Optical coherence tomography (OCT) is a new imaging technique that generates high-resolution cross-sectional images of transparent and semi-transparent media. It is used in industrial metrology, for example in component monitoring, as well as in biomedical diagnostics such as ophthalmology or tissue diagnostics. Companies and research institutes with a focus on industrial metrology and medical technology can also expect a wide range of other fields of application. They work together in the VDI/VDE Society for Measurement and Automation Technology (GMA) in a technical committee on OCT and have now published an initial draft guideline with standardized process descriptions.
Bringing together expertise from industry and research in order to jointly publish a standardized set of rules for OCT and thus pave the way for further OCT application fields in the future - that is the aim of the GMA's Technical Committee 8.19 "Optical Coherence Tomography". This is because the comparatively new measurement method has not yet been described in a generally valid manner, and various methods and performance characteristics have not yet been standardized. This means that the comparability of different OCT systems is not yet given and wider dissemination is limited. The work of the technical committee is intended to change this: "Knowledge of and confidence in OCT should be promoted by a general set of technical rules. As a first step, we have now defined terms and measurement methods for performance parameters and described typical process variants," explains Niels König, head of the Production Metrology department at the Fraunhofer IPT and chairman of the technical committee.
Non-contact and high-resolution imaging - from biomedicine to industry
Originally used in ophthalmology, OCT is a measurement method based on short-coherent interferometry for non-contact and high-resolution imaging of tomographic cross-sectional images. It has a penetration depth of several millimeters and a resolution in the single-digit micrometer range. In medical diagnostics, OCT can be used to examine organic tissue, such as tumor tissue, at a very early stage of the disease, either intraoperatively or in vitro. Thanks to its universal properties, OCT is also used in industry for material and defect testing, for example for plastic products. OCT is used to measure surfaces and distances in opaque materials that cannot be penetrated by light, such as metal.
The first results of the work of the new technical committee on OCT are now available in the form of the draft guideline VDI/VDE 5565 Sheet 1. The draft describes the OCT procedures and defines the necessary terms. In order to reach the entire OCT community, the draft has already been published bilingually in German and English. The draft can be commented on by objection until 31.07.2022. Once the objections have been dealt with, the valid guideline will be published. The committee is already working on VDI/VDE 5565 Sheet 2 on the subject of "Signal processing and data evaluation". The metrological characterization of OCT systems is on the roadmap for further guideline projects.
