scholarly journals Determination of DVB-T2 Signal Quality in Nigeria: A Case Study of Jos, Plateau State, Nigeria

2021 ◽  
Vol 40 (1) ◽  
pp. 81-88
Author(s):  
E.E.C. Igbonoba ◽  
O. Omoifo
Keyword(s):  
Signal To Noise Ratio ◽  
Empirical Method ◽  
Signal Quality ◽  
Television System ◽  
Jos Plateau ◽  
Television Signal ◽  
Service Areas ◽  
Noise Ratio ◽  
Plateau State

This study presents the evaluation of digital video broadcasting-terrestrial second generation (DVB-T2) Television signal quality in Jos using Integrated Television Services Limited signal. The delivery of quality Television signal remains problematic in Nigeria due to signal attenuation and degradation between the transmitter and receiver station. This is primarily due to environmental and atmospheric perturbations prevalent along the signal paths. This research aim is to determine the signal quality of DVB-T2 Television system in Jos, Plateau State. The simple field measurement methodology was adopted in measuring field strength and channel power parameters. These measurement parameters were used to calculate for carrier-to-noise ratio (CNR) and signal-to-noise ratio (SNR) through empirical method. Finally, CNR and SNR were used to determine the signal quality of DVB-T2 signal in Jos. The result of the research shows that DVB-T2 signal in the primary service areas has good and reliable signal apart from the rocky environments.

scholarly journals METHOD OF IMPROVED TDICCD DESIGN BASED ON SENSOR CLOCKING

2020 ◽  
Vol V-3-2020 ◽  
pp. 689-693
Author(s):  
M. Wan ◽  
Y. Guo ◽  
S. Li ◽  
T. Liu
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Sequence Diagram ◽  
Signal Quality ◽  
Signal To Noise ◽  
Application Range ◽  
Final Output ◽  
Noise Ratio ◽  
Derivation Process

Abstract. The final output signal quality of TDICCD is related to the key parameters such as working mode, output mode, signal-to-noise ratio, dynamic range and so on. We can improve these parameters of TDICCD by reasonably designing the sensor clocking. Therefore, this text discussed four methods of improved TDICCD sensor clocking to solve some problem in TDICCD application based on using the principle of TDICCD. The technique of TDICCD Taps merging can reduce the number of TDICCD Taps, which helps to reduce the size of the TDICCD rear-end circuit significantly; The technique of TDICCD continuous transfer clocking can improve the charge transfer efficiency, which helps to promote the final signal-to-noise ratio; The technique of pixel binning clocking can enlarge the dynamic range of image; The technique of TDICCD area-array working mode can extend the field of TDICCD working; The principle, derivation process, clocking sequence diagram and application range of these clocking design schemes are given in this paper. At the same time, it also explains its actual effect and the matters to be noted.

scholarly journals Automated Assessment of the Quality of Phonocardographic Recordings through Signal-to-Noise Ratio for Home Monitoring Applications

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7246
Author(s):  
Noemi Giordano ◽  
Samanta Rosati ◽  
Marco Knaflitz
Keyword(s):  
Heart Sound ◽  
Signal To Noise Ratio ◽  
Home Monitoring ◽  
Clinical Applications ◽  
Signal Quality ◽  
Sample Population ◽  
Signal To Noise ◽  
Monitoring Applications ◽  
Noise Ratio

The signal quality limits the applicability of phonocardiography at the patients’ domicile. This work proposes the signal-to-noise ratio of the recorded signal as its main quality metrics. Moreover, we define the minimum acceptable values of the signal-to-noise ratio that warrantee an accuracy of the derived parameters acceptable in clinics. We considered 25 original heart sounds recordings, which we corrupted by adding noise to decrease their signal-to-noise ratio. We found that a signal-to-noise ratio equal to or higher than 14 dB warrants an uncertainty of the estimate of the valve closure latencies below 1 ms. This accuracy is higher than that required by most clinical applications. We validated the proposed method against a public database, obtaining results comparable to those obtained on our sample population. In conclusion, we defined (a) the signal-to-noise ratio of the phonocardiographic signal as the preferred metric to evaluate its quality and (b) the minimum values of the signal-to-noise ratio required to obtain an uncertainty of the latency of heart sound components compatible with clinical applications. We believe these results are crucial for the development of home monitoring systems aimed at preventing acute episodes of heart failure and that can be safely operated by naïve users.

Image Quality Enhancing by Efficient Histogram Equalization

2014 ◽  
Vol 2 (2) ◽  
pp. 47-58
Author(s):  
Ismail Sh. Baqer
Keyword(s):  
Image Quality ◽  
Contrast Enhancement ◽  
Mean Squared Error ◽  
Signal To Noise Ratio ◽  
Histogram Equalization ◽  
Gray Level ◽  
Signal To Noise ◽  
Squared Error ◽  
Noise Ratio

A two Level Image Quality enhancement is proposed in this paper. In the first level, Dualistic Sub-Image Histogram Equalization DSIHE method decomposes the original image into two sub-images based on median of original images. The second level deals with spikes shaped noise that may appear in the image after processing. We presents three methods of image enhancement GHE, LHE and proposed DSIHE that improve the visual quality of images. A comparative calculations is being carried out on above mentioned techniques to examine objective and subjective image quality parameters e.g. Peak Signal-to-Noise Ratio PSNR values, entropy H and mean squared error MSE to measure the quality of gray scale enhanced images. For handling gray-level images, convenient Histogram Equalization methods e.g. GHE and LHE tend to change the mean brightness of an image to middle level of the gray-level range limiting their appropriateness for contrast enhancement in consumer electronics such as TV monitors. The DSIHE methods seem to overcome this disadvantage as they tend to preserve both, the brightness and contrast enhancement. Experimental results show that the proposed technique gives better results in terms of Discrete Entropy, Signal to Noise ratio and Mean Squared Error values than the Global and Local histogram-based equalization methods

Singular Values Decomposition and Lifting Wavelet Transform for Speech Signal Embedding into Digital Image

2019 ◽  
Vol 12 (2) ◽  
pp. 138-151
Author(s):  
Mourad Talbi ◽  
Med Salim Bouhlel
Keyword(s):  
Wavelet Transform ◽  
Speech Signal ◽  
Signal To Noise Ratio ◽  
Perceptual Quality ◽  
Lifting Wavelet Transform ◽  
Signal To Noise ◽  
Perceptual Evaluation ◽  
Lifting Wavelet ◽  
Noise Ratio

Background: In this paper, we propose a secure image watermarking technique which is applied to grayscale and color images. It consists in applying the SVD (Singular Value Decomposition) in the Lifting Wavelet Transform domain for embedding a speech image (the watermark) into the host image. Methods: It also uses signature in the embedding and extraction steps. Its performance is justified by the computation of PSNR (Pick Signal to Noise Ratio), SSIM (Structural Similarity), SNR (Signal to Noise Ratio), SegSNR (Segmental SNR) and PESQ (Perceptual Evaluation Speech Quality). Results: The PSNR and SSIM are used for evaluating the perceptual quality of the watermarked image compared to the original image. The SNR, SegSNR and PESQ are used for evaluating the perceptual quality of the reconstructed or extracted speech signal compared to the original speech signal. Conclusion: The Results obtained from computation of PSNR, SSIM, SNR, SegSNR and PESQ show the performance of the proposed technique.

scholarly journals Signal quality as Achilles’ heel of graph theory in functional magnetic resonance imaging in multiple sclerosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Johan Baijot ◽  
Stijn Denissen ◽  
Lars Costers ◽  
Jeroen Gielen ◽  
Melissa Cambron ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Signal To Noise Ratio ◽  
Pearson Correlation ◽  
Signal Quality ◽  
Network Parameters ◽  
Fmri Signal ◽  
Noise Ratio ◽  
Global And Local ◽  
The Brain ◽  
Local Brain

AbstractGraph-theoretical analysis is a novel tool to understand the organisation of the brain.We assessed whether altered graph theoretical parameters, as observed in multiple sclerosis (MS), reflect pathology-induced restructuring of the brain's functioning or result from a reduced signal quality in functional MRI (fMRI). In a cohort of 49 people with MS and a matched group of 25 healthy subjects (HS), we performed a cognitive evaluation and acquired fMRI. From the fMRI measurement, Pearson correlation-based networks were calculated and graph theoretical parameters reflecting global and local brain organisation were obtained. Additionally, we assessed metrics of scanning quality (signal to noise ratio (SNR)) and fMRI signal quality (temporal SNR and contrast to noise ratio (CNR)). In accordance with the literature, we found that the network parameters were altered in MS compared to HS. However, no significant link was found with cognition. Scanning quality (SNR) did not differ between both cohorts. In contrast, measures of fMRI signal quality were significantly different and explained the observed differences in GTA parameters. Our results suggest that differences in network parameters between MS and HS in fMRI do not reflect a functional reorganisation of the brain, but rather occur due to reduced fMRI signal quality.

scholarly journals Encryption Based Image Watermarking Algorithm in 2DWT-DCT Domains

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5540
Author(s):  
Nayeem Hasan ◽  
Md Saiful Islam ◽  
Wenyu Chen ◽  
Muhammad Ashad Kabir ◽  
Saad Al-Ahmadi
Keyword(s):  
Signal To Noise Ratio ◽  
Image Watermarking ◽  
Similarity Index ◽  
Structural Similarity ◽  
Reconstructed Image ◽  
Discrete Wavelet ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Watermarking Scheme

This paper proposes an encryption-based image watermarking scheme using a combination of second-level discrete wavelet transform (2DWT) and discrete cosine transform (DCT) with an auto extraction feature. The 2DWT has been selected based on the analysis of the trade-off between imperceptibility of the watermark and embedding capacity at various levels of decomposition. DCT operation is applied to the selected area to gather the image coefficients into a single vector using a zig-zig operation. We have utilized the same random bit sequence as the watermark and seed for the embedding zone coefficient. The quality of the reconstructed image was measured according to bit correction rate, peak signal-to-noise ratio (PSNR), and similarity index. Experimental results demonstrated that the proposed scheme is highly robust under different types of image-processing attacks. Several image attacks, e.g., JPEG compression, filtering, noise addition, cropping, sharpening, and bit-plane removal, were examined on watermarked images, and the results of our proposed method outstripped existing methods, especially in terms of the bit correction ratio (100%), which is a measure of bit restoration. The results were also highly satisfactory in terms of the quality of the reconstructed image, which demonstrated high imperceptibility in terms of peak signal-to-noise ratio (PSNR ≥ 40 dB) and structural similarity (SSIM ≥ 0.9) under different image attacks.

The Influence of Alteration of kVp and mAs towards the Image Quality of Acrylic Using CBCT

2019 ◽  
Vol 829 ◽  
pp. 252-257
Author(s):  
Azhari ◽  
Yohanes Hutasoit ◽  
Freddy Haryanto
Keyword(s):  
Image Quality ◽  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Signal To Noise ◽  
Bite Block ◽  
Significant Difference ◽  
Noise Ratio ◽  
Post Hoc ◽  
Radiograph Image

CBCT is a modernized technology in producing radiograph image on dentistry. The image quality excellence is very important for clinicians to interpret the image, so the result of diagnosis produced becoming more accurate, appropriate, thus minimizing the working time. This research was aimed to assess the image quality using the blank acrylic phantom polymethylmethacrylate (PMMA) (C­5H8O2)n in the density of 1.185 g/cm3 for evaluating the homogeneity and uniformity of the image produced. Acrylic phantom was supported with a tripod and laid down on the chin rest of the CBCT device, then the phantom was fixed, and the edge of the phantom was touched by the bite block. Furthermore, the exposure of the X-ray was executed toward the acrylic phantom with various kVp and mAs, from 80 until 90, with the range of 5 kV and the variation of mA was 3, 5, and 7 mA respectively. The time exposure was kept constant for 25 seconds. The samples were taken from CBCT acrylic images, then as much as 5 ROIs (Region of Interest) was chosen to be analyzed. The ROIs determination was analyzed by using the ImageJ® software for recognizing the influence of kVp and mAs towards the image uniformity, noise and SNR. The lowest kVp and mAs had the result of uniformity value, homogeneity and signal to noise ratio of 11.22; 40.35; and 5.96 respectively. Meanwhile, the highest kVp and mAs had uniformity value, homogeneity and signal to noise ratio of 16.96; 26.20; and 5.95 respectively. There were significant differences between the image uniformity and homogeneity on the lowest kVp and mAs compared to the highest kVp and mAs, as analyzed with the ANOVA statistics analysis continued with the t-student post-hoc test with α = 0.05. However, there was no significant difference in SNR as analyzed with the ANOVA statistic analysis. The usage of the higher kVp and mAs caused the improvement of the image homogeneity and uniformity compared to the lower kVp and mAs.

scholarly journals Photometric Characteristics of Data from the Hubble Space Telescope Goddard-High Resolution Spectrograph

1988 ◽  
Vol 132 ◽  
pp. 35-38
Author(s):  
Dennis C. Ebbets ◽  
Sara R. Heap ◽  
Don J. Lindler
Keyword(s):  
Exposure Time ◽  
Hubble Space Telescope ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Signal To Noise ◽  
Space Telescope ◽  
Additional Noise ◽  
Reduction Strategies ◽  
Noise Ratio

The G-HRS is one of four axial scientific instruments which will fly aboard the Hubble Space Telescope (ref 1,2). It will produce spectroscopic observations in the 1050 A ≤ λ ≤ 3300 A region with greater spectral, spatial and temporal resolution than has been possible with previous space-based instruments. Five first order diffraction gratings and one Echelle provide three modes of spectroscopic operation with resolving powers of R = λ/ΔΔ = 2000, 20000 and 90000. Two magnetically focused, pulse-counting digicon detectors, which differ only in the nature of their photocathodes, produce data whose photometric quality is usually determined by statistical noise in the signal (ref 3). Under ideal circumstances the signal to noise ratio increases as the square root of the exposure time. For some observations detector dark count, instrumental scattered light or granularity in the pixel to pixel sensitivity will cause additional noise. The signal to noise ratio of the net spectrum will then depend on several parameters, and will increase more slowly with exposure time. We have analyzed data from the ground based calibration programs, and have developed a theoretical model of the HRS performance (ref 4). Our results allow observing and data reduction strategies to be optimized when factors other than photon statistics influence the photometric quality of the data.

Quality of Computed Tomography Pulmonary Embolism and Aortic Phase Images Acquired with Power Injection via an Arm Port

2017 ◽  
Vol 22 (2) ◽  
pp. 88-92
Author(s):  
Ryan Verity ◽  
David Leswick ◽  
Brent Burbridge ◽  
Rhonda Bryce ◽  
Hyun Lim
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Thin Section ◽  
Signal To Noise Ratio ◽  
Contrast Injection ◽  
Signal To Noise ◽  
Streak Artifact ◽  
Noise Ratio

Abstract Background: The safety of power-injectable implanted arm ports is well established, but there is insufficient data to conclude that image quality of computed tomography resulting from contrast introduced via the port is of equal quality to images derived from contrast introduced via traditional peripheral access. The objective of this study was to determine whether the image quality of computed tomography pulmonary embolism and computed tomography aorta studies would differ when injecting contrast via an implanted arm port vs a peripheral intravenous site. We hypothesized that injecting via an implanted arm port would produce better-quality images, the result of more appropriate timing and less streak artifact. Methods: Scans from a provincial database search for patients who underwent a computed tomography pulmonary embolism or aorta study with contrast injection via the implanted arm port and thin section images available, were reviewed (pulmonary embolism studies n = 3, aorta studies n = 3). Only a limited number of patients were available for review because there are currently few patients with these ports in place and we limited evaluation to thin section images. Comparison was made with 6 control patients who did not have a port and had received a peripheral arm intravenous contrast injection for these study types. Objective measurements included signal-to-noise ratio and contrast-to-noise ratio of the pulmonary arteries (4 sites) and aorta (2 sites) as appropriate for scan type. Subjective analysis of image quality was performed by 2 radiologists. Results: Although sample size was limited, the implanted arm port group had similar or higher mean signal-to-noise ratio and contrast-to-noise ratio values at all sites. Subjective assessments showed the implanted arm port group to have similar or better opacification and diagnostic confidence; similar or less streak artifact was also observed at each of the sites. Conclusions: These exploratory results suggest that studies with implanted arm port injection can generate high-quality images on both objective and subjective assessment, similar to, or possibly better than, images generated from usual peripheral intravenous access for contrast injection.

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