Savitzky-Golay filtering for Scattered Signal De-noising

A forward-scatter meter measures a small portion of light scattered out of a light beam into a relatively narrow band of scattering angles. The forward-scatter meter measurement is then used to estimate the extinction coefficient; the scattered signal is assumed to be proportional to the extinction coefficient.

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Investigation of X-band backscattering from wave breaking in a laboratory experiment

10.5194/egusphere-egu21-9084 ◽

2021 ◽

Author(s):

Nikita Rusakov ◽

Georgy Baidakov ◽

Evgeny Poplavsky ◽

Yuliya Troitskaya ◽

Maksim Vdovin

Keyword(s):

Cross Section ◽

Wave Breaking ◽

Spectral Characteristics ◽

Wave Number ◽

Scattered Signal ◽

Channel Cross Section ◽

Frequency Wave ◽

First Case ◽

X Band ◽

Working Section

The work is concerned with the study of the breaking surface wave effect on the intensity and spectral characteristics of a scattered radar signal in laboratory conditions.The experiments were carried out on the reconstructed TSWiWaT wind wave flume of the IAP RAS. The channel is 12 m long, the channel cross-section varies from 0.7 x 0.7 m at the entrance to 0.7 x 0.9 m in the working section at a distance of 9 m. The airflow speed on the axis is 3-35 m/s, which corresponds to the values of the wind speed U10 of 11-50 m/s.The wave characteristics in the flume were measured by an array of three wave gauges positioned in the corners of an equal-side triangle with 2.5 cm side, the data sampling rate was 200 Hz. Such a system gives the opportunity to retrieve 3D frequency-wave number spectra of surface waves.The airflow parameters were measured using the profiling method. The velocity profiles were measured in the working section using an S-shaped Pitot tube. Microwave measurements were carried out using an X-band coherent Doppler scatterometer with a wavelength of 3.2 cm with sequential reception of linear polarizations.&#160; The absolute value of the radar cross-section (RCS) on the wavy water surface was determined by comparing the scattered signal with the signal reflected from the calibrator with a known value of the RCS - a metal ball with a diameter of 6 cm. The dimensions of the observation cross-section were 40 cm x 40 cm, the incidence angles were 30&#176;, 40&#176;, 50&#176; for the upwind direction, the distance to the target was 3.15 m.Two series of experiments were carried out. In the first case, wind waves on the surface of pure deep water, developing under the action of a fan generated wind, were studied. In the second case, a train of three waves was generated at the beginning of the channel, with the fan turned on, in order to simulate shallow water an inclined plate was placed under water in front of the measurement area. As a result, the breaking waves occurred at a fixed point and at weaker winds compared to the first case.As a result, an increase in the scattered signal intensity during artificial wave breaking in the case of weak winds was noted. For strong winds, the effect turned out to be insignificant, despite the increased amplitude of the waves under study. The Doppler spectra analysis is also presented.This work was supported by the RFBR projects No. 19-05-00249, 19-05-00366. &#160;

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Atmospheric CO2 measurements with a 2-μm DIAL instrument

EPJ Web of Conferences ◽

10.1051/epjconf/201817605045 ◽

2018 ◽

Vol 176 ◽

pp. 05045 ◽

Cited By ~ 1

Author(s):

Erwan Cadiou ◽

Jean-Baptiste Dherbecourt ◽

Guillaume Gorju ◽

Jean-Michel Melkonian ◽

Antoine Godard ◽

...

Keyword(s):

Carbon Dioxide ◽

Long Range ◽

Direct Detection ◽

Atmospheric Co2 ◽

Scattered Signal ◽

Differential Absorption ◽

Differential Absorption Lidar ◽

Atmospheric Concentration ◽

Concentration Measurements ◽

Parametric Source

We report on ground-based atmospheric concentration measurements of carbon dioxide, using a pulsed direct detection differential absorption lidar operating at 2051 nm. The transmitter is based on a tunable parametric source emitting 10-mJ energy, 10-ns duration Fourier-limited pulses. Range resolved concentration measurements have been carried out on the aerosol back-scattered signal. Cloud signals have been used to get long range integrated-path measurements.

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Time-frequency analysis of the scattered signal from chipless RFID tags

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) ◽

10.1109/usnc-ursi-nrsm.2014.6927945 ◽

2014 ◽

Cited By ~ 2

Author(s):

Reza Rezaiesarlak ◽

Majid Manteghi

Keyword(s):

Frequency Analysis ◽

Scattered Signal ◽

Rfid Tags ◽

Time Frequency Analysis ◽

Time Frequency ◽

Chipless Rfid

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Numerical analysis of back scattered signal in infrared optical fibers

10.1117/12.637011 ◽

1992 ◽

Author(s):

Mandavilli M. Rao ◽

Chenniappan Ravichandran ◽

P. Mythili

Keyword(s):

Numerical Analysis ◽

Optical Fibers ◽

Scattered Signal

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Fabrication of Multimode-Single Mode Polymer Fiber Tweezers for Single Cell Trapping and Identification with Improved Performance

Sensors ◽

10.3390/s18092746 ◽

2018 ◽

Vol 18 (9) ◽

pp. 2746 ◽

Cited By ~ 4

Author(s):

Sandra Rodrigues ◽

Joana Paiva ◽

Rita Ribeiro ◽

Olivier Soppera ◽

João Cunha ◽

...

Keyword(s):

Single Mode ◽

Single Mode Fiber ◽

Physical Contact ◽

Scattered Signal ◽

Fabrication Method ◽

Cell Trapping ◽

Low Degree ◽

Single Cell Trapping ◽

Improved Performance ◽

Multi Mode

Optical fiber tweezers have been gaining prominence in several applications in Biology and Medicine. Due to their outstanding focusing abilities, they are able to trap and manipulate microparticles, including cells, needing any physical contact and with a low degree of invasiveness to the trapped cell. Recently, we proposed a fiber tweezer configuration based on a polymeric micro-lens on the top of a single mode fiber, obtained by a self-guided photopolymerization process. This configuration is able to both trap and identify the target through the analysis of short-term portions of the back-scattered signal. In this paper, we propose a variant of this fabrication method, capable of producing more robust fiber tips, which produce stronger trapping effects on targets by as much as two to ten fold. These novel lenses maintain the capability of distinguish the different classes of trapped particles based on the back-scattered signal. This novel fabrication method consists in the introduction of a multi mode fiber section on the tip of a single mode (SM) fiber. A detailed description of how relevant fabrication parameters such as the length of the multi mode section and the photopolymerization laser power can be tuned for different purposes (e.g., microparticles trapping only, simultaneous trapping and sensing) is also provided, based on both experimental and theoretical evidences.

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The influence of reflection coefficient statistics on the seismic method: scattering and the minimum detectable reflection coefficient

Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences ◽

10.1098/rspa.1993.0013 ◽

1993 ◽

Vol 440 (1909) ◽

pp. 221-240 ◽

Cited By ~ 1

Keyword(s):

Reflection Coefficient ◽

Seismic Reflection ◽

Target Strength ◽

Scattered Signal ◽

Reflection Coefficients ◽

Signal To Noise ◽

Statistical Parameters ◽

Conservation Of Energy ◽

Scattered Energy ◽

Short Period

Propagation of seismic reflection energy through layered media is discussed in terms of one-dimensional elastic scattering and the effect of a layered overburden on the detectability of the underlying target horizons is investigated. In a previous paper, using Walden & Hosken’s statistical models of real reflection series, Q -like attenuation laws were derived for the two-way transmission. Considerable use was made of the O’Doherty and Anstey relation between the amplitude spectrum of the two-way transmission and the energy spectrum of the reflection coefficients. With reference to the seismic reflection bandwidth, in general the equivalent Q is seen to increase with frequency, except over an intermediate band of frequencies where it often decreases with frequency. Also, the minimum phase wavelet predicted by the theory was shown to model adequately the first pulse of the two-way transmission waveform, carrying the greater part of the energy, and the lag of the first peak was approximately described in terms of the statistical parameters of the reflection coefficients in the overburden. The spectrum of the back-scattered energy can be determined from the conservation of energy into and out of the overburden and is seen to be complementary to the forward scattered signal and thus it can also be described in term s of the Walden and Hosken statistical parameters. The back-scattered energy can be divided into two components: (i) the primary reflections from within the overburden together with their associated short period multiples and (ii) the long period internal multiple noise which may arrive at the same time as the reflections from the underlying target horizons, obscuring them . The ratio of forward-scattered signal to back-scattered noise is a function of frequency and travel time through the overburden and it sets a fundamental signal-to-noise ratio for the section. An approximate expression is derived for the signal-to-noise peak power ratio which we use to determine both a natural cut-off frequency above which the noise dominates over signal from a given target strength, and α min , the minimum reflection coefficient detectable below the overburden. α min is seen to depend on the statistical properties of the overburden and can usually be decreased by decreasing the high and low-cut frequencies of the seismic bandwidth. There is thus a trade-off between detectability level and resolution.

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