Signal-to-noise Ratio Analysis Research Articles

SNR Analysis for Quantitative Comparison of Line Detection Methods

The need for line detection in images is growing rapidly due to its importance in many image processing applications. The selection of an appropriate line detection method is essential for accurate detection of line pixels, but few studies provide an analytical basis for selecting a specific line detection method. In this study, to solve the problem, a method to analytically determine the signal-to-noise ratio (SNR) of line detection methods is proposed. Three line detection methods were selected for comparison: edge-detection (ED)-based, second derivative (SD)-based, and the sum of gradient angle differences (SGAD)-based line detection methods. Then, this study quantifies the SNR of the three line detectors through error propagation and signal noise coupling. In addition, the derived SNRs are graphically visualized to explicitly compare the performance of line detectors. Then, the quantified SNRs were validated by showing that they are highly correlated with the completeness and correctness observed in the experiment with a set of natural images. The experimental results show that the proposed SNR analysis can be used to select or design a suitable line detector.

Quantitative analysis of diffusion-weighted imaging and signal-to-noise ratio on the efficacy of albendazole liposome in the treatment of cerebral alveolar echinococcosis

OBJECTIVE: To investigate the feasibility of diffusion-weighted imaging (DWI) and signal-to-noise ratio (SNR) of lesions in evaluating the efficacy of albendazole liposomes in the treatment of cerebral alveolar echinococcosis (CAE). MATERIALS AND METHODS: Sixteen patients with CAE who met the inclusion criteria from April 2017 to December 2020 were enrolled. All patients underwent routine magnetic resonance sequence examination and DWI examination. The b-value were 1000 s/mm2 and 3000 s/mm2. The apparent diffusion coefficient (ADC) value and SNR of lesions before and after treatment were compared. The data of each group were statistically analyzed by Wilcoxon signed-rank sum test. RESULTS: After 1 year of treatment with albendazole liposomes, the SNR of lesions on T2WI sequence increased. There was a significant difference between the SNR of the same lesion before and after follow-up (P < 0.05). The ADC values of lesion parenchyma and edema area before and after treatment were compared. The difference between them was statistically significant in the both b values (ADC of parenchyma, P < 0.05; ADC of edema area, P < 0.001). Through binary linear classification, it was found that under the same b value, the effect of drugs on the edema area was more obvious than that on the parenchyma area; under different b values, the higher the b value, the higher the ability to evaluate the curative effect of drug therapy. CONCLUSION: Albendazole liposome is effective in the treatment of CAE, and long-term imaging follow-up of patients with CAE treated with albendazole liposome is necessary. When the change in conventional images is inapparent, the quantitative analysis of ADC value and SNR of lesions on T2WI can provide an objective basis for the evaluation of the curative effect of drug treatment in CAE.

BER performance study for optical OFDM of optical camera communication

In this article, different forms of optical orthogonal frequency division multiplexing (OFDM) were observed which were suitable for optical camera communication (OCC) systems. This research aims to establish the bit error rate (BER) versus signal-to-noise ratio (SNR) of the OCC system. This research will focus on OCC systems and the design that produces the noise of the clipping but will gain SNR as a whole if an optimum clipping factor is chosen. The BER versus SNR analysis was investigated for the different clipping factors 0.7, 1.4, and 2.6. The BER performance of the asymmetrically clipped optical OFDM (ACO-OFDM) was also compared with the direct current optical OFDM (DCO-OFDM) to show the suitable effectiveness of the proposed approach. ACO-OFDM was considered to be better due to lower bit loading, but DCO-OFDM was efficient for higher SNR values. This was because the DC bias used was inefficient in terms of optical capacity, while ACO-OFDM used only half of the subcarriers to transmit the information. Moreover, ACO-OFDM two-dimensional half-subcarriers of mapping rule would introduce the clipping noise to its unused 2D subcarriers, although further data can be provided by the 2D DCO-OFDM mapping rule.

Study of the effect of preparation parameters on thermal conductivity of metal oxide nanofluids using Taguchi method

The optimization of process parameters of the nanofluid preparation process for maximum stability and high heat transfer is an active and important area of research. In this work, the effect of the surfactant material, surfactant weight, and ultrasonication time are studied on distilled water-based CuO, Fe3O4, and CuO+Fe3O4 nanofluids. Taguchi L9 orthogonal array was used for the design of the experiment and 9 samples were prepared using this array. The effect of each level of process parameter on the thermal conductivity is analyzed by calculating Signal to Noise Ratio (SNR) and optimum levels of these parameters are identified. The crucial role of stability in delivering high thermal conductivity nanofluids as predicted by SNR analysis is further confirmed using Analysis of Variance (ANOVA).

Identification of Most Influential Parameters for Interactive Communication using DOE Technique

Multimedia applications and platforms are widely being accepted in industry, business and academia as an alternative to classical communication equipment and techniques. Applications and platforms like distance learning, video conferencing, instant messaging, on-demand entertainment and group collaborations are the general usage areas. Advancement in the multimedia industry evolved around the development of infrastructure for delivery and algorithms for content compression. Though, end to end quality is not only affected by such factors. Customer Premises Equipment (CPE) and their particular configurations also play a vital role in the customer’s perceived quality i.e. Quality of Experience (QoE). An effort was required to identify the most influential parameters affecting an interactive communication application. Experiments conducted using Design of Experiment (DOE) technique which helped in the sensitivity analysis. In this study, three parameters Resolution Limit (RL), Scaling Factor (SF) and Frames per Seconds (FPS) were identified from the literature. The experiment was conducted in a controlled environment as per the L9 orthogonal array. Correlation and Fleiss Kappa were used for data validation whereas Signal to Noise Ratio (SNR) analysis was performed to identify the most influential parameter. SNR analysis helped us conclude that FPS is the most influential parameter that affects video quality at the CPE.

A standard system phantom for magnetic resonance imaging.

PurposeA standard MRI system phantom has been designed and fabricated to assess scanner performance, stability, comparability and assess the accuracy of quantitative relaxation time imaging. The phantom is unique in having traceability to the International System of Units, a high level of precision, and monitoring by a national metrology institute. Here, we describe the phantom design, construction, imaging protocols, and measurement of geometric distortion, resolution, slice profile, signal‐to‐noise ratio (SNR), proton‐spin relaxation times, image uniformity and proton density.MethodsThe system phantom, designed by the International Society of Magnetic Resonance in Medicine ad hoc committee on Standards for Quantitative MR, is a 200 mm spherical structure that contains a 57‐element fiducial array; two relaxation time arrays; a proton density/SNR array; resolution and slice‐profile insets. Standard imaging protocols are presented, which provide rapid assessment of geometric distortion, image uniformity, T 1 and T 2 mapping, image resolution, slice profile, and SNR.ResultsFiducial array analysis gives assessment of intrinsic geometric distortions, which can vary considerably between scanners and correction techniques. This analysis also measures scanner/coil image uniformity, spatial calibration accuracy, and local volume distortion. An advanced resolution analysis gives both scanner and protocol contributions. SNR analysis gives both temporal and spatial contributions.ConclusionsA standard system phantom is useful for characterization of scanner performance, monitoring a scanner over time, and to compare different scanners. This type of calibration structure is useful for quality assurance, benchmarking quantitative MRI protocols, and to transition MRI from a qualitative imaging technique to a precise metrology with documented accuracy and uncertainty.

A Satellite Synthetic Aperture Radar Concept Using P-Band Signals of Opportunity

The spaceborne aperture radar (SAR) technique based on a combination of P -band signals of opportunity (SoOp) reflectometry with a sparse array of receivers at low earth orbits (LEOs) and transmit signals from the United States Navy's Mobile User Objective System operating on a geosynchronous altitude has been analyzed. The design focuses on the forward-looking geometry near the specular direction, which allows a high surface reflectivity, in order to obtain adequate signal-to-noise ratio (SNR) with a moderate receiving antenna gain. The sparse array is utilized to sharpen the across-track resolution and reduce the iso-range ambiguity. The formulation for match filtering and illustrations of point target response are presented. This work shows that an array of five to seven receivers is able to achieve an across-track resolution of about 200 m in the outer portion of swath and about 1 km in the center part of swath. The along-track resolution can reach 10 m or better due to the feasibility of a long dwell time for Doppler filtering. We find that the sparse array allows the reduction of the iso-range ambiguity to a level of lower than 5% for a major portion of swath, ∼70% or greater depending on the number of receivers and spacing. We have completed an SNR formulation, which can consistently account for both coherent and incoherent scattering regardless the spatial resolution. An analysis of SNR based on the Kirchhoff approximation for rough surface scattering has been performed. We find that it is possible to obtain a swath width of 100 km with an SNR of 5 dB or better for a constellation of seven satellites with a receiving antenna directivity of 15 dBi at a LEO altitude of 675 km for a wide range of surface roughness. Our study suggests the promise of the SoOpSAR concept for high-resolution remote sensing of land surfaces.

A Magnetic Resonance-Guided Focused Ultrasound Neuromodulation System With a Whole Brain Coil Array for Nonhuman Primates at 3 T.

The phased-array radio frequency (RF) coil plays a vital role in magnetic resonance-guided focused ultrasound (MRgFUS) neuromodulation studies, where accurate brain functional stimulations and neural circuit observations are required. Although various designs of phased-array coils have been reported, few are suitable for ultrasound stimulations. In this study, an MRgFUS neuromodulation system comprised of a whole brain coverage non-human primate (NHP) RF coil and an MRI-compatible ultrasound device was developed. When compared to a single loop coil, the NHP coil provided up to a 50% increase in the signal-to-noise ratio (SNR) in the brain and acquired better anatomical image-quality. The NHP coil also demonstrated the ability to achieve higher spatial resolution and reduce distortion in echo-planer imaging (EPI). Ultrasound beam characteristics and transcranial magnetic resonance acoustic radiation force (MR-ARF) were measured for simulated positions, and calculated B0 maps were employed to establish MRI-compatibility. The differences between focused off and on ultrasound techniques were measured using SNR, g-factors, and temporal SNR (tSNR) analyses and all deviations were under 2.3%. The EPI images quality and stable tSNR demonstrated the suitability of the MRgFUS neuromodulation system to conduct functional MRI studies. Last, the time course of the blood oxygen level dependent (BOLD) signal of posterior cingulate cortex in a focused ultrasound neuromodulation study was detected and repeated with MR thermometry.

Multi-parameter Analytical Method for B1 and SNR Analysis (MAMBA): An open source RF coil design tool

In Magnetic Resonance Imaging (MRI), radio frequency (RF) coils of different forms and shapes are used to maximize signal-to-noise ratio (SNR). RF coils are designed for clinical applications and have dimensions comparable with the target body part to be imaged, and they perform best when loaded by human tissue majority of which have conductivity values higher than 0.5 S/m. However, they are not properly tuned and matched for samples having low conductivity such as solid samples with low water content. Moreover, for samples with low filling factor and low conductivity, the noise in MRI is dominated by RF coil losses. In this case, RF coil design can be optimized to improve image SNR.Here, a new software tool (Multi-parameter Analytical Method for B1 and SNR Analysis) MAMBA is presented to design and compare volume coils of birdcage, solenoid, and loop-gap design for these samples. The input parameters of the tool are the sample properties, the coil design and the hardware properties, of which a relative SNR is determined. For that, a figure of merit is calculated from the coil sensitivity, applied resonant frequency and the resistive losses of sample, coil and capacitive components. The tool was tested in an ancient Egyptian mummy head which represents an extreme case of MRI with short T2*. Two optimized birdcage coils were designed using MAMBA, constructed and compared to a commercial transmit receive head coil. Calculated relative SNR values are in good agreement with the measurements.

Detecting ionospheric disturbances using GPS without aliasing caused by non-uniform spatial sampling: Algorithm, validation and illustration

Ionospheric disturbance (ID) detected using GPS based Total Electron Content (TEC) measurements are widely used to study the morphology and dynamics of the ionosphere, and its impact on radio communication and satellite based navigation. The IDs normally derived as rate of change of TEC (ROT) between consecutive ionospheric pierce points at uniform time interval implicitly results in non-uniform spatial sampling along the GPS satellite tracks. The non-uniform spatial sampling introduces aliasing in ROT. These aliasing corrupt amplitude and Signal-to-Noise Ratio (SNR) of the detected IDs. In this study, we propose a Spatio-Periodic Leveling Algorithm (SPLA) to remove such aliasing. Efficiency of the proposed algorithm was tested by simulating the IDs along a satellite track and validated with GPS observations carried out during 2015 St. Patrick's day geomagnetic storm. Spatiotemporal, and SNR analyses of simulated and observed IDs reveal that the SPLA is (i) efficient in removing the aliases, (ii) increases the SNR on an average of 99.5% compared to ROT, (iii) removes the need of applying elevation cut-off, and (iv) expands the area of coverage up to 65%.

SNR-Centric Power Trace Extractors for Side-Channel Attacks

Existing power trace extractors consider the case where the number of power traces available to the attacker is sufficient to guarantee successful attacks, and the goal of power trace extraction is to extract a small part of traces with high signal-to-noise ratio (SNR) to reduce the complexity of attacks rather than to increase the success rates. Although strict theoretical proofs are given, the existing power trace extractors are too simple and leakage characteristics of Points-of-Interest (POIs) have not been thoroughly analyzed. They only maximize the variance of the data-dependent power consumption component and ignore the noise component, which results in very limited SNR that hampers the performance of extractors. In this article, we provide a rigorous theoretical analysis of SNR of power traces, and propose a simple yet efficient SNR-centric extractor, named shortest distance first (SDF), to extract power traces with the smallest estimated noise by taking advantage of known plaintexts. In addition, to maximize the variance of the exploitable component while minimizing the noise, we refer to the SNR estimation model and propose another novel extractor named maximizing estimated SNR first (MESF). Finally, we further propose an advanced extractor called mean-optimized MESF (MMESF) that exploits the mean power consumption of each plaintext byte value to more accurately and reasonably estimate the data-dependent power consumption of the corresponding samples. Experiments on both simulated power traces and measurements from an ATmega328p micro-controller demonstrate the superiority of our new extractors.

Quantitative analysis of SNR in bilinear time frequency domain

Signal-to-noise ratio (SNR) is an essential concept or quantity on the result of a process or on the output of a filter, which helps us in designing, analyzing or evaluating a system. In this paper, we study SNR for bilinear time–frequency transform (TFT). Firstly, according to the definition of SNR in time domain, we define a proper form for SNR in time–frequency (T–F) plane for bilinear TFT; then, we extract SNR relation in terms of TFT kernel, signals power and noise power in time domain. The extracted relation of SNR for bilinear TFT that can be represented in terms of Wigner–Ville distribution (WVD) shows its dependence on the kernel used in the TFT. Finally, to illustrate the applicability of the proposed SNR, the relations of SNR for several distributions are extracted in the T–F domain, and the variation of SNR versus the noise variance is shown by curves. The results show that the WVD has higher SNR than the Rihaczek, Page, spectrogram and Levin respectively.

GOES-16 Advanced Baseline Imager visible near-infrared channel low-light signal-to-noise ratio

Quantifying Geostationary Operational Environmental Satellite R-series (GOES-R) Advanced Baseline Imager (ABI) Channel (Ch) 2 low-light signal-to-noise ratio (SNR) is a core ABI postlaunch product test to validate prelaunch performance expectations of this parameter. For GOES-16, an SNR analysis has been performed to accomplish this goal using ABI Mode-3 MESO visible near-infrared (VNIR) channel L1b radiance product images taken every 30 s between 17:00 UTC and 17:15 UTC on May 23, 2017. Scene pixel data used in the analysis are first screened to ensure they meet the low-light criteria and to minimize scene temporal variability associated with meteorological evolution and geolocation uncertainty in highly inhomogeneous scenes. After such screening, image-to-image radiance time difference statistics are compiled and analyzed to estimate instrument SNR. Based on GOES-R ABI vendor prelaunch testing, minimum and mean expected ABI Ch 2 postlaunch SNR performance at 5% albedo was estimated to be 44.2 and 64.5, respectively. Meanwhile, the SNR computed in this analysis is found to be about 57 ± 8. Thus, low-light SNR for ABI Ch 2 is shown to meet minimum user expectations. The analysis for the other five GOES-16 ABI VNIR channels is also shown to contrast the SNR for these channels.

Presenting a Signal to Noise Ratio Model Based on the Combined Effect of Sound Pressure Level/frequency, Exposure Time and Oral Potassium: Experimental Study in Rats

Exposure to noise can lead to anatomical, nonauditory, and auditory impacts. The auditory influence of noise exposure is manifested in the form of Noise-induced hearing loss (NIHL). The current study aimed at present a signal to noise ratio model of otoacoustic emission of rats’ ears in the light of the combined effect of sound pressure level, sound frequency, exposure time, and potassium concentration of the used water. In total, 36 adult male rates, whose age varied from 3 to 4 months and had a weight of 200 ± 50 g, were randomly divided into 12 groups, with each group consisting of 3 rats. The rats in both groups (case and control groups) were exposed to SPLs of 85, 95, and 105 dB, emitted from sources that generated white noise. A distortion product otoacoustic emission (DPOAE) machine (4000 I/O manufactured by Homoth of Germany) was utilized to gauge the signal to noise ratio (SNR) of otoacoustic emissions of rats’ ears at various frequencies in an acoustic room. The inclusion criterion was SNR ≥ 6 dB. The collected data were fed into the Statistical Package for Social Sciences (SPSS) version 18, followed by conducting descriptive and inferential data analysis procedures. The results of SNR analysis indicated that over 82% of all data had SNRs that were equal to or greater than 6 dB. These data were considered as acceptable response. Furthermore, SPL and sound frequency had significant associations with SNR (P < 0.0001). Exposure time also significantly correlated with SNR (P = 0.008). However, the potassium concentration of the used water had no significant correlation with SNR (P = 0.97). High sound pressure levels result in lower DPOAE. Furthermore, higher frequency leads to higher SNR. On the contrary, longer exposure time reduces SNR. Finally, the potassium concentration of the used water has no effect on SNR.

Optimization of Cutting Conditions for Surface Roughness in VMC 5-Axis

Vertical machining center (VMC) five-axis is advanced metal cutting process which used tomachine advanced materials for creating parts for industries like die, automotive, aerospace, machinerydesign, etc. Input parameters selection very important in VMC-five axis to obtain better surface finishon milled part and enhanced machining economics. In the present work, experimental analysis has beenplanned to study the significances of milling parameters on quality response, surface roughness (Ra) ofD3 steel. The experiments have been planned on D3 steel in VMC five axis as per Box-Behnken designof response surface methodology (RSM). Modeling and optimization have been done by hybrid RSMand Jaya optimization algorithm. The factor effects on Ra has been studied by analysis of signal-tonoise ratio. The concluding remarks has been drawn from the study

A framework on the performance analysis of relay-assisted FSO transmission systems

In this work, we tend to analyze the performance of dual-hop relayed free-space optical (FSO) transmission systems. To do this, the FSO links are modeled as the Double Generalized Gamma (DGG) distribution with generalized pointing error impairment and under both heterodyne detection (HD) and intensity modulation with direct detection (IM/DD) methods. Using amplify-and-forward (AF) fixed-gain relaying as well as channel state information (CSI)-assisted AF relaying along with decode-and-forward (DF) relaying, we derive closed-form expressions for the outage probability (OP), the average bit error rate (BER) and the ergodic capacity (EC) in terms of the bivariate Fox-H function. Additionally, we analyze high signal-to-noise-ratio (SNR) behavior of the OP and formerly we derive the diversity order of the considered system. To asses the accuracy of the obtained results, numerical and Monte-Carlo simulation results are provided. Based on the high SNR analysis, we further provide a diversity gain analysis and discuss the bottlenecks in the dual-hop FSO systems.

Characterization of Al–Si12Fe/silicon nitride composites based on microstructure and influence of weight fraction of silicon nitride particles on the mechanical and tribological behaviour

In the present study, Al–Si12Fe alloy/silicon nitride (Si3N4)p composites were processed through the stir casting route, due to its cost-effectiveness and availability. Vickers microhardness and tensile tests were conducted to examine the effect of the intrinsic parameter (weight fraction of the silicon nitride particles) on the mechanical behavior of the composites. Also, the composite samples were tested under the pin-on-disc wear tester, by varying the intrinsic and extrinsic parameters such as weight fraction of the silicon nitride particles, load, sliding velocity and sliding distance. For the wear tests, the Taguchi L27 orthogonal array was employed for designing the experiments. SNR (Signal-to-noise ratio) analysis and Analysis of Variance (ANOVA) were employed for estimating the level of significance of each parameter on the dry sliding wear of the composites. Also, the microstructure of the composites was examined using SEM and EBSD and it was revealed that the wear mechanisms were predominantly due to abrasion and de-lamination, which resulted in the formation of microgrooves over the surfaces and the grain refinement of the composites was greatly influenced by the weight fraction of the silicon nitride particles.

Outage Analysis and Finite SNR Diversity-Multiplexing Tradeoff of Hybrid-Duplex Systems for Aeronautical Communications

A hybrid-duplex aeronautical communication system (HBD-ACS) consisting of a full-duplex-enabled ground station (GS) and two half-duplex (HD) air stations (ASs) is proposed as a direct solution to the spectrum crunch faced by the aviation industry. The closed-form outage probability and finite signal-to-noise ratio (SNR) diversity gain expressions in aeronautical communications over Rician fading channels are derived for a successive interference cancellation (SIC) detector. Similar expressions are also presented for an interference ignorant (II) detector and the HD-equivalent modes at GS and ASs. Through the outage and finite SNR diversity gain analysis conducted at the nodes, and system level, residual self-interference (SI) and inter-AS interference are found to be the primary limiting factors in the proposed HBD-ACS. Further investigations revealed that the II and SIC detectors in the proposed HBD-ACS are suitable for the weak and strong interference scenarios, respectively. When compared with the HD-ACS, the proposed HBD-ACS achieves a lower outage probability and higher diversity gains at higher multiplexing gains when operating at low SNRs. The finite SNR analysis also showed the possibility of the proposed HBD-ACS being able to attain interference-free diversity gains through proper management of the residual SI. Hence, the proposed HBD-ACS is more reliable and can provide a better throughput compared with the existing HD-ACS at low-to-moderate SNRs.

SNR analysis of contrast-enhanced MR imaging for early detection of rheumatoid arthritis.

ObjectiveTo investigate whether signal to noise (SNR) analysis of contrast-enhanced MRI gives additional benefit for early disease detection by Magnetic Resonance Imaging (MRI) of experimental rheumatoid arthritis (RA) in a small animal model.MethodsWe applied contrast-enhanced MRI at 7T in DBA mice with or without collagen-induced arthritis (CIA). Clinical score, OMERACT RAMRIS analysis and analysis of signal to noise ratios (SNR) of regions of interest in RA bearing mice, methotrexate/methylprednisolone acetate treated RA and control animals were compared with respect to benefit for early diagnosis.ResultsWhile treated RA and control animals did not show signs of RA activity in any of the above-mentioned scoring methods at any time point analyzed, RA animals revealed characteristic signs of RA in RAMRIS at the same time point when RA was detected clinically through scoring of the paws. The MR-based SNR analysis detected signs of synovitis, the earliest indication of RA, not only in late clinical stages, but also at an early stage when little or no clinical signs of RA were present in CIA animals and RAMRIS did not allow a distinct early detection.ConclusionSNR analysis of contrast-enhanced MR imaging provides additional benefit for early arthritis detection in CIA mice.

Probability Density Function Analysis of SNR for Time-Reversed Transmission System

The time reversal (TR) transmission technique can harvest energy from the surrounding environment by exploiting multipath, and focus the signal energy which would have otherwise been lost in most existing communication modes on the desired user with a relatively low system complexity. In this paper, we derived the probability density function (PDF) of the received signal-to-noise ratio (SNR) in a single antenna communication system. Simulation results show the PDF curve is correct.