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Virtual experiments

Working group 8.42


In a virtual experiment a measurement process is modeled mathematically and simulated on a computer. The employed mathematical model of the physical experiment is sought to be as realistic as possible. Virtual experiments allow different scenarios to be easily explored. In this way, measurement processes can be designed and specified with the help of the computer. Virtual experiments can be used to estimate the accuracy that is reached by a real measurement device. Dominant sources of uncertainty can be identified and quantitatively explored by carrying out a sensitivity analysis of the virtual experiment. The results obtained can be used to optimize the considered measurement system. Virtual experiments can help in the development of procedures from data analysis for real experiments, for example to assess and compare different estimation procedures under realistic conditions, or to validate assumptions made about the distribution of measured data.

Simulation of a tilted-wave interferometer (left) and a virtual 3D-measurement of an optical surface (right) using SimOptDevice.


The research of PTB’s Working Group 8.42 focuses on virtual experiments for optical measurement devices and the development of procedures from data analysis for evaluating corresponding measurements. To this end, the simulation environment SimOptDevice has been developed as a software library, which is successfully employed in many applications regarding length-/form- and coordinate measurements, as well as photometry. SimOptDevice is regularly maintained and its functionality improved. It is currently applied to the tilted-wave interferometer, which is suitable for the optical form measurement of aspheres and freeforms. Methods of data analysis in conjunction with virtual experiments are developed and applied to solve the involved inverse problem and to calibrate the measurement process. Other research topics include the evaluation of uncertainties associated with real measurements utilizing the results of the corresponding virtual experiment, or the use of methods from deep learning in connection with virtual experiments. For example, virtual experiments can be used to create a database needed to train a neural network that is designed for analyzing experimental data.


Publication single view


Title: System of four distance sensors for high-accuracy measurement of topography
Author(s): I. Weingärtner;C. Elster
Journal: Precision Engineering
Year: 2004
Volume: 28
Issue: 2
Pages: 164 - 170
DOI: 10.1016/j.precisioneng.2003.10.001
ISSN: 0141-6359
Web URL: http://www.sciencedirect.com/science/article/pii/S0141635903001235
Keywords: High lateral resolution
Tags: 8.42,Form
Abstract: A novel sensor system consisting of four distance sensors is proposed for the scanning measurement of topography. The system achieves high accuracy and allows high lateral resolution. The configuration of the system can be chosen such that it guarantees perfect reconstruction of the topography in the presence of offset and pitch errors of the scan system provided the sensor measurements are error-free. Moreover, a favorable propagation of the random and systematic errors of the sensor measurements is achieved. The error influences are investigated and the sensor system is compared to a previously proposed three-sensor system by analyzing simulated data.

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