Study of Mexico City quake helps students develop drone assessment system
By Celeste Arbogast
Two CEE students visited Mexico City in the wake of the 7.1-magnitude earthquake that shook the city September 20. They gathered data on damaged buildings that CEE researchers will use in the development of a system that will utilize drones to help assess structural damage with the ultimate goal of speeding up post-disaster recovery efforts.
Vedhus Hoskere, a CEE Ph.D. student, is working under academic adviser Professor Bill Spencer to develop the assessment system, which will use drones that are capable of flying autonomously to capture images of damaged structures and develop 3D surface models. Then Hoskere’s image-processing algorithms, which have been trained to detect various types of damage using machine learning, can be used to filter out important information from these models automatically. This information can then be used to direct the attention of inspectors to defects identified by the algorithm instead of examining all buildings in detail and perhaps even eventually allow the process to be completely automated. Hoskere is trying to base the algorithms on widely accepted standards for post-disaster building inspections developed by the Applied Technology Council and used by the Federal Emergency Management Agency.
In pursuit of real-world data to inform and improve his algorithms, Hoskere traveled to Mexico City just 10 days after the quake, along with CEE senior Michael Neal, president of the student chapter of the Earthquake Engineering Research Institute (EERI). Hoskere is also a member of EERI.
“Essentially what happens after an earthquake is that there’s a standard safety evaluation that human inspectors do from the outside,” Hoskere said. “We’re trying to mimic that using these algorithms. There is usually a huge shortage of inspectors. If you’re able to acquire images of the entire structure and create a 3D surface model of the building, you should be able to make an assessment of whether it’s possible to continue using that building or if it requires a more detailed inspection.”
The students’ trip, funded by CEE at Illinois and the EERI, gave them real-world exposure to post-earthquake damage, a critical component for designing an accurate assessment system.
“So far we’ve been developing algorithms just on images available on the Internet, images we’ve taken just of regular buildings, and damaged specimens in the lab,” Hoskere said. “Now we want to try to apply it to a scenario where there’s actually damage.”
The students were hosted on the trip by Professor Manuel Ruiz-Sandoval, a former doctoral student of Spencer’s, who is now on the faculty of Mexico City’s Metropolitan Autonomous University. An unanticipated collaboration occurred with Mexico’s College of Engineering, a professional organization of structural engineers that was doing building inspections to gather information for local authorities.
“We needed to get access to the damaged building sites from them, so they gave us official inspection badges and in return we contributed to their database,” Hoskere said. “So we helped with the actual inspections, because we are structural engineers, and also got information that is useful for the research. That wasn’t how we had initially planned it, but it turned out to be better.”
Hoskere and Neal gathered data on about a dozen buildings. One of the buildings they visited but did not assess was the famous Latino-Americana Tower, the seismic design of which was done by Nathan Newmark. The students saw no visible damage, but they were not allowed to fly their drone in that area. There were some sobering moments, they said, such as happening upon a scene where even more than a week after the earthquake, emergency personnel were still recovering bodies from the rubble. But damage was uneven throughout the city, they said.
“One thing I was surprised by, was how life had gone on,” Neal said. “People were still grieving, and there were still areas that were very affected, but there were some neighborhoods we went to where you wouldn’t really know there had been an earthquake. Life has to go on for them.”
This latest addition of real-world data to Hoskere’s research may hasten the day when recovery efforts can be accelerated so life can go on even more promptly.
See also: UI students go to Mexico for earthquake relief (Daily Illini)