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226 results on '"Guan, Yanan"'

12. Ship Wake Detection in a Single SAR Image via a Modified Low-Rank Constraint.

Author

Guan, Yanan, Xu, Huaping, Li, Wei, and Li, Chunsheng

Subjects
*WAKES (Fluid dynamics), *DECOMPOSITION method, *FALSE alarms, *IMAGE intensifiers, *RADON
Abstract

Ship wake detection stands as a pivotal task in marine environment monitoring. The main challenge in ship wake detection is to improve detection accuracy and mitigate false alarms. To address this challenge, a novel procedure for ship wake detection in a single SAR image is proposed in this study. Initially, an entropy distance similarity criterion is designed to measure nonlocal image patch similarity. Based on the proposed criterion, a low-rank and sparse decomposition method is modified using nonlocal similar patch matrix construction to separate the sparse wake. Subsequently, a field-of-experts (FOE) model is introduced to generate a series of multi-view wake feature maps, which are fused to construct an enhanced feature map. The sparse wake is further enhanced in the Radon domain with the enhanced feature map. The experimental results demonstrate the effectiveness of the proposed method on real SAR ship wake images. [ABSTRACT FROM AUTHOR]

Published
2024
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40. A False-Alarm-Controllable Modified AdaBoost Wake Detection Method Using SAR Images

Author

Guan, Yanan, Xu, Huaping, Liu, Wei, Li, Chunsheng, and Liu, Yuheng

Abstract

A false-alarm-controllable modified AdaBoost-based method is proposed for detecting ship wake from sea clutter in synthetic aperture radar (SAR) images. It reformulates the wake detection problem as a binary classification task in the multifeature space. The update strategy of the sample weights in the original AdaBoost is modified for wake detection. First, a detection result confidence factor is designed to deal with class imbalance between sea clutter and ship wake; then, the AdaBoost is further modified as a false alarm rate (FAR) controllable detector by introducing penalty parameters to adjust weights update strategies for the sea clutter. Meanwhile, the multifeature space is spanned by a novel frequency peak height ratio (FPHA) feature and four salient features. FPHA is proposed to enhance the separation between the wake and sea clutter, which is computed from the amplitude spectrum peak of the image after the Fourier transform. Experimental results show that the proposed detector can tackle the imbalanced data problem and flexibly control FAR by adjusting penalty parameters. Moreover, improved detection probability is also achieved compared with existing methods.

Published
2023
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41. Cascade Fluorescent Determination of Mercury (II) and Captopril Using Tungsten-Nitrogen Doped Carbon Dots.

Author

Guan, Yanan, Zu, Yueyue, Ma, Pengyi, Li, Shutao, Ma, Qi, Song, Jinping, and Guo, Yong

Subjects
*CAPTOPRIL, *DOPING agents (Chemistry), *TUNGSTEN, *SURFACE morphology, *DETECTION limit, *MERCURY
Abstract

Tungsten and nitrogen co-doped carbon dots (W, N-CDs) with a high quantum yield of 51.08% were synthesized by a facile hydrothermal process. Doping of tungsten effectively enhanced luminescent properties of the carbon dots, and the quantum yield was increased by 10.3%. The surface composition and morphology of the synthesized W, N-CDs were characterized. W, N-CDs were employed as nanoprobes to develop a sensor for the selective and sensitive determination of Hg2+ and captopril. Under the optimal conditions, the linear response range for Hg2+ and captopril were 0.125 to 9.0 μM and 0.5 to 10 μM with detection limits of 40 nM and 300 nM, respectively. The developed sensor was successfully applied for the determination of Hg2+ in water and captopril in urine with recoveries from 95.50 to 105.50% and 96.33 to 105.13%, which demonstrates suitable accuracy and reliability. The fluorescence mechanisms of W, N-CDs toward Hg2+ and captopril were also evaluated. [ABSTRACT FROM AUTHOR]

Published
2023
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