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Processing of high-resolution retinal images
Vraňáková, Sofia ; Chmelík, Jiří (oponent) ; Valterová, Eva (vedoucí práce)
The master’s thesis is focused on the processing of high-resolution retinal images. The aim of this work is to obtain images of higher quality from a sequence of low-quality frames. The frames are first pre-processed by using bilateral filtering and contrast enhancement. The shift between the frames in the imaging sequence is estimated using phase correlation, and these frames are then fused together using the averaging through the frames and the super-resolution technique, more specifically regularization based on bilateral total variance. The resulting median quality scores of obtained images are PIQUE 0.2600, NIQE 0.0701, and BRISQUE 0.3936 for the averaging technique and PIQUE 0.1063, NIQE 0.0507, and BRISQUE 0.1570 for super-resolution technique.
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Konstrukce adaptivního zrcadla pro výkonové laserové aplikace
Kroutil, Tomáš ; Zatočilová, Aneta (oponent) ; Koutný, Daniel (vedoucí práce)
Bakalářská práce se zabývá návrhem a výrobou prototypu adaptivního zrcadla pro výkonové lasery. Deformace zrcadla je vytvořena sadou tahových elementů a tlakem vzduchu. Velikost deformace odrazné plochy je v řádu desetin milimetrů. Rešeršní část je věnována laserové technologii s adaptivní optikou. Konstrukční část obsahuje různé varianty řešení a optimální řešení, které bylo zvoleno pro realizaci. Skutečná deformace odrazné plochy zrcadla byla vyhodnocena 3D skenerem.
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Spatial registration of partially overlapping retinal images
Žiak, Milan ; Harabiš, Vratislav (oponent) ; Valterová, Eva (vedoucí práce)
Adaptive optics give us opportunity to capture high resolution images of retina, even we are able to detect cones. Spatial registration of retina images has to be done due to scanning process of capturing, because current opthalmoscops with adaptive optics aren't able to capture whole area of retina. Diploma thesis demonstrates basic princip of automatic spatial registration of overlaping images. It uses constellation features for matching some of the detected cones. K-means combinate wiht RANSAC is used for outlier detection. Inliers matching pairs are then used to define a affine transformation matrix. This method was aplied on dataset retina images from AO-FIO modality and evaluation of quality was computed according to normalized mutual information. Result shows that this metod is suitable for registration AO-FIO images with "cell-to-cell" accuracy.
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Photoreceptor detection methods in high-resolution retinal images
Vicianová, Jana ; Mézl, Martin (oponent) ; Odstrčilík, Jan (vedoucí práce)
This thesis deals with the detection of photoreceptors in images captured by a camera using adaptive optics. The theoretical part of the work describes the anatomy and physiology of the eye, the retina and the diseases affecting it. Subsequently, current approaches in the field of photoreceptor detection are described. Selected methods are implemented in the practical part of the work. Modifying them, a photoreceptor detector is created. The results of individual methods are evaluated and compared.
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Spatial registration of partially overlapping retinal images
Žiak, Milan ; Harabiš, Vratislav (oponent) ; Valterová, Eva (vedoucí práce)
Adaptive optics give us opportunity to capture high resolution images of retina, even we are able to detect cones. Spatial registration of retina images has to be done due to scanning process of capturing, because current opthalmoscops with adaptive optics aren't able to capture whole area of retina. Diploma thesis demonstrates basic princip of automatic spatial registration of overlaping images. It uses constellation features for matching some of the detected cones. K-means combinate wiht RANSAC is used for outlier detection. Inliers matching pairs are then used to define a affine transformation matrix. This method was aplied on dataset retina images from AO-FIO modality and evaluation of quality was computed according to normalized mutual information. Result shows that this metod is suitable for registration AO-FIO images with "cell-to-cell" accuracy.
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Automatic Adaptive Optics Retinal Images Montaging
Valterova, Eva
The adaptive optics images capture limited field of view. Nevertheless, the quantitativeretina assessment requires analysis over extended areas captured by images on various retina positions.The fully automated method for image registration and montaging is presented. The methodutilizes scale invariant feature transform (SIFT) for feature extraction from preprocessed images.The method is tested on 200 images of normal healthy patients. The montages of 20 eyes were createdand evaluated by normalized mutual information metrics and the results showed high alignmentaccuracy.
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Automated Fovea Center Estimation In Adaptive Optics Images
Valterova, Eva
The adaptive optics (AO) is an insightful tool with high potential. Since the first demonstration in ophthalmology has undergone immense growth in its diagnostic application, mainly because the AO enables to capture retina in vivo with resolution on the cellular level. In the center of the retina is macula, containing the fovea. The fovea detection is possible with utilizing the knowledge of its characteristical properties. We developed and applied two methods for fovea center estimation. The first method is based on image maximum detection. The second is based on the 2D Gaussian curve fitting. The first method has proved better results in comparison with manual grading. The measured difference was 32_x0006_27 pixels. The second approach has in comparison with manual grading slightly higher difference equal to 108_x0006_64 pixels. Both of the methods estimated the foveal center within the expected foveal area.
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Processing of high-resolution retinal images
Vraňáková, Sofia ; Chmelík, Jiří (oponent) ; Valterová, Eva (vedoucí práce)
The master’s thesis is focused on the processing of high-resolution retinal images. The aim of this work is to obtain images of higher quality from a sequence of low-quality frames. The frames are first pre-processed by using bilateral filtering and contrast enhancement. The shift between the frames in the imaging sequence is estimated using phase correlation, and these frames are then fused together using the averaging through the frames and the super-resolution technique, more specifically regularization based on bilateral total variance. The resulting median quality scores of obtained images are PIQUE 0.2600, NIQE 0.0701, and BRISQUE 0.3936 for the averaging technique and PIQUE 0.1063, NIQE 0.0507, and BRISQUE 0.1570 for super-resolution technique.
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Konstrukce adaptivního zrcadla pro výkonové laserové aplikace
Kroutil, Tomáš ; Zatočilová, Aneta (oponent) ; Koutný, Daniel (vedoucí práce)
Bakalářská práce se zabývá návrhem a výrobou prototypu adaptivního zrcadla pro výkonové lasery. Deformace zrcadla je vytvořena sadou tahových elementů a tlakem vzduchu. Velikost deformace odrazné plochy je v řádu desetin milimetrů. Rešeršní část je věnována laserové technologii s adaptivní optikou. Konstrukční část obsahuje různé varianty řešení a optimální řešení, které bylo zvoleno pro realizaci. Skutečná deformace odrazné plochy zrcadla byla vyhodnocena 3D skenerem.
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Konstrukce adaptivního zrcadla pro výkonové laserové aplikace
Kroutil, Tomáš ; Zatočilová, Aneta (oponent) ; Koutný, Daniel (vedoucí práce)
Bakalářská práce se zabývá návrhem a výrobou prototypu adaptivního zrcadla pro výkonové lasery. Deformace zrcadla je vytvořena sadou tahových elementů a tlakem vzduchu. Velikost deformace odrazné plochy je v řádu desetin milimetrů. Rešeršní část je věnována laserové technologii s adaptivní optikou. Konstrukční část obsahuje různé varianty řešení a optimální řešení, které bylo zvoleno pro realizaci. Skutečná deformace odrazné plochy zrcadla byla vyhodnocena 3D skenerem.
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