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Fulltext Comparison studies of resolution and noise properties between drum type and laser type film digitization systems

Khairul Anuar Mohd Salleh, Ab. Razak Hamzah, Wan Muhammad Saridan Wan Hassan

Journal of Nuclear and Related Technologies, 2008;2008(2):35-45.
MyJurnal

Developments of computer technology and image processing have shifted conventional industrial radiography application to industrial digital radiography (IDR) system. In this study, two types of IDR modules for non destructive testing (NDT), namely drum- and laser- type film digitizer with 50 μm pixel pitch have been evaluated for NDT applications. The modulation transfer function (MTF) and noise power spectrum (NPS) measurement were adapted to evaluate the image quality of IDR images. Results shown the averaged MTF for drum- and laser- type film digitizer at 20% modulation were 6.15 cycles/mm and 6.55 cycles/mm respectively. For NPS measurement and calculation, the result obtained shows that drum type film digitizer produced higher noise then laser type film digitizer. The study shows that the laser type film digitizer is the best system to be used for film digitization purposes because the MTF result shows that it modulates better than drum type and has the lowest and stable NPS.

Matched MeSH terms: Noise
Fulltext Morphological techniques for microcalcification and mass enhancement

Nor'aida Khairuddin, Norriza Mohd Isa, Wan Muhamad Saridan Wan Hassan

Journal of Nuclear and Related Technologies, 2012;2012(2):102-108.
MyJurnal

The recognition of microcalcifications and masses from digital mammographic images are important to aid the detection of breast cancer. In this paper, we applied morphological techniques to extract the embedded structures from the images for subsequent analysis. A mammographic phantom was created with embedded structures such as micronodules, nodules and fibrils. For the preprocessing techniques, intensity transformation of gray scale was applied to the image. The structures of the image were enhanced and segmented using dilation for a morphological operation with morphological closing. Next, low pass Gaussian filter was applied to the image to smooth and reduce noises. It was found that our method improved the detection of microcalcifications and masses with high Peak Signal To Noise Ratio (PSNR).

Matched MeSH terms: Noise; Signal-To-Noise Ratio
The outcomes of bilateral cochlear implant users in Universiti Kebangsaan Malaysia

Mohammad Azmi HH, Goh BS, Abdullah A, Umat C

Acta Otolaryngol, 2020 Oct;140(10):838-844.
PMID: 32564640 DOI: 10.1080/00016489.2020.1775887

INTRODUCTION: Bilateral cochlear implants are seen to improve hearing capabilities.
OBJECTIVE: To assess the auditory outcome of paediatric bilateral cochlear implant in Universiti Kebangsaan Malaysia.
MATERIALS AND METHODS: This was a cross-sectional and descriptive study single centre analysis. Categories of Auditory Performance (CAP-II) scale and Speech, Spatial and Qualities (SSQ) of Hearing questionnaire were used.
RESULTS: Forty-six patients were recruited. Majority of the children (30.4%) rated 7 and 23.9% scored perfectly (9) based on the CAP-II Scale. The least performing children were rated 5 (average). Children that were implanted sequentially within 24 months showed median CAP-II scale of 7. No significant correlation seen between CAP-II and the duration interval, use and age of 1st CI (p > .05). The speech domain of SSQ-P scale showed median value of 8 indicating good speech understanding. The spatial hearing domain had median value of 7, quality of hearing domain had median of 8. Significant correlation seen in hearing in noise with the duration of use of CI (p

Matched MeSH terms: Noise
Fulltext Development of a Linear Acoustic Array for Aero-Acoustic Quantification of Camber-Bladed Vertical Axis Wind Turbine

Butt AH, Akbar B, Aslam J, Akram N, Soudagar MEM, García Márquez FP, et al.

Sensors (Basel), 2020 Oct 21;20(20).
PMID: 33096774 DOI: 10.3390/s20205954

Vertical axis wind turbines (VAWT) are a source of renewable energy and are used for both industrial and domestic purposes. The study of noise characteristics of a VAWT is an important performance parameter for the turbine. This study focuses on the development of a linear microphone array and measuring acoustic signals on a cambered five-bladed 45 W VAWT in an anechoic chamber at different tip speed ratios. The sound pressure level spectrum of VAWT shows that tonal noises such as blade passing frequencies dominate at lower frequencies whereas broadband noise corresponds to all audible ranges of frequencies. This study shows that the major portion of noise from the source is dominated by aerodynamic noises generated due to vortex generation and trailing edge serrations. The research also predicts that dynamic stall is evident in the lower Tip speed ratio (TSR) region making smaller TSR values unsuitable for a quiet VAWT. This paper compares the results of linear aeroacoustic array with a 128-MEMS acoustic camera with higher resolution. The study depicts a 3 dB margin between two systems at lower TSR values. The research approves the usage of the 8 mic linear array for small radius rotary machinery considering the results comparison with a NORSONIC camera and its resolution. These observations serve as a basis for noise reduction and blade optimization techniques.

Matched MeSH terms: Noise
Signal-to-noise ratio estimation on SEM images using cubic spline interpolation with Savitzky-Golay smoothing

Sim KS, Kiani MA, Nia ME, Tso CP

J Microsc, 2014 Jan;253(1):1-11.
PMID: 24164248 DOI: 10.1111/jmi.12089

A new technique based on cubic spline interpolation with Savitzky-Golay noise reduction filtering is designed to estimate signal-to-noise ratio of scanning electron microscopy (SEM) images. This approach is found to present better result when compared with two existing techniques: nearest neighbourhood and first-order interpolation. When applied to evaluate the quality of SEM images, noise can be eliminated efficiently with optimal choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time.

Matched MeSH terms: Signal-To-Noise Ratio*
Noise variance estimation using image noise cross-correlation model on SEM images

Sim KS, Nia ME, Tso CP

Scanning, 2013 May-Jun;35(3):205-12.
PMID: 22961698 DOI: 10.1002/sca.21055

A number of techniques have been proposed during the last three decades for noise variance and signal-to-noise ratio (SNR) estimation in digital images. While some methods have shown reliability and accuracy in SNR and noise variance estimations, other methods are dependent on the nature of the images and perform well on a limited number of image types. In this article, we prove the accuracy and the efficiency of the image noise cross-correlation estimation model, vs. other existing estimators, when applied to different types of scanning electron microscope images.

Matched MeSH terms: Noise; Signal-To-Noise Ratio
Image noise cross-correlation for signal-to-noise ratio estimation in scanning electron microscope images

Sim KS, Nia ME, Tso CP

Scanning, 2011 Mar-Apr;33(2):82-93.
PMID: 21381045 DOI: 10.1002/sca.20223

A new and robust parameter estimation technique, named image noise cross-correlation, is proposed to predict the signal-to-noise ratio (SNR) of scanning electron microscope images. The results of SNR and variance estimation values are tested and compared with nearest neighborhood and first-order interpolation. Overall, the proposed method is best as its estimations for the noise-free peak and SNR are most consistent and accurate to within a certain acceptable degree, compared with the others.

Matched MeSH terms: Noise; Signal-To-Noise Ratio
Reducing charging effects in scanning electron microscope images by Rayleigh contrast stretching method (RCS)

Wan Ismail WZ, Sim KS, Tso CP, Ting HY

Scanning, 2011 Jul-Aug;33(4):233-51.
PMID: 21611953 DOI: 10.1002/sca.20237

To reduce undesirable charging effects in scanning electron microscope images, Rayleigh contrast stretching is developed and employed. First, re-scaling is performed on the input image histograms with Rayleigh algorithm. Then, contrast stretching or contrast adjustment is implemented to improve the images while reducing the contrast charging artifacts. This technique has been compared to some existing histogram equalization (HE) extension techniques: recursive sub-image HE, contrast stretching dynamic HE, multipeak HE and recursive mean separate HE. Other post processing methods, such as wavelet approach, spatial filtering, and exponential contrast stretching, are compared as well. Overall, the proposed method produces better image compensation in reducing charging artifacts.

Matched MeSH terms: Signal-To-Noise Ratio
Noise-induced hearing loss and associated factors among vector control workers in a Malaysian state

Masilamani R, Rasib A, Darus A, Ting AS

Asia Pac J Public Health, 2014 Nov;26(6):642-50.
PMID: 22548779 DOI: 10.1177/1010539512444776

This study aims to determine the prevalence and associated factors of noise-induced hearing loss (NIHL) among vector control workers in the state of Negeri Sembilan, Malaysia. This was an analytical cross-sectional study conducted on 181 vector control workers who were working in district health offices in a state in Malaysia. Data were collected using a self-administered questionnaire and audiometry. Prevalence of NIHL was 26% among this group of workers. NIHL was significantly associated with the age-group of 40 years and older, length of service of 10 or more years, current occupational noise exposure, listening to loud music, history of firearms use, and history of mumps/measles infection. Following logistic regression, age of more than 40 years and noise exposure in current occupation were associated with NIHL with an odds ratio of 3.45 (95% confidence interval = 1.68-7.07) and 6.87 (95% confidence interval = 1.54-30.69), respectively, among this group of vector control workers.

Matched MeSH terms: Hearing Loss, Noise-Induced/epidemiology*
Hearing impairment as occupational hazard in airport: a comparative cross sectional study in Malaysia

Ibrahimzubil, A.R., Nor Hassim, I., Thaherah Nor

Journal of Occupational Safety and Health, 2013;10(1):39-48.
MyJurnal

Comparative cross sectional study was conducted to determine the prevalence of hearing impairment among workers in one of the airport in Malaysia and the factors associated with it. A total of 248 subjects comprising 175 from the exposed group and the remaining control group were sampled. The main tools used in this study were validated questionnaire on hearing assessment and pure tone audiometric test. Response rate was 94%. Both area and personal exposure monitoring have exceeded action level for 8 Hrs TWA in the exposed group but within normal limit in the control group. The prevalence of hearing impairment was 88% among the noise exposed group and 11% in the control group with prevalence odds ratio (POR) 3.569 (95%CI 1.210-10.53, p

Matched MeSH terms: Noise
Analysis of model-based and model-free CEST effect quantification methods for different medical applications

Foo LS, Yap WS, Hum YC, Manan HA, Tee YK

J Magn Reson, 2020 01;310:106648.
PMID: 31760147 DOI: 10.1016/j.jmr.2019.106648

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) holds great potential to provide new metabolic information for clinical applications such as tumor, stroke and Parkinson's Disease diagnosis. Many active research and developments have been conducted to translate this emerging MRI technique for routine clinical applications. In general, there are two CEST quantification techniques: (i) model-free and (ii) model-based techniques. The reliability of these quantification techniques depends heavily on the experimental conditions and quality of the collected data. Errors such as noise may lead to misleading quantification results and thus inaccurate diagnosis when CEST imaging becomes a standard or routine imaging scan in the future. This paper investigates the accuracy and robustness of these quantification techniques under different signal-to-noise (SNR) levels and magnetic field strengths. The quantified CEST effect before and after adding random Gaussian White Noise using model-free and model-based quantification techniques were compared. It was found that the model-free technique consistently yielded larger average percentage error across all tested parameters compared to its model-based counterpart, and that the model-based technique could withstand SNR of about 3 times lower than the model-free technique. When applied on noisy brain tumor, ischemic stroke, and Parkinson's Disease clinical data, the model-free technique failed to produce significant differences between normal and abnormal tissue whereas the model-based technique consistently generated significant differences. Although the model-free technique was less accurate and robust, its simplicity and thus speed would still make it a good approximate when the SNR was high (>50) or when the CEST effect was large and well-defined. For more accurate CEST quantification, model-based techniques should be considered. When SNR was low (<50) and the CEST effect was small such as those acquired from clinical field strength scanners, which are generally 3T and below, model-based techniques should be considered over model-free counterpart to maintain an average percentage error of less than 44% even under very noisy condition as tested in this work.

Matched MeSH terms: Signal-To-Noise Ratio
Simultaneous analysis of silicon and boron dissolved in water by combination of electrodialytic salt removal and ion-exclusion chromatography with corona charged aerosol detection

Mori M, Sagara K, Arai K, Nakatani N, Ohira S, Toda K, et al.

J Chromatogr A, 2016 Jan 29;1431:131-7.
PMID: 26755416 DOI: 10.1016/j.chroma.2015.12.064

Selective separation and sensitive detection of dissolved silicon and boron (DSi and DB) in aqueous solution was achieved by combining an electrodialytic ion isolation device (EID) as a salt remover, an ion-exclusion chromatography (IEC) column, and a corona charged aerosol detector (CCAD) in sequence. DSi and DB were separated by IEC on the H(+)-form of a cation exchange resin column using pure water eluent. DSi and DB were detected after IEC separation by the CCAD with much greater sensitivity than by conductimetric detection. The five-channel EID, which consisted of anion and cation acceptors, cathode and anode isolators, and a sample channel, removed salt from the sample prior to the IEC-CCAD. DSi and DB were scarcely attracted to the anion accepter in the EID and passed almost quantitatively through the sample channel. Thus, the coupled EID-IEC-CCAD device can isolate DSi and DB from artificial seawater and hot spring water by efficiently removing high concentrations of Cl(-) and SO4(2-) (e.g., 98% and 80% at 0.10molL(-1) each, respectively). The detection limits at a signal-to-noise ratio of 3 were 0.52μmolL(-1) for DSi and 7.1μmolL(-1) for DB. The relative standard deviations (RSD, n=5) of peak areas were 0.12% for DSi and 4.3% for DB.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Modified algorithm for image watermarking using 2D-DCT and Elgamal Cryptosyst

Nur Azien Yazid, Kamilah Abdullah, Suhaila Abd Halim

ESTEEM Academic Journal, 2019;15(1):44-55.
MyJurnal

Image watermarking embeds identifying information in an image in such a manner that it cannot easily be removed. For the past several years, image digital watermarking has become a necessary element used for hiding secret image and enabling secured communication such as
privacy, confidentiality, authentication and data integrity. Although numerous watermarking schemes are present in grayscale images, the present work focuses on the RGB color image. This study proposed a new hybrid method that would satisfy the essential needs of modern image watermarking. The color image watermarking is based on the 2D Discrete Cosine Transform and Elgamal cryptosystem. The 2D Discrete Cosine Transform depends on the matrix products, while the Elgamal cryptosystem depends on the discrete logarithm problem. The cryptosystem is combined with existing Arnold transform in watermarking algorithm to enhance the security of secret image. Value of Peak Signal to Noise Ratio was taken as performance evaluation parameters. On the whole, the performance evaluation shows that combining the two algorithms improved the performance of image watermarking.

Matched MeSH terms: Signal-To-Noise Ratio
Optimization of dose and image quality of paediatric cardiac catheterization procedure

Lubis LE, Bayuadi I, Pawiro SA, Ng KH, Bosmans H, Soejoko DS

Phys Med, 2015 Nov;31(7):659-68.
PMID: 26050060 DOI: 10.1016/j.ejmp.2015.05.011

The purpose of this study is to quantify the quality of the available imaging modes for various iodine-based contrast agent concentration in paediatric cardiology. The figure of merit (FOM) was defined as the squared signal to noise ratio divided by a patient dose related parameter. An in house constructed phantom simulated a series of vessel segments with iodine concentrations from 10% or 30 mg/cc to 16% or 48 mg/cc of iodine in a blood plasma solution, all within the dimensional constraints of a paediatric patient. The phantom also used test inserts of tin (Sn). Measurements of Entrance Surface Air Kerma (ESAK) and exit dose rate were performed along with calculations of the signal-to-noise ratio (SNR) of all the objects. A first result showed that it was favourable to employ low dose fluoroscopy mode and lower frame rate modes in cine acquisition if dynamic information is not critical. Normal fluoroscopy dose mode provided a considerably higher dose level (in comparison to low dose mode) with only a slight improvement in SNR. Higher frame rate cine modes should be used however when the clinical situation dictates so. This work also found that tin should not be intended as iodine replacement material for research purposes due to the mismatching SNR, particularly on small vessel sizes.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Brain activation display functional asymmetry in response to action, background and tonal frequency during a pitch memory processing: an fMRI study

Ahmad Nazlim Yusoff, Khairiah Abdul Hamid, Farah Nabila Ab Rahman, Mazlyfarina Mohamad, Khairiah Abdul Hamid, Siti Zamratol-Mai Sarah Mukari

Jurnal Sains Kesihatan Malaysia, 2018;16(1):35-44.
MyJurnal

In this study, the asymmetry of the main effects of action, background and tonal frequency during a pitch memory processing
were investigated by means of brain activation. Eighteen participants (mean age 27.6 years) were presented with low and
high frequency tones in quiet and in noise. They listen, discriminate and recognize the target tone against the final tone
in a series of four distracting tones. The main effects were studied using the analysis of variance (ANOVA) with action (to
wring (rubber bulb) vs. not to wring), background (in quiet vs. in noise) and frequency (low vs. high) as the factors (and
levels respectively). The main effect of action is in the right pre-central gyrus (PCG), in conformation with its contralateral
behavior. The main effect of background indicated the bilateral primary auditory cortices (PAC) and is right lateralized,
attributable to white noise. The main effect of frequency is also observed in PAC but bilaterally equal and attributable to
low frequency tones. Despite the argument that the temporo-spectral lateralization dichotomy is not especially rigid as
revealed by the main effect of frequency, right lateralization of PAC for the respective main effect of background clearly
demonstrates its functional asymmetry suggesting different perceptual functionality of the right and left PAC.

Matched MeSH terms: Noise
Fulltext Noise exposure and hearing symptoms among laundry workers and mechanical cutters in a teaching hospital

Asaritaminaziah binti Hisam, Siti Marwanis binti Anua

Journal of Occupational Safety and Health, 2018;15(1):35-41.
MyJurnal

Workers who are exposed to high noise level were at risk of noise-induced hearing loss (NIHL). This crosssectional study was conducted to investigate the noise exposure level and hearing symptoms among workers exposed to noise in a teaching hospital. Utilising convenience sampling method, 20 laundry workers and 17 mechanical cutters were recruited into this study. Noise exposure levels were measured using noise dosimeter for 8 hours and information on hearing symptoms were gathered using a modified questionnaire adopted from the American Speech Language Hearing Association (ASHA). A significantly higher mean noise level (85±2 dB(A)) was reported among mechanical cutters as compared to laundry workers (80±3 dB(A)), p=0.001 although the former had shorter duration of noise exposure (20±3 hours per week vs. 28±12 hours per week). Fourteen (70%) laundry workers and six (35%) mechanical cutters had reported having hearing problem in noisy background. Higher proportion of laundry workers (n=8, 57%) had reported hearing symptoms compared to mechanical cutters (n=6, 43%) and longer work years was found to be significantly associated with hearing symptoms (p=0.049). There is a need of appropriate education and training on noise exposure, NIHL and hearing protection devices usage in the workplaces

Matched MeSH terms: Hearing Loss, Noise-Induced; Noise, Occupational
Image signal-to-noise ratio and noise variance estimation using autoregressive model

Kamel NS, Sim KS

Scanning, 2004 12 23;26(6):277-81.
PMID: 15612204

During the last three decades, several techniques have been proposed for signal-to-noise ratio (SNR) and noise variance estimation in images, with different degrees of success. Recently, a novel technique based on the statistical autoregressive model (AR) was developed and proposed as a solution to SNR estimation in scanning electron microscope (SEM) image. In this paper, the efficiency of the developed technique with different imaging systems is proven and presented as an optimum solution to image noise variance and SNR estimation problems. Simulation results are carried out with images like Lena, remote sensing, and SEM. The two image parameters, SNR and noise variance, are estimated using different techniques and are compared with the AR-based estimator.

Matched MeSH terms: Signal-To-Noise Ratio
Evaluation of real-world preferences and performance of hearing aids fitted according to the NAL-NL1 and DSL v5 procedures in children with moderately severe to profound hearing loss

Quar TK, Ching TY, Newall P, Sharma M

Int J Audiol, 2013 May;52(5):322-32.
PMID: 23570290 DOI: 10.3109/14992027.2012.755740

The study aims to compare the performance of hearing aids fitted according to the NAL-NL1 and DSL v5 prescriptive procedure for children.

Matched MeSH terms: Noise/adverse effects
Fulltext Factors of job satisfaction among workers exposed to occupational noise

Irniza Rasdi, Noraini Mohd Zin, Sharifah Norkhadijah Syed Ismail

Malaysian Journal of Medicine and Health Sciences, 2019;15(204):141-146.
MyJurnal

Introduction: Noise was evident to reduce job satisfaction among workers which will negative impacts to workers including increase job turnover, decrease motivation and increased number of accidents. This study aims to explore job satisfaction and its risk factors among workers working in a noisy workplace. Method: The study design was cross-sectional study which involved 167 workers in a cable manufacturing factory selected by simple random sam- pling. MSQ was used to assess employee’s satisfaction with their job on seven facets and sound level meter was used to measure workplace noise level. Results: All respondents were exposed to noise above permissible exposure limit. Most workers (49%) were moderately satisfied with their work. Factors that were rated as lowest level of satisfaction were work itself (the ability to work alone) (40%) and the way company system policies are implemented (40%). Factors with the highest level of satisfaction were their freedom to implement their judgement (responsibility) (51%) and the supervision quality of their superiors (51%). The most dominant facet predicting total satisfaction level was recognition followed by advancement and company policy and administration. All variables in socio-demographical and job characteristics were not significantly associated with their level of job satisfaction except noise. Noise was significant in predicting one facet of job satisfaction which was physical work condition. Conclusion: Overall, the average level of job satisfaction among respondents were moderate and they were exposed to occupational noise which was the only significant study variable correlated with their job satisfaction.

Matched MeSH terms: Noise, Occupational
The use of warning lights and siren by the ambulance crew in the Universiti Kebangsaan Malaysia Medical Centre

Ismail AK, Mohd Salleh NI, Hamdan NA, Mohd Jawi MI, Abdul Razak SN, Md Jamal S, et al.

Eur J Emerg Med, 2012 Dec;19(6):408-9.
PMID: 22343753 DOI: 10.1097/MEJ.0b013e328351e62e
Matched MeSH terms: Noise, Transportation*

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