Promoting confidence in optical coherence tomography.

A new imag­ing tech­nique that gen­er­ates high-res­o­lu­tion cross-sec­tion­al images of trans­par­ent and semi­trans­par­ent media: this involves opti­cal coher­ence tomog­ra­phy (OCT). This method is used both in indus­tri­al metrol­o­gy, for exam­ple in com­po­nent mon­i­tor­ing, and in bio­med­ical diag­nos­tics. Com­pa­nies and research insti­tutes with a focus on indus­tri­al metrol­o­gy and med­ical tech­nol­o­gy expect a large num­ber of oth­er fields of appli­ca­tion. They are work­ing in the VDI/VDE-Gesellschaft Mess- und Automa­tisierung­stech­nik (GMA) in an expert com­mit­tee on OCT and have pub­lished a first draft guide­line with stan­dard­ized process descriptions.

Bring­ing togeth­er exper­tise from indus­try and research to joint­ly pub­lish a stan­dard­ized set of rules for OCT and thus open the way for fur­ther fields of appli­ca­tion in the future — that is the goal of 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 pro­ce­dures and per­for­mance char­ac­ter­is­tics have not yet been standardized.

This means that the com­pa­ra­bil­i­ty of dif­fer­ent sys­tems is not yet giv­en and a more wide­spread use is lim­it­ed. This is to change through the guide­line work of the tech­ni­cal committee.

“Knowl­edge about and con­fi­dence in OCT are to be pro­mot­ed by a gen­er­al set of tech­ni­cal rules. To this end, we have now defined terms and mea­sure­ment meth­ods for per­for­mance para­me­ters and described typ­i­cal process vari­ants as a first step.”

- Niels König, Head of the Pro­duc­tion Metrol­o­gy Department

Non-contact and high-resolution imaging — from biomedicine to industry

Orig­i­nal­ly used in oph­thal­mol­o­gy, OCT is a mea­sure­ment tech­nique 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 resolv­ing pow­er 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 dis­ease, either intra­op­er­a­tive­ly or in vit­ro. But OCT is also used in indus­try thanks to its uni­ver­sal prop­er­ties in mate­r­i­al and defect test­ing, for exam­ple in plas­tic prod­ucts. In the case of opaque mate­ri­als into which light can­not pen­e­trate, for exam­ple met­al, OCT is used for sur­face and dis­tance measurements.

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 Part 1. The draft describes the OCT meth­ods and defines the nec­es­sary terms. In order to reach as much of the OCT com­mu­ni­ty as pos­si­ble, the draft has already been pub­lished bilin­gual­ly in Ger­man and Eng­lish. The draft can be com­ment­ed on by objec­tion until July 31, 2022. After the objec­tions have been dealt with, the valid guide­line will then be pub­lished. The com­mit­tee is already work­ing on VDI/VDE 5565 Sheet 2 on “Sig­nal pro­cess­ing and data eval­u­a­tion”. The metro­log­i­cal char­ac­ter­i­za­tion of OCT sys­tems is on the roadmap for fur­ther guide­line projects.