By Roger Groves
SPIE Optics for Arts, Architecture and Archaeology (O3A) is a well-established conference series which was founded in Munich in 2001 by Prof. Renzo Salimbeni, CNR, Italy. It brings together the community of researchers in optical diagnostics for cultural heritage with conservators and art historians interested in scientific techniques and often acts as a first bridge for scientists to engage with the heritage community. This year’s conference was held in Munich from 24-26 June 2019.
This year’s SPIE O3A conference was chaired for the first time by Dr Roger Groves (TU Delft) and Prof. Haida Liang (Nottingham Trent University). This year we had an increased number of submissions, with 63 papers accepted, 2½ days of presentations and a poster session. The conference was organised by SPIE as one of the conferences in the SPIE Optical Metrology Symposium and was held at the Munich International Congress Centre.
The main topics for 2019 were 3D Tomography, Light-matter Interaction, Imaging & Spectroscopy, Structural Analysis, Optical Coherence Tomography (OCT), Advanced Signal Processing, Remote Imaging, 3D Surface Analysis, Multimodal Imaging and Application in Cultural Heritage. Below, I will introduce you to the 2019 programme, highlight some of the technical presentations given at the conference and connect their relevance to conservation practice. I will then give my opinion of the hot topics for new techniques that should become more widely available in conservation laboratories in the next few years.
MONDAY 24th JUNE PROGRAMME
The opening invited speaker of the conference was Kaori Fukunaga (National Institute of Information and Communications Technology, Japan) who presented her research in non-destructive inspection with electromagnetic waves, in particular with terahertz imaging. The morning theme continued with non-destructive inspection, then focused on materials degradation with an invited talk by Daniela Comelli (CNR, Italy) and further presentations.
After lunch, the afternoon sessions were devoted to imaging spectroscopy, also known as hyperspectral imaging, and on structural analysis. I would like to comment that due to recent advances, 3D shape measurement is now becoming regularly used in heritage and is of particular importance for documenting heritage sites, for assessing the deformation of larger heritage structures and for the digital replication of heritage objects. The day concluded with a beer and bretzel reception with the attendees of the symposium.
TUESDAY 25th JUNE PROGRAMME
Tuesday morning started early with an invited paper by Jeroen Kalkman (TU Delft, Netherlands) on multi-scale optical coherence tomography (OCT) of the painting The Girl with a Pearl Earring by Johannes Vermeer, held in the collection of the Mauritshuis, The Hague, and in particular on automated measurement and processing of large OCT data sets. The morning session continued with presentations addressing high resolution OCT imaging, multi-modal sensing with OCT and advanced signal processing. The morning session concluded with 5-minute poster pitches for the poster session in the afternoon.
After a short lunch break, the conference poster session was held. This session was an opportunity to meet junior researchers and to see new ideas and emerging technical topics and applications of heritage diagnostics. On the technical side, using a smartphone for heritage diagnostics caught my attention, as did using machine learning algorithms for heritage applications. I was particularly intrigued by the special considerations that conservators have to make when treating works by living artists, when discussing the poster by Miroslaw Wachowiak and colleagues (Nicolaus Copernicus University, Poland).
The afternoon session continued with an invited paper by John Delaney (National Gallery of Art, USA) on mid-infrared imaging spectroscopy and further presentations on remote imaging spectroscopy. The final session of the day kicked-off with an invited presentation on OCT of 19th-century glass by Lynn Branstoff (Library of Congress, USA) in the Applications in Cultural Heritage session.
WEDNESDAY 26th JUNE PROGRAMME
I started Wednesday morning by chairing the session on 3D surface analysis. We had some interesting presentations in this session on Reflectance Transformation Imaging (RTI) for surface image enhancement, conoscopic sensors for micro-deformation measurements and a study of mediaeval graffiti. The final conference session was devoted to multimodal sensing and concluded with a presentation on spectroscopy and imaging of Pietra Dura style marble inlay at the Taj Mahal. We had a relaxed afternoon, and the conference dinner was held at the Ratskeller in Munich city centre in the evening. I personally then stayed in Munich over the weekend to allow some more time to visit the city.
Here I give my recommendations for emerging techniques that you may find in your conservation laboratories during the next few years. First I would like to highlight the increasing maturity and accessibility of 3D shape measurements for conservation. Also the newly developed conoscopic sensors offer a simple solution for micro-scale deformation measurement. Multi-modal sensing is a hot topic currently and I also expect to see much more data fusion, machine learning and visualisation for all optical diagnostics techniques in future. The integration of smart phone sensing offers a new direction and forms part of the trend towards to portable and compact sensors for in-situ measurements.
This years’ SPIE Optics for Arts, Architecture and Archaeology VII was a successful conference that connected many of the leading researchers in optical diagnostics with each other and with conservators interested in emerging technology. The program was very international with researchers from almost 20 countries represented, including USA, Brazil, India, China and Japan. I am looking forward to chairing the next O3A conference with Haida Liang in 2021.
The next SPIE Conference on Optics for Arts, Architecture and Archaeology (O3A) will be held in Munich from 21st to 24th June 2021.
(The views expressed are the personal views of the author.)
Dr Roger Groves is Associate Professor in Aerospace NDT/SHM and Heritage Diagnostics at Delft University of Technology, The Netherlands. He has a background in Chemistry & Physics and has been developing optical instrumentation for materials testing for more than 20 years. Since 2005, he has been active in developing diagnostic instrumentation for cultural heritage. He is a member of IIC and is the chair of the SPIE O3A conference, held in June 2019.