Mapping at the Speed of Flight

DORIS …
Aerial Mapping at the Speed of Flight
Differential ifferential Ortho rtho-Rectification
ectification Imagery magery System ystem

Photogrammetry …
Development Cycles *
– Plane table photogrammetry, from about 1850
to 1900
– Analog photogrammetry (mechanical
stereoscopic plotting), from about 1900 to 1960
– Analytical photogrammetry (computer-based
(computer based
analytical stereo-plotter), stereo plotter), from about 1960 to
present
– Softcopy (Digital) photogrammetry (electronic
ortho-photographs), ortho photographs), current industry standard
*Adopted from “A Short History of Photogrammetry” by Robert Burtch,
THE INSTITUTE FOR DIGITAL MAPPING, FERRIS STATE UNIVERSITY

Photogrammetry …
The New Trend
• Imagery … from digital sensors
• DTM … from LiDAR systems
• Geo-referencing
Geo referencing … direct using
GPS/INS systems

Technology
Aerial Aerial Surveys Surveys
Laser terrain
scanning
direct geo-
referencing
High-resolution
High resolution
highly accurate 3D
ortho-rectified
ortho rectified
digital image-map
image map
GIS Base Layer
Resource Resource Mapping Mapping
Digital
imaging

DORIS System …
Airborne imaging system that
combines a laser scanner digital
elevation model with simultaneously
captured digital images to produce
geo-referenced geo referenced and highly accurate
ortho-rectified ortho rectified image-map
image map

DORIS System …
LiDAR
Camera
• Customized for
Integrated Laser/Camera

DORISys GeoCam …
• Kodak 4096x4096 ccd
with MegaVision
Back, lens and
RGB/CIR Filters
• NovAtel BDS-IMU BDS IMU-11 11
with OEM4
• Mount and power
module

True Color and Color Infra- Infra
Red DORIS Imagery
• 0.15 m (6”) (6 ) Ground Sampled Distance RGB and CIR Images

Camera Geomatric Calibration
• Target Field
– Precisely Pre-Surveyed
Pre Surveyed
(0.1 mm 1σ) 1
• Calibration Para
– Intrinsic Camera
Parameters
– Radial Lens Distortion

Camera/IMU Fine Alignment
• In-flight In flight Calibration
– 1-3 3 pixel (1σ) (1σ)
• Lever-arm Lever arm Offset
Estimation
– 0.01-0.1 0.01 0.1 m (1σ) (1σ)
• Bore-sight Bore sight angles fine
tuning (fap data)
– 0.01-0.05 0.01 0.05 deg (1σ) (1σ)

DORIS Information Flow
• Real-time Real time Acquisition of
Imagery and Geo-referencing
Geo referencing
information
• Image and Geo-referencing
Geo referencing
information development
• ImageMap production

Processing Overview
• DEM generation from laser points
– Handling large data sets
• Rectify individual image frames
– Corrects for
• Sensor platform orientation
• Relief displacement
• Lens distortion
Digital Imagery
raw format
Image Manipulation
Standard Tiff Images
• Combine rectified images into
mosaic
– Color balancing and Automated
seams
• Tiling
– Efficient file management and speed
GPS Event Markers
exposure stations
Acquisition System
Raw Data
Lab Alignment
Coarse Geo-Referencing
Fine Alignment
Fine Geo-Referencing
Differential Rectification
Mosaicking
GPS/INS
flight trajectory
Laser Data
XYZ Points
Points Gridding
DEM Generation

Processing Overview (cont)
Non Rectified Image
DEM
Rectified Image
Mosaic
Tiff/Geotiff Tiff/ Geotiff image format utilized

Tile Processing Efficiency
1:20:38
1:09:07
0:57:36
0:46:05
0:34:34
0:23:02
0:11:31
0:00:00
DEM Generation
4x4 2x2
Tile Size
1x1
1:40:48
1:26:24
1:12:00
0:57:36
0:43:12
0:28:48
0:14:24
0:00:00
Differential Rectification
4x4 km 2x2 km
Tile Size
1x1km
4:48:00
3:50:24
2:52:48
1:55:12
0:57:36
0:00:00
Mosaic
4x4 km 2x2 km
Tile Size
1x1km

Quick Processing
• Why?
– Same day quality check of data
– Preview data prior to processing
• How?
– Create reduced-resolution reduced resolution images (1/10)
– Thin laser points (1 of 1,000)
– Use real-time real time Geo-referencing Geo referencing info
– DEM generation, rectification & mosaic
(reduced resolution)

DORIS Advantage
• Flexibility
– Acquisition of images of tens of
thousands of hectares per day
– Ready-to Ready to-use use digital data
– Automated fine alignment
• Quality Control
– Real-time Real time Data Quality Assurance
– Near-zero Near zero data loss

DORIS Advantage (cont.)
• Turn-Around Turn Around Time
– Near real-time real time quick mosaics
– Better than 5:1 data processing time for
full resolution image maps
• Accuracy
– High-resolution High resolution imagery
– One image pixel rms ground truthing
– 30-50 30 50 cm accuracy (1-1.5 (1 1.5 pixel)

DORIS Advantage (cont.)
• Current State of the System
– State-of State of-the the-art art Fully Digital
– Easy to Use
– Detailed, Accurate, Automated
– Tested and Operational
– Real-time Real time Navigation and Orhto-
rectification … in the works

Quick Mosaic:
Haynes Creek
20,000 ha
523 images
10,000 laser pts
10m pixels
5m contours
Processing time
1.75 hours
Processing Computer:
1 GHz CPU 256 Mb RAM

Full Resolution Mosaic:
Haynes Creek
Haynes Creek Quick Mosaic at 10m
Mosaic of 2kmx2km block at 0.75m

Accuracy Assessment
• LiDAR
• Fine alignment of Sensors
• Rectify and mosaic imagery
• Compare target positions in imagery
with ground survey

LiDAR Accuracy
Assessment
• LiDAR Target Painting

LiDAR Accuracy
Assessment (cont.)
• LiDAR Hits
• Surveyed Marker
Top View
Elevation
Error [cm]
20
15
10
5
0
-5
-10
-15
LiDAR Point Accuracy
COP Low Pass 1
A1 A2 A3 A4 A5 A6 A7 A8
Target Point
DE
DN
DH
rmse:
8 cm (1D)
11 cm (2D)
13 cm (3D)
Flying Height
AGL: 150'
Point Spacing:
6"
TargetSize: 8'x2"
X 8'x2"
Post Height: 4'-
12'
• +/- +/ 10 cm error envelope

Imagery Accuracy
Assessment
# of RMS RMS
targets (m) (pix)
• Quebecor 15 0.48 1.6
• Millwoods 30 0.46 1.5
• Calgary 22 0.32 1.1
• Toronto 65 0.29 0.8

Accuracy Assessment:
Millwoods
Mosaic of 15 images of ARC/Millwoods. The red crosses in the
enlargements are ground survey positions overlaid on the targets. Kodak
DCS 520 Camera.

DORIS ImageMap Applications
• What Does a DORIS ImageMap Add?
– Accurate high-resolution high resolution 2D spatial information
– Multi-Spectral Multi Spectral Texture/Content information
• ImageMap + DEM
– 3D Spatial Base Layer in a GIS system
– Fully Digital and Automated Resource Mapping
System (e.g. Forestry)
– Complete Aerial Survey System (mapping
agencies, municipalities, reconnaissance,
surveillances, right-of right of-way way (oil, hydro, power, …
etc.), … etc.)

DORIS ImageMap Applications
• Kinsella 3D Fly
though - DORIS
ImageMap
draped over DEM

Mosaic ImageMap Draped onto DEM Image