Photogrammetry

Photogrammetry is a method of measurement through the use of photography. We were primarily interested in how photogrammetry can be used to provide a interactive, holistic view of an artifact or larger area. Using the program Photoscan by Agisoft, 3-D models can be generated from a collection of images. The photos imported into Photoscan must capture the subject from several angles and heights. For each trench/artifact, we took pictures using a Canon EOS Rebel T3i and captured shots at three different heights. For each height we rotated 360 degrees around the subject taking pictures at roughly seven pictures per full circle. The images were saved in the .tif format and then imported into Photoscan. The program works by taking the images and inferring the camera’s position and orientation from each photo by matching the pixels from each image to the same pixels in the other images. Through this process the program is able to generate a cloud of points which represent the subject. From there a textured mesh based on the colors from the original pictures is placed on the cloud of points creating a finished 3-D model of the subject. Our examples of 3-D models can be seen below:

The set up in the photo studio to take images of an artifact, to be used for a 3-D model.

The set up in the photo studio to take images of an artifact, to be used for a 3-D model.

We intended to use photogrammetry as a means to provide an interactive way to view both the process and final results of the excavation. Models of each excavation trench were created using images from the final day of excavating in order to show the depth and features of each trench. Additionally, a model of a bone found in Trench 1 was created to demonstrate how photogrammetry can be used to analyze artifacts. Below you can find a screenshot of each model with a link to the PDF interactive model beneath, which can be downloaded and conveniently opened with Adobe Reader.

Model of Trench 1

Model of Trench 1

Trench One Model PDF– right click and download file to view model

Model of Trench 2

Model of Trench 2

Trench Two Model PDF– right click and download file to view model

Model of Trench 3

Model of Trench 3

Trench Three Model PDF– right click and download file to view model

Model of the bone found in Trench 1

Model of the bone found in Trench 1

Model of the Bone PDF– right click and download file to view model

Page Created by Charles Linneman and Sara McAuliffe