Three‐dimensional microvascular network reconstruction from in vivo images with adaptation of the regional inhomogeneity in the signal‐to‐noise ratio

Owls use interaural time differences (ITDs) to locate a sound source. They compute ITD in a specialized neural circuit that consists of axonal delay lines from the cochlear nucleus magnocellularis (NM) and coincidence detectors in the nucleus laminaris (NL). Recent physiological recordings have shown that tonal stimuli induce oscillatory membrane potentials in NL neurons (Funabiki K, Ashida G, Konishi M. J Neurosci 31: 15245–15256, 2011). The amplitude of these oscillations varies with ITD and is strongly correlated to the firing rate. The oscillation, termed the sound analog potential, has the same frequency as the stimulus tone and is presumed to originate from phase-locked synaptic inputs from NM fibers. To investigate how these oscillatory membrane potentials are generated, we applied recently developed signal-to-noise ratio (SNR) analysis techniques (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274–2290, 2010) to the intracellular waveforms obtained in vivo. Our theoretical prediction of the band-limited SNRs agreed with experimental data for mid- to high-frequency (>2 kHz) NL neurons. For low-frequency (≤2 kHz) NL neurons, however, measured SNRs were lower than theoretical predictions. These results suggest that the number of independent NM fibers converging onto each NL neuron and/or the population-averaged degree of phase-locking of the NM fibers could be significantly smaller in the low-frequency NL region than estimated for higher best-frequency NL.

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A new method for ultrasonic detection of peel ply at the bondline of out-of-autoclave composite assemblies

Journal of Composite Materials ◽

10.1177/0021998318781887 ◽

2018 ◽

Vol 53 (2) ◽

pp. 245-259

Author(s):

Gary S LeMay ◽

Davood Askari

Keyword(s):

Signal To Noise Ratio ◽

Three Dimensional ◽

Ultrasonic Pulse ◽

Woven Fabric ◽

Material System ◽

Signal To Noise ◽

Structural Applications ◽

Peel Ply ◽

Noise Ratio ◽

Out Of Autoclave

Out-of-autoclave materials have long been an established material system for secondary structural applications; however, recent advancements in material properties allow for more advanced structural applications. Even though certain out-of-autoclave properties have achieved parity with autoclaved cured materials, out-of-autoclave materials are cured at reduced temperatures and pressures resulting in less compaction and homogeneity. The consequence is extraneous ultrasonic signals, due to internal reflections and refractions that cause attenuation, potentially masking defects leading to unidentifiable indications. Advanced algorithms were developed to improve the signal to noise ratio between constituents of similar acoustic impedance in bonded out-of-autoclave carbon fiber reinforced polymer assemblies. Conventional ultrasonic nondestructive testing techniques and analysis software cannot consistently achieve signal to noise ratios that meet quantifiable rejection thresholds of accurately sized peel ply inserts at the bonded interface of composite assemblies. Ultrasonic pulse echo with full waveform capture was used to inspect a reference standard with peel ply inserts placed between the adhesive and three-dimensional-woven fabric preform. The ultrasonic signal was produced by a 64 element array transducer with a central frequency of 2.8 MHz. Waveform post-acquisition analysis with post processing software was used to analyze and enhance the signal response between the peel ply and the bondline resulting in the final algorithm. To verify the results, the signal to noise ratio of each insert was calculated for both the raw and processed data. As the measure of detectability, the method relies on principles of statistical measurement to provide an industry standard signal to noise response of 3:1.

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Three-Dimensional Imaging via Time-Correlated Single-Photon Counting

Applied Sciences ◽

10.3390/app10061930 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1930

Author(s):

Chengkun Fu ◽

Huaibin Zheng ◽

Gao Wang ◽

Yu Zhou ◽

Hui Chen ◽

...

Keyword(s):

3D Imaging ◽

Single Photon ◽

Signal To Noise Ratio ◽

Photon Counting ◽

Three Dimensional ◽

Similarity Index ◽

Signal To Noise ◽

Single Photon Counting ◽

Imaging Results ◽

Noise Ratio

Three-dimensional (3D) imaging under the condition of weak light and low signal-to-noise ratio is a challenging task. In this paper, a 3D imaging scheme based on time-correlated single-photon counting technology is proposed and demonstrated. The 3D imaging scheme, which is composed of a pulsed laser, a scanning mirror, single-photon detectors, and a time-correlated single-photon counting module, employs time-correlated single-photon counting technology for 3D LiDAR (Light Detection and Ranging). Aided by the range-gated technology, experiments show that the proposed scheme can image the object when the signal-to-noise ratio is decreased to −13 dB and improve the structural similarity index of imaging results by 10 times. Then we prove the proposed scheme can image the object in three dimensions with a lateral imaging resolution of 512 × 512 and an axial resolution of 4.2 mm in 6.7 s. At last, a high-resolution 3D reconstruction of an object is also achieved by using the photometric stereo algorithm.

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Sequential average segmented microscopy for high signal-to-noise ratio motion-artifact-free in vivo heart imaging

Biomedical Optics Express ◽

10.1364/boe.4.002095 ◽

2013 ◽

Vol 4 (10) ◽

pp. 2095 ◽

Cited By ~ 12

Author(s):

Claudio Vinegoni ◽

Sungon Lee ◽

Paolo Fumene Feruglio ◽

Pasquina Marzola ◽

Matthias Nahrendorf ◽

...

Keyword(s):

Signal To Noise Ratio ◽

Motion Artifact ◽

High Signal ◽

Signal To Noise ◽

Heart Imaging ◽

Noise Ratio

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Three-Dimensional Optical Bit Memory in Sm(DBM)3Phen-Doped and Un-Doped Poly(methyl methacrylate)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.284-286.2251 ◽

2011 ◽

Vol 284-286 ◽

pp. 2251-2254

Author(s):

Zhao Gang Nie ◽

Xin Zhong Li ◽

Yu Ping Tai ◽

Ki Soo Lim ◽

Myeongkyu Lee

Keyword(s):

Refractive Index ◽

Methyl Methacrylate ◽

Signal To Noise Ratio ◽

Three Dimensional ◽

Pulsed Laser ◽

High Signal ◽

Signal To Noise ◽

Fluorescent Signal ◽

Poly Methyl Methacrylate ◽

Noise Ratio

The feasibility of three-dimensional optical bit memory is demonstrated by using the change of fluorescence and refractive index in Sm(DBM)3Phen-doped and un-doped Poly(methyl methacrylate). After a femtosecond pulsed laser irradiation, a refractive-index bit and a fluorescent bit can be formed at the same position inside the bulk sample. Multilayer patterns recorded by tightly focusing the pulsed laser beam were read out by a reflection-type fluorescent confocal microscope, which can detect the reflection signal and also the fluorescent signal of the stored bits. The signal-to-noise ratio via the two retrieval modes was compared as a function of recording depth. The stored bits were retrieved with a high signal-to-noise ratio in the absence of any crosstalk and the detection of the fluorescent signal enables retrieval of the stored bits with a higher S/N ratio.

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Self-Reset Image Sensor With a Signal-to-Noise Ratio Over 70 dB and Its Application to Brain Surface Imaging

Frontiers in Neuroscience ◽

10.3389/fnins.2021.667932 ◽

2021 ◽

Vol 15 ◽

Author(s):

Thanet Pakpuwadon ◽

Kiyotaka Sasagawa ◽

Mark Christian Guinto ◽

Yasumi Ohta ◽

Makito Haruta ◽

...

Keyword(s):

Neural Activity ◽

Signal To Noise Ratio ◽

Image Sensor ◽

Oxide Semiconductor ◽

High Signal ◽

Unstable State ◽

Signal To Noise ◽

Compact Size ◽

Noise Ratio

In this study, we propose a complementary-metal-oxide-semiconductor (CMOS) image sensor with a self-resetting system demonstrating a high signal-to-noise ratio (SNR) to detect small intrinsic signals such as a hemodynamic reaction or neural activity in a mouse brain. The photodiode structure was modified from N-well/P-sub to P+/N-well/P-sub to increase the photodiode capacitance to reduce the number of self-resets required to decrease the unstable stage. Moreover, our new relay board was used for the first time. As a result, an effective SNR of over 70 dB was achieved within the same pixel size and fill factor. The unstable state was drastically reduced. Thus, we will be able to detect neural activity. With its compact size, this device has significant potential to become an intrinsic signal detector in freely moving animals. We also demonstrated in vivo imaging with image processing by removing additional noise from the self-reset operation.

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Artifacts by Misalignment of Cardiac Magnetic Resonance Phased-array Coil Elements: From Simulation to In vivo Test

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405613666171024150250 ◽

2019 ◽

Vol 15 (3) ◽

pp. 301-307

Author(s):

Daniele De Marchi ◽

Alessandra Flori ◽

Nicola Martini ◽

Giulio Giovannetti

Keyword(s):

Cardiac Magnetic Resonance ◽

Magnetic Resonance ◽

Phased Array ◽

Signal To Noise Ratio ◽

Whole Body ◽

Signal To Noise ◽

Phased Array Coil ◽

Noise Ratio ◽

Array Coil

Background: Cardiac magnetic resonance evaluations generally require a radiofrequency coil setup comprising a transmit whole-body coil and a receive coil. In particular, radiofrequency phased-array coils are employed to pick up the signals emitted by the nuclei with high signal-tonoise ratio and a large region of sensitivity. Methods: Literature discussed different technical issues on how to minimize interactions between array elements and how to combine data from such elements to yield optimum Signal-to-Noise Ratio images. However, image quality strongly depends upon the correct coil position over the heart and of one array coil portion with respect to the other. Results: In particular, simple errors in coil positioning could cause artifacts carrying to an inaccurate interpretation of cardiac magnetic resonance images. Conclusion: This paper describes the effect of array elements misalignment, starting from coil simulation to cardiac magnetic resonance acquisitions with a 1.5 T scanner. </P><P> Phased-array coil simulation was performed using the magnetostatic approach; moreover, phantom and in vivo experiments with a commercial 8-elements cardiac phased-array receiver coil permitted to estimate signal-to-noise ratio and B1 mapping for aligned and shifted coil.

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Development and Characterization of an Electrocochleography-Guided Robotics-Assisted Cochlear Implant Array Insertion System

Otolaryngology ◽

10.1177/01945998211049210 ◽

2021 ◽

pp. 019459982110492

Author(s):

Allan M. Henslee ◽

Christopher R. Kaufmann ◽

Matt D. Andrick ◽

Parker T. Reineke ◽

Viral D. Tejani ◽

...

Keyword(s):

Cochlear Implant ◽

Real Time ◽

Signal To Noise Ratio ◽

Electrode Array ◽

High Signal ◽

Animal Testing ◽

Signal To Noise ◽

Noise Ratio ◽

Hearing Outcomes

Objective Electrocochleography (ECochG) is increasingly being used during cochlear implant (CI) surgery to detect and mitigate insertion-related intracochlear trauma, where a drop in ECochG signal has been shown to correlate with a decline in hearing outcomes. In this study, an ECochG-guided robotics-assisted CI insertion system was developed and characterized that provides controlled and consistent electrode array insertions while monitoring and adapting to real-time ECochG signals. Study Design Experimental research. Setting A research laboratory and animal testing facility. Methods A proof-of-concept benchtop study evaluated the ability of the system to detect simulated ECochG signal changes and robotically adapt the insertion. Additionally, the ECochG-guided insertion system was evaluated in a pilot in vivo sheep study to characterize the signal-to-noise ratio and amplitude of ECochG recordings during robotics-assisted insertions. The system comprises an electrode array insertion drive unit, an extracochlear recording electrode module, and a control console that interfaces with both components and the surgeon. Results The system exhibited a microvolt signal resolution and a response time <100 milliseconds after signal change detection, indicating that the system can detect changes and respond faster than a human. Additionally, animal results demonstrated that the system was capable of recording ECochG signals with a high signal-to-noise ratio and sufficient amplitude. Conclusion An ECochG-guided robotics-assisted CI insertion system can detect real-time drops in ECochG signals during electrode array insertions and immediately alter the insertion motion. The system may provide a surgeon the means to monitor and reduce CI insertion–related trauma beyond manual insertion techniques for improved CI hearing outcomes.

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