Photogrammetry

Photogrammetry is the determination of the geometric properties of an object/surface from photos.  Using two or more images of the same surface taken from different positions we can determine the 3D coordinates of points on that surface based on single or multi-point triangulation.  This method has been around since the 1850s, but has been undergoing rapid changes with the development of digital imaging and the use of new software packages that have automated much of the process and are capable of producing point clouds and meshes from a series of overlapping images.  The term “close-range” is used to distinguish terrestrial from aerial-based photogrammetry.  Both methods are used by the KAMBE Project.

During out 2012 season, we began using close-range photogrammetry to record the progress of the excavation of our two test trenches at Kalavasos-Ayios Dhimitrios.  This involved taking an overlapping series of high-resolution digital photos at the start of most work days or at the end of an important context.  Photos were taken with either a Canon D5 or a Pentax K7 using 60% overlap.

Digital photos of Kalavasos-Ayios Dhimitrios, Unit 7 Test, for use in the production of photogrammetric models (photos taken by K. Fisher using a Pentax K-7).

Uploading the photos to Agisoft’s Photoscan allows us to produce 3D models of the excavations on a daily basis.  Below is a screen capture of such a model of Unit 7 Test from Kalavasos-Ayios Dhimitrios , which reveals parts of the newly-discovered Bulding XVI.

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