5 research outputs found
Automated fundus image quality assessment and segmentation of optic disc using convolutional neural networks
An automated fundus image analysis is used as a tool for the diagnosis of common retinal diseases. A good quality fundus image results in better diagnosis and hence discarding the degraded fundus images at the time of screening itself provides an opportunity to retake the adequate fundus photographs, which save both time and resources. In this paper, we propose a novel fundus image quality assessment (IQA) model using the convolutional neural network (CNN) based on the quality of optic disc (OD) visibility. We localize the OD by transfer learning with Inception v-3 model. Precise segmentation of OD is done using the GrabCut algorithm. Contour operations are applied to the segmented OD to approximate it to the nearest circle for finding its center and diameter. For training the model, we are using the publicly available fundus databases and a private hospital database. We have attained excellent classification accuracy for fundus IQA on DRIVE, CHASE-DB, and HRF databases. For the OD segmentation, we have experimented our method on DRINS-DB, DRISHTI-GS, and RIM-ONE v.3 databases and compared the results with existing state-of-the-art methods. Our proposed method outperforms existing methods for OD segmentation on Jaccard index and F-score metrics
Dispersion Stabilized Se/Te···π Double Chalcogen Bonding Synthons in in Situ Cryocrystallized Divalent Organochalcogen Liquids
We
report the experimental observation and detailed quantum chemical
analysis of the rare bifurcated type Se···π and
Te···π “double” chalcogen bonded
synthons observed through the in situ cryocrystallization of two room
temperature organochalcogen liquids, namely, diphenylselenide and
diphenyl telluride. The attractive intermolecular interactions between
the heavier chalcogens and π-clouds are primarily stabilized
by the dispersion forces, which is in contrast to many known model
examples in the literature. Electrostatic and orbital delocalization
effects also play a secondary but important role in the overall stabilization,
besides providing directionality to these interactions