창의적이고 잠재력 있는 대학원생을 발굴하는 문화기술대학원
장소 : 비대면강연(ZOOM)
주제 : Remote Sensing–Remote Control? Advanced ICT for Heritage Documentation and Management of UNESCO World Heritage properties
연사 : Georgios Toubekis (Researcher at Fraunhofer-Institute for Applied Information Technology)
- Graduate in Architecture at RWTH Aachen University
- Researcher at Fraunhofer Institute for Applied Information Technology (2019-present)
- ICOMOS Field Mission Expert in the context of the UNESCO World Heritage Convention (2009-present)
- Researcher at Oman Center for Documentation and Conservation (2018-2019)
- Researcher and Lecturer at RWTH Aachen University, Aachen Center for Documentation and Conservation (2007-2018)
- ICOMOS expert -Safeguarding Campaign for the preservation of the Bamiyan Buddhas (2003-2007)
Advances in remote sensing technologies in recent years have become essential for monitoring environmental processes at the Earth's surface and in the atmosphere. The increasing number of sensors contributes significantly to efficient land management in general, and to the detection of land and sea surface changes in particular, in almost all scientific fields related to the human and natural environment. Consequently, the field of cultural heritage management also benefits from the increased availability and reduced cost of using this technology.
This presentation will provide a brief introduction to the physical principles of remote sensing and provide examples of its application in archaeological investigations from discovery to documentation and risk assessment, as well as in the development, management and conservation of cultural heritage and landscapes.
The benefits for the management of cultural landscapes are presented through a detailed case study of the UNESCO World Heritage Sites in Afghanistan, where the protection of cultural heritage and landscapes is now a priority, also with the aim of using them as strategic and valuable economic assets in the context of tourism.The balance between landscape protection and sustainable development is an extremely important key factor for countries that have exceptional cultural heritage, which is nowadays particularly at risk for many reasons, including uncontrolled development, pollution impacts and degradation factors. Remote sensing provides regular and repeated imagery of unprecedented importance for monitoring the impacts of climate change, urban and rural development, and conflict.
Georgios Toubekis is a researcher of Fraunhofer-Institute for Applied Information Technology in Germany since 2019. And since 2009, he also works as an ICOMOS Expert in UNESCO World Heritage and as CIPA Heritage Documentation expert. He received his degree in architecture at RWTH Aachen University in Germany and he is an expert in documentation of cultural heritage sites with use of remote sensing, laser scanning, GIS, databases, and mixed reality.
Remote sensing is defined by Georgios Toubekis as “making use of your senses from far away to observe and understand the world around you.” Origins of remote sensing starts way back at the renaissance times where people started to investigate the environment in a more systematic way. This involves the analysis of perspective and light rays. Camera obscura is a notable example which is a room-sized apparatus first used to study celestial bodies where a hole is placed in the wall and an image is projected to the opposing walls from the hole. This led Leonardo da Vinci to realize that the human eye acts like the camera obscura. The camera obscura also became a study instrument for artists years later where artists used it to understand the natural behavior of shadows and light to produce better art.
To explore the origin of remote sensing, Prof. Toubekis talked about the history of using lightweight instruments such as the camera Lucida to capture the sensation of the world. Camera Lucida was a very small and portable instrument that can be used as a drawing aid. Camera Lucida projects the view in front of the artist on a paper and allows the artist to simultaneously observe the object in front and control the drawing on the paper. The device helped world explorers in the early 17th and the late 19th centuries to produce very accurate paintings, resembling reproductions of the real world.
In the 19th century, the world changed dramatically by industrialization. The invention of photography in the first half of the 19th century probably was the most influential open source technology in history. At that time a lot of people investigated in a way to capture images resembling the environment around us. However, the only possible way was either to capture them by drawing or the early way of photography. It was very difficult to capture the world as images on chemical substances, and the process was very cumbersome. In 1839, Louis Daguerre invented a procedure to make the capturing process easier and faster. He presented his idea to the president of the academy of sciences at that time, and the president decided to make the procedure available to the public. Newspapers reported about the procedure to capture images, and within just a few months, the invention of photography spread across the world and became a hype.
The invention of photography also had a very deep impact on science because new ways were available to capture not only the immediate environment around scientists, but also capturing in a far more rapid way. Considering applications of photography in the military and industry, photography is used in land surveying, for example for making railways or industrial expansion. Therefore, it was very important to get the topography quickly documented and drawn on maps that facilitated the invention of new optical instruments and lenses. Photogrammetry was also invented in 1867 to accurately capture metrically correct images of buildings. From German and European perspective, Albrecht Meydenbauer was very influential for the new science of photogrammetry because he looked for a way to make accurate drawings of buildings by inventing special cameras. He became the president of the so-called general archive of photogrammetry which was the first institution world-wide that was occupied with taking pictures of historical monuments for reproducing drawings of buildings and storing them into an archive. The invention of photogrammetry was a way to capture reality in such a way that one, at least, was able to make drawings of a monument even if the original has been lost.
The cameras were not just used on the ground. Adventurous people like Nadar took the camera into the sky by constructing a huge balloon to carry his entire laboratory including up to 20 people. He flew over Paris and captured the city from the sky. Already at that time, stereoscopic view was invented and using it as a kind of today’s virtual reality became popular. Fifty years after Nadal in 1980, five million pictures were taken from allied forces in the last nine months of world war 2, showing the influence of military research in developing aerial photography.
A big jump to a variety of sensors today
A hundred years ago, probably having cameras on an airplane was advanced.
Our complete environment is full of sensors.
-> We now have sensors capturing our environment instruments, capturing environment at almost every scale (from as high as 500 kilometers, and even higher - in the atmosphere until the ground). It is able to capture not only images, even videos with small satellites in real time. This brings me now to of course to the definition of remote sensing that you find in the books, so what is remote sensing today, and what is it used for?
The standard definition of remote sensing is, the process of detecting and monitoring the physical characteristics of an area of an environment, which is made use of the reflected and emitted radiation at a distance (typically from satellite or aircraft). So remote sensing is the study of emitted radiation from a distance in order to study physical characteristics of the world.
Satellites are all around us, that are observing from space: phenomena, weather, climate, etc. Every industrialized country, even India has its own set of satellites to be somehow autonomous in capturing and receiving information of environments, and not to rely on the information source from the others.
Very basic principles of this technology
Basically you can divide the systems that are around us when it is about observing the Earth into two types. The first type is the one that is making use of radiation (the energy the the Sun is sending onto the Earth - the electromagnetic radiation from the Sun, is reflected from the Earth surface and this relefection can be measured by instruments on its energy level, on its level of intensity of reflectance, and of course its colors). These types of satellite instruments are called passive, so they receive the energy that some other source is emitting.
Once we have passive systems, we also have active systems. Active systems carry a source of radiation with them, they send electromagnetic radiation to the ground, then they capture the reflection with a large antenna carried with them. You can also differentiate sensors in the way how accurately they are able to capture the surface of the environment. The active observation satellites have less radiation because their scope of observation is a little bit different larger areas. So it is measuring the quality of the air, for example, that is what those active systems are used for.
The difference what resolution makes
It is not so easy to observe what is happening on the Earth from the sky, because our atmosphere basically is quite dense and it does not allow all the spectrum of wavelengths which are coming from outside of the universe to enter even the ground. There are so called atmospheric windows only in these small ranges. We have a lot of instruments in the sky, and the amount of these instruments will continuously grow. For almost every atmospheric and scientific area, new specialized instruments are sent up into the atmosphere to capture especially environmental parameters over the course of time, and to provide better information on predicting weather, or change the quality of life.
Electromagnetic spectrum of the radiation which is emitted across us has a quite broad range, and based on the home appliances or medical devices that use electromagnetic radiation, depending on the energy level it can be made use for different application areas, and it can be used for different ways of observation as well. This is due to the electromagnetic wave which has two specific parameters, depending on the wavelength it is possible to study even very small objects or larger objects. The visible light we see around us only covers a very small fraction of the electromagnetic spectrum. Regarding our subject it is especially the area on the right hand side, the infrared spectrum which interests us the most because that is approximately the size of the wavelength (you can say something like the point of a needle which is the size these wavelengths capture, that makes it ideal to capture the physical environment that interests us from the architectural point of view in the best way).
Airborne observation is also used to measure land . Its combination of active and passive sensors. This allows aircrafts to measure objects in different size and different scales. This calls to new technology, Lidar which stands for Light Detection and Ranging using laser beams in the infrared spectrum. As a result, this outputs 3D plot data of an object. LIDAR works as follows : 1) Pulse based Scanners measures Time-of-Flight(TOF) of a laser pulse beam. That is, it measures how long it takes for light to come back after hitting an object.
- Airborne observation (summarized by Kyung Taek Oh, 33min~)
- Remote sensing has become very important when it comes to observing and monitoring architectures and planning at heritage sites. Dr.Toubekis uses the Light Detection and Ranging (LIDAR) technology in order to create digital elevation models. Utilizing both pulse-based and phase shift-based scanners allowed him to survey large amounts of land from air and uncover the surfaces of hidden cultural sites. These instruments are able to scan through vegetation and provide accurate measurements of an environment or building.
- Heritage at Risk (summarized by Kyung Taek Oh, 40min~)
- In practice, Dr.Teoubekis made use of these technologies in the heritage sites that are at risk of destruction due to either natural or human-made factors. The main goal of his projects is to obtain as much information or data about the heritage sites in a short period of time, so that those collected data can be reutilized to maintain or preserve currently threatened heritages. Moreover, he acknowledged the issues of illicit excavation and trafficking of artifacts. He suggested that satellite imaging technology can be used to monitor the sites.
- Cultural landscapes.. “..combined works of nature and of man”
- Vision - Future complex socio-cultural information systems
- New generation of 4D information systems with seamless integration of heterogeneous data sources
Closer observation can be done with drones. At the time, it was complicated tasks. This allowed more sophisticated 3D scale, which was not possible from viewing from satellite. A lot of erosion was made to the environment. Compare these two photos. One was taken in 1910 and the other was taken recently. We can clearly see how environment affected the structures. Towers melt down as the time passed by. So, we need some measurements to conserve this monuments. To do this, we first took satellite imagery. However, this picture was not enough for restoration. To overcome this, we used detailed pictures taken from the land. With some training (one week), workforce marked their position.
Last thing to consider is mediation. Whatever you do to the land, it affects the property of people already living in. So it is important to engage with people in all means. For us, we took maps and showed them their location and explained that our work will help them in the future. Bamiyans have very beautiful mountains which could expect a lot of tourisms. So, they have reasonable fear what environmental change might bring them.
The value of digital documentation is audacity which is FAIR use and reuse. By FAIR, i mean Findable, Accessible, Interoperable, and Reusable. Hopefully, this principle can lead to new values.
Conclusion of the lecture is suggesting significance of digital heritage. 1)Argue with digital heritage for a new role model of cultural institutions 2) Foster the role of digital heritage as facilitator of meaning within complex socio-technical systems 3) Refer to ethical principles to address societal challenges.
Q & A session
- Since it is hard to manually detect damaged areas, is there a dataset to train AI that certain monuments are damaged?
- Is there a startup or company that monitors heritage with drones?
- What do you think would be the “End Game” of photography? Zoom in to view cell-level? Photoshooting distant planets?
A : Its hard to determine what is the end technology of photography. Before, there was no idea that we would be able to carry photography in mobile. However we do now. Likewise happened to other technology when air balloon and airplanes were invented. A lot of things did not seem possible but it became possible now. Currently, apple devices carry LIDAR technology. So, rather than having preset limitation, it would be better for young technologists to apply diverse possibilities.
- Does data that you obtain at the heritage sites get outdated or obsolete due to technological advancement or replacement?
- Given that there’s limited human resources, how do we prioritize which heritage sites to document?