Interactive Landscape Relighting

There’s a short article in the Remote Sensing and Photogrammetry Society’s Archaeology Special Interest Group Spring 2011 Newsletter looking briefly at how archaeologists can investigate landscapes using digital techniques, co-authored by Tom Goskar and myself. Using Reflectance Transformation Imaging (RTI) techniques it is possible to look in detail at surface morphology of Digital Surface Models (DSMs) by creating Polynomial Texture Maps (PTMs) representing parts of or even entire landscapes which can then be dynamically relit, a process Tom has named Interactive Landscape Relighting.

The approach is based on the real-world PTM system used at Wessex Archaeology for examining artefacts but replicated in a totally virtual environment using virtual surfaces, lights and cameras. The results from this got me interested in the possibilities for landscape studies of the kind I undertake. The combination of RTI and highly detailed terrain models based on Airborne Laser Scanning (ALS) datasets makes for some truly interesting analysis possibilities.

Still very much work in progress at the moment, Tom and I hope to have more on this later this year. I am currently working on the integration of this technique with GIS so that transcriptions can be made from the RTI views of LiDAR DSMs directly into real-world coordinate systems, a bit like a souped up version of the hillshading methodology described by English Heritage in their publicationThe Light Fantastic‘. The idea is that by drawing multiple strands of research together, far more is possible; the digitisation environment being developed combines:

  • LiDAR surface models (and derived products)
  • Interactive RTI views of surface morphology
  • National Mapping Programme (NMP) style transcription
  • Modern maps, historic maps, excavation, geophysics and other remotely sensed data.

As this develops, there will be more posted here, on the Wessex Archaeology computing blog and on Pastthinking.