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Enhanced CAE system for detection of exudates and diagnosis of diabetic retinopathy stages in fundus retinal images using soft computing techniques

Janaki Sathya D., Geetha K.

Polish Journal of Medical Physics and Engineering

2019

Vol. 25, Iss. 2

131--139

Diabetic Retinopathy (DR) is one of the leading causes of visual impairment. Diabetic Retinopathy is the most recent technique of identifying the intensity of acid secretion in the eye for diabetic patients. The identification of DR is performed by visual analysis of retinal images for exudates (fat deposits) and the main patterns are traced by ophthalmologists. This paper proposes a fully automated Computer Assisted Evaluation (CAE) system which comprises of a set of algorithms for exudates detection and to classify the different stages of Diabetics Retinopathy, which are identified as either normal or mild or moderate or severe. Experimental validation is performed on a real fundus retinal image database. The segmentation of exudates is achieved using fuzzy C-means clustering and entropy filtering. An optimal set obtained from the statistical textural features (GLCM and GLHM) is extracted from the segmented exudates for classifying the different stages of Diabetics Retinopathy. The different stages of Diabetic Retinopathy are classified using three classifiers such as Back Propagation Neural Network (BPN), Probabilistic Neural Network (PNN) and Support Vector Machine (SVM). The experimental results show that the SVM classifiers outperformed other classifiers for the examined fundus retinal image dataset. The results obtained confirm that with new a set of texture features, the proposed methodology provides better performance when compared to the other methods available in the literature. These results suggest that our proposed method in this paper can be useful as a diagnostic aid system for Diabetic Retinopathy.

Spectrophotometric determination of nitrite using phenosafranine

Geetha K., Balasubramanian N.

Chemia Analityczna

2001

Vol. 46, No. 4

579-588

A simple and sensitive spectrophotometric method for the determination of nitrite is described. Diazotisation of the primary amino group in the dye phenosafranine resulted in a decrease in absorbance at 520 nm. This decrease in absorbance is directly proportional to nitrite concentration obeying Beer's law in the range 0-12 ug of nitrite in a final aqueous volume of 25 ml with a relative standard deviation of 2.9% at 8ug of nitrite (n = 10). Sensitivity of the method is enhanced by extracting the dye into 3-methyl-1 -butanol under alkaline condition, followed by the addition of methanolic sulfuric acid. Beer's law is obeyed over the range 0-1ug of nitrite at 530 nm, after extraction with a relative standard deviation of 1.9% at 0.6ug of nitrite (n = 10). The developed method has been applied for the determination of residual NO(2) in the laboratory fume cupboard after fixing it as nitrite in suitable absorber solution. Nitrate and nitrite contents in analytical grade chemicals, medicated tooth paste, soil and water samples were determined. The effects of interfering gases and other ions on the determination of nitrite are described. Reliability of the method was established by parallel determination using a diazocoupling reaction and by studying recovery of added nitrite and nitrate.

Opisano prostą i czułą spektrofotometryczną metodą oznaczania azotynów. Diazowanie pierwszorzędowej grupy aminowej barwnika fenosafraniny powoduje zmniejszenie wartości absorbancji przy 520 nm. Zmniejszenie to jast proporcjonalne do stężenia azotynów i wykazuje zgodność z prawem Beera w zakresie 0-12 ug azotynów w końcowej objętości 25 ml (RSD = 2.9% dla 8ug azotynów, n = 10). Czułość metody zwiększa się po ekstrakcji barwnika 3-mety lo-1 -butanolem ze środowiska alkalicznego i dodaniu metanolowego roztworu kwasu siarkowego. Po ekstrakcji, zgodność z prawem Beera stwierdzono w zakresie 0-1 ug azotynów przy 530 nm (RSD = l .9% dla 0.6 mg azotynów, n = 10). Opracowaną metodę zastosowano do oznaczania NO(2) w dymie z wyciągu laboratoryjnego po absorpcji gazu w odpowiednim roztworze. Zawartość azotanów i azotynów oznaczano także w odczynnikach chemicznych, próbkach wody i gleby oraz w leczniczej paście do zębów. Opisano wpływ różnych jonów i gazów na wyniki oznaczania azotynów. Wiarygodność wyników opracowanej metody sprawdzono metodą diazowania i sprzęgania oraz metodą dodawania wzorca (azotyny i azotany) określono dokładność metody.