Summary
The joint time‐frequency representation (TFR) provides the useful hidden information of a nonstationary signal consisting of several components. The time‐frequency analysis methods with high resolution are of utmost importance in visual localization and recognition of nonstationary waveform in power quality (PQ) disturbance signals. This paper introduces a newly developed TFR technique known as synchroextracting transform (SET) for the detection and identification of various kinds of single and combined nonstationary PQ disturbances. The SET is a high‐resolution TFR technique that belongs to a post‐processing procedure of short‐time Fourier transform (STFT) incorporating components of mode decomposition and signal reconstruction. The SET aims to retain the TF information related to time‐varying features of the signal and removes most smeared TF energy. In the case studies considered here, several PQ disturbance signals are thoroughly analyzed by using SET.
Glaucoma is a chronic and irreversible eye disease that leads to the loss of vision. Evaluation of the Cup to Disc Ratio (CDR) plays a prominent role in the early detection of glaucoma. This paper presents a novel algorithm to compute the CDR for the fundus images. In order to calculate the CDR, the vertical diameter of Optic Disc (OD) and the vertical diameter of the Optic Cup (OC) are calculated from the segmented OD and segmented OC, respectively. This study presents OD and OC segmentation algorithms based on a new statistics‐based kurtosis test. A unique OC boundary segmentation method is presented, which is the combination of partial cup extraction and the cup boundary under the Central Retinal Blood vessels (CRBV). A novel preprocessing technique is introduced to extract the CRBV from the automated Region of Interest (ROI). The experimental results confirm that the proposed algorithm outperforms the state‐of‐art OD and OC segmentation on the three publicly available datasets: ORIGA, DIARETDB0, and DIARETDB1. The proposed OD and OC segmentation achieve accuracies of up to 0.99 and 0.97, respectively. In addition, the proposed model achieves excellent CDR evaluation with an average error percentage reduced to up to 9.6496 for the considered datasets.
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