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This paper discusses the calibration and geometric stability of digital cameras at the Nevada Test Site Calibration Range. Topics include sensor engineering, radiometric calibration, terrestrial geometric calibration, in situ calibration, and calibration verification. The results show the effectiveness of using regional test ranges for camera calibration and verification.
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Nevada Test Site Calibration Range and Geometric Calibration of Digital CamerasISPRS I/2Bob KletzliSpectrum Mapping, LLCDecember 2-4, 2003
Outline • Engineer Sensor For Geometric Stability • Lock Lenses at Infinity Before Calibration • Lab Radiometric Calibration • Terrestrial Geometric Calibration • In Situ Calibration • Calibration Verification NTS
Geometric Stability • CDD Fixed To Milled Optical Bench • Lens Receptacle Is Opposite Side • Each Lens Fixed To Aluminum Socket • Lenses Are Interchangeable • Alignment Pins Eliminate Rotation • TEC Surrounds CCD • “Shake and Bake”
Lens Focus • Lens Focused At Infinity • High Frequency Target At 100m • Each Lens Adjusted & Pinned
Radiometric Calibration • Lab Tools Include: • Integrating Sphere • Spectralon Panels • Spectral Line Lamps • Lab Processes • Dark Current • Flat Fielding • White Balance
Insitu Range (NM) • 400+ points by RTK • 2-3 cm accuracy • Photo Identifiable • Variable terrain • Used for both laser & photography • Building corners surveyed
Summary • Digital Cameras Can be Calibrated to Conventional Specifications • Calibrations Are Maintained Over Time • Regional Test Ranges Are Extremely Useful For Calibration and Verification