scholarly journals Optimizing Single-Shot Coherent Power-Spectrum Scattering Imaging Adaptively by Tuning Feedback Coefficient for Practical Exposure Conditions

2019 ◽  
Vol 9 (18) ◽  
pp. 3676
Author(s):  
Wei Wang ◽  
Yanfang Guo ◽  
Wusheng Tang ◽  
Wenjun Yi ◽  
Mengzhu Li ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Real Time ◽  
Exposure Level ◽  
Single Shot ◽  
Scattering Media ◽  
Diffractive Imaging ◽  
Driving Assistance ◽  
Spectrum Imaging ◽  
Feedback Coefficient ◽  
Exposure Conditions

With only one piece of the power-spectrum pattern, the single-shot coherent power-spectrum imaging can provide a clear object image for real-time applications even if the object is hidden by opaque scattering media, in which the feedback coefficient β value for the reconstruction with least retrievals and fastest speed has to be pre-estimated through time-consuming iterative loops. Here we report a method for estimating the optimal β value from the captured raw power-spectrum images adaptively to optimize the single-shot coherent power-spectrum imaging for practical exposure conditions. The results demonstrate that, based on exposure level analysis of the captured raw power-spectrum images even of underexposure, moderate exposure, and overexposure cases, the β value could be quickly determined with a compact expression for the algorithm to achieve clear reconstruction output efficiently. The proposed method helps to push ahead of the coherent diffractive imaging devices for real-time imaging through turbid mediums in Artificial Intelligence (AI), driving assistance, and flight assistance applications.

Single-shot coherent power-spectrum imaging of objects hidden by opaque scattering media

2019 ◽  
Vol 58 (4) ◽  
pp. 1033 ◽  
Author(s):  
Wusheng Tang ◽  
Jiankun Yang ◽  
Wenjun Yi ◽  
Qianwen Nie ◽  
Jubo Zhu ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Single Shot ◽  
Scattering Media ◽  
Spectrum Imaging

scholarly journals Real-time frequency-encoded spatiotemporal focusing through scattering media using a programmable 2D ultrafine optical frequency comb

2020 ◽  
Vol 6 (8) ◽  
pp. eaay1192 ◽  
Author(s):  
Xiaoming Wei ◽  
Yuecheng Shen ◽  
Joseph C. Jing ◽  
Ashton S. Hemphill ◽  
Changsheng Yang ◽  
...  
Keyword(s):  
Real Time ◽  
Frequency Comb ◽  
Optical Frequency Comb ◽  
Optical Frequency ◽  
Single Shot ◽  
Scattering Media ◽  
Wave Source ◽  
Time Frequency ◽  
Temporal Focusing ◽  
Wavefront Shaping

Optical wavefront shaping is a powerful tool for controlling photons in strongly scattering media. Its speed, however, has been the bottleneck for in vivo applications. Moreover, unlike spatial focusing, temporal focusing from a continuous-wave source has rarely been exploited yet is highly desired for nonlinear photonics. Here, we present a novel real-time frequency-encoded spatiotemporal (FEST) focusing technology. FEST focusing uses a novel programmable two-dimensional optical frequency comb with an ultrafine linewidth to perform single-shot wavefront measurements, with a fast single-pixel detector. This technique enables simultaneous spatial and temporal focusing at microsecond scales through thick dynamic scattering media. This technology also enabled us to discover the large-scale temporal shift, a new phenomenon that, with the conventional spatial memory effect, establishes a space-time duality. FEST focusing opens a new avenue for high-speed wavefront shaping in the field of photonics.

scholarly journals Toward unsupervised single-shot diffractive imaging of heterogeneous particles using X-ray free-electron lasers

2013 ◽  
Vol 21 (23) ◽  
pp. 28729 ◽  
Author(s):  
Hyung Joo Park ◽  
N. Duane Loh ◽  
Raymond G. Sierra ◽  
Christina Y. Hampton ◽  
Dmitri Starodub ◽  
...  
Keyword(s):  
Free Electron ◽  
Single Shot ◽  
Free Electron Lasers ◽  
Diffractive Imaging ◽  
X Ray

scholarly journals Real-time and single shot CMR increases throughput and improves reliability

2012 ◽  
Vol 14 (S1) ◽  
Author(s):  
Abdul Wattar ◽  
Subha V Raman ◽  
Orlando P Simonetti
Keyword(s):  
Real Time ◽  
Single Shot

scholarly journals Real-time switching dynamics of ferroelectric tunnel junctions under single-shot voltage pulses

2018 ◽  
Vol 113 (23) ◽  
pp. 232902 ◽  
Author(s):  
S. Boyn ◽  
A. Chanthbouala ◽  
S. Girod ◽  
C. Carrétéro ◽  
A. Barthélémy ◽  
...  
Keyword(s):  
Real Time ◽  
Tunnel Junctions ◽  
Single Shot ◽  
Time Switching ◽  
Switching Dynamics ◽  
Voltage Pulses

Evaluating fetal head dimension changes during labor using open magnetic resonance imaging

2017 ◽  
Vol 45 (3) ◽  
Author(s):  
Christian Bamberg ◽  
Jan Deprest ◽  
Nikhil Sindhwani ◽  
Ulf Teichgräberg ◽  
Felix Güttler ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Real Time ◽  
Vaginal Delivery ◽  
Single Shot ◽  
Resonance Imaging ◽  
Midsagittal Plane ◽  
Fetal Head ◽  
Second Stage ◽  
Open Magnetic Resonance Imaging

AbstractAim:Fetal skull molding is important for the adaptation of the head to the birth canal during vaginal delivery. Importantly, the fetal head must rotate around the maternal symphysis pubis. The goals of this analysis were to observe a human birth in real-time using an open magnetic resonance imaging (MRI) scanner and describe the fetal head configuration during expulsion.Methods:Real-time cinematic MRI series (TSE single-shot sequence, TR 1600 ms, TE 150 ms) were acquired from the midsagittal plane of the maternal pelvis during the active second stage of labor at 37 weeks of gestation. Frame-by-frame analyses were performed to measure the frontooccipital diameter (FOD) and distance from the vertex to the base of the fetal skull.Results:During vaginal delivery in an occiput anterior position, the initial FOD was 10.3 cm. When expulsion began, the fetal skull was deformed and elongated, with the FOD increasing to 10.8 cm and 11.2 cm at crowning. In contrast, the distance from the vertex to the base of the skull was reduced from 6.4 cm to 5.6 cm at expulsion.Conclusions:Fetal head molding is the change in the fetal head due to the forces of labor. The biomechanics of this process are poorly understood. Our visualization of the normal mechanism of late second-stage labor shows that MRI technology can for the first time help define the changes in the diameters of the fetal head during active labor.

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