Press release

The press office of the Julius-Maximilians-Universität Würzburg has published a press release at the start of the project.


A photographic trip through time and space

To visualize a city’s development with the aid of old photographs: This is the aim of a new research project, which is at home in Würzburg and Dresden. Both art historians and computer scientists are working on this together.

It is the aim of the new research project to link images of Deutsche Fotothek’s collection spatially and chronologically, and thus making them accessible for other interested parties. Views of the street Prager Straße in Dresden – shown here in a photograph from 1908, with a North-Eastern view towards the hotel “Europäischer Hof” – are playing a major role in this.

More than 1.8 million digitalized photographs, paintings, drawings, maps and architectural drafts are in stock at Deutsche Fotothek, where they can be accessed by users worldwide. Many of them display city views and buildings of Dresden – from 1850 to today. This pool of images is of special interest to scientists from Würzburg and Dresden; their new research project aims at linking these images spatially and chronologically, and thus making them accessible for other interested parties. “HistStadt4D – multimodal access to historical image repositories” – this is the name of the project, which will be supported by the Federal Ministry of Education and Research with 2 million Euros over the next four years.

„Our projects links two different perspectives: those of Humanities and of Informatics“, says computer scientist Dr. Florian Niebling. Representing the Informatics perspective, he leads the junior research group HistStadt4D at Erich Latoschik’s chair for Computer Science IX at Würzburg University.

The computer scientists‘ contribution

The Informatics perspective: „ Those searching for images at Deutsche Fotothek can today use free text search in a browser based interface“, says Florian Niebling. Whether the right hits are made depends a lot on the quality of the metadata the images are tagged with. This quality is often lacking, however, especially in photographs that have not been explored yet. They might lack information about the photographer, the year or the place the photo was taken, which is why they might not turn into a search hit.

Niebling and his PhD students want to process these images for a spatial search. As the computer scientist says: “We want the photographs to be automatically linked in 3D in a city model”. This will enable users of the Fotothek to virtually walk through a model of Dresden and take closer views of the images that are saved in the archive for the user’s specific location. In addition, a fourth dimension – time – is to enable research on street and building development.

Information through Augmented Reality

An improved search function is only one aspect the information scientists will work on in the research project. Another aspect is the information transfer. “Today the information about a city and its development are usually transferred by means of historically oriented exhibitions”, according to Niebling. Together with his junior research team he wants to open up a new way – Augmented Reality.

With the help of an application developed by the computer scientists, visitors in Dresden will, amongst others, be able to place their tablet or smart phone in front of a building, such as Zwinger. On the display they will then receive information about the pictured details of the world famous baroque building, can regard historical views, and follow the chronological development on a timeline.

The keyword „Dresden-Altstadt“ gives 11,143 hits in the Deutsche Fotothek database. Hundreds of photographs exist for many of the buildings – taken from varying locations and angles. From the computer scientists’ point of view, this amount of data is a unique treasure. Their plan is to take the 2D photos and generate a 3D model with the help of their own software. First on-site tests with a modern camera have shown that 50 photos, taken semi-circularly, are sufficient to generate such a model while keeping a close attention to detail. Whether the historical treasure pool of images is sufficient is yet to be seen. “Many of the historical photos are blurred with little contrast”, according to Florian Niebling. This makes the reconstruction more difficult.

The art historians‘ contribution

The historical science perspective of the project is represented by art historian professor Stefan Bürger and his colleague Dr. Kristina Friedrichs. The centre of their interest is the interaction of architecture, human and image, or – in Stefan Bürger’s words – the questions: “How does city space affect people, and how does the image of the city move in their heads?”

Naturally, the art historian also wants to know how certain buildings in Dresden have changed in the course of time. The city on the river Elbe has a lot to offer in this respect, covering the building activities of the 19th and early 20th century, the destruction during World War II, the reconstruction and the new development of vitally situated successions of houses in historical style after 1989.

Research on Kronentor gate and Prager Straße

Using photographs from the archive of Deutsche Fotothek, the scientists want to visualize the changes on a timeline – 3D if possible. Initially, they are concentrating on two objects: the Zwinger Kronentor gate and the street Prager Straße, a prominent, square-like street that was built between 1851 and 1853 to directly link the inner city and the main train station.

First, suitable photographs for this project need to be found in the Fotothek’s rich collection. This is Kristina Friedrichs’ current task. Regarding the Kronentor gate, Stefan Bürger is confident that a 3D reconstruction, as planned by the information scientists, will be possible. “Many images exist of the gate.” The case of Prager Straße is different. “It is possible that no photographs of the whole street exist, only of individual impressive views”, according to Bürger. Moreover, he is keen to find out whether the method is suitable for large spaces, and how many images would be needed.

Photographs defined the image

Even if only photos of impressive views exist, not of unattractive parts, this is of interest to the art historians. “An image is the result of a certain behaviour and informs about city identities”, says Bürger. Frequently photographed views can define the image of a city and even influence its development. A good example is the reconstruction of the Church of Our Lady between 1995 and 2005. “The visibility of its dome was a frequently used argument. It was to complete the image of the city.”

How often are images taken of a certain object? Which locations are preferred? Which intention is behind? These and other questions will hopefully be answered in the course of this research project. Though this is not necessarily the primary goal. “At the moment we are aiming at developing a tool with the help of computer science. We want to make sure that this tool will be usable for us and be transferable to other applications in the long run”, says Stefan Bürger.

Regardless of how the project will end, the team work across disciplines is a big benefit: “We are learning a lot from each other. This is a great success!”

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