The Cathedral Window in a New Light
© 2013 EPFL
At the intersection of science and art: theAudiovisual Communications Laboratory has developpedsoftware toobserve stained glasswitha light andviewing angle that have been chosen toreveal unexpected details.
Admiring the largewindowon the south façadeof the Cathedral ofLausannewithabrightness setting seems impossible. Yet that's what ateamfrom theAudiovisual Communications Laboratoryhas achieved.It is at once unusual andpromising: the software being developped canseeon a screenany windowwith a selected brightnessin order to graspevery detail.Backed byGoogle,this workis part of eFacsimile, a research project thataims to developa new paradigmof acquisition,representation,and renderingfor high-quality reproductions ofart.
As a testament to the quality ofthis ancient art, stained glass hasthe advantage of beingwell preserved.Colorsremain almostunchangedover centuries,as evidenced by theimpressive 13th century Rose adorning the southern facade ofthe church buildingof the Vaudcapital.Despite their translucence, in order to grasp all aspects of their colors, viewers must dedicate numerous visitsover several hours –andin differentweather conditions.
To overcome thephysical impossibilityof movingthe windowor choosingtheweather, the researchers began by analyzingthe characteristics ofthe microstructure of thewindow glassin the laboratory.While aportion of the rayscamedirectlytothe viewer's eye, others dispersed,causingthe sensation ofglarein some places.The analysis ofphotographsof the material underdifferent light intensitieshelped highlight theimpuritiesand scatteredrays.The researcherscreated a listtranslated intoalgorithms.
In conjunction with this, acamera located inthe domeopposite theRoseacquiredimages over a dayand a halfto capturea largerange ofluminosities. Simultaneously,threetime-lapse cameras placedat the same level, but outsidethe building,captured a180 degree viewof theincidentlight onthe window.
Ultimately, the program written by doctoral student NiranjanThanikachalamis responsible for superimposing the images and selecting the brightness. Inthe example setfor this experiment, seenon YouTube,atime lapseof theSan Francisco Bay is placed behindthe work.The result inspires ideas for otheramazingunionsthat willtransportthe windowsto otherlatitudes, luminosities, and weather conditions,therebydiscovering them in a new light.
Thegoal now is tomake asimple softwareto reproduceotherwindows. It is worth noting thatmorework around the Cathedral wasdonein 2013and is available onthe LCAV website. A virtual touris available there.With a simple click, for example, it is possibleto heara piece oforganin the exactacousticsof the location.