Spatial/Morphological measurement using close range photogrammetry-

guidance from ISPRS V6

Jim Chandler1, Rene Wackrow1 and Dirk Rieke-Zapp2

1Loughborough University, UK2University of Berne, Switzerland

j.h.chandler@lboro.ac.uk

Remote sensing- meeting industry needs with NERC expertise, 6th 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- 1995 (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- 2-3mmOrthophotos

Visualisation “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, AustraliaStephen 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 (xP, yP)• radial lens distortion (K1, K2, K3)• tangential distortion (P1, P2)

-300

-250

-200

-150

-100

-50

00.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

(mic

rons

)

Radial Dist (mm)

Radial lens distortion

Fieldwork/control

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

Photo acquisition:• Infinity focus/f8• Fastest shutter speed possible/tripod• Obtain redundant imagery

Control Don’t skimp! Well distributed Withhold 20% and use as “checkpoints”

Visit site prior capture images “in pairs/triplets”

Zhouqu- China 8th Aug. 2010

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: http://isprsv6.lboro.ac.uk/

Special Issue of the Photogrammetric Record: http://onlinelibrary.wiley.com/doi/10.1111/j.1477-9730.2010.00590.x/full

“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