Finding and tracking Bragg spots in GISAXS maps of Block Co-Polymer Thin Films

Christian Kjeldberg, Sina Ariaee, Sergey Chernyy, Kristoffer Almdal, Florian Jung, Christine M. Papadakis, Detlef-M. Smilgies, Anders Lassen, Dorthe Posselt

Research output: Contribution to conferencePosterResearchpeer-review


Real time restructuring behaviour of ~100nm spin-coated nanostructured ABC miktoarm star terpolymer films during solvent vapor annealing was monitored using GISAXS. Throughout the investigation, a large quantity of 2D GISAXS maps was produced. Some of these maps exhibit Bragg rods or Bragg spots and other features, which changes position, shape and intensity in accord with structural changes in the film. For the purpose of identifying and tracking Bragg spots with changing position, two different feature extraction algorithms have been tested: 1) a cascade based algorithm based on the Viola-Jones algorithm [1] and 2) an approach based on the Circular Hough Transform [2]. The cascade based algorithm is able to identify the Bragg spots in the dataset tested, consisting of ~3000 maps, with very few false positives or false negatives (< 10) at a rate of ~18 frames per second. The Circular Hough Transform is generally a faster algorithm (~70 frames per second) but fails for part of the dataset, during the drying stage of vapor annealing, due to changes in the shape of the Bragg spots tracked.
Original languageEnglish
Publication date22 Nov 2019
Publication statusPublished - 22 Nov 2019
EventInternational workshop GISAXS2019 - DESY, Hamburg, Germany
Duration: 20 Nov 201922 Nov 2019


WorkshopInternational workshop GISAXS2019
OtherFrom November 20 to November 22, 2019, the international workshop GISAXS2019 will be held in Hamburg, Germany ( It is a continuation of the very successful series of several international GISAXS workshops at DESY (in 2005, 2007, 2011, 2013, 2016) and the satellite conferences to the SAS conference series in Hamburg (in 2009), in Kyoto (in 2012), in Nice (in 2015) and in Gyeongju (in 2018). This workshop brings together different communities working in the field of thin films, nanostructures, surfaces and interfaces, to gain insights to the very powerful method of grazing incidence small angle x-ray scattering and related techniques. In keynote and invited lectures the possibilities and new trends in GISAXS and GISANS will be highlighted with a special emphasis on real-time investigations and data analysis. As in all the years, we expect about 100 participants from all over the world.<br/><br/>Keynote and invited lectures will highlight the possibilities and new trends in GISAXS and GISANS. Poster sessions will allow for a profound discussion among the participants. For poster contributions, you are kindly asked to submit your abstract using the template on under Abstract submission. Only poster contributions with a submitted abstract can be accepted This workshop addresses students, experienced researchers, senior scientists working in the field of and exploiting the potentials of GISAXS and GISANS in the area of thin film technology<br/><br/>The program is divided in two parts: In the first part, introductory lectures will be combined with expert lectures by leading expert scientists of grazing incidence technology and application. In the second part of the workshop we will have hands-on GISAXS, focusing on on-line data treatment and simulation of GISAXS data. In addition, we will offer a visit to the new micro-and nano-focus beamline dedicated to GISAXS at the 3rd generation synchrotron radiation source PETRA III.<br/>
Internet address

Cite this