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Detection of Diseases Caused by Diabetes in Retinal Images
Zapletal, Michal ; Semerád, Lukáš (referee) ; Kavetskyi, Andrii (advisor)
The goal of this thesis is to design and implement an algorithm for detecting exudates and microaneurysms in colored retinal images. These diseases are the first signs of diabetic retinopathy and early detection is crucial. The proposed algorithm begins with preprocessing, where excess background is removed, contrast is enhanced using CLAHE and histogram stretching, and noise filtering is applied. Optic disc localization is based on iterative background removal and row and column variances. Exudates detection is performed based on gamma correction, thresholding and optic disc removal. Microaneurysm detection is based on morphological operations, hit-or-miss transformation and principal component analysis (PCA). The algorithm was tested on 4 datasets with accuracy 73,1 % for exudates and 73,3 % for microaneurysms. The resulting program could assist in automatic disease detection, which could potentially save time for doctors.
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Transformation of butterfly fauna on a middle scale: Situation in the South Bohemian Region.
ZAPLETAL, Michal
This thesis summarises historical and recent information on the distribution of butterflies in South Bohemian region, based on 130 records from literature, collections and recording reports, amassed during Mapping of Czech Republic butterflies. Historical and present distributions of each of 130 butterfly species found in their region are displayed on distribution maps. Out of the 130 species, 42,1 % is already extinct, while 24,1 % is threatened to some extend. Comparison with the situation in entire Czech Republic reveals a higher rate of extinctions, which is probably a function of smaller total area. Compared with the Czech Republic total, xerophilous species suffered higher losses in South Bohemia, whereas species of mesic habitats are relatively less endangered and for peat bogs specialists, the region represents a major refugium. Priorities for further research and active conservation measures are discussed.
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