Experiments with loss function for improvement of multi-class segmentation of diabetic retinopathy lesions

2021 ◽  
Author(s):  
Pedro Furtado
Keyword(s):  
Diabetic Retinopathy ◽  
Loss Function ◽  
Class Segmentation

scholarly journals Automatic Choroid Vascularity Index Calculation in Optical Coherence Tomography Images Low Contrast Sclerochoroidal Junction Using Deep Learning

2021 ◽  
Author(s):  
Roya Arian ◽  
Tahereh Mahmoudi ◽  
Hamid Riazi-Esfahani ◽  
Rahele Kafieh ◽  
Hooshang Faghihi ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Deep Learning ◽  
Loss Function ◽  
Optical Coherence ◽  
Low Contrast ◽  
Automated Method ◽  
Local Thresholding ◽  
Luminal Area ◽  
Localization Errors

Abstract Choroidal vascularity index (CVI) is a new biomarker defined for retinal optical coherence tomography (OCT) images for measuring and evaluating the choroidal vascular structure. CVI is the ratio of the choroidal luminal area (LA) to the total choroidal area (TCA). The automatic calculation of this index is important for ophthalmologists but has not yet been explored. In this study, we proposed a fully automated method based on deep learning for calculating CVI in three main steps: 1- segmentation of the choroidal boundary, 2- detection of the choroidal luminal vessels, and 3- computation of the CVI. The proposed method is evaluated in complex situations like the presence of diabetic retinopathy and pachychoroid spectrum. In pachychoroid spectrum, the choroid is thickened, and the boundary between choroid and sclera (sclerochoroidal junction) is blurred, which makes the segmentation more challenging. The proposed method is designed based on the U-Net model, and a new loss function is proposed to overcome the segmentation problems. The vascular LA is then calculated using Niblack’s local thresholding method, and the CVI value is finally computed. The experimental results for the segmentation stage with the best-performing model and the proposed loss function were used showed dice coefficients of 0.941 and 0.936 in diabetic retinopathy and pachychoroid spectrum patients, respectively. The unsigned boundary localization errors in the presence of diabetic retinopathy were 0.0020 and 0.0138 pixels for the BM boundary and sclerochoroidal junction, respectively. Similarly, the unsigned errors in the presence of pachychoroid spectrum were 0.0072 and 0.0254 pixels for BM and sclerochoroidal junction. The performance of the proposed method for calculating CVI was evaluated; the Bland-Altman plot indicated acceptable agreement between the values allocated by experts and the proposed method in the presence of diabetic retinopathy and pachychoroid spectrum.

Valence electron spectroscopy of inhomogeneous media

1992 ◽  
Vol 50 (2) ◽  
pp. 1150-1151
Author(s):  
A. Howie ◽  
D.W. McComb
Keyword(s):  
Specific Gravity ◽  
Loss Function ◽  
Electron Spectroscopy ◽  
Valence Electron ◽  
Peak Height ◽  
Loss Functions ◽  
Loss Peak ◽  
High Energies ◽  
Valence Electron Density ◽  
Electron Microscopist

The bulk loss function Im(-l/ε (ω)), a well established tool for the interpretation of valence loss spectra, is being progressively adapted to the wide variety of inhomogeneous samples of interest to the electron microscopist. Proportionality between n, the local valence electron density, and ε-1 (Sellmeyer's equation) has sometimes been assumed but may not be valid even in homogeneous samples. Figs. 1 and 2 show the experimentally measured bulk loss functions for three pure silicates of different specific gravity ρ - quartz (ρ = 2.66), coesite (ρ = 2.93) and a zeolite (ρ = 1.79). Clearly, despite the substantial differences in density, the shift of the prominent loss peak is very small and far less than that predicted by scaling e for quartz with Sellmeyer's equation or even the somewhat smaller shift given by the Clausius-Mossotti (CM) relation which assumes proportionality between n (or ρ in this case) and (ε - 1)/(ε + 2). Both theories overestimate the rise in the peak height for coesite and underestimate the increase at high energies.

Apnea May Ramp Up Diabetic Retinopathy Risk

2011 ◽  
Vol 44 (13) ◽  
pp. 59
Author(s):  
SHERRY BOSCHERT
Keyword(s):  
Diabetic Retinopathy

Abstract # P-13: Characteristics of Korean T2DM Patients with Diabetic Retinopathy and Macular Edema: A Study Based on a Standardized Clinical Data

2016 ◽  
Vol 22 ◽  
pp. 19-20
Author(s):  
Sang Youl Rhee ◽  
Sejeong Park ◽  
Ki Young Kim ◽  
Suk Chon ◽  
Seung-Young Yu ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Macular Edema ◽  
Clinical Data

Use of viscodissection and silicone oil in vitrectomy for severe diabetic retinopathy

2003 ◽  
Vol 18 (3) ◽  
pp. 121-126
Author(s):  
Grigorian R.A. ◽  
Castellarin A. ◽  
Bhagat N. ◽  
Del Priore ◽  
Von Hagen ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Silicone Oil
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