Document Type

Thesis - University Access Only

Award Date

2001

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering

Abstract

The primary intent of this investigation, funded by NASA/Goddard Space Flight Center, was to provide calibration of the Landsat TM thermal band. Relative radiometric responses for Thematic Mapper {TM) band 6 data from Landsat- 4 and Landsat-5 were analyzed and an algorithm has been developed that significantly reduces the striping in Band 6 images due to detector mismatch. The TM internal calibration system as originally designed includes a DC restore circuit, which acts as a feedback system designed to keep detector bias at a constant value. There is a strong indication that the DC restore circuitry implemented in Band 6 does not function as it had been designed to. It operates as designed only during a portion of the calibration interval, and not at all during acquisition of scene data. This renders the data acquired during the calibration shutter interval period virtually useless for correction of the individual responses of the four detectors in Band 6. It was observed and statistically quantified that the relative response of each of the detectors to the band average is stable over both the dynamic range and throughout the instrument's lifetime. This allows an alternate approach to relative radiometric correction of TM Band 6 images. Absolute calibration of the thermal band was accomplished by using Band-6 specific Landsat ground truth data and relating the absolute response of the instrument to scene input radiance. Band-6 specific Landsat data covering the Lake Tahoe area, acquired between February and August 2000, was used to perform an absolute calibration analysis. Concurrent with Landsat overpasses, thermal field and local meteorological radiances and satellite were measurements water body compared to were collected. At-sensor temperatures measured at the ground truth (GT) predicted measurements corrected for atmospheric effects. The position of the GT collection locations within the digital image was determined through geographical registration to a digital orthophoto quadrangle (DOQ) reference. A 3X3-pixel block of Band-6 thermal raw DNs was then created using the position of the GT data collection location as the center of the block. The results of the calibration study indicate that the TM Band-6 data reasonably approximated the GT temperature measurements. This work is organized into six chapters. Chapter 1 briefly reviews the Landsat program and discusses the overall design of the Landsat-5 TM instrument. Chapter 2 contains a review of the relevant literature, discusses the radiometry governing the calibration of satellite systems and specific artifacts present in the Thematic Mapper. Chapter 3 describes the analysis, which demonstrates that the DC restore circuitry implemented in Band 6 does not function as designed. Chapter 4 describes a procedure for performing a "Relative Radiometric Calibration" of the detectors and shows the results from applying relative calibration. Chapter 5 explains "Absolute Radiometric Calibration", which enables the conversion of DN values in an image to physical units of radiance (Wm-2 sr-1 μm-1). Chapter 6 concludes the work with a results summary and discussion.

Library of Congress Subject Headings

Landsat satellites -- Calibration

Imaging systems -- Image quality

Format

application/pdf

Number of Pages

186

Publisher

South Dakota State University

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