Stereo Visualisation of Historical Aerial Photos - an Useful and Important Aerial Archeology Research Tool

In this article we present some case studies in which historical aerial photos are central elements in the research process and we demonstrate how the investigation benefits from a stereo visualisation of these images, resulting in a useful tool for Aerial Archaeology. These examples include photographs from both WWI and WWII as well as images from the post war era, showing a landscape that is now transformed or not even accessible due to human constructions. Stereo images are useful as they give a much better understanding of what is actually seen on the ground than single photos ever can, thanks to the depth cue that helps understanding the content and adds the ability to distinguish each element on the ground. Hence, stereo helps in estimating heights of single objects, just as well as the relative height of all objects on the ground that form a site. Nonetheless, it is also important to stress that stereo also helps in understanding the surrounding landscape. This paper will discuss the challenges that still have to be faced in order to create stereo images useful for archaeologists and will reflect on the many possibilities and advantages that stereo visualisation of aerial photos offers