My colleague Martino Pesaresi from the European Community’s Joint Research Center (JRC) recently shared one of his co-authored studies with me on the use of advanced computing to analyze UAV (aerial) imagery. Given the rather technical nature of the title, “Rubble Detection from VHR Aerial Imagery Data Using Differential Morphological Profiles,” it is unlikely that many of my humanitarian colleagues have read the study. But the results have important implications for the development of next generation humanitarian technologies that focus on very high resolution (VHR) aerial imagery captured by UAVs.
As Martino and his co-authors note, “The presence of rubble in urban areas can be used as an indicator of building quality, poverty level, commercial activity, and others. In the case of armed conflict or natural disasters, rubble is seen as the trace of the event on the affected area. The amount of rubble and its density are two important attributes for measuring the severity of the event, in contribution to the overall crisis assessment. In the post-disaster time scale, accurate mapping of rubble in relation to the building type and location is of critical importance in allocating response teams and relief resources immediately after event. In the longer run, this information is used for post-disaster needs assessment, recovery planning and other relief activities on the affected region.”
Martino and team therefore developed an “automated method for the rapid detection and quantification of rubble from very high resolution aerial imagery of urban regions.” The first step in this model is to transfer the information depicted in images to “some hierarchical representation structure for indexing and fast component retrieval.” This simply means that aerial images need to be converted into a format that will make them “readable” by a computer. One way to do this is by converting said images into Max-Trees like the one below (which I find rather poetic).
The conversion of aerial images into Max Trees enables Martino and company to analyze and compare as many images as they’d like to identify which combination of nodes and branches represent rubble. This pattern enables the team to subsequently use advanced statistical techniques to identify the rest of the rubble in the remaining aerial images, as shown below. The heat maps on the right depict the result of the analysis, with the red shapes denoting areas that have a high probability of being rubble.
The detection success rate of Martino et al.’s automated rubble detector was about 92%, “suggesting that the method in its simplest form is sufficiently reliable for rapid damage assessment.” The full study is available here and also appears in my forthcoming book “Digital Humanitarians: How Big Data Changes the Face of Disaster Response.”
- Welcome to the Humanitarian UAV Network [link]
- How UAVs are Making a Difference in Disaster Response [link]
- Humanitarians Using UAVs for Post Disaster Recovery [link]
- Grassroots UAVs for Disaster Response [link]
- Using UAVs for Search & Rescue [link]
- Debrief: UAV/Drone Search & Rescue Challenge [link]
- Crowdsourcing Analysis of UAV Imagery for Search/Rescue [link]
- Check-List for Flying UAVs in Humanitarian Settings [link]