE.22.031826.
Three dimensional shape measurement in the microscopic range becomes increasingly important with the development of micro manufacturing technology. Microscopic fringe projection techniques offer a fast, robust, and full-field measurement for field sizes from approximately 1 mm to several cm. However, the depth of field is very small due to the imaging of non-telecentric microscope, which is often not sufficient to measure the complete depth of a 3D-object. And the calibration of phase-to-depth conversion is complicated which need a precision translation stage and a reference plane. In this paper, we propose a novel telecentric phase-shifting projected fringe profilometry for small and thick objects. Telecentric imaging extends the depth of field approximately to millimeter order, which is much larger than that of microscopy. To avoid the complicated phase-to-depth conversion in microscopic fringe projection, we develop a new system calibration method of camera and projector based on telecentric imaging model. Based on these, a 3D reconstruction of telecentric imaging is presented with stereovision aided by fringe phase maps. Experiments demonstrated the feasibility and high measurement accuracy of the proposed system for thick object.
随着微制造技术的发展，微观范围内的三维形状测量变得越来越重要。微观条纹投影技术为大约1毫米到几厘米的视场尺寸提供了快速、稳健和全场测量。然而，由于非远心显微镜的成像，景深非常小，这通常不足以测量三维物体的完整深度。而且相深度转换的校准很复杂，需要一个精密平移台和一个参考平面。在本文中，我们提出了一种用于小而厚物体的新型远心相移投影条纹轮廓术。远心成像将景深扩展到大约毫米级，这比显微镜的景深大得多。为了避免微观条纹投影中复杂的相深度转换，我们基于远心成像模型开发了一种新的相机和投影仪系统校准方法。基于这些，利用条纹相位图辅助立体视觉，给出了远心成像的三维重建。实验证明了该系统对厚物体测量的可行性和高测量精度。
