How to drive optical measurement systems to outstanding performance

Abstract

In the context of measurement technology, optical methods have a number of unique features. These features include in particular the non-contact and high speed interaction with the object under test, the largely free scalability of the dimension of the probing tool, the high resolution of the data, the diversity of information channels in the light field, and the flexible adaptability of the comparative standard – the wavelength. On the other hand the user is confronted with a number of serious challenges. Two of the biggest challenges that currently attract high attention in both the technical as well as life sciences, relate to exceeding the physical limits of resolution and to improve the precision of the measurement. Therefore optical measurement methods are subject to constant improvement. The characteristics that give rise to improve the performance of the systems are obviously dependent on the purpose of the measurement and the object under test. But there are also general features that can be used to assess the performance of a measurement system. Here we refer to the spatial and temporal resolution, the area related resolution, the precision and trueness of the results, the robustness, the degree of automation, the process capability and the ability to work as close as possible to the process. In this contribution we describe the current challenges for measurement systems. Based on this we discuss general and application dependent features for the assessment of modern optical measurement systems. Afterwards, we describe measures to assess and to improve their performance. Finally, we show an advanced optical measurement system where several of these features were considered with regard to ensuring a high performance.