the design of georeferencing techniques for unmanned autonomous aerial vehicle video for use ...

95 Pages·2007·13.41 MB·English

THE DESIGN OF GEOREFERENCING TECHNIQUES FOR UNMANNED AUTONOMOUS
AERIAL VEHICLE VIDEO FOR USE WITH WILDLIFE INVENTORY SURVEYS: A CASE
STUDY OF THE NATIONAL BISON RANGE, MONTANA

By

BENJAMIN EVERETT WILKINSON

A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2007
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© 2007 Benjamin Everett Wilkinson

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To my parents and Zhao.

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ACKNOWLEDGMENTS
My fiancée, Zhao, somehow always finds time to make me ridiculously happy while first-
authoring papers in prestigious virology journals, volunteering, and working crazy hours. I
cannot believe I get to marry such an incredible woman. I also want to thank Zhao’s and my
parents, for being unconditionally proud of me, faithful, and always encouraging. I want to
thank my dad for suggesting that I go to Reed Lab and talk to Dr. Gibson about the geomatics
program, and I want to thank my mom for being the strongest person I know.
My supervisory committee members were very helpful in the preparation of this thesis, and
I would like to thank them for their time, knowledge, and patience. I look forward to working
again with Drs. Bon Dewitt, Franklin Percival, and Scot Smith in the coming years as I pursue a
Ph.D. at UF. I would especially like to thank my supervisory committee chair, Dr. Dewitt, for
always having his door open even though he knows I could be on my way to bug him about
something at any moment. He is a great teacher and friend, and I feel lucky to be able to work
with him.
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TABLE OF CONTENTS

page
ACKNOWLEDGMENTS...............................................................................................................4
LIST OF TABLES...........................................................................................................................7
LIST OF FIGURES.........................................................................................................................8
ABSTRACT...................................................................................................................................11
CHAPTER
1 INTRODUCTION..................................................................................................................13
Background on the National Bison Range..............................................................................13
Wildlife Inventory Surveys.....................................................................................................14
Unmanned Autonomous Aerial Vehicles...............................................................................15
The University of Florida’s Wildlife UAV Program..............................................................16
Georeferencing and Orthophoto Mosaicking of UAV Images...............................................16
2 UAV VIDEOGRAPHY GEOREFERENCING PROCESS...................................................22
Introduction.............................................................................................................................22
The Dataset......................................................................................................................22
Tie and Pass Points, and the Bundle Adjustment............................................................23
Orthorectification............................................................................................................24
The Developed Method..........................................................................................................24
Step 1: Decompilation of Video Data into Individual Frames........................................25
Step 2: Conversion of GPS and INS Navigation Data to a Local Vertical
Coordinate System and Photogrammetric Standard Definitions Respectively............25
Step 3: Interpolation of Resulting Navigation Data and Linking of the Data to
Individual Images.........................................................................................................26
Step 4: Determination of Pass-points for a Strip of Photos using Rigorous Point-
matching Techniques...................................................................................................26
Step 5: Determination of Interior Orientation Parameters and Relative Orientation
for Subsets of Photos in a Strip using Arbitrary Coordinate Systems.........................27
Step 6: Attaching Relatively Oriented Subsets Using Multiple 3D Coordinate
Transformations from Subsets along the Entire Strip..................................................28
Step 7: Transforming the Resulting Points into 3D Ground Coordinates using
Navigation Data...........................................................................................................28
Step 8: Performing a Bundle Adjustment on the Entire Strip Using the Results of
the Previous Transformation as Initial Approximations..............................................29
Step 9: Attaching Each Strip (Found from Steps 4-8) from the Flight to Each Other....29
Step 10: Performing a Final Bundle Adjustment Using all Strip Observations..............30
Step 11: Creation of a DTM from the Resulting Points..................................................30
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Step 12: Using the DTM and Absolute Orientation Parameters, Creating a Digital
Orthophoto Mosaic of the Project Area.......................................................................30
3 DESIGN OF AN ADAPTIVE POINT MATCHING ALGORITHM...................................32
Introduction.............................................................................................................................32
The Algorithm........................................................................................................................34
Calibration.......................................................................................................................34
Allocation and Initialization............................................................................................37
Iterations of Adaptive Point Matching............................................................................37
Normalized cross-correlation...................................................................................37
Least squares image matching..................................................................................39
Position prediction and blunder detection by conformal transformation.................41
Adaptation................................................................................................................42
Last chance for unmatched points............................................................................43
General least-squares projective transformation check............................................43
Establishing new points............................................................................................44
Formatting and output..............................................................................................45
4 RELATIVE ORIENTATION.................................................................................................52
Introduction.............................................................................................................................52
Self-Calibration.......................................................................................................................53
A Relative Orientation Method for the NBR UAV Dataset...................................................55
Singular Value Decomposition...............................................................................................60
5 CAMERA CALIBRATION...................................................................................................68
Introduction.............................................................................................................................68
DOQ Scale Comparison Method............................................................................................69
Airborne Calibration (Ground Control Method)....................................................................70
6 CONCLUSION.......................................................................................................................79
APPENDIX: MATCHED IMAGE SUBSET................................................................................81
LIST OF REFERENCES...............................................................................................................93
BIOGRAPHICAL SKETCH.........................................................................................................95

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TABLE
Table page

1-1. Navigation System Specifications.........................................................................................21

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LIST OF FIGURES
Figure page

1-1. Location of Flathead Indian Reservation, Montana (in pink). The NBR project area is
located within the red square.............................................................................................18
1-2. Navigation points from the four UAV flights over the National Bison Range....................19
1-3. 3D map of navigation points from the four UAV flights over the National Bison
Range.................................................................................................................................20
2-1. Flowchart of the developed overall process for georeferencing UAV videography.............31
3-1. Image pair matching epoch flowchart..................................................................................46
3-2 Image coordinates of point 1 for 116 consecutive images from flight 2 of the NBR
mission...............................................................................................................................47
3-3 Image coordinates for point 1 for the first 20 consecutive images illustrating retrograde
motion of the point coordinates in the x direction on the 11th epoch of image pair
matching.............................................................................................................................48
3-4. Left image: Grid spacing of 64, template dimension of 64. Right image: Grid spacing
of 32, template dimension of 16........................................................................................48
3-5. Poorly matched image pair 1................................................................................................49
3-6. Poorly matched image pair 2................................................................................................49
3-7. Well matched image pair......................................................................................................49
3-8. Original (right) vs. resampled arrays (left) of a point for the 1st, 20th, 30th, and 90th
photo pair from bottom to top............................................................................................50
3-9. New point locations using the anticipation method (a) vs. the random method (b).............51
4-1. Lines 2 and 6 of the 2nd flight over the NBR.........................................................................62
4-2. Comparison of base-height ratios of 0.6 (a) and 0.4 (b).......................................................63
4-3. Increase in pitch at the end of line 2 associated with anticipatory turning of the UAV
(a), and the plotted section of line 2 highlighted in red (b)................................................64
4-4. Effects of divergent photography on base-height ratio........................................................65
4-5. Statistics for the only converging solution found in line 6 (a) and a solution from line 2
(b).......................................................................................................................................66
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4-6. Plan view of the digital terrain model created from relative 3D coordinate from a
relative orientation in line 2 (a), and 3D view of the same model (b)...............................67
5-1. Field calibration target point (a) and the control point cage (b) at the USGS EROS Data
Center, Sioux Falls, SD......................................................................................................73
5-2. Camera calibration team at EROS performing a calibration of a digital camera using
the CPC method.................................................................................................................73
5-3. Wide area (a) and close up (b) DOQ imagery of the National Bison Range’s Summit
Road...................................................................................................................................74
5-4. DOQ imagery (a) and UAV imagery (b) of Summit Road...................................................74
5-5. Plot of GPS altitude (green) and barometric altitude (blue) and their differences................75
5-6. Plot of GPS altitude (green) and barometric altitude (blue) with a 13 second shift
applied................................................................................................................................76
5-7. Plot of GPS altitude (green) and barometric altitude (blue) with shifts accounting for all
data gaps greater than 2 seconds applied...........................................................................77
5-8. Planned (blue) versus actual (red) calibration flight lines illustrating the exaggerated
autopilot anticipation of turns............................................................................................77
5-9. Second flight of the NBR mission........................................................................................78
A-1. Images 1-6 of the matched image set..................................................................................81
A-2. Images 7-14 of the matched image set................................................................................82
A-3. Images 15-22 of the matched image set..............................................................................83
A-4. Images 23-30 of the matched image set..............................................................................84
A-5. Images 30-37 of the matched image set..............................................................................85
A-6. Images 38-45 of the matched image set..............................................................................86
A-7. Images 46-53 of the matched image set..............................................................................87
A-8. Images 54-61 of the matched image set..............................................................................88
A-9. Images 62-69 of the matched image set..............................................................................89
A-10. Images 70-77 of the matched image set............................................................................90
A-10. 78-85 of the matched image set.........................................................................................91
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A-11. 86-92 of the matched image set.........................................................................................92

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