大尺度复杂加工面的连续变角度光学全息干涉测量原理

Large and complex surfaces often exist in mechanical machining. Knowing the answer of how to measure this kind of surface with sub-micron precision, full field and high speed can promote the mechanical machinning to the next level of high-grade, precision and advanced development. The current technique, “multi-wavelength holographic interference measuring technique”,is the only disclosed technique which can achieve the high-speed, full-field and sub-micron measurement. But it still has some limits such as small measurement range, low stability, complicated structure and high cost. So this technique is hard to be fully applied. In this project we present a technique with a new principle-- “continuous multi-angle holographic interference measurement”. The measuring information extraction in this new technique is single-point independence. It can measure the complex shape with high speed, full field and sub-micron precision without phase unwrapping. In this project, we will ascertain the information demodulation principle of this new technique and the influence of various factors on the measuring accuracy. A prototype measurement system will be built to validate the proposed principle and method, which will lay a solid foundation for the practical promotion and application. The proposed research will overcome the defect of the current Information demodulation methods of optical interference (Phase-shifting holography and Multi-Wavelength holography). The proposed research will promote the key break through in measurement range, stability and cost effective and is more suitable for wide range application. The research results will bring a advanced method for mechanical and other related industry. The theoretical and practical significance of the research will be important.

机械行业中有许多面积大、形状复杂的加工面，对其进行亚微米级精度、全场、高速测量是机械工业向高、精、尖发展的关键技术瓶颈之一。目前，国际上唯一能实现大面积、复杂机械加工面在线、高速、全场测量的是“多步变波长全息干涉测量”技术，但其还存在测量范围小、稳定性差和非常昂贵等缺点，难以推广应用。本项目提出研究一种“连续变角度全息干涉测量”新原理，该原理对待测信息单点独立提取、“无需相位去包裹”、可以对任意复杂形状加工面进行全场、高速、亚微米精度测量。项目将探明这种新思想的信息解调原理和方法、各种影响因素对测量精度的影响规律，建立测量系统原型样机，为实际推广应用打下基础。项目提出的新方法克服了现有的两种光学干涉信息解调法（“相移法”和“变波长法”）的缺点，具有测量范围大、测量稳定、成本低等优势，适宜大面积推广应用，将为机械、航空航天等行业提供一种先进的测试方法和技术，具有重要的理论和实际意义。

在机械加工制造领域中，对物体三维形貌信息的需求日益增长。数字全息干涉技术是近年李发展起来的一种光学非接触检测技术,被广泛用于物体三维形貌测量应用中。目前较为常用的是多波长数字全息干涉测量技术，但该方法需要多波长光源，存在系统成本高，波长调节范围小等缺点，且商用化的多波长数字全息干涉测量仪基本只适合测量平表面结果，实际推广应用受到一定限制。为此，课题组提出了仅需单一波长的变角度数字全息干涉测量技术来克服现有数字全息干涉方法所遇到的难题。项目组围绕着连续变角度数字全息干涉测量技术，数字全息干涉自动聚焦技术，数字全息散斑去噪技术，基于点源球面波的数字全息干涉大尺寸物体三维形貌测量技术等内容展开研究。提出的连续变角度数字全息干涉测量技术无需相位解包裹，能够实现单点独立测量，有效解决在具有较大突变，非连续表面物体测量时避免相位解包裹和降低测量误差相互限制的难题，与同类方法相比，该方法能够减少50%左右的测量误差，有效地提高了数字全息干涉测量精度。提出的基于相关系数的数字全息自动聚焦算法具有很高的鲁棒性，能够实现数字全息成像自动聚焦，保证了数字全息重建结果的准确性。为了减小数字全息散斑噪声对测量结果的影响，提出了基于散射片的角度多样化数字全息成像散斑噪声抑制方法以及基于4F相干成像光学系统仿真技术，为降低数字全息干涉测量误差提供解决策略。提出的点源球面波照明的变角度数字全息干涉测量技术，理论上可以提供任意大小的照明光束，可以有效扩大单次测量面积。项目组所开发的变角度数字全息干涉测量技术有效克服了现有数字全息干涉测量成本高，波长调节范围低等难题，具有全场、非接触、成本低等优点，为数字全息干涉测量技术的进一步应用推广提供了技术支撑，具有重要的理论和实际意义。.项目进行中发表论文14篇（其中SCI论文10篇，EI论文2篇，北大中文核心论文2篇），另有2篇SCI论文已投出，申请国家发明专利5项（已授权专利4项）。