Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Quantification and morphology studies of nanoporous alumina membranes: A new algorithm for digital image processing(2013) Choudhari, K.S.; Jidesh, P.; Sudheendra, P.; Kulkarni, S.D.A new mathematical algorithm is reported for the accurate and efficient analysis of pore properties of nanoporous anodic alumina (NAA) membranes using scanning electron microscope (SEM) images. NAA membranes of the desired pore size were fabricated using a two-step anodic oxidation process. Surface morphology of the NAA membranes with different pore properties was studied using SEM images along with computerized image processing and analysis. The main objective was to analyze the SEM images of NAA membranes quantitatively, systematically, and quickly. The method uses a regularized shock filter for contrast enhancement, mathematical morphological operators, and a segmentation process for efficient determination of pore properties. The algorithm is executed using MATLAB, which generates a statistical report on the morphology of NAA membrane surfaces and performs accurate quantification of the parameters such as average pore-size distribution, porous area fraction, and average interpore distances. A good comparison between the pore property measurements was obtained using our algorithm and ImageJ software. This algorithm, with little manual intervention, is useful for optimizing the experimental process parameters during the fabrication of such nanostructures. Further, the algorithm is capable of analyzing SEM images of similar or asymmetrically porous nanostructures where sample and background have distinguishable contrast. Copyright © Microscopy Society of America 2013.Item Development and validation of a novel automated method for quantification of choroidal thickness in age-related macular degeneration(SPIE, 2021) Smitha, A.; Jidesh, P.; Janarthanam, J.; Lakshminarayanan, V.Age-related Macular Degeneration (AMD) is a progressive, irreversible retinal disorder, and one of the leading causes of severe visual impairment or even blindness in the elderly population. The choroid plays a vital role in the pathophysiology of AMD. It is known that abnormal choroidal blood flow leads to retinal photoreceptor dysfunction and eventual death. We propose a new automated algorithm that can be used to quantify choroidal thickness (CT) from Optical Coherence Tomography (OCT) images of the retina. This thickness evaluation procedure includes image contrast enhancement, localization around the fovea centralis, segmentation of Retinal Pigment Epithelium (RPE) and choroidal layer, followed by CT measurement at multiple locations in the sub-foveal region at intervals of 0.5 mm on both nasal and temporal sides up to a distance of 1 mm from the center of the foveal pit. The horizontal radial scan OCT images (Cirrus 5000, Carl Zeiss Meditec Inc., Dublin, CA) of both healthy and AMD patients were used to measure the CT using the new algorithm. The statistical tests convey that the CT of AMD patients is relatively smaller than the normal condition. Furthermore, t-Test conducted between the proposed approach and clinical approach of extracting CT measurements confirm that the proposed method is in good agreement with the clinical measurements. On an average, the thickness of the choroid is found to be 0.32 ± 0.10 mm for the normal category and 0.21 ± 0.06 mm for the AMD category, in the central sub-foveal region, as obtained from the proposed automatic CT measurement method. The clinical significance and the results of automated choroid extraction are discussed in this paper. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.