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Highly accurate deflectometric shape measurement including the non ideal properties of a display as reference plane

高精度偏转形状测量，包括作为参考平面的显示器的非理想特性

基本信息

批准号：
298137953
负责人：
Professor Dr. Ralf Bernhard Bergmann
金额：
--
依托单位：
BIAS - Bremer Institut für Angewandte Strahltechnik GmbH
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/298137953?language=en
关键词：
Highly accurate deflectometric shape measurement

项目摘要

Phase-measuring deflectometry is a highly sensitive, 2-D optical measurement method that can determine details of reflective surfaces very accurately. It measures quantitatively the distortion of a reference structure (often represented by a computer monitor) that is reflected by the surface to be measured. The measured quantity resulting from the distortion measurement is the slope for each point of the object surface. By differentiating the data, the local surface curvature can be obtained, and the very high sensitivity of the method with regard to local disturbances leads to a height resolution on the order of one nanometre with little effort. Therefore, this method has found its way into industrial quality inspection. Integration of the slope data to determine the absolute object form is by far the harder task. While various methods for calibration of the camera and the system geometry have been modelled and tested successfully, very little is known about the deviations that a real display imparts to a reference pattern assumed to be ideal in all hitherto existing analyses. Large displays can no longer be regarded as planar surfaces, and neither the impact of the scattering screen located in front of the luminescent pixels nor the influence of the observation angle on the intensity have hitherto been systematically investigated.The goal of the proposed project is to do research on an adequate characterization of the display, including the camera and measurement system calibration in order to reduce the measurement uncertainty of measurement systems based on deflectometry using a monitor from currently around 4 to 15 µm at flat or shallow curved surfaces by around one order of magnitude to smaller than 0,5 µm even for stronger curved surfaces. Within the project, the following sub-goals have to be achieved: i) Characterization of displays and development of a model describing the behavior of real displays. ii) Integration of the display model in the vision ray calibration of the camera. iii) Novel system calibration including the display model and the vision ray calibration for procedures for the measurement of steady and unsteady surfaces. iv) Empirically based results to systematically describe deviations of the measurement procedure via qualification measurements using flat and curved test samples. v) Experimental evidence of reduced measurement uncertainty comparing results without and with consideration of the properties of real displays and improved system calibration.The project is designed as a cooperation of two applicants. During the first part of the project, IPROM investigates the influence of the behavior of real displays, while BIAS formulates and experimentally verifies extended approaches of system calibration for measurement systems based on deflectometry. Towards the end of the project, a joint measurement system will be realized.

位相测量弯沉法是一种高灵敏度的二维光学测量方法，可以非常精确地确定反射表面的细节。它定量地测量被测量表面反射的参考结构(通常由计算机监视器表示)的变形。由变形测量产生的测量量是物体表面每个点的斜率。通过对数据进行微分，可以得到局部曲面曲率，并且该方法对局部扰动具有很高的灵敏度，因此几乎不费力气就可以获得一纳米量级的高度分辨率。因此，这种方法在工业质量检测中得到了应用。到目前为止，整合坡度数据以确定绝对目标形式是一项艰巨的任务。虽然已经成功地对相机和系统几何形状的各种校准方法进行了建模和测试，但对于在所有迄今为止的现有分析中被认为是理想的参考图案的真实显示所带来的偏差，我们知之甚少。大型显示器不能再被视为平面，目前还没有系统地研究位于发光像素前面的散射屏对亮度的影响。该项目的目标是对显示器进行充分的表征，包括相机和测量系统的校准，以便将基于偏转测量的测量系统的测量不确定度从目前的约4到15微米在平面或浅曲面上降低约一个数量级，即使对于较强的曲面也小于0.5微米。在该项目中，必须实现以下子目标：i)表征显示器和开发描述真实显示器行为的模型。Ii)在摄像机的视觉光线校准中整合显示模型。3)新的系统校准，包括显示模型和用于测量稳定和非稳定表面的程序的视觉光线校准。四)以经验为基础的结果，通过使用平面和弯曲测试样本的合格测量，系统地描述测量程序的偏差。V)减少测量不确定度的实验证据，在不考虑和不考虑真实显示器的特性和改进系统校准的情况下比较结果。该项目是两个申请者的合作项目。在项目的第一部分，IPROM研究了真实显示器行为的影响，而BIAS则制定并实验验证了基于偏转测量的测量系统的扩展系统校准方法。在项目接近尾声时，将实现联合测量系统。