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Notre Dame is expected to be completely restored! Is Notre Dame laser modeling really possible?

On the evening of April 15, Paris time, Notre Dame, the landmark of Paris, was destroyed in a fire. The 80 meter tall wooden spire collapsed in the smoke, leaving people all over the world in grief. Fortunately, there are a few news that can make the public feel a little relieved. First of all, the fire was not caused by intentional arson. Second, the fire has been basically put out, and most of the remaining buildings and cultural relics of the cathedral have been protected. Finally, in the long run, the losses already caused may not be too great. The bell tower of Casimodo is still there, which makes many people who are interested in Notre Dame a little bit relieved. So can Notre Dame be completely restored this time?

One person's research can make it look less bad. In 2015, Dr. Andrew Tallon, an art historian and historical modeler, conducted a comprehensive study of Notre Dame in Paris, creating a digital archive of the building. Although notre dame has a long history, there is little information about the architects and designers who built it. So Talon hopes to use laser scanning technology to decipher the ancient building.

Talon's laser modeling technology refers to the use of laser to 'shoot' Notre Dame, mount the scanner on a tripod, and then measure the distance between the scanner and each point hit by the laser. Because each point represents a different distance, by analyzing these millions of points, Talon can understand how Notre Dame expands and contracts in daylight, and how it changes over a longer period of time. Combining the 'point data cloud' generated by the laser scanner with the pictures taken on site, Talon has built a fine model for the underlying structure and the design of Notre Dame, so as to judge where the original architect deviated from the original plan, or because of the instability of the ground conditions, he stopped work.

Talon described the technology in detail in an interview with national geographic, 'I have to build a network of targets that represent points of position in space. After defining the scanning density (scanning resolution), release the laser. When a beam of light is emitted, it measures the time it takes for the beam to travel from launch to hit the target, as well as the time it takes to return to the target. '