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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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Segmentation of important structures in retinal images
Trojánek, Václav ; Mézl, Martin (referee) ; Odstrčilík, Jan (advisor)
This bachelor thesis focuses on the segmentation of significant structures in retinal image data to improve the diagnosis and treatment of ocular diseases. Methods of retinal image analysis are investigated and implemented in this thesis. The thesis begins with an overview of the anatomy of the eye and the principles of background eye imaging using a fundus camera and an experimental video ophthalmoscope. This is followed by a detailed literature search focusing on current methods for the detection and segmentation of diagnostically important structures such as the optic disc, macula and blood vessels. A key part of the work is the implementation and testing of selected algorithms, including Hough transform for optic disc detection and OTSU thresholding for blood vessel segmentation and yellow spot detection based on previous optic disc segmentation.
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Localisation of the optic disc from fundus photographs
Pěchotová, Barbora ; Kolář, Radim (referee) ; Odstrčilík, Jan (advisor)
This thesis deals with the analysis of retinal images from digital fundus camera, especially with structure of optic disc (OD). The theoretic part describes main features of the human visual system and princip of eyeground examination. The paper discussed sevaral available methods that have been used for localization of the optic disc. In the second part is proposed the automatic detector of the optic disc based on the principle of genetic algorithm by using the method of segmentation of vessels by matched filtering. Original images are tested with this automatic method.
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Segmentation in the color fundus imges
Malínský, Miloš ; Jiřík, Radovan (referee) ; Kolář, Radim (advisor)
Optic nerve head and macula are important structures in fundus images. Detection and measurement plays crucial role in several diagnosis methods of optic disease. This work is focused on the detection of the central point of macula and optic nerve head, where the inner border is detected too. There are many methods for extracting this structure in retinal images. Due to the unique properties of each acquisition technique, a single generally acknowledged detection algorithm does not exist. The whole detection process is described from preprocessing through segmentation towards postprocessing. Presented methods are based on the combination of correlation techniques, Hough transform, active contours and morphological operations. The detected contours of the optic nerve head are evaluated and quantitatively compared with the contour drawn by experienced ophthalmologist. The master thesis contains quantity of images that help to describe detection methods.
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Analysis of vessel pulsation in retinal video sequences
Valentová, Vanessa ; Kolář, Radim (referee) ; Odstrčilík, Jan (advisor)
Glaucoma is the third most common cause of blindness in the world. There are several types of glaucomma, which makes early diagnosis of this illness harder. One posibble way for early diagnosis could be analysis of a retinal vessel pulsation. Data in this work were captured by experimental device called video ophtalmoscope. Several methods for optic disc segmentation were designed. From segmented parts, pulsation curve was recorded. Analysis of the pulsation curve was provided in two ways: Analysis of the whole pulsation curve and Averaged pulse analysis. Both methods were tested with diferent reference signals.
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Localisation of Optic Disc from Fundus Photographs
Pěchotová, Barbora ; Kolář, Radim (referee) ; Odstrčilík, Jan (advisor)
This thesis deals with the analysis of retinal images from digital fundus camera, especially with structure of optic disc (OD). The theoretic part describes main features of the human visual system and princip of eyeground examination. The paper discussed available methods that have been used for localization of optic disc. For further work is selected proposal of the geometrical model of vessel structure by using the method of segmentation of vessels by matched filtering. Original images are tested with semi-automatic method for optic disc localization.
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Optic disc segmentation in retinal images
Vymazal, Bronislav ; Odstrčilík, Jan (referee) ; Kolář, Radim (advisor)
Cílem této práce bylo vytvořit kompaktní algoritmus sloužící k lokalizaci, segmentaci a sledování optického disku v sekvencích obrazů sítnice. Pro účely lokalizace byla použita nová metoda založena na „fast radial transform“. Segmentace optického disku je založena na klasické metodě Chan-Vese, která byla rozšířena o další prvky a implementována v lokalizované podobě, která umožňuje lépe segmentovat obrazy s vysokou mírou nehomogenity. Pro sledování optického disku v sekvencích obrazů byl využit optický tok založený na Lucas-Kanade algoritmu. Všechny metody byly vyhodnoceny na dvou databázích obrazů s odlišnými charakteristikami. První databází je klasická databáze s vysokým rozlišením. Druhou je pak databáze s nízkým rozlišením a vysokou mírou šumu. Všechny výsledky jsou pak porovnány s referenčními hodnotami a vyhodnoceny.
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Optic disc detection in video sequences from video ophthalmoscope
Čermák, Marek ; Mézl, Martin (referee) ; Odstrčilík, Jan (advisor)
This work is focused on automatic detection of optic disc in retinal images. There is briefly described anatomy of human eye, principles of retinal imaging and also overview of the methods used for optic disc detection. The practical part describes developed procedures for optic disc detection, ie detection based on watershed transform, active contours and also on region growing technique. The main method of this work is the method of circular transformation, which as the only one allowed to detect the optic disc on the images of video ophtalmoscope and also on the high quality images from fundus cameras. This method was tested on three datasets. The average overlap 92,44 % was achieved for HRF dataset, 91,03 for DRIONS dataset and 77,36 for images of video ophtalmoscope.
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Extracting of the optic disc in optical coherence tomography images
Šeda, Jan ; Harabiš, Vratislav (referee) ; Kolář, Radim (advisor)
The main target of this work is a design of the program for border localization of the optic disc in OCT data. Part of this program is also localization of the „optic cup“ and calculation of several values that characterize optic disc. The work is also dealing with a description of the optical coherence tomography principle which is used in ophthalmology. One chapter describes some published methods of optic cup localization. Success of the program and its comparison with OCT Zeiss Stratus 3000 is evaluated at the end of the work.
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Detection of optic disc from fundus camera sequences
Juráček, Radek ; Harabiš, Vratislav (referee) ; Hracho, Michal (advisor)
This bachelor thesis deals with optical disc detection in retinal images taken by an experimental video ophthalmoscope. At the beginning, it briefly describes the anatomy of the eyesight and retina, retinal disease and selected diagnostic methods of retinal imaging. There are described methods of detecting objects in the image, which are subsequently used in the practical part dealing with optical disc detection using Hough transformation and matched filtration. Proposed procedures were tested on a 100-image set. Hough Transformation Detection was successful in 64% of cases, matched filtration was successful in 44% of cases.
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