U.S. Department of the Interior U.S. Geological Survey ASPRS Panel on Digital Sensor...
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S. Department of the Interior S. Geological Survey ASPRS Panel on Digital Sensor Calibration/Evaluation USGS Early Testing Efforts of Digital Camera Systems May 26, 2004 Jon Christopherson, SAIC USGS EROS Data Center [email protected]
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Transcript of U.S. Department of the Interior U.S. Geological Survey ASPRS Panel on Digital Sensor...
U.S. Department of the InteriorU.S. Geological Survey
ASPRSPanel on Digital Sensor
Calibration/Evaluation
USGS Early Testing Efforts of Digital Camera Systems
May 26, 2004
Jon Christopherson, SAICUSGS EROS Data Center
Background
USGS has beencalibrating film cameras since1973 Optical Science
Lab at USGS HQ in Reston, VA
Uses multi-collimator assembly developed in 1953
Metric aerial film cameras very flat, very stable
Laboratory Calibration Research
June ’03 - Control point cage installed at EDC Contract w/ Pictometry
Australis software used to determine camera coefficients
In early stages of research now Multiple cameras &
lenses have been tested (~10+)
USGS Digital Camera Testing
USGS facilities suitable for small- and medium-format cameras Ill-suited for most large-format systems
EDC has tested USGS camera plus selected few outside systems
Range from Medium-format, medium-expense systems (~$20K) to “pocket” cameras (< $1K)
Caveats!
The results presented here are from exploratory research only
Not meant to imply the quality of any camera/back/lens
These results are: Far from complete! Far from conclusive! However, they are a start and indicate areas of
interest for ongoing research
Exploratory Research
Sample Initial Results of Various Cameras & Lenses
-20
0
20
40
60
80
100
0 5 10 15 20 25 30
Radius from FPA Center (mm)
Dis
tort
ion
(p
ixe
ls)
14n 60mm Micro
D1X 20mm (30.1mm eff) FOV
Contax Megavision, 35mm
Contax 645C, 35mm
Minolta Dimage 71 zoom (7mm)
Exploratory Research (cont.)
Radial Distortion (in pixels) by FOV angle
-40.0
-20.0
0.0
20.0
40.0
60.0
80.0
100.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
Half-angle Field of View (degrees)
Ra
dia
l D
isto
rtio
n (
pix
els
)
Kodak 14n, 60mm Micro
Contax/Megavision, 35mm
Contax 645C, 35mm
Nikon D1X, 20mm
Minolta Dimage 7i, Zoom (7mm)
Exploratory Research (cont.)
Angular Distortion Across FOV
-0.500
0.000
0.500
1.000
1.500
2.000
2.500
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
Field of View (Half-angle)
Rad
ial
Dis
tort
ion
in
deg
rees
Kodak 14n 60mm Micro
Contax Megavision 35mm
Contax 645C 35mm
Nikon D1X 20mm
Minolta Dimage 7i Zoom (7mm)
Interim Observations
No system tested approaches the flatness of film metric cameras
Repeatability of results varies with system Variability can likely be controlled – on
some systems only Concern – can calibrations be trusted
over time?
Interim Observations (cont.)
In General: the more “consumer” the less “metric” The less “consumer” the more expensive
There is potential for small- and medium-format metric sensors Potential for great benefits in size, cost, speed,
ease-of-use Possibilities with new aerial platforms
Continued investigation warranted
Near-Term Plans
Basic environmental testing (temperature, vibration) of EDC cameras Explore other camera/sensor types Explore methods to ensure stability
MTF Testing Both Lab & in-situ
Begin radiometric testing Validate all of above with In-Situ testing Enhance EDC photogrammetry capability
MTF Characterization
EDC working with SDSU to develop MTF characterization tools & software
In lab using ISO 12233
In-situ withground targets
Ease-of-use
Radiometric Testing
Start basic: measure s/n, linearity, stability
Would like to move farther Spectral profiling, monitoring Long-term stability
Can systems can deliver “calibrated” multispectral data? How to maintain performance?
EDC In-Situ Range
65 ea. targets in 4mi × 4mi area around EDC surveyed to ± 2cm absolute accuracy
Additional 65 targets in higher density pattern for testing in-situ camera calibration
Site contains operating CORS station Option to set to 1 sec. intervals
Site has been flown once at 6” resolution and at 2’ resolution We need more overflights!
EDCRange
EDC Range
Targets patterned after OSU range
Conclusions
USGS research is underway Small- and medium-format systems
are problematic, but there is promise USGS needs help exploring
techniques being used Partnerships, assistance with
overflights, cameras/sensors, etc.
Contact Information
Gregory L [email protected]
(605) 594-2569
USGS EROS Data Centerhttp://edc.usgs.gov/
Commercial Remote Sensing Characterization, Calibration, Verification, and
Validation (C2V2) Project
