Article
Optics
Chendong Gao, Minglin Zhao, Fuyang Cao, Zhaoyang Wang, Dehe Lu, Youyou Hu, Jiantai Dou, Jun Dai
Summary: Previous polarization imaging methods have focused less on targets with nonuniform polarization characteristics and require background areas or prior knowledge, limiting their practical application in underwater polarization imaging. In this paper, a new underwater polarization de-scattering method is proposed that can automatically distinguish the polarization characteristics of underwater targets without the need for background areas or prior information. Experimental results demonstrate that this method effectively improves the quality of underwater images.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Haopeng Xue, Ronghua Li, Yongfeng Zhao, Yuan Deng
Summary: Based on the principle of polarization imaging, a split-focus plane polarization imaging system is developed, and an image clarity method is proposed. Compared with traditional light intensity imaging detection methods, it is easier to detect metal targets from sediment backgrounds in underwater low-visibility scenes.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Marine
Di Wu, Lanyue Zhang, Jia Wang, Xueru Hu
Summary: In this work, a method based on high-order particle velocity gradient polarization characteristics is proposed to distinguish the presence of coherent interference, which is necessary as it affects the estimation of the desired target. The characteristics of the high-order particle velocity gradient, including ellipse ratio and inclination angles, are chosen as effective detection features because they remain unchanged for the desired target but change for coherent signals when there is coherent interference. Both simulation and experimental results validate the proposed detection method.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Physics, Applied
Haofeng Hu, Pengfei Qi, Xiaobo Li, Zhenzhou Cheng, Tiegen Liu
Summary: This paper proposes an effective method for enhancing underwater image quality using histogram processing and polarization filter, which can simultaneously improve contrast and reduce color distortion.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Optics
Feng Zhao, Rusi Lu, Xiangning Chen, Chunqi Jin, Sai Chen, Zicheng Shen, Cheng Zhang, Yuanmu Yang
Summary: This study introduces a compact polarization imaging apparatus that uses a multifunctional planar dielectric metalens to capture two orthogonally polarized images of an underwater scene simultaneously, demonstrating large enhancement of image contrast and real-time depth estimation of target objects.
LASER & PHOTONICS REVIEWS
(2021)
Article
Optics
Haofeng Hu, Yilin Han, Xiaobo Li, Liubing Jiang, Li Che, Tiegen Liu, Jingsheng Zhai
Summary: This paper proposes an effective solution combining polarimetric physical model and deep neural network for suppressing scattered light and restoring target signals in underwater imaging. Experimental results demonstrate that this method improves image quality and outperforms other existing methods, even in high turbidity conditions.
Article
Optics
Joy Singh, Sudhanshu Kumar Jha, Vimlesh Singh, Y. K. Awasthi
Summary: This paper discusses the design of a passive low pass filter operating in the terahertz spectrum, constructed from optimized split-ring resonators (SRR) and achieving satisfactory performance with low insertion loss and adequate bandwidth. The innovation lies in enhancing the passive LPF by individually adding a unit cell of SRR to the filter design.
Article
Nanoscience & Nanotechnology
Rubing Li, Yueyun Weng, Siyuan Lin, Chao Wei, Liye Mei, Shubin Wei, Yifan Yao, Fuling Zhou, Du Wang, Keisuke Goda, Cheng Lei
Summary: Optical time-stretch imaging (OTS) has advantages in high-throughput cell screening, but is limited by data transmission and storage pressure. This study proposes all-optical Fourier-domain-compressed time-stretch imaging with low-pass filtering to simplify the system structure and improve signal-to-noise ratio and image quality.
Article
Optics
Adrian Tomasov, Petr Dejdar, Petr Munster, Tomas Horvath, Peter Barcik, Francesco Da Ros
Summary: The paper discusses the security of fiber-optic cable infrastructures through vibration detection using an optical polarization analyzer. The developed system can detect various security breaches without classifying them. It relies on a machine-learning model to analyze optical polarization differences caused by mechanical or acoustic vibrations for real-time anomaly detection. The experiments aim to find the best combination of normalization method and anomaly detector. The proposed system achieves an F1-score over 95.65%, demonstrating its suitability for protecting fiber-optic infrastructures.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Optics
Jian Liang, Liyong Ren, Rongguang Liang
Summary: The polarimetric dehazing method shows promise in enhancing image quality in scattering media, but is sensitive to noise, requiring digital image processing algorithms for stability. A novel method utilizing a low pass filter was proposed in this paper to effectively handle dense haze.
Article
Engineering, Electrical & Electronic
Yuanzhi Zhao, Wenjun He, Hang Ren, Yuhui Zhang, Yuegang Fu
Summary: In this work, we propose a method that uses the polar decomposition technique to estimate the Mueller matrix of a target and calculate the illumination light with globally varying polarization state to overcome the limitations of traditional polarization imaging techniques and suppress noise. The descattering imaging experiments demonstrate that the images recovered by our method show similarity to targets without scattering, and the noise is effectively suppressed. Furthermore, the superiority of our proposed method is proven by comparing with other polarization underwater imaging strategies.
IEEE PHOTONICS JOURNAL
(2022)
Article
Optics
Ali P. Vafa, Parisa Karimi, Amin Khavasi
Summary: The optical high-pass filters introduced in this study utilize total internal reflection and multilayer reflection to enhance resolution for edge detection applications. An optimization algorithm is used to adjust the thickness of layers in the multilayer structure for better approximation of an ideal high-pass filter. These compact and lithography-free devices operate in both 1D and 2D modes, demonstrating edge detection capabilities without the need for a Fourier lens.
OPTICS COMMUNICATIONS
(2021)
Article
Optics
Xizhen Zhang, Mengqi Lin, Lizhu Guo, Yuhang Zhang, Chuanhui Cheng, Jiashi Sun, Yi Cheng, Yongze Cao, Sai Xu, Xiangping Li, Jinsu Zhang, Baojiu Chen
Summary: Perovskite CsPbBr3 quantum dots glass is suitable for long-wavelength pass filter applications, with different preparation conditions resulting in variations in transmittance, transition wavelength, and optical density.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
M. M. Ariannejad, Jian Ding Tan, Chia Chao Kang, M. Ghasemi, S. M. Hamidi, P. K. Choudhury
Summary: Silicon photonic square-layout ring resonator-based circuits were designed to control the stop-band and pass-band filtering of transmission spectrum. The presence of a master MZI and multiple rings improved the filtering quality and created a larger pass-band. Without the master MZI, a narrow stop-band was observed, but with a two-ring configuration, the width of the stop-band increased. The optical response of the combined circuit resulted in a single pass-band with a flat-hat lobe.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Computer Science, Information Systems
Saurabh Agarwal, Ki-Hyun Jung
Summary: This paper proposes a novel scheme to detect the use of low-pass filters in image processing. A convolutional neural network is designed to identify different types of low-pass filters, and the learning experiences of three solvers are combined to enhance the detection ability. Global pooling layers and a new global variance pooling layer are employed to improve detection accuracy. Features extracted from the network are mapped to the frequency domain to enrich the feature set. The proposed scheme achieves high detection accuracy on small images compressed with JPEG.
