Last season we began using aerial photography and photogrammetry to document excavation at Marj Rabba. We used a quadcoptor, an r/c plane, and a pole aerial photography rig to record images of the site at several altitudes. The pole was great for low level recording of features and individual squares, the quadcoptor was great for getting photos of the entire excavation area, and the plane was getting aerial photos of the entire area around the excavation. Our original plane, however, was only set up for carrying a GoPro Hero camera which takes great pictures but is not ideal for doing 3d photogrammetry because of its extremely wide angle lens. This set up gave us some good initial results and some excellent individual images of the site, like this:
This year we are using a larger model that has a better payload carrying capacity. It can fly longer, carry 2 cameras simultaneously, and is more robust:
Today we had the first successful flight of the season. The 2 camera setup means that we can get a nice video recording of what the landscape looks like from above while simultaneously recording vertical images that will be utilized for 3d modeling and mapping.
Here is a video of what the site looks like from onboard the plane:
As was discussed in the earlier post, the vertical still images provide the basis for 3d modeling. Here is a composite image (an ortho-mosaic) of the field system surrounding our site. This composite image is fairly low resolution, as it was constructed from a small subset of the total images to check how well the image recording went. However, this is a distortion free image and can be exported directly into our GIS map of the site. By doing a few more flights, processing the photographs more intensively, and combining them with data collected with our Total Station, we will be able to generate a complete high resolution composite image of the area as well as a high resolution digital elevation mode (DEM):