A Simple Optical Dendrometer based on a Digital Camera and
Visible Laser Pointer
John A. Kershaw, Jr.Western Mensurationists Meeting
Vancouver, WA
June 21-23, 2009
(The Art of Kamera Sutra)
Panoramic Tripod MountPanoramic Tripod Mount
Stitching ProcessStitching Process
• Used software called panorama factory– http://www.panoramafactory.com/
• Automates the process• Corrects geometrical lens errors
Panoramic Photo PlotsPanoramic Photo Plots
Enhanced Photo PointsEnhanced Photo Points
• Tagged trees– Indexes trees in the image– Width of the tag is a constant
• ARTaghttp://www.cv.iit.nrc.ca/
research/ar/artag/
Previous commentsPrevious comments
• If you have to “tag” each tree, why not simply measure it?
• Seems to be substituting office time for field time?
NSERC Discovery GrantNSERC Discovery Grant• Go from “off-the-shelf” technology to
dedicated camera-field data collector system• Explore advantages/disadvantages of tagging
system and possible alternatives– Stereo Panoramic Photos– 360/180 hemisphere photos– Image Segmentation– Hidden Tree Identification
• Nagging problem of determining scale with a vanishing point horizon
Stereo PanoramasStereo Panoramas
360/180 Panoramas360/180 Panoramas (Mercator Projection) (Mercator Projection)
An innocent startAn innocent start
A Distance functionA Distance function
Too Sensitive to Camera PlaneToo Sensitive to Camera Plane
Dual Laser SetupDual Laser Setup
Canon SD430 – 5.0MP
Canon SD990 – 15.0MP
Canon 5D – 22.0MP
A New Distance FunctionA New Distance Function
DBH Resolution (cm/pixel)DBH Resolution (cm/pixel)
Quick Test on 4 Trees by 5 DistancesQuick Test on 4 Trees by 5 Distances(Canon 5D)(Canon 5D)
Predicted Distance vs Observed Distance Predicted DBH versus Observed DBH
Upper Stem DiametersUpper Stem Diameters
Automating the Process (100% laser)Automating the Process (100% laser)
Automating the Process (20% laser)Automating the Process (20% laser)
Full Panorama PlotFull Panorama Plot
Next StepsNext Steps
• Stabilize Laser Mounts• Test on Upper Stem Diameters• Automate Process• Build Image Analysis System on SD990
Questions?Questions?