Texture is one of the crucial primitives in human vision Containing important information about the structural arrangement of surfaces and their relationship to the surrounding environment In the past many years texture based methods are developed for extracting features & matching of medical images. Medical images have become the recent key investigation tools for medical diagnosis and treatment planning. Due to the advent of digital imaging the need of data storage and retrieval of medical images increased rapidly. Although medical images contain useful information, their use is limited to access and availability. Therefore, storage solutions to facilitate cataloguing, browsing, and retrieval of medical images are required. In this paper a system for effective texture based matching of and medical images is presented. Firstly various levels of texture features of database image are extracted and saved. Features of query image are then compared with corresponding features of database images and the difference between the two is then used to compute cost function which implies maximum matching category for query image.
We introduce a technique for extracting the vessel structure in the fundus image of a retina. Retinal vessel segmentation achieved by categorizing every pixel belonging to vessel structure or not, derived from characteristic vector consisting of the gray level values and coefficients of 2-D Gabor wavelet at various scales. Specific frequency tuning of Gabor wavelet allows vessel segmentation even in the presence of noise in the image. We use Adaptive Network Fuzzy-Inference System (ANFIS) classifier with linguistic expression modeling capability and self-learning, yielding accurate classification. The openly accessible DRIVE database is used for performance evaluation of manually labeled images. In addition, Performance evaluation carried on fundus images provided by the ophthalmologist. The results obtained are quiet promising when inspected visually in both normal as well as pathological images.
Purpose:The aim of this study was to evaluate choroidal neovascular (CNV) lesions with fluorescein angiography (FA) and to identify quantitative parameters and correlate these parameters to treatment outcomes.Subjects and Methods:This institution based cross-sectional study evaluated 30 eyes with active sub-foveal predominantly classic CNV treated with bevacizumab. Pre- and post-injection segmented FA images were analyzed. Lesion area and CNV lesion were manually delineated. Outcome measure was the change 1-month after each injection in different intensity values (0–255 divided in eight regions A [lowest intensity] to H [highest intensity] on a linear scale) in lesion area, perimeter, greatest linear dimension (GLD), area, visual acuity (VA) and central macular thickness (CMT).Results:At month 3, statistically significant changes from baseline occurred in VA, CMT, lesion area, GLD and perimeter (P < 0.05 all comparisons). Change in CMT from baseline to 3 months postinjection was correlated with change in VA (P = 0.009, r = 0.469) and intensity regions B (P = 0.001, r = −0.565), D (P = 0.001, r = 0.560), E (P = 0.035, r = 0.386). At month 3, change in intensity values 0–63 (A + B) was negatively correlated with CMT (P = 0.001, r = −0.575) and lesion area (P = 0.019, r = −0.427); change in intensity values 64–223 (C-G) was positively correlated with CMT (P = 0.000, r = 0.636) and lesion area (P = 0.002, r = 0.551).Conclusions:Decrease in area, GLD, perimeter and area with intensity ≥ 64 on segmented FA were associated with a favorable outcome of treatment. These parameters may be useful adjuncts to existing evaluation techniques during follow-up of CNV.
Measurement of pressure fluctuations due to acoustic environment is important in the investigation of turbulent flow phenomena associated with several classes of aerospace problems. These measurements, utilizing piezoelectric transducers, are accompanied by noise from vibrations of the structure on which the transducers are mounted. Two schemes for the vibration isolation of the transducers are experimentally investigated. These are: individual isolation of transducers, and isolation of an insert on which the transducers are mounted. Experiments were conducted in a 14 in.×14-in. supersonic wind tunnel at a nominal Much number of 1.96 and stagnation pressures of 30 and 45 psia. Comparison of the spectra of the pressure fluctuations measured by transducers mounted on a flat wall of the tunnel shows that structural noise above 3 kc/sec may be eliminated by any one of the two schemes, and that below 3 kc/sec may be eliminated by any one of the two schemes, and that below 3 kc/sec the structural noise is considerably reduced by these isolation techniques. In order to attain further insight into the manner in which a pressure transducer is affected by structural vibrations, coherence functions have been calculated for structural noise and observed pressure fluctuations.
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