| Title: | Image enhancement techniques applied to solar feature detection |
| Author: | |
| Document Type: | Dissertation |
| Department: | Department of Computer Science |
| Degree: | Doctor of Philosophy |
| Major: | Computer Science |
| Advisory Committee: |
Shih, Frank Y.
McHugh, James A.
Wang, Haimin
Theodoratos, Dimitri
Liu, Chengjun
|
| Thesis Date: | 2003, May |
| Keywords: |
solar image processing
mathematical morphology
feature extraction
directional filtering
filament detection
|
| Availability: | Unrestricted |
| Abstract: |
This dissertation presents the development of automatic image enhancement techniques for solar feature detection. The new method allows for detection and tracking of the evolution of filaments in solar images. Series of H-alpha full-disk images are taken in regular time intervals to observe the changes of the solar disk features. In each picture, the solar chromosphere filaments are identified for further evolution examination. The initial preprocessing step involves local thresholding to convert grayscale images into black-and-white pictures with chromosphere granularity enhanced. An alternative preprocessing method, based on image normalization and global thresholding is presented. The next step employs morphological closing operations with multi-directional linear structuring elements to extract elongated shapes in the image. After logical union of directional filtering results, the remaining noise is removed from the final outcome using morphological dilation and erosion with a circular structuring element. Experimental results show that the developed techniques can achieve excellent results in detecting large filaments and good detection rates for small filaments. The final chapter discusses proposed directions of the future research and applications to other areas of solar image processing, in particular to detection of solar flares, plages and sunspots. |
| Complete Thesis: | njit-etd2003-076 (139 pages ~ 15,180 KB pdf) |
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Created June 10, 2004
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