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Imaging below the diffraction limit is always a public interest because of the restricted resolution of conventional imaging systems. To beat the limit, evanescent harmonics decaying in space must participate in the imaging process. Here,…

Optics · Physics 2019-10-02 Tie-Jun Huang , Li-Zheng Yin , Ya Shuang , Jiang-Yu Liu , Yunhua Tan , Pu-Kun Liu

Synthetic aperture radar (SAR) is a tomographic sensor that measures 2D slices of the 3D spatial Fourier transform of the scene. In many operational scenarios, the measured set of 2D slices does not fill the 3D space in the Fourier domain,…

Signal Processing · Electrical Eng. & Systems 2026-02-20 Nithin Sugavanam , Emre Ertin

A densely-sampled light field (LF) is highly desirable in various applications, such as 3-D reconstruction, post-capture refocusing and virtual reality. However, it is costly to acquire such data. Although many computational methods have…

Image and Video Processing · Electrical Eng. & Systems 2020-09-29 Jing Jin , Junhui Hou , Jie Chen , Huanqiang Zeng , Sam Kwong , Jingyi Yu

We demonstrate numerical refocusing in coherent confocal laser scanning microscopy based on synthetic optical holography. This physics-based approach implements a computational propagation on the complex signal recovered in synthetic…

Scattering scanning near-field optical microscopy enables optical imaging and characterization of plasmonic devices with nanometer-scale resolution well below the diffraction limit. This technique enables developers to probe and understand…

A Synthetic Aperture Microwave Imaging (SAMI) system has been designed and built to obtain 2-D images at several frequencies from fusion plasmas. SAMI uses a phased array of linearly polarised antennas. The array configuration has been…

Plasma Physics · Physics 2012-10-12 Vladimir F. Shevchenko , Roddy G. L. Vann , Simon J. Freethy , Billy K. Huang

Synthetic Aperture Radar (SAR) provides all-weather, high-resolution imaging capabilities, but its unique imaging mechanism often requires expert interpretation, limiting its widespread applicability. Translating SAR images into more easily…

Computer Vision and Pattern Recognition · Computer Science 2024-07-09 Xinyu Bai , Feng Xu

This paper proposes a non-computational method of counteracting the effect of image degradation introduced by the diffraction phenomenon in lensless microscopy. All the optical images (whether focused by lenses or not) are diffraction…

Optics · Physics 2021-04-08 Sanjeev Kumar , Manjunatha Mahadevappa , Pranab Kumar Dutta

We have developed a new on-axis digital holographic technique, heterodyne holography. The resolution of this technique is limited mainly by the amount of data recorded on two-dimensional photodetectors, i.e., the number of pixels and their…

Optics · Physics 2011-12-26 Frédérique Le Clerc , Michel Gross , Laurent Collot

Optical microscopy has so far been restricted to superficial layers, leaving many important biological questions unanswered. Random scattering causes the ballistic focus, which is conventionally used for image formation, to decay…

Optics · Physics 2012-08-28 Ke Si , Reto Fiolka , Meng Cui

Benefiting from a relatively larger aperture's angle, and in combination with a wide transmitting bandwidth, near-field synthetic aperture radar (SAR) provides a high-resolution image of a target's scattering distribution-hot spots.…

Image and Video Processing · Electrical Eng. & Systems 2022-11-29 Xu Zhan , Xiaoling Zhang , Wensi Zhang , Jun Shi , Shunjun Wei , Tianjiao Zeng

Synthetic aperture radar (SAR) is a day or night any-weather imaging modality that is an important tool in remote sensing. Most existing SAR image formation methods result in a maximum a posteriori image which approximates the reflectivity…

Applications · Statistics 2020-07-14 Victor Churchill , Anne Gelb

Synthetic aperture sonar (SAS) image resolution is constrained by waveform bandwidth and array geometry. Specifically, the waveform bandwidth determines a point spread function (PSF) that blurs the locations of point scatterers in the…

Computer Vision and Pattern Recognition · Computer Science 2021-12-17 Albert Reed , Thomas Blanford , Daniel C. Brown , Suren Jayasuriya

Recent extended reality headsets and field robots have adopted covers to protect the front-facing cameras from environmental hazards and falls. The surface irregularities on the cover can lead to optical aberrations like blurring and…

Computer Vision and Pattern Recognition · Computer Science 2024-11-12 Liuyue Xie , Jiancong Guo , Laszlo A. Jeni , Zhiheng Jia , Mingyang Li , Yunwen Zhou , Chao Guo

We consider imaging the reflectivity of scatterers from intensity-only data recorded by a single moving transducer that both emits and receives signals, forming a synthetic aperture. By exploiting frequency illumination diversity, we obtain…

Computational Physics · Physics 2019-05-15 Miguel Moscoso , Alexei Novikov , George Papanicolaou , Chrysoula Tsogka

We propose an approach to far-field optical imaging beyond the diffraction limit. The proposed system allows image magnification, is robust with respect to material losses and can be fabricated by adapting existing metamaterial technologies…

Optics · Physics 2009-11-13 Zubin Jacob , Leonid V. Alekseyev , Evgenii Narimanov

This thesis is concerned with problems related to Synthetic Aperture Radar (SAR). The thesis is structured as follows: The first chapter explains what SAR is, and the physical and mathematical background is illuminated. The following…

Classical Analysis and ODEs · Mathematics 2010-10-26 Jens Klein

Although several optical techniques have been recently developed in order to overcome the resolution limit in microscopy, the imaging of sub-wavelength features is still a real challenge. In practise, super-resolution techniques remain…

Physics Education · Physics 2019-07-24 Stephane Perrin , Keshia Badu , Paul Montgomery , Sylvain Lecler

We report a novel microscopy platform, termed Multi-Aperture Fourier ptychographic microscopy (MA-FPM), capable of realizing gigapixel complex field images with large data acquisition bandwidths - in gigapixels per second. MA-FPM is a…

Optics · Physics 2020-10-14 Pavan Chandra Konda , Jonathan M. Taylor , Andrew R. Harvey

On-chip optical trapping systems allow for high scalability and lower the barrier to access. Systems capable of trapping multiple particles typically come with high cost and complexity. Here we present a technique for making parabolic…