Spatial/Morphological measurement using close range photogrammetry- guidance from ISPRS V6 Jim Chandler 1, Rene Wackrow 1 and Dirk Rieke-Zapp 2 1 Loughborough University, UK 2 University of Berne, Switzerland Remote sensing- meeting industry needs with NERC expertise, 6 th April 2011 (with notable input from members of ISPRS Working Group V6)

Overview  What can close range photogrammetry provide?  Why produce “tips”?  Key points?  An illustration! Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

What can close range photogrammetry provide? Remote sensing- meeting industry needs with NERC expertise, 6th April 2011 Italian Alps- 1990

Remote sensing- meeting industry needs with NERC expertise, 6th April 2011 Antwerpen- 1991

Black Ven Landslide (1)  ARSF imagery March 2nd, 1995  Scale: 1:4,500 Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

1995 (2)  Processed using digital photogrammetry  Unix workstation (£15K, 1995) Remote sensing- meeting industry needs with NERC expertise, 6th April 2011 Automated measurement! –1m resolution DEM- 1.6 million points in 10 hours

Aboriginal rock art recording, 2004 Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

Rock Art- Outputs Digital Elevation Models (DEMs) Accuracies- 2-3mm Orthophotos Visualisation “fly-thru” fly-thru Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

Northumberland and Durham Regional Rock Art project 9 of 42 Partnership between English Heritage and the County Councils for Northumberland and Durham Loughborough University advising on the photogrammetry Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

Lessons learnt  Don’t underestimate volunteers  Added political benefits!  Technology and the volunteer  Hi tech or low? Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

Why are “tips” necessary? Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  Stated activity!  Past experiences- particularly postgraduates/ volunteers  Two sets!

Who contributed? Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  Primarily WG Officers  Also notable input from industry! including: Marko Tuomien, Datapix Pty Ltd, Queensland, Australia Stephen Bird, Fluvial Systems Research Inc, Whiterock, Canada

Start simple- start small!  150 small format images of a river channel in Spain- I fly next week and my supervisor doesn’t know about photogrammetry! Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  Common sense!  Familiarisation- techniques and how software works!  Start with:  Small test area captured with perhaps two pairs  Ideally use a pre-calibrated camera  Establish abundant photo control- easy restitution plus checks

Which camera?  All cameras have spatial measurement potential! Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  Digital SLR!  Fixed or variable zoom lens?  Never purchase “top of the range”

Camera calibration  Necessary for accurate spatial data acquisition! Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  What software?  Matlab, PhotoModeler, IWitness, etc. camera focal length (f) principal point offset(x P, y P ) radial lens distortion (K 1, K 2, K 3 ) tangential distortion (P 1, P 2 )

Fieldwork/control Remote sensing- meeting industry needs with NERC expertise, 6th April 2011 Photo acquisition: Infinity focus/f8 Infinity focus/f8 Fastest shutter speed possible/tripod Fastest shutter speed possible/tripod Obtain redundant imagery Obtain redundant imagery Control  Don’t skimp!  Well distributed  Withhold 20% and use as “checkpoints” Visit site prior Visit site prior capture images “in pairs/triplets” capture images “in pairs/triplets”

Zhouqu- China 8 th Aug Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  “Tips” document, freely available- more later! Zhou Qu debris flow: Zhouqu mudslides death toll rose to 337 people, 1148 people missing

Measurement potential of imagery! Remote sensing- meeting industry needs with NERC expertise, 6th April 2011

Measurement potential of imagery! Remote sensing- meeting industry needs with NERC expertise, 6th April 2011  Video fly-thru!  Gradient of debris slope!  Next phase

Conclusion  Prime purpose, raise awareness of photogrammetry and ISPRS Working Group V6:  Special Issue of the Photogrammetric Record:  “Tips” document, providing simple guidance.  Also some recent work/interests:  Potential of terrestrial imagery  Potential of consumer grade digital cameras Remote sensing- meeting industry needs with NERC expertise, 6th April 2011