Mike James

Dr. Mike James

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Research Focus & Metrics

Academic Career Length

36Years (1991-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 August 2012 in Journal of Geophysical Research: Earth Surface
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Journal Article
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MJMike James
Mike James
SRStuart Robson
Stuart Robson

31 May 2014 in Earth Surface Processes and Landforms
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Journal Article
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MJMike James
Mike James
SRStuart Robson
Stuart Robson
High resolution digital elevation models (DEMs) are increasingly produced from photographs acquired with consumer cameras, both from the ground and from unmanned aerial vehicles (UAVs). However, although such DEMs may achieve centimetric detail, they can also display systematic broad‐scale error that restricts their wider use. Such errors which, in typical UAV data are expressed as a vertical ‘doming’ of the surface, result from a combination of near‐parallel imaging directions and inaccurate correction of radial lens distortion. Using simulations of multi‐image networks with near‐parallel viewing directions, we show that enabling camera self‐calibration as part of the bundle adjustment process inherently leads to erroneous radial distortion estimates and associated DEM error. This effect is relevant whether a traditional photogrammetric or newer structure‐from‐motion (SfM) approach is used, but errors are expected to be more pronounced in SfM‐based DEMs, for which use of control and check point measurements are typically more limited. Systematic DEM error can be significantly reduced by the additional capture and inclusion of oblique images in the image network; we provide practical flight plan solutions for fixed wing or rotor‐based UAVs that, in the absence of control points, can reduce DEM error by up to two orders of magnitude. The magnitude of doming error shows a linear relationship with radial distortion and we show how characterization of this relationship allows an improved distortion estimate and, hence, existing datasets to be optimally reprocessed. Although focussed on UAV surveying, our results are also relevant to ground‐based image capture. © 2014 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.

1 December 2014 in Journal of Structural Geology
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Journal Article
Closed access
SBSean P. Bemis
Sean P. Bemis
SMSteven Micklethwaite
Steven Micklethwaite
DTDarren Turner
Darren Turner
MJMike James
Mike James
SASinan Akciz
Sinan Akciz
HBHasnain Ali Bangash
Hasnain Ali Bangash

1 March 2017 in Geomorphology
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Journal Article
Closed access
MJMike James
Mike James
SRStuart Robson
Stuart Robson
SDSebastian D'Oleire-Oltmanns
Sebastian D'Oleire-Oltmanns
UNU. Niethammer
U. Niethammer

1 March 2012 in Engineering Geology
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Journal Article
Closed access
UNU. Niethammer
U. Niethammer
MJMike James
Mike James
SRS. Rothmund
S. Rothmund
JTJ. Travelletti
J. Travelletti
MJM. Joswig
M. Joswig