Light Noise Research Articles

Risk assessment of hearing loss of noise workers in three petrochemical enterprises

To evaluate the risk of noise induced hearing loss among workers in petrochemical enterprises. Number of workers exposed to noise were recruited from three petrochemical enterprises. The noise exposure level(L_(EX, W)) of the research objects was measured, their occupational history was investigated, and the audiometric testing was carried out. The ISO 1999:2013 model was used to calculate the change of hearing threshold level and the risk of hearing loss in each post, and compared the result of model with the result of the audiometric testing. The median of L_(EX, W) is range from 79.8 to 85.0 dB(A). L_(EX, W) among all posts were greater than 80 dB(A) except naphtha processing operators. The result of pure tone hearing threshold test showed that the prevalence of high-frequency hearing loss among workers exposed to noise was 12.8%. According to the classification of noise operation according to the maximum value of L_(EX, W), the operator for styrene dry gas combined unit is the only post that is extremely dangerous in the department of chemical, the other posts in the department of chemical and all posts in the department of public works are exposed to light and medium noise hazards, and 62.5% the external operators of the oil refining department are under heavy and extremely hazardous. According to the evaluation result of ISO 1999:2013, the risk of high-frequency hearing loss among workers in crude distillation unit, hydrogen production unit and the electricians of electrical system is high. The measured median of noise-induced pernament threshold shift(NIPTS) among male workers in different workstation was higher than the predicted median of NIPTS of ISO 1999, and the difference was statistically significant(P<0.01), and the predicted values for four-fifths of positions were more than 10 dB lower than the measured value. The risk of noise induced hearing loss of workers in petrochemical enterprises is high.

Image restoration of luminous objects in dense fog

Images captured in dense fog are always severely degraded. For luminous objects, the luminance and contrast of the image are severely reduced due to the strong absorption of suspended particles. In this case, owing to the influence of forward scattered light and detector noise, the signal-to-noise ratio of the image is greatly reduced. Traditional image dehazing algorithms will enhance the noise while improving the image contrast. Here a dynamic equation-based filter is proposed, which can strongly suppress speckle and noise while improving target contrast. Based on this filter, we design an image restoration method for luminous targets in dense fog. The effectiveness of the proposed method is verified by experiments. The experimental results show that the proposed method has a good recovery effect on the luminous targets in dense fog with an optical thickness of 4.51. The proposed method has better performance than the traditional dehazing algorithms and conventional filtering method.

Degradation-aware and color-corrected network for underwater image enhancement

Underwater image enhancement has played an important role in marine resource monitoring and preservation. However, the visual quality of underwater images is degraded due to light attenuation, background noise and water types, which brings challenging problems to underwater image enhancement. Existing Convolutional Neural Network (CNN) based methods do not fully explore degradation issues in different underwater scenes and also ignore color corrected priors, which limit their generalization and representation ability. To address the above mentioned problems, we propose a new Degradation-aware and Color-Corrected Network (DCN). Since it is difficult to estimate the degradation information of underwater image, we use Contrastive Learning (CL) to learn accurate degradation representation from input underwater images via a new degradation encoder. Then, to make the enhancement process adapt to different underwater images with the help of learned degradation representation and a color corrected prior, the DCN is built based on the proposed Degradation-aware and Color-corrected Block (DCB) for enhancing underwater images, which contains a degradation-aware branch, a color-corrected branch and an Edge Sharpness Layer (ESL). The degradation-aware branch recovers the clear image with the help of the degradation representation, while the color-corrected branch based on the color corrected prior compensates for the loss of information in the red channel. Furthermore, the ESL based on the unsharp masking principle is proposed and inserted at the end of the DCB for preserving details and sharpening edges. Such a design enables the DCN enhance underwater images, correct colors and sharpen edges simultaneously. The experiments on both synthetic and real images demonstrate that our method achieves pleasing visual results and outperforms state-of-the-art methods by a large margin.

Analysis and Optimization of Signal Detection Noise of Single-Beam Modulated Atomic Magnetometer Array

Highly sensitive atomic magnetometers (AMs) have been wildly used to form magnetocardiography (MCG) or magnetoencephalography (MEG) devices recently. However, signal detection noise, including light noise due to pump light fluctuations and electrical noise introduced by the detection circuit, will inevitably affect the sensitivity of the AM. Therefore, this article proposes a novel method to suppress signal detection noise and improve the sensitivity of AM. We first propose a low-noise preamplifier circuit to suppress the electrical noise of the signal detection part. Then, based on the equivalent magnetic noise amplitude, a method to optimize the pump light intensity is proposed. The experimental setup has been established. Both the analysis and experimental results can be evaluated that the magnetometer sensitivity can always be maintained at a relatively high-sensitivity level (around 24 fT/Hz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2}$ </tex-math></inline-formula> ) over a wide range of light intensities. We hope that the method proposed in this article can contribute to the improvement of sensor sensitivity in array AM systems.

Using FADOF to eliminate the background light influence in ghost imaging.

The high solar background during the day adversely affects the long distance daytime operations of ghost imaging. It is extremely hard to distinguish the signal light from the background noise light after they are both converted to voltage or current signals by the bucket detector, so spectral filtering before the detector is quite important. In this work, a Faraday anomalous dispersion optical filter (FADOF) is used in eliminating the background light influence in ghost imaging. Results of lab experiment show that the background light noise tolerance of the ghost imaging with FADOF is at least 18 times bigger than that with a 10 nm optical filter. The method has simple structure, great performance and great algorithms compatibility.

Research on 24-Hour Dense Crowd Counting and Object Detection System Based on Multimodal Image Optimization Feature Fusion

Motivation. In the environment of day and night video surveillance, in order to improve the accuracy of machine vision dense crowd counting and target detection, this paper designs a day and night dual-purpose crowd counting and crowd detection network based on multimode image fusion. Methods. Two sub-models, RGBD-Net and RGBT-Net, are designed in this paper. The depth image features and thermal imaging features are effectively fused with the features of visible light images, so that the model has stronger anti-interference characteristics and robustness to the light noise interference caused by the sudden fall of light at night. The above models use density map regression-guided detection method to complete population counting and detection. Results. The model completed daytime training and testing on MICC dataset. Through verification, the average absolute error of the model was 1.025, the mean square error was 1.521, and the recall rate of target detection was 97.11%. Night vision training and testing were completed on the RGBT-CC dataset. After verification, the average absolute error of the network was 18.16, the mean square error was 32.14, and the recall rate of target detection was 97.65%. By verifying the effectiveness of the multimode medium-term fusion network, it is found to exceed the current most advanced bimodal fusion method. Conclusion. The experimental results show that the proposed multimodal fusion network can solve the counting and detection problem in the video surveillance environment during day and night. The ablation experiment further proves the effectiveness of the parameters of the two models.

High performance telescope system design for the TianQin project

China is planning to construct a new space-borne gravitational-wave (GW) observatory, the TianQin project, in which the spaceborne telescope is an important component in laser interferometry. The telescope is aimed to transmit laser beams between the spacecrafts for the measurement of the displacements between proof-masses in long arms. The telescope should have ultra-small wavefront deviation to minimize noise caused by pointing error, ultra-stable structure to minimize optical path noise caused by temperature jitter, ultra-high stray light suppression ability to eliminate background noise. In this paper, we realize a telescope system design with ultra-stable structure as well as ultra-low wavefront distortion for the space-based GW detection mission. The design requirements demand extreme control of high image quality and extraordinary stray light suppression ability. Based on the primary aberration theory, the initial structure design of the mentioned four-mirror optical system is explored. After optimization, the maximum RMS wavefront error is less than λ/300 over the full field of view, which meets the noise budget on the telescope design. The stray light noise caused by the back reflection of the telescope is also analyzed. The noise at the position of optical bench is less than 10−10 of the transmitted power, satisfying the requirements of space GW detection. We believe that our design can be a good candidate for TianQin project, and can also be a good guide for the space telescope design in any other similar science project.

An automated pipeline for scattered light noise characterization

Scattered light noise (or scattering) affects the sensitivity of gravitational wave detectors in their detection frequency band. The mitigation of such nonlinear and nonstationary noise can be carried out experimentally and employing data analysis techniques, e.g., applying adaptive algorithms to the data affected by noise. We present gwas , a fully automated pipeline based on the time-varying filter empirical mode decomposition (tvf-EMD) algorithm, to identify, characterize, and monitor objects inducing scattering to the gravitational wave detector’s output. The tvf-EMD algorithm is suitable for decomposing signals with time-dependent frequency, such as scattering. The pipeline application to LIGO Livingston data shows that most of the scattering noise present in the third observation run was due to the penultimate mass at the end of the X-arm of the detector (EXPUM), whose motion is excited in the 0.1 Hz to 0.3 Hz frequency range (so-called microseismic band). Furthermore, we show that the pipeline can perform daily analyses, and we test it on six days of LIGO Livingston data. These analyses allowed monitoring of the onset and time evolution of scattering due to the EXPUM in connection with the variability of microseismic band noise measured at the detector site.

Single-Shot Pulsed-LiDAR SPAD Sensor with on-chip Peak Detection for Background Rejection

In recent years, direct Time-of-Flight techniques have been exploited with single-photon detectors to provide long distance ranges and high-frame rates measurements. Detectors based on Silicon Photon Multipliers commonly collect repetitive laser shots to reconstruct a histogram of the TOF of returning pulsed-laser photons, so to discriminate between signal, background light, and detector noise. Instead of performing multi-shot measurements, we propose a single-shot technique capable to provide just one useful TOF per laser pulse, corresponding to the returning peak signal with the highest number of concurrent photons. In this way, ambient background photons and dark counts are rejected, being mostly randomly distributed over time compared to the laser pulse photons. Therefore, there is no need for repetitive laser shots, neither to acquire and store multiple TOFs, nor to post-process any TOF histogram, since each laser shot can provide the useful distance information. We present a sensor chip based on a pixel with 272 SPADs, which concurrently provide an analog signal to a peak detector triggering a multi-hit TDC each time the number of concurrent photons exceeds the previous peak. We report preliminary tests up to 25 m, rejecting 60 klux solar background, with > 95% single-shot success ratio.

Three-dimensional rapid visualization of flame temperature field via compression and noise reduction of light field imaging

Light field (LF) imaging, as an emerging temperature measurement technique, can simultaneously capture the intensity and direction information of radiation in the combustion flow field and has recently attracted extensive attention. However, the dense sampling of the LF introduces a large amount of redundant information and makes the plenoptic data susceptible to noise pollution, which can significantly affect the performance of 3D temperature field reconstruction. To address this problem, a novel approach, i.e., light field compression and noise reduction (LFCNR), is proposed to extract the main features of the projection matrix and separate the noise-related and signal-related subspaces of the plenoptic data, thus improving the reconstruction accuracy and efficiency. The performance of the proposed LFCNR method and the effect of the hyper-parameters on reconstructed quality are investigated thoroughly. It has been observed that the proposed LFCNR-based method for 3D temperature tomography imaging has higher accuracy, more efficiency, and better anti-noise ability compared to the well-established method. LFCNR can improve the reconstructed temperature accuracy by approximately 20%, and the calculation time is shortened to 10%. Priori smoothing is introduced into the optimization objective to constrain the fluctuation of the retrieval temperature, called LFCNR-PS, which can further improve the reconstructed accuracy of axisymmetric and non-axisymmetric fields about 1.79% and 1.23%. Furthermore, experiments of the LFCNR-based method are carried out to reconstruct the 3D temperature field of ethylene diffusion flames. The reconstructed temperature slices demonstrate that the flame topology can be clearly and rapidly identified at different depths. The efficiency and robustness of the proposed method can be applied to the harsh environment, which will be beneficial to the reliable operation of thermal equipment, the study of turbulent chemical reaction mechanisms, fuel utilization, and the optimization design of the engine combustion chamber.

Deep learning based end-to-end visible light communication with an in-band channel modeling strategy.

Aside from ambient light noise, shot noise, and linear/nonlinear effects, strong low-frequency noise (LFN) severely affects the signal quality in LED-based visible light communication (VLC) systems, which hinders the implementation of data-driven end-to-end (E2E) deep learning approaches in real LED-VLC systems. We present a deep learning-based autoencoder to deal with this challenge. A novel modeling strategy is proposed to bypass the influence of the LFN and other low signal-to-noise ratio data when training the channel model of our E2E framework. The deep learning-based autoencoder then embeds the differentiable channel model and learns to combat the majority of channel impairments. In the E2E LED-VLC experiment, 1.875 Gbps transmission is achieved under the 7% HD-FEC threshold, 0.325 Gbps faster than the baseline. The E2E framework is robust to signal bias and amplitude variations, implying dimming support in the indoor environment.

Investigating audible and ultrasonic noise in modern animal facilities

Background: The environmental housing conditions of laboratory animals are important for both welfare and reliable, reproducible data. Guidelines currently exist for factors such as lighting cycles, temperature, humidity, and noise, however, for the latter the current guidelines may overlook important details. In the case of the most common laboratory species, the mouse, the range of frequencies they can hear is far higher than that of humans. The current guidelines briefly mention that ultrasonic (>20 kHz) frequencies can adversely affect mice, and that the acoustic environment should be checked, though no recommendations are provided relating to acceptable levels of ultrasonic noise. Methods: To investigate the ultrasonic environment in a large mouse breeding facility (the Mary Lyon Centre at MRC Harwell), we compared two systems, the Hottinger Bruel and Kjaer PULSE sound analyser, and an Avisoft Bioacoustics system. Potential noise sources were selected; we used the PULSE system to undertake real-time Fourier analysis of noise up to 100 kHz, and the Avisoft system to record noise up to 125 kHz for later analysis. The microphones from both systems were positioned consistently at the same distance from the source and environmental conditions were identical. In order to investigate our result further, a third system, the AudioMoth (Open Acoustic Devices), was also used for recording. We used DeepSqueak software for most of the recording analysis and, in some cases, we also undertook further spectral analysis using RX8 (iZotope, USA). Results: We found that both systems can detect a range of ultrasonic noise sources, and here discuss the benefits and limitations of each approach. Conclusions: We conclude that measuring the acoustic environment of animal facilities, including ultrasonic frequencies that may adversely affect the animals housed, will contribute to minimising disruption to animal welfare and perturbations in scientific research.

A novel self-powered filterless narrow-band near-infrared photodiode of Cu2S/Si p+-p isotype heterojunction device with very low visible light noise

This study aims to achieve a filterless, narrow-band, near-infrared photodiode based on a p+-Cu2S/p-Si isotype heterojunction device. The device is developed by depositing 60 nm thick Cu2S thin film on Si substrates from Copper Sulfide pieces via the Thermionic Vacuum Arc technique (TVA). The molecular structure of the thin film is analyzed by utilizing Raman and X-Ray photoelectron spectroscopy (XPS) and confirmed to be in the Cu2S phase. Moreover, the high hole concentration in Cu2S is correlated with XPS results. The photodiode exhibits a response climax centered at 1049 nm and a full-width at half-maximum (FWHM) value of 104 nm. An outstanding responsivity value of 375 mA/W (at 0 V bias) is obtained at a peak wavelength of 1049 nm, which surpasses most filterless, narrow-band photodiodes. Furthermore, while operating at 0 V bias, the photodiode showed an excellent specific detectivity value of 4.17 × 1011 Jones with a 1.7 × 103 on/off ratio (at 1049 nm, 11.47 mW/cm2), in addition to its high photocurrent stability and response speed (under 0.8 s). In light of these findings, this proof-of-concept device is a great candidate as a filterless, narrow-band, NIR self-powered photodiode.

Performance of the Reed-Solomon-coded underwater optical wireless communication system with orientation-based solar light noise.

Various physical and chemical properties of seawater degrade the performance of the underwater optical wireless communication (UOWC) system. Implementing a forward error correction (FEC) coding scheme, advanced modulation, and signal processing techniques improves the UOWC system performance. So far, the implementation of FEC codes over the UOWC system has not been discussed with the system receiver (Rx) orientations. The undersea background noise is a challenge to the UOWC system, and the solar noise is robust in this category. The system Rx experiences unequal solar noise density when it faces different orientations. This paper evaluates the performance of the UOWC system, implementing the Reed-Solomon (RS) coding scheme when the Rx meets different orientations, and presents a computational model to find out energy-efficient RS code for a specific direction. The theoretical evaluation demonstrates that a fixed RS code is not always energy-efficient to the system when the Rx moves in various orientations.

Evaluation of the Physical Work Environment of Miners in Kutai Kartanegara, East Kalimantan

Introduction: Mining is a field of work that has a high potential of risk, both in terms of health risks and safety risks. In its business processes, environmental factors are one of the potential risks that cannot be avoided by every employee. Physical work environment factors are everything around the workplace that can affect workers, either directly or indirectly, and can cause health problems such as headaches, dizziness, nausea, shortness of breath, fatigue, and dehydration. This study aims to determine the physical environmental factors that greatly influence employee productivity. Methods: This study used quantitative methods and the secondary data. Measurement of physical factors applied the standard Threshold Limit Value (TLV) in accordance with the Regulation of the Minister of Manpower of the Republic of Indonesia Number 05 of 2018. Measurements were carried out in the workshop areas, ports, heavy equipment units, and office spaces of each department. In this study, measurements of physical climate include work climate, placement, and lighting. Results: The physical work environment is found to be good enough despite being below the standard in some areas, e.g., the lighting at the administration desk, the noise in the generator room, and some heavy equipment such as bulldozers and dump trucks. Conclusions: The physical work environment is still considered safe and will not cause health problems. However, the arrangement of lighting conditions, work climate, and noise can be improved to meet the overall OHS standards and the evaluation of other work environment factors.Keywords: literature review, metal industry, occupational contact dermatitis.

Investigating audible and ultrasonic noise in modern animal facilities.

Background: The environmental housing conditions of laboratory animals are important for both welfare and reliable, reproducible data. Guidelines currently exist for factors such as lighting cycles, temperature, humidity, and noise, however, for the latter the current guidelines may overlook important details. In the case of the most common laboratory species, the mouse, the range of frequencies they can hear is far higher than that of humans. The current guidelines briefly mention that ultrasonic (>20 kHz) frequencies can adversely affect mice, and that the acoustic environment should be checked, though no recommendations are provided relating to acceptable levels of ultrasonic noise. Methods: To investigate the ultrasonic environment in a large mouse breeding facility (the Mary Lyon Centre at MRC Harwell), we compared two systems, the Hottinger Bruel and Kjaer PULSE sound analyser, and an Avisoft Bioacoustics system. Potential noise sources were selected; we used the PULSE system to undertake real-time Fourier analysis of noise up to 100 kHz, and the Avisoft system to record noise up to 125 kHz for later analysis. The microphones from both systems were positioned consistently at the same distance from the source and environmental conditions were identical. In order to investigate our result further, a third system, the AudioMoth (Open Acoustic Devices), was also used for recording. We used DeepSqueak software for most of the recording analysis and, in some cases, we also undertook further spectral analysis using RX8 (iZotope, USA). Results: We found that both systems can detect a range of ultrasonic noise sources, and here discuss the benefits and limitations of each approach. Conclusions: We conclude that measuring the acoustic environment of animal facilities, including ultrasonic frequencies that may adversely affect the animals housed, will contribute to minimising disruption to animal welfare and perturbations in scientific research.

0850 Exploding Head syndrome and Hypersomnia

Abstract Introduction Exploding head syndrome (EHS) is a hypnagogic parasomnia where the patient experiences a loud noise or flash of light and often reports distress secondary to the stimulus. EHS is relatively uncommon, and to our knowledge, there has been only one published report of comorbid EHS and narcolepsy, describing a 38-year-old male. This report focuses on a pediatric case of EHS, evaluating possible comorbid narcolepsy and sleep apnea. Report of Cases: Eight-year-old male was referred for excessive daytime sleepiness. He endorsed trouble staying awake in school, both in the morning and after lunch time. His Epworth in clinic was a 16, despite nightly sleep duration ≥8 hours. He also endorsed weakness secondary to strong emotions and was observed to have difficulty grasping and holding a pencil while tickled. Patient and his caregiver denied snoring, witnessed apnea, dream enactment, and symptoms of restless leg syndrome. However, the patient did admit to auditory hallucinations, occurring about twice per week during the transition from wakefulness to sleep. He described the hallucination as a banging sound and the sound of clinging bracelets, noting he has searched for the source of the stimulus, but has never been able to find a cause. Patient’s mother denied hearing similar noises. No visual hallucinations or sleep paralysis noted. Polysomnography revealed 0 Central Sleep Apneas, 0 Mixed Apneas, 10 Obstructive Apneas, and 12 hypopneas. The mean duration of these events was 0 seconds. The patient’s Apnea-Hypopnea Index (AHI) was 2.5 and had a REM AHI of 8.3. Patient was supine 75% of the night. Conclusion This case illustrates a unique hypnagogic parasomnia in a pediatric patient. At this point, the patient’s symptoms would suggest EHS characterized by auditory hallucinations that involve hearing the banging sound, upon transition from sleep to wake. The patient also exhibits some narcolepsy type symptoms - hypersomnia, Epworth of 16, and subtle symptoms of cataplexy. In lab PSG – showed overall AHI of 2.5, REM AHI of 8.3- oxygen nadir 90%. Patient referred to ENT for tonsillectomy and adenoidectomy. With follow up NPSG and MSLT if still sleepy. He was referred to behavioral sleep medicine clinic to address anxiety secondary to EHS, but did not attend. Support (If Any)

Research on the applicability of color vision-based roughness inspection method

This study was designed to address the issue that the machine vision-based measurement method of surface roughness based on color information cannot be universally applicable to different machining processes and materials. To this end, the performance of the average color difference (CD) and five typical spectrum indices in the characterization of the surface roughness of two representative texture processes, namely milling and grinding, were explored in the present study. The research results proved that the CD had a stronger correlation with surface roughness and a better robustness to the incident angle than spectrum indices, and the cause for the correlation of index with milling sample being weaker than that with grinding sample was studied from the mechanism. Besides, the correlation between the CD and the surface roughness of different materials was investigated. The results showed that the correlation between roughness and the CD of different materials was stable under different incident angles and ambient light noise. However, the differences in the mathematical relationship models between the indices and the roughness of different materials proved that the materials had a mathematical nature effect on color information detection roughness. In conclusion, this experiment validates the effectiveness of machine vision-based roughness inspection method based on color information and common light sources.

Impact of optogenetic pulse design on CA3 learning and replay: A neural model

SummaryOptogenetic manipulation of hippocampal circuitry is an important tool for investigating learning in vivo. Numerous approaches to pulse design have been employed to elicit desirable circuit and behavioral outcomes. Here, we systematically test the outcome of different single-pulse waveforms in a rate-based model of hippocampal memory function at the level of mnemonic replay extension and de novo synaptic weight formation in CA3 and CA1. Lower-power waveforms with long forward or forward and backward ramps yield more natural sequence replay dynamics and induce synaptic plasticity that allows for more natural memory replay timing, in contrast to square or backward ramps. These differences between waveform shape and amplitude are preserved with the addition of noise in membrane potential, light scattering, and protein expression, improving the potential validity of predictions for in vivo work. These results inform future optogenetic experimental design choices in the field of learning and memory.

EXTRAVERTED CHILDREN SWIM FASTER COMPARED TO INTROVERTED COUNTERPARTS REGARDLESS OF LIGHT AND SOUND NOISE LEVELS

Individual differences of personality are thought to influence motor performance. In terms of cortical arousal levels, because extraverts are infra-activated and introverts are hyper-activated, environment stimuli might enhance the impact of the extraversion trait on task performance. This study investigated the effect of light and sound noise on the swimming performance of extraverted and introverted children. 19 extraverts (12 boys, 7 girls) and 22 introverts (12 boys, 10 girls), ages 8.2 ± 0.9 years, adapted to water and swimming at intermediate levels. Participants performed two trials of the task (swimming 15 meters as fast as possible in crawl style) under two environment conditions: bright light/loud noise (A) and dim light/slight noise (B). Movements were filmed to allow calculation of time to complete the task and the stroke cycle. There was a significant effect for the group factor, with extraverts swimming faster than introverts. No effect was detected for the environment factor or the interaction group/environment. Regarding stroke cycle, no differences were found for group, environment or interaction. Although extraversion has not affected mechanical aspects of crawl style, compared to introverts, extraverts swan faster, showing a more effective process of reacting and executing movements in time-constraints tasks.