Oblique photogrammetry with visible and thermal images of active lava flows.
105 - 108.
Digital images from hand-held cameras are increasingly being acquired for scientific purposes, particularly where non-contact measurement is required. However, they frequently consist of oblique views with significant camera-to-object depth variations and occlusions that complicate quantitative analyses. Here, we report the use of oblique photogrammetric techniques to determine ground-based thermal camera orientations (position and pointing direction), and to generate scene information for lava flows at Mount Etna, Sicily. Multiple images from a consumer grade digital SLR camera are used to construct a topographic model and reference associated ground-based thermal imagery. We present data collected during the 2004-2005 eruption and use the derived surface model to apply viewing distance corrections (to account for atmospheric attenuation) to the thermal images on a pixel-by-pixel basis. For viewing distances of similar to 100 to 400 m, the corrections result in systematic changes in emissive power of up to 13% with respect to values calculated assuming a uniform average viewing distance across an image.
|Title:||Oblique photogrammetry with visible and thermal images of active lava flows|
|Keywords:||close-range photogrammetry, Etna volcano, lava flows, thermal imaging, DIGITAL PHOTOGRAMMETRY, VOLCANO, ASTER|
|UCL classification:||UCL > School of BEAMS
UCL > School of BEAMS > Faculty of Engineering Science
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