Near-infrared fundus imaging system with light illumination from an electronic contact lens

2022 ◽  
Vol 15 (2) ◽  
pp. 027001
Author(s):  
Yang Cui ◽  
Taiki Takamatsu ◽  
Koichi Shimizu ◽  
Takeo Miyake
Keyword(s):  
Contact Lens ◽  
Near Infrared ◽  
Imaging System ◽  
Low Cost ◽  
Light Illumination ◽  
Fundus Images ◽  
Fundus Imaging ◽  
Point Spread ◽  
Spread Function ◽  
Dependent Point

Abstract As for the diagnosis and treatment of eye diseases, an ideal fundus imaging system is expected to be portability, low cost, and high resolution. Here, we demonstrate a non-mydriatic near-infrared fundus imaging system with light illumination from an electronic contact lens (E-lens). The E-lens can illuminate the retinal and choroidal structures for capturing the fundus images when voltage is applied wirelessly to the lens. And we also reconstruct the images with a depth-dependent point-spread function to suppress the scattering effect that eventually visualizes the clear fundus images.

Measurement of the Point Spread Function of a Photoacoustic Imaging System using Step Method

2013 ◽  
Vol 33 (4) ◽  
pp. 0411002
Author(s):  
周红仙 Zhou Hongxian ◽  
周有平 Zhou Youping ◽  
王毅 Wang Yi
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Photoacoustic Imaging ◽  
Step Method ◽  
Point Spread ◽  
Spread Function

Point Spread Function Model of Grating Imaging System Based on Boltzmann Function Edge Fitting

2020 ◽  
Vol 40 (14) ◽  
pp. 1405003
Author(s):  
卢泉 Lu Quan ◽  
张泽昊 Zhang Zehao ◽  
张卫平 Zhang Weiping ◽  
刘诣荣 Liu Yirong
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Function Model ◽  
Point Spread ◽  
Boltzmann Function ◽  
Spread Function

Point Spread Function of Pinhole Imaging System for Deviating from Center of Incident γ-Ray

2015 ◽  
Vol 44 (3) ◽  
pp. 311004
Author(s):  
马庆力 MA Qing-li ◽  
唐世彪 TANG Shi-biao ◽  
吴彦华 WU Yan-hua
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Point Spread ◽  
Spread Function ◽  
Pinhole Imaging ◽  
Γ Ray

scholarly journals Estimation of Ultrasound Echogenicity Map from B-Mode Images Using Convolutional Neural Network

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4931
Author(s):  
Che-Chou Shen ◽  
Jui-En Yang
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Imaging System ◽  
Speckle Pattern ◽  
Image Resolution ◽  
Post Processing ◽  
Point Spread ◽  
Spread Function ◽  
In Silico Simulation ◽  
Tissue Structures

In ultrasound B-mode imaging, speckle noises decrease the accuracy of estimation of tissue echogenicity of imaged targets from the amplitude of the echo signals. In addition, since the granular size of the speckle pattern is affected by the point spread function (PSF) of the imaging system, the resolution of B-mode image remains limited, and the boundaries of tissue structures often become blurred. This study proposed a convolutional neural network (CNN) to remove speckle noises together with improvement of image spatial resolution to reconstruct ultrasound tissue echogenicity map. The CNN model is trained using in silico simulation dataset and tested with experimentally acquired images. Results indicate that the proposed CNN method can effectively eliminate the speckle noises in the background of the B-mode images while retaining the contours and edges of the tissue structures. The contrast and the contrast-to-noise ratio of the reconstructed echogenicity map increased from 0.22/2.72 to 0.33/44.14, and the lateral and axial resolutions also improved from 5.9/2.4 to 2.9/2.0, respectively. Compared with other post-processing filtering methods, the proposed CNN method provides better approximation to the original tissue echogenicity by completely removing speckle noises and improving the image resolution together with the capability for real-time implementation.

scholarly journals Companion Detection Limits with Adaptive Optics Coronagraphy

2004 ◽  
Vol 202 ◽  
pp. 99-102
Author(s):  
B. R. Oppenheimer ◽  
R. G. Dekany ◽  
M. Troy ◽  
T. Hayward ◽  
B. Brandl
Keyword(s):  
Adaptive Optics ◽  
Focal Plane ◽  
Near Infrared ◽  
Dynamic Range ◽  
Infrared Camera ◽  
Nearby Star ◽  
Point Spread ◽  
Spread Function ◽  
Adaptive Optics System ◽  
Circular Disks

We present a study of the Palomar Adaptive Optics System and the PHARO near infrared camera in coronagraphic mode. The camera provides two different focal plane occulting masks–opaque circular disks 0.43 and 0.97″ across. Three different pupil plane apodizing masks (Lyot masks) are also provided. The six different combinations of Lyot mask and focal plane mask suppress differently the point spread function of a bright star centered on the focal plane mask. We obtained images of the bright nearby star Gliese 614 with all six different configurations in the K filter. We measured the dynamic range achievable with these configurations. Within 2.5″, the dynamic range is at least 8 magnitudes at the 5σ level and as high as 12 in a 1 s exposure. This represents a substantial gain over similar techniques without adaptive optics.

scholarly journals Ultrabroadband Absorption Enhancement via Hybridization of Localized and Propagating Surface Plasmons

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1625
Author(s):  
Tian Sang ◽  
Honglong Qi ◽  
Xun Wang ◽  
Xin Yin ◽  
Guoqing Li ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Near Infrared ◽  
Low Cost ◽  
Polarized Light ◽  
Wavelength Region ◽  
Transverse Magnetic ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Geometrical Parameters ◽  
Light Illumination

Broadband metamaterial absorbers (MAs) are critical for applications of photonic and optoelectronic devices. Despite long-standing efforts on broadband MAs, it has been challenging to achieve ultrabroadband absorption with high absorptivity and omnidirectional characteristics within a comparatively simple and low-cost architecture. Here we design, fabricate, and characterize a novel compact Cr-based MA to achieve ultrabroadband absorption in the visible to near-infrared wavelength region. The Cr-based MA consists of Cr nanorods and Cr substrate sandwiched by three pairs of SiO2/Cr stacks. Both simulated and experimental results show that an average absorption over 93.7% can be achieved in the range of 400–1000 nm. Specifically, the ultrabroadband features result from the co-excitations of localized surface plasmon (LSP) and propagating surface plasmon (PSP) and their synergistic absorption effects, where absorption in the shorter and longer wavelengths are mainly contributed bythe LSP and PSP modes, respectively. The Cr-based MA is very robust to variations of the geometrical parameters, and angle-and polarization-insensitive absorption can be operated well over a large range of anglesunder both transverse magnetic(TM)- and transverse electric (TE)-polarized light illumination.

Effect of point spread function position bias in wavefront coding infrared imaging system

2020 ◽  
Vol 22 (2) ◽  
pp. 025703
Author(s):  
Bin Feng ◽  
Zelin Shi ◽  
Haizheng Liu ◽  
Yaohong Zhao ◽  
Jianlei Zhang
Keyword(s):  
Point Spread Function ◽  
Infrared Imaging ◽  
Imaging System ◽  
Position Bias ◽  
Point Spread ◽  
Infrared Imaging System ◽  
Wavefront Coding ◽  
Spread Function

scholarly journals Deep point spread function photometric catalog of the VVV survey data

2019 ◽  
Vol 632 ◽  
pp. A85
Author(s):  
M. Zhang ◽  
J. Kainulainen
Keyword(s):  
Point Spread Function ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Galactic Plane ◽  
High Reliability ◽  
Point Spread ◽  
Deep Point ◽  
Spread Function ◽  
Local Crowding ◽  
Source Number

Context. The Vista Variables in the Vía Láctea (VVV) survey has performed a multi-epoch near-infrared imaging of the inner Galactic plane. High-fidelity photometric catalogs are needed to utilize the data. Aims. We aim at producing a deep, point spread function (PSF) photometric catalog for the VVV survey J-,H-, and Ks-band data. Specifically, we aim to take advantage of multiple epochs of the survey to reach high limiting magnitudes. Methods. We developed an automatic PSF-fitting pipeline based on the DaoPHOT algorithm and performed photometry on the stacked VVV images in J,  H, and Ks bands. Results. We present a PSF photometric catalog in the Vega system that contains about 926 million sources in the J,  H, and Ks filters. About 10% of the sources are flagged as possible spurious detections. The 5σ limiting magnitudes of the sources with high reliability are about 20.8, 19.5, and 18.7 mag in the J,  H, and Ks bands, respectively, depending on the local crowding condition. Our photometric catalog reaches on average about one magnitude deeper than the previously released PSF DoPHOT photometric catalog and includes less spurious detections. There are significant differences in the brightnesses of faint sources between our catalog and the previously released one. The likely origin of these differences is in the different photometric algorithms that are used; it is not straightforward to assess which catalog is more accurate in different situations. Our new catalog is beneficial especially for science goals that require high limiting magnitudes; our catalog reaches such high magnitudes in fields that have a relatively uniform source number density. Overall, the limiting magnitudes and completeness are different in fields with different crowding conditions.

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