I’ve shared a couple of blog posts this week about the laser scanning project currently in progress at Mount Rushmore – who’s doing the work and why. But, I haven’t really shared the “How” of the whole process – until today. With some information from the partners involved in the project, here goes…

Laser scanning (like the type happening at Mount Rushmore) records the 3-D surface of objects in digital form. A huge amount of data can be gathered in an unbelievably short amount of time. For example, the Leica scan stations that are being used can record up to 50,000 points per second!

The laser beams hit a surface and then “bounce” (technical term) back to a receiver. The length of time that it takes for the beam to return helps determine the size, shape and composure of the surfaces that the beam touched. The clip below demonstrates this by showing the different colors for the different materials: wood, stone, bronze, etc.

In total, millions of points are gathered  and collected together to form “point clouds” that will be used to form the extremely accurate 3-D model of Mount Rushmore.

Point clouds are recorded from several different points of view and then joined together to produce accurate dimensions for the model. These point clouds can be useful on their own or they can be further processed to produce photo-realistic animations.

The entire process of scanning Mount Rushmore National Memorial will end up producing a virtual model that is accurate to within 4-6 millimeters of the actual sculpture! Pretty impressive stuff, if you ask me.

Check out this cool video of preliminary scan results from inside the Sculptor’s Studio at Mount Rushmore. The Sculptor’s Studio is the building that was actually used by Gutzon Borglum, and later his son Lincoln, to manage the monumental carving.