Aerial Photography and Visualisation for Built Heritage - PhD Portfolio by Kieran Baxter
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Monday, 27 February 2012

Croft House Museum Model

This model of the Crofthouse Museum in Boddam, Shetland, was created from a sequence of Pole Aerial Photographs processed using Microsoft Photosynth, Meshlab and textured using Autodesk Mudbox.

I have chosen this site as a exercise and to potentially inform an interpretive reconstruction of the medieval farmhouse at nearby Jarlshof, a ruined site which may have had some similarities in it's structure.

These photographs are part of the set used to generate the model. Direct sunlight was added later to the computer generated version.

Tuesday, 21 February 2012

Demonstrations at the Scottish Crannog Centre

Recently I was invited to give a talk and demonstration to pupils from Breadalbane Academy during their field trip to The Scottish Crannog Centre, an event split over two days. The photograph above was from the first day with the mist set in. This made some great photos with smoke from the fire seeping through the thatch roof although sadly these conditions meant no kite flying on day one.

These kite photographs were taken on the second day when the wind picked up considerably. I was ably assisted on this shoot by some of the pupils, seen here trying to find shelter from the bitter cold!

After looking at how kite aerial photography can be used to document and illustrate heritage we attempted a demonstration of photogrammetry using the reconstructed dugout canoes at the Crannog Centre.

For a change I was able to sit back and direct while the class did all the hard work taking hundreds of photographs along the length of the canoes using a camera fixed to the end of a pole for better coverage.

This model was based on the data collected from one of the canoes. The proximity of the inside and outside surfaces made it very tricky to mesh and accuracy of the thin parts of the edges in particular could still be improved. I have cleaned off the points relating to the modern ropes and surrounding trees and also amended the underside of the canoe, which was obscured by the ground, using Autodesk Mudbox.

As an exercise this was useful for me to explore methods of projecting the photographs back onto the geometry to create the colour texture. I started by transfer mapping the automatic texture from Autodesk 123D Catch onto the final mesh. I then amended this patchy result by manually projecting photographs using the camera position derived from 123D Catch, and finally tidied up cloning, patching and painting in Photoshop and Mudbox. I left the red and white meter stick visible on the floor of the boat for scale.

Friday, 3 February 2012

Completed Jarlshof Mesh v.1

Ten segments of photogrammetry combined to make this mesh, here given the 'snow' treatment for viewing purposes. It consists of 2.8 million vertices and was derived from around 2,500 photographs.

Some areas have severe noise which I hope to remove by filtering out bad data. There are areas of missing data, in particular around the periphery of the site, in corners and the interior of the wheelhouses. Some of this data will be able to retrieved from unused photographs, some will not be able to be completed until a return visit to capture more.

After some more iterations to attempt a better model I will go ahead and apply colour texture by projecting photographs back onto the surface.