The image data obtained from an infrared sensor are matrices with digital pixel values – which are equivalent to the image data obtained from digital cameras in the visual region. The goal with all imaging is that the information in the image should represent the scene as close as possible, which is affected by noise sources like the nonuniform response of each pixel in the detector.
This thesis describes and evaluates a number of approaches and algorithms for nonuniform correction (NUC) and suppression of fixed pattern noise in a image sequence. The main task for this thesis work was to create a general NUC for infrared focal plane arrays…
Contents
1 Introduction
1.1 Background
1.2 Previous work
1.3 Goal of the thesis
1.4 Implementation
1.5 Thesis overview
2 Basic concepts
2.1 Basic radiometry
2.1.1 Properties of radiators
2.1.2 Lambertian radiator
2.2 Infrared imaging
2.2.1 Detectors
2.2.2 From detector to an imaging system
2.2.3 Responsivity
2.2.4 Noise
3 Equipment used in thesis
3.1 Cameras
3.1.1 Multimir
3.1.2 Emerald
3.1.3 Information from files
3.2 Radiation sources
4 Nonuniform correction of IR-images
4.1 Scene based correction
4.1.1 Statistic methods
4.1.2 Registration-based
4.2 Reference based correction
4.2.1 Correction function
4.3 Quality measurement
xi5 Identifying and replacing dead pixels
5.1 Temporal noise
5.2 Extreme values
5.3 Value on polynomial coefficients
5.4 Principal component analysis
5.5 Replacement of bad pixels
6 Results
6.1 NUC and bad pixel filtering
6.2 Linear responsivity
6.3 Correctability
6.4 Measurement considerations
6.5 The user-interface of Matlab program
6.6 DN → physical unit
7 Conclusions
7.1 Future work
Bibliography
Author: Isoz, Wilhelm
Source: Linköping University
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