Theoretical Analysis of the Signal-to-Noise Ratio of Two-Photon Oxygen Imaging Probes

Introduction: Two-photon microscopy is the ideal tool to study how signals are processed in the functional brain tissue. However, early raster scanning strategies were inadequate to record fast 3D events like action potentials. Aim: The aim of the authors was to record various neuronal activity patterns with high signal-to-noise ratio in an optical manner. Method: Authors developed new data acquisition methods and microscope hardware. Results: Multiple Line Scanning enables the experimenter to select multiple regions of interests, doing this not just increases repetition speed, but also the signal-to-noise ratio of the fluorescence transients. On the same principle, an acousto-optical deflector based 3D scanning microscope has been developed with a sub-millisecond temporal resolution and a millimeter z-scanning range. Its usability is demonstrated by obtaining 3D optical recordings of action potential backpropagation in several hundred micrometers long neuronal processes of single neurons and by 3D random-access scanning of Ca2+ transients in hundreds of neurons in the mouse visual cortex. Conclusions: Region of interest scanning enables high signal-to-noise ratio and repetition speed, while keeping good depth penetration of the two-photon microscopes. Orv. Hetil., 2015, 156(52), 2120–2126.

Download Full-text

Novel Implementation of Audio Encryption Using Pseudorandom Byte Generator

Applied Sciences ◽

10.3390/app112110190 ◽

2021 ◽

Vol 11 (21) ◽

pp. 10190

Author(s):

Borislav Stoyanov ◽

Tsvetelina Ivanova

Keyword(s):

Theoretical Analysis ◽

Chaos Theory ◽

Signal To Noise Ratio ◽

Mathematical Function ◽

Signal To Noise ◽

Change Rate ◽

Different Types ◽

Audio Encryption ◽

Noise Ratio ◽

Audio Files

In this paper, we present an algorithm for encrypting audio files based on the Ikeda map, a mathematical function of chaos theory. Detailed experimental, security and theoretical analysis is provided on the proposed algorithm using histogram analysis, using different measurements including the signal-to-noise ratio, the peak signal-to-noise ratio, the number of samples change rate and the correlation coefficient. The provided results show a highly secure and strong algorithm against different types of attacks.

Download Full-text

Red-Emitting Mitochondrial Probe with Ultrahigh Signal-to-Noise Ratio Enables High-Fidelity Fluorescent Images in Two-Photon Microscopy

Analytical Chemistry ◽

10.1021/acs.analchem.5b02807 ◽

2015 ◽

Vol 87 (24) ◽

pp. 12088-12095 ◽

Cited By ~ 58

Author(s):

Ge Zhang ◽

Yuming Sun ◽

Xiuquan He ◽

Weijia Zhang ◽

Minggang Tian ◽

...

Keyword(s):

Signal To Noise Ratio ◽

High Fidelity ◽

Signal To Noise ◽

Two Photon Microscopy ◽

Two Photon ◽

Noise Ratio

Download Full-text

Determination of the Best Emulsion for the Microscopy of Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096886 ◽

1981 ◽

Vol 39 ◽

pp. 32-33

Author(s):

David A. Grano ◽

Kenneth H. Downing

Keyword(s):

Spatial Frequency ◽

Information Transfer ◽

Signal To Noise Ratio ◽

Experimental Situation ◽

Photographic Emulsion ◽

Modulation Transfer ◽

Signal To Noise ◽

Frequency Space ◽

Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Download Full-text

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097703 ◽

1981 ◽

Vol 39 ◽

pp. 226-227

Author(s):

W. Kunath ◽

K. Weiss ◽

E. Zeitler

Keyword(s):

Signal To Noise Ratio ◽

Carbon Support ◽

Electronic System ◽

Optic Axis ◽

Hollow Cone ◽

Signal To Noise ◽

Bright Field ◽

Noise Ratio ◽

Single Field ◽

Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

Download Full-text

Information capacity and bandwidth limitations in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152392 ◽

1989 ◽

Vol 47 ◽

pp. 84-85

Author(s):

D. C. Joy ◽

R. D. Bunn

Keyword(s):

Signal To Noise Ratio ◽

Critical Dimension ◽

Information Capacity ◽

Acquisition Time ◽

Signal To Noise ◽

Sem Image ◽

Probe Size ◽

Minimum Number ◽

Noise Ratio ◽

Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

Download Full-text

Speech Reception in the Presence of Classroom Noise

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.1004.221 ◽

1979 ◽

Vol 10 (4) ◽

pp. 221-230 ◽

Cited By ~ 2

Author(s):

Veronica Smyth

Keyword(s):

Signal To Noise Ratio ◽

Learning Processes ◽

Speech Discrimination ◽

Signal To Noise ◽

Speech Reception ◽

Monosyllabic Words ◽

Noise Ratio

Three hundred children from five to 12 years of age were required to discriminate simple, familiar, monosyllabic words under two conditions: 1) quiet, and 2) in the presence of background classroom noise. Of the sample, 45.3% made errors in speech discrimination in the presence of background classroom noise. The effect was most marked in children younger than seven years six months. The results are discussed considering the signal-to-noise ratio and the possible effects of unwanted classroom noise on learning processes.

Download Full-text

Quantifying the Effects of Background Speech Babble on Preschool Children's Novel Word Learning in a Multisession Paradigm: A Preliminary Study

Journal of Speech Language and Hearing Research ◽

10.1044/2019_jslhr-h-19-0083 ◽

2020 ◽

Vol 63 (1) ◽

pp. 345-356

Author(s):

Meital Avivi-Reich ◽

Megan Y. Roberts ◽

Tina M. Grieco-Calub

Keyword(s):

Word Learning ◽

Signal To Noise Ratio ◽

Preschool Age ◽

Exposure Condition ◽

Signal To Noise ◽

Verbal Recall ◽

Referent Selection ◽

Main Effect ◽

Noise Ratio ◽

Novel Word Learning

Purpose This study tested the effects of background speech babble on novel word learning in preschool children with a multisession paradigm. Method Eight 3-year-old children were exposed to a total of 8 novel word–object pairs across 2 story books presented digitally. Each story contained 4 novel consonant–vowel–consonant nonwords. Children were exposed to both stories, one in quiet and one in the presence of 4-talker babble presented at 0-dB signal-to-noise ratio. After each story, children's learning was tested with a referent selection task and a verbal recall (naming) task. Children were exposed to and tested on the novel word–object pairs on 5 separate days within a 2-week span. Results A significant main effect of session was found for both referent selection and verbal recall. There was also a significant main effect of exposure condition on referent selection performance, with more referents correctly selected for word–object pairs that were presented in quiet compared to pairs presented in speech babble. Finally, children's verbal recall of novel words was statistically better than baseline performance (i.e., 0%) on Sessions 3–5 for words exposed in quiet, but only on Session 5 for words exposed in speech babble. Conclusions These findings suggest that background speech babble at 0-dB signal-to-noise ratio disrupts novel word learning in preschool-age children. As a result, children may need more time and more exposures of a novel word before they can recognize or verbally recall it.

Download Full-text