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[IEEE 2018 IEEE 18th International Power Electronics and Motion Control Conference (PEMC) - Budapest, Hungary (2018.8.26-2018.8.30)] 2018 IEEE 18th International Power Electronics and Motion Control Conference (PEMC) - Novel Segmentation Algorithm for Maximum Power Point Tracking in PV Systems Under Partial Shading Conditions
摘要： The paper proposes new MPPT Segmentation method for partial shading conditions. The proposed method is based on principle of division of the power-voltage curve into uniform segments and location of global maximum power point inside the chosen segment. In order to validate the algorithm, it was tested under different shading condition and with different PV systems. The simulation results show that the Segmentation algorithm precisely identifies the highest MPP on the power-voltage curve. The Segmentation algorithm was compared with standard P&O and also with other MPPT algorithms for partial shading conditions. This comparison showed that Segmentation algorithm provides better results and insures higher output power of the PV system than standard P&O and also with other MPPT algorithms. Simulation results also show that Segmentation algorithm works faster than P&O.
关键词： Segmentation algorithm,power-voltage curve,partial shading conditions,PV systems,MPPT
更新于2025-09-23 15:21:01
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An Improved Fuzzy Connectedness Method for Automatic Three-Dimensional Liver Vessel Segmentation in CT Images
摘要： In this paper, an improved fuzzy connectedness (FC) method was proposed for automatic three-dimensional (3D) liver vessel segmentation in computed tomography (CT) images. The vessel-enhanced image (i.e., vesselness image) was incorporated into the fuzzy a?nity function of FC, rather than the intensity image used by traditional FC. An improved vesselness ?lter was proposed by incorporating adaptive sigmoid ?ltering and a background-suppressing item. The fuzzy scene of FC was automatically initialized by using the Otsu segmentation algorithm and one single seed generated adaptively, while traditional FC required multiple seeds. The improved FC method was evaluated on 40 cases of clinical CT volumetric images from the 3Dircadb (n ? 20) and Sliver07 (n ? 20) datasets. Experimental results showed that the proposed liver vessel segmentation strategy could achieve better segmentation performance than traditional FC, region growing, and threshold level set. Average accuracy, sensitivity, speci?city, and Dice coe?cient of the improved FC method were, respectively, (96.4 ± 1.1)%, (73.7 ± 7.6)%, (97.4 ± 1.3)%, and (67.3 ± 5.7)% for the 3Dircadb dataset and (96.8 ± 0.6)%, (89.1 ± 6.8)%, (97.6 ± 1.1)%, and (71.4 ± 7.6)% for the Sliver07 dataset. It was concluded that the improved FC may be used as a new method for automatic 3D segmentation of liver vessel from CT images.
关键词： vesselness filter,fuzzy connectedness,CT images,liver vessel segmentation,Otsu segmentation algorithm
更新于2025-09-10 09:29:36
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Comparison of Reliability in Diabetic Macular Edema Estimates between Two Image Analysis Algorithms
摘要： Purpose: To evaluate segmentation reliability in diabetic macular edema (DME) estimates between a CirrusTM HD-OCT image analysis algorithm and an Iowa reference algorithm, which are an automatic segmentation software. Methods: Thirty eyes from 23 patients diagnosed with DME were included and underwent spectral-domain optical coherence scans (CirrusTM HD-OCT). Central foveal thickness (CFT) and ganglion cell layer-inner plexiform layer segmentation data were compared with those produced by the CirrusTM HD-OCT segmentation algorithm and Iowa reference algorithm. Measurement agreement was assessed using intraclass correlation (ICC) and segmentation errors were confirmed by 2 ophthalmologists. Results: The mean CFT in the 1-mm central area determined by the manufacturer-supplied Cirrus software and Iowa reference algorithm was 512.07 ± 182.35 μm and 476.53 ± 32.36 μm, respectively (p < 0.05). The mean paired difference was 35.53 ± 92.46 μm (ICC, 0.929). Segmentation errors were demonstrated in eyes with a CFT less than 400 μm, specifically for 45% of scans obtained by the Cirrus algorithm and 9% from the Iowa algorithm; in eyes with a CFT equal to or higher than 400 μm, the error rates were 95% and 42%, respectively. Conclusions: CFT measurement in eyes with diabetic macular edema using the Cirrus algorithm and Iowa algorithm showed relatively high degrees of agreement and significant correlation. In eyes with a CFT equal to or higher than 400 μm, the Iowa algorithm showed higher reliability in retinal segmentation than the Cirrus algorithm.
关键词： Reliability,Segmentation algorithm,Diabetic macular edema,Optical coherence tomography,Central foveal thickness
更新于2025-09-10 09:29:36