scholarly journals Single-shot wide-field topography measurement using spectrally multiplexed reflection intensity holography via space-domain Kramers–Kronig relations

2022 ◽  
Author(s):  
Chungha Lee ◽  
YoonSeok Baek ◽  
Herve Hugonnet ◽  
YongKeun Park
Keyword(s):  
Wide Field ◽  
Single Shot ◽  
Space Domain ◽  
Reflection Intensity

scholarly journals High-dynamic-range imaging for cloud segmentation

2018 ◽  
Vol 11 (4) ◽  
pp. 2041-2049 ◽  
Author(s):  
Soumyabrata Dev ◽  
Florian M. Savoy ◽  
Yee Hui Lee ◽  
Stefan Winkler
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Wide Field ◽  
Single Shot ◽  
Generation Process ◽  
Image Generation ◽  
Large Dynamic Range ◽  
Exposure Fusion ◽  
Wide Field Of View ◽  
High Dynamic

Abstract. Sky–cloud images obtained from ground-based sky cameras are usually captured using a fisheye lens with a wide field of view. However, the sky exhibits a large dynamic range in terms of luminance, more than a conventional camera can capture. It is thus difficult to capture the details of an entire scene with a regular camera in a single shot. In most cases, the circumsolar region is overexposed, and the regions near the horizon are underexposed. This renders cloud segmentation for such images difficult. In this paper, we propose HDRCloudSeg – an effective method for cloud segmentation using high-dynamic-range (HDR) imaging based on multi-exposure fusion. We describe the HDR image generation process and release a new database to the community for benchmarking. Our proposed approach is the first using HDR radiance maps for cloud segmentation and achieves very good results.

scholarly journals High-Dynamic-Range Imaging for Cloud Segmentation

2017 ◽  
Author(s):  
Soumyabrata Dev ◽  
Florian M. Savoy ◽  
Yee Hui Lee ◽  
Stefan Winkler
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Wide Field ◽  
Single Shot ◽  
Generation Process ◽  
Large Dynamic Range ◽  
Exposure Fusion ◽  
Wide Field Of View ◽  
High Dynamic ◽  
Fish Eye

Abstract. Sky/cloud images obtained from ground-based sky-cameras are usually captured using a fish-eye lens with a wide field of view. However, the sky exhibits a large dynamic range in terms of luminance, more than a conventional camera can capture. It is thus difficult to capture the details of an entire scene with a regular camera in a single shot. In most cases, the circumsolar region is over-exposed, and the regions near the horizon are under-exposed. This renders cloud segmentation for such images difficult. In this paper, we propose HDRSeg – an effective method for cloud segmentation using High-Dynamic-Range (HDR) imaging based on multi-exposure fusion. We describe the HDR generation process and release a new database to the community for benchmarking. Our proposed approach is the first using HDR images for cloud segmentation and achieves very good results.

CHARACTERISTICS OF A LOW F-NUMBER BROADBAND VISIBLE THERMAL OPTICAL LIMITER

1993 ◽  
Vol 02 (04) ◽  
pp. 577-611 ◽  
Author(s):  
G.A. SWARTZLANDER ◽  
B.L. JUSTUS ◽  
A.L. HUSTON ◽  
A.J. CAMPILLO ◽  
C.T. LAW
Keyword(s):  
Dielectric Breakdown ◽  
Threshold Energy ◽  
Exposure Level ◽  
Wide Field ◽  
Single Shot ◽  
Design Strategies ◽  
Optical Limiter ◽  
Rayleigh Length ◽  
Wide Field Of View ◽  
A Cell

The operation of a wide field-of-view optical limiter is described for self-defocusing type nonlinear refractive materials, and design strategies were developed with the aid of numerical modeling. Experiments with a cell thickness on the order of the Rayleigh length (25–100 µm) were conducted with 6 and 30 nsec pulse lengths (single shot) at a wavelength of 532 nm. Broadband optical limiting with the transmitted fluence below the eye MPE (maximum permissible exposure) level was achieved using nigrosin dye dissolved in CS 2, owing to the large thermal nonlinearity of the solvent, and the large changes in the refractive index allowed by a liquid. The device performance was accurately predicted by the numerical model up to the point of dielectric breakdown. Using 6 nsec pulses, we measured a limiting threshold energy of 40 nJ, which corresponds to a fluence of only 100 mJ/cm 2 in the solution, in an f/5 optical system with neutral gray transmission of ~ 50%.

A wide-field arrangement for single-shot CARS imaging of living cells

2012 ◽  
Vol 43 (5) ◽  
pp. 644-650 ◽  
Author(s):  
A. Silve ◽  
N. Dorval ◽  
T. Schmid ◽  
L.M. Mir ◽  
B. Attal-Tretout
Keyword(s):  
Living Cells ◽  
Wide Field ◽  
Single Shot ◽  
Cars Imaging

scholarly journals Fast wide-field upconversion luminescence lifetime thermometry enabled by single-shot compressed ultrahigh-speed imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xianglei Liu ◽  
Artiom Skripka ◽  
Yingming Lai ◽  
Cheng Jiang ◽  
Jingdan Liu ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Wide Field ◽  
Single Shot ◽  
Temperature Mapping ◽  
Optical Instruments ◽  
Lifetime Imaging ◽  
Alternating Direction ◽  
Optical Thermometry ◽  
Photoluminescence Lifetime ◽  
Intensity Decay

AbstractPhotoluminescence lifetime imaging of upconverting nanoparticles is increasingly featured in recent progress in optical thermometry. Despite remarkable advances in photoluminescent temperature indicators, existing optical instruments lack the ability of wide-field photoluminescence lifetime imaging in real time, thus falling short in dynamic temperature mapping. Here, we report video-rate upconversion temperature sensing in wide field using single-shot photoluminescence lifetime imaging thermometry (SPLIT). Developed from a compressed-sensing ultrahigh-speed imaging paradigm, SPLIT first records wide-field luminescence intensity decay compressively in two views in a single exposure. Then, an algorithm, built upon the plug-and-play alternating direction method of multipliers, is used to reconstruct the video, from which the extracted lifetime distribution is converted to a temperature map. Using the core/shell NaGdF4:Er3+,Yb3+/NaGdF4 upconverting nanoparticles as the lifetime-based temperature indicators, we apply SPLIT in longitudinal wide-field temperature monitoring beneath a thin scattering medium. SPLIT also enables video-rate temperature mapping of a moving biological sample at single-cell resolution.

scholarly journals Intelligent Image-Based Railway Inspection System Using Deep Learning-Based Object Detection and Weber Contrast-Based Image Comparison

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4738 ◽  
Author(s):  
Jinbeum Jang ◽  
Minwoo Shin ◽  
Sohee Lim ◽  
Jonggook Park ◽  
Joungyeon Kim ◽  
...  
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Inspection System ◽  
Wide Field ◽  
Single Shot ◽  
Image Comparison ◽  
Line Scan ◽  
Region Detection ◽  
Sustainable Operation ◽  
Railway Infrastructure

For sustainable operation and maintenance of urban railway infrastructure, intelligent visual inspection of the railway infrastructure attracts increasing attention to avoid unreliable, manual observation by humans at night, while trains do not operate. Although various automatic approaches were proposed using image processing and computer vision techniques, most of them are focused only on railway tracks. In this paper, we present a novel railway inspection system using facility detection based on deep convolutional neural network and computer vision-based image comparison approach. The proposed system aims to automatically detect wears and cracks by comparing a pair of corresponding image sets acquired at different times. We installed line scan camera on the roof of the train. Unlike an area-based camera, the line scan camera quickly acquires images with a wide field of view. The proposed system consists of three main modules: (i) image reconstruction for registration of facility positions, (ii) facility detection using an improved single shot detector, and (iii) deformed region detection using image processing and computer vision techniques. In experiments, we demonstrate that the proposed system accurately finds facilities and detects their potential defects. For that reason, the proposed system can provide various advantages such as cost reduction for maintenance and accident prevention.

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