Digital Noise Research Articles

Development of Multiobjective High-Level Synthesis for FPGAs

Traditionally, the High-Level Synthesis (HLS) for Field Programmable Gate Array (FPGA) devices is a methodology that transforms a behavioral description, as the timing-independent specification, to an abstraction level that is synthesizable, like the Register Transfer Level. This process can be performed under a framework that is known as Design Space Exploration (DSE), which helps to determine the best design by addressing scheduling, allocation, and binding problems, all three of which are NP-hard problems. In this manner, and due to the increased complexity of modern digital circuit designs and concerns regarding the capacity of the FPGAs, designers are proposing novel HLS techniques capable of performing automatic optimization. HLS has several conflicting metrics or objective functions, such as delay, area, power, wire length, digital noise, reliability, and security. For this reason, it is suitable to apply Multiobjective Optimization Algorithms (MOAs), which can handle the different trade-offs among the objective functions. During the last two decades, several MOAs have been applied to solve this problem. This paper introduces a comprehensive analysis of different MOAs that are suitable to perform HLS for FPGA devices. We highlight significant aspects of MOAs, namely, optimization methods, intermediate structures where the optimizations are performed, HLS techniques that are addressed, and benchmarks and performance assessments employed for experimentation. In addition, we show the analysis of how multiple objectives are optimized currently in the algorithms and which are the objective functions that are optimized. Finally, we provide insights and suggestions to contribute to the solution of major research challenges in this area.

Effect of Digital Noise Reduction of Hearing Aids on Music and Speech Perception.

Background and ObjectivesAlthough many studies have evaluated the effect of the digital noise reduction (DNR) algorithm of hearing aids (HAs) on speech recognition, there are few studies on the effect of DNR on music perception. Therefore, we aimed to evaluate the effect of DNR on music, in addition to speech perception, using objective and subjective measurements.Subjects and MethodsSixteen HA users participated in this study (58.00±10.44 years; 3 males and 13 females). The objective assessment of speech and music perception was based on the Korean version of the Clinical Assessment of Music Perception test and word and sentence recognition scores. Meanwhile, for the subjective assessment, the quality rating of speech and music as well as self-reported HA benefits were evaluated.ResultsThere was no improvement conferred with DNR of HAs on the objective assessment tests of speech and music perception. The pitch discrimination at 262 Hz in the DNR-off condition was better than that in the unaided condition (p=0.024); however, the unaided condition and the DNR-on conditions did not differ. In the Korean music background questionnaire, responses regarding ease of communication were better in the DNR-on condition than in the DNR-off condition (p=0.029).ConclusionsSpeech and music perception or sound quality did not improve with the activation of DNR. However, DNR positively influenced the listener’s subjective listening comfort. The DNR-off condition in HAs may be beneficial for pitch discrimination at some frequencies.

A review of airport dual energy X-ray baggage inspection techniques: Image enhancement and noise reduction.

In this paper, we present a review of the research literature regarding applying X-ray imaging of baggage scrutiny at airport. It discusses multiple X-ray imaging inspection systems used in airports for detecting dangerous objects inside the baggage. Moreover, it also explains the dual energy X-ray image fusion and image enhancement factors. Different types of noises in digital images and noise models are explained in length. Diagrammatical representations for different noise models are presented and illustrated to clearly show the effect of Poisson and Impulse noise on intensity values. Overall, this review discusses in detail of Poisson and Impulse noise, as well as its causes and effect on the X-ray images, which create un-certainty for the X-ray inspection imaging system while discriminating objects and for the screeners as well. The review then focuses on image processing techniques used by different research studies for X-ray image enhancement, de-noising, and their limitations. Furthermore, the most related approaches for noise reduction and its drawbacks are presented. The methods that may be useful to overcome the drawbacks are also discussed in subsequent sections of this paper. In summary, this review paper highlights the key theories and technical methods used for X-ray image enhancement and de-noising effect on X-ray images generated by the airport baggage inspection system.

Effect of digital enhancement on the radiographic assessment of vertical root fractures in the presence of different intracanal materials: an in vitro study.

To evaluate the effect of enhancement tools of intraoral digital radiographs on the assessment of vertical root fracture (VRF) and to quantify the resultant image noise. Thirty single-rooted human teeth (15 control and 15 fractured) were each radiographed in four intracanal conditions: no filling, gutta-percha, metal post, and fiberglass post, totaling 120 original images. Two filters were applied to the original images-Sharpen filter (SF) and Edge Enhancement filter (EE), and brightness and contrast were adjusted in four combinations (B&C1 to 4), resulting in 840 images. Five oral radiologists analyzed the images for VRF detection. Pixel intensity was obtained in two regions from the radiographs. Diagnostic values were calculated and compared by two-way ANOVA, and the SD values of pixel intensity values were compared by one-way ANOVA (α = 0.05). There were no significant differences in accuracy for VRF detection between the experimental groups (p > 0.05). Teeth with metal post presented the lowest sensitivity (p < 0.05) for all experimental conditions, except for SF and EE (p > 0.05). B&C2, B&C3, and B&C4 had higher specificity than SF (p ≤ 0.05) for all intracanal conditions. Analysis of pixel intensity showed that all enhanced images presented statistically significant higher noise compared to those of the original images (p ≤ 0.05). Digital enhancement tools in digital radiography increase image noise; however, they can be used without compromising VRF detection. The use of digital enhancement does not impair the detection of VRF and, therefore, can be applied for this purpose according to the observer preference.

Randomized benchmarking in the analogue setting

Current development in programmable analogue quantum simulators (AQS), whose physical implementation can be realised in the near-term compared to those of large-scale digital quantum computers, highlights the need for robust testing techniques in analogue platforms. Methods to properly certify or benchmark AQS should be efficiently scalable, and also provide a way to deal with errors from state preparation and measurement (SPAM). Up to now, attempts to address this combination of requirements have generally relied on model-specific properties. We put forward a new approach, applying a well-known digital noise characterisation technique called randomized benchmarking (RB) to the analogue setting. RB is a scalable experimental technique that provides a measure of the average error-rate of a gate-set on a quantum hardware, incorporating SPAM errors. We present the original form of digital RB, the necessary alterations to translate it to the analogue setting and introduce the analogue randomized benchmarking protocol (ARB). In ARB we measure the average error-rate per time evolution of a family of Hamiltonians and we illustrate this protocol with two case-studies of analogue models; classically simulating the system by incorporating several physically motivated noise scenarios. We find that for the noise models tested, the data fit with the theoretical predictions and we gain values for the average error rate for differing unitary sets. We compare our protocol with other relevant RB methods, where both advantages (physically motivated unitaries) and disadvantages (difficulty in reversing the time-evolution) are discussed.

Analysis of the accuracy of actuation electronics in the laser interferometer space antenna pathfinder.

The Laser Interferometer Space Antenna Pathfinder (LPF) main observable, labeled Δg, is the differential force per unit mass acting on the two test masses under free fall conditions after the contribution of all non-gravitational forces has been compensated. At low frequencies, the differential force is compensated by an applied electrostatic actuation force, which then must be subtracted from the measured acceleration to obtain Δg. Any inaccuracy in the actuation force contaminates the residual acceleration. This study investigates the accuracy of the electrostatic actuation system and its impact on the LPF main observable. It is shown that the inaccuracy is mainly caused by the rounding errors in the waveform processing and also by the random error caused by the analog to digital converter random noise in the control loop. Both errors are one order of magnitude smaller than the resolution of the commanded voltages. We developed a simulator based on the LPF design to compute the close-to-reality actuation voltages and, consequently, the resulting actuation forces. The simulator is applied during post-processing the LPF data.

RETRACTED ARTICLE: A brain tumor image segmentation technique in image processing using ICA-LDA algorithm with ARHE model

In digital image processing, image segmentation is the key methodology which is to be used frequently. In digital image processing, noise reduction and enhancement techniques are plays as a vital role. Brain is major and major organ of the human body which is to be controlled by the nervous system. In this paper, we proposed a brain tumor image enhancement technique with the help of the ICA-LDA (independent component analysis-linear discriminate analysis algorithm with ARHE (adaptive region based histogram enhancement) model. Image fusion technique is to apply for combination of the two or more input image. In this paper, the weighted average technique is to be used for image fusion techniques. The noise reduction and enhancement techniques are to be applied in preprocessing stage. The adaptive median filter is to be used for preprocessing stage. The ARHE (adaptive region based histogram enhancement) model is to be used for enhancement present in the preprocessing stage. The feature extraction and the feature optimization have to be utilized with the ICA (independent component analysis). The LDA (linear discriminate analysis) is to be used for the classification techniques. Using this classifier which is to separate the abnormal and normal stages. When the brain tumor is denoted as abnormal case then the morphological based segmentation is to be done. The simulation and result shows the analysis of various parameters such as specificity, sensitivity, positive predictive value, negative predictive value, accuracy, precision, and recall.

Revisiting the digital noise reduction in automatic contouring of “ice-water” objects

This work describes the practical implementation of the method for digital noise suppression during processing images containing ice information to recognize automatically the contours of «ice-water» objects during aerial photography. Images containing ice information have special characteristic structural features related to noise, e.g.granularity, glare, ice crumbs. This makes difficult or even impossible to recognize automatically the contours of ice-water objects. It is known that the success of the application of edge recognition methods depends on how much image noise is reduced. The paper discusses the construction method for the management of noise. The method is based on the sequential application of the Haar wavelet transform denoising using thresholding, clustering by k-means method. For the subsequent automatic construction of ice floes contours the Sobel operator is applied.The aim of the work is to develop a method capable to process digital images effectively that contain ice information with strong digital noise. In this work we treated the images of one-year ice containing strong digital image noise in the form of granularity and in the form of ice crumbs. A description of the features of each of the steps of the proposed method and practical application is given.As a result, the method was developed for processing images of ice information containing digital noise in absolute value commensurate with the basic data. It was noted that the use of the k-means method expands the scope. The k-rare method allows more detailed processing of ice information and distinguishes not only the contours of ice-water objects, but also the contours of ice crumbs.The conclusion formulates the main advantages of the method and the possible application of the algorithm in the process of local exploration of the ice conditions of the Northern Sea Route channel using unmanned aerial vehicle for aerial photography. The usage of unmanned aerial vehicle for aerial photography will increase the frequency of weather forecast updates and predict the appearance of ice objects at the ship’s heading. That will allow us to select the safest and most economical efficient route along the Northern Sea Route.The authors have no competing interests.

DIGITAL OSCILLATOR CIRCUIT WITH AN EXTENDED REPETITION PERIOD OF A PSEUDO-RANDOM PULSE SEQUENCE

In this paper, we consider the issue of upgrading the circuit of a digital generator of a pseudo-random pulse sequence, which can be used to create cryptographic encryption algorithms. The need to modernize the digital generator circuit is associated with an increase in the number of pseudorandom pulse train sequences generated at its output and with pseudorandom intervals between them. To achieve this, a small number of additional elements are included in the circuit of a digital pseudorandom sequence of pulses based on a five-digit shift register with linear feedback. Based on the modernized circuit of a digital generator of a pseudorandom sequence of pulses and an active secondorder Slenlen-Key RC low-pass filter, a digital acoustic noise generator is constructed, which, unlike the prototype, has a truly random output signal over a period of ~ 4 * (2N - 1), subject to circuit simplicity.

Antenna sensitivity variation depending on the installation of a shield can

AbstractThis letter investigates antenna sensitivity with various installations of a shield can. A commonly used shield can, which is widely used to mitigate electromagnetic interference (EMI) in electronic devices, will produce a spurious resonance by the gap between the shield can and the ground when the shield can is mounted on a printed circuit board (PCB) with only a few soldering points. A noise source is simulated as a loop‐type circuit on the ground to model the digital noise produced in an actual device. The installation methods of the shield can is discussed to verify the performance of the antenna sensitivity. In the analysis, the spurious resonance from the shield can is an important factor to the coupling between the antenna and the noise source. A high sensitivity antenna can be achieved by modifying the installation of the shield can. The measurement of a commercial WiFi module is also conducted to demonstrate experimental antenna sensitivity.

Interactions Between Digital Noise Reduction and Reverberation: Acoustic and Behavioral Effects.

Digital noise reduction (DNR) processing is used in hearing aids to enhance perception in noise by classifying and suppressing the noise acoustics. However, the efficacy of DNR processing is not known under reverberant conditions where the speech-in-noise acoustics are further degraded by reverberation. The purpose of this study was to investigate acoustic and perceptual effects of DNR processing across a range of reverberant conditions for individuals with hearing impairment. This study used an experimental design to investigate the effects of varying reverberation on speech-in-noise processed with DNR. Twenty-six listeners with mild-to-moderate sensorineural hearing impairment participated in the study. Speech stimuli were combined with unmodulated broadband noise at several signal-to-noise ratios (SNRs). A range of reverberant conditions with realistic parameters were simulated, as well as an anechoic control condition without reverberation. Reverberant speech-in-noise signals were processed using a spectral subtraction DNR simulation. Signals were acoustically analyzed using a phase inversion technique to quantify improvement in SNR as a result of DNR processing. Sentence intelligibility and subjective ratings of listening effort, speech naturalness, and background noise comfort were examined with and without DNR processing across the conditions. Improvement in SNR was greatest in the anechoic control condition and decreased as the ratio of direct to reverberant energy decreased. There was no significant effect of DNR processing on speech intelligibility in the anechoic control condition, but there was a significant decrease in speech intelligibility with DNR processing in all of the reverberant conditions. Subjectively, listeners reported greater listening effort and lower speech naturalness with DNR processing in some of the reverberant conditions. Listeners reported higher background noise comfort with DNR processing only in the anechoic control condition. Results suggest that reverberation affects DNR processing using a spectral subtraction algorithm in such a way that decreases the ability of DNR to reduce noise without distorting the speech acoustics. Overall, DNR processing may be most beneficial in environments with little reverberation and that the use of DNR processing in highly reverberant environments may actually produce adverse perceptual effects. Further research is warranted using commercial hearing aids in realistic reverberant environments.

Investigation of the influence of optical range sensor noise on the characteristics of the description of objects in cancer diagnosis

The influence of digital noise of the optical range sensor on the characteristics of microscopic objects of study was experimentally evaluated. A reference sample of smears, from which images of medical objects of research were obtained, was formed for the research. Blood cells were used as such objects. As a result of research textural signs are calculated and the analysis of their change is carried out. The obtained estimates allow to draw preliminary conclusions about the degree of noise influence.

Noise Characterization for Time Interleaved Photonic Analog to Digital Converters

We build noise models for analyzing the effect of four main noise terms consisting of the amplitude fluctuation of optical sampling pulse trains, timing jitter of optical sampling pulse trains, quantization and aperture jitter noise of electrical analog to digital converters, and noise in photodiodes on time interleaved photonic analog to digital converters. The analyses indicate that the random processes in the optical sampling pulse train and aperture of electrical analog to digital converters have significant effect on both the unmodulated and modulated components in the sampling results. Both quantization noise of electrical analog to digital converters and noise in photodiodes are unrelated to the optical sampling and can be considered as additive noises. Furthermore, we analyzed digital frequency spectra of different noises after time interleaving. To validate the theoretical model, we conduct the corresponding experiments, indicating the experimental results being consistent with the proposed noise models.

Execution of Median Filter Built on FPGA for Trimming Noise Meeting the Real Time Requirements

As images plays a vital in all aspects, there is a need to met the real time requirements in processing the image. Major challenges raised in processing the image is noise. The utmost typical difficult is effective denoising creation as well as quick functioning in the processing of digital image noise suppression process for the need of real time consequences to afford image with high quality this project was introduced. Generally filters plays a major role to remove the impulse noise in acquired images. The filter named sliding window spatial filter which is familiar as median filter is effective technique to eradicate impulse noise from the devoleped image. But in real time, it is very difficult to execute. To overcome this, FPGA methodology is introduced to fulfills the support besides the optimization of major constraints like area, speed, power. In addition to this, it assures technical sustenance of eradicating noise in image as per requirements in real time. Regarding the design and structure appearances in FPGA, Xilinx software is used for simulation and code has been written in Verilog language.

Study on Residual Phase Noise Effect of Sampling Clock in Fully Digital Phase Noise Measurement

Study on Residual Phase Noise Effect of Sampling Clock in Fully Digital Phase Noise Measurement

An 8 Bit 12.4 TOPS/W Phase-Domain MAC Circuit for Energy-Constrained Deep Learning Accelerators

A small-gate-count 8 bit bidirectional phase-domain MAC (PMAC) circuit is proposed to minimize both area and energy consumption of extremely energy-efficient deep neural network (DNN) accelerators, targeting the Internet-of-Things (IoT) edge devices operating with very strict power budgets (e.g., energy harvesting). PMAC consumes significantly less energy than standard fully digital MACs, due to its efficient analog accumulation nature based on gated-ring oscillator (GRO). The architectural analysis of energy-efficient accelerators is performed, and the energy budget analysis is disclosed. Furthermore, theoretical analysis of PMAC is conducted and comparisons with the conventional analog approaches are shown. By exploiting the DNN digital quantization noise, we further improve the PMAC energy efficiency by designing the internal gain. The bidirectional architecture proposed in this paper achieves an area comparable to those of digital MACs and up to a fivefold improvement in power efficiency. Moreover, the system design constraints are relaxed by eliminating the phase error originating in leakage currents. An asynchronous readout technique and a two-step digital-to-time converter (DTC) to enhance system throughput and compact implementation, respectively, are presented for the first time. We also present DNN hardware-software co-training procedures to show further scaling of the PMAC efficiency. Utilizing such techniques, the measured PMAC achieves peak efficiency of 12.4 TOPS/W in 28 nm CMOS.

Preferences for digital noise reduction and microphone mode settings in hearing-impaired listeners with low and high tolerances for background noise

Objective: To examine whether people with low and high acceptable noise levels (ANLs) have different preferences for aggressiveness of noise reduction (NR) and microphone mode, and whether they get different noise tolerance benefit with these two features.Design: Participants completed laboratory tests of unaided ANL and aided modified ANLs (with speech fixed at two levels) and preferences (at two SNRs) while listening to four levels of NR, three microphone modes and four combinations of NR/directionality.Study sample: Twenty adults with hearing loss; 10 with low ANLs and 10 with high ANLs.Results: Seven individuals with low ANLs and 10 individuals with high ANLs preferred the maximum NR setting; the remaining three individuals with low ANLs had inconsistent preference for NR. Eight people in each ANL group preferred the maximum directional setting (broadband (BB) directionality), the remaining two people in each group had inconsistent preferences for microphone mode.Conclusions: Because most participants preferred the maximum NR and directionality settings, ANLs could not be used to differentially prescribe these hearing aid settings.

Efficacy and Effectiveness of Advanced Hearing Aid Directional and Noise Reduction Technologies for Older Adults With Mild to Moderate Hearing Loss.

The purpose of the present study was to investigate the laboratory efficacy and real-world effectiveness of advanced directional microphones (DM) and digital noise reduction (NR) algorithms (i.e., premium DM/NR features) relative to basic-level DM/NR features of contemporary hearing aids (HAs). The study also examined the effect of premium HAs relative to basic HAs and the effect of DM/NR features relative to no features. Fifty-four older adults with mild-to-moderate hearing loss completed a single-blinded crossover trial. Two HA models, one a less-expensive, basic-level device (basic HA) and the other a more-expensive, advanced-level device (premium HA), were used. The DM/NR features of the basic HAs (i.e., basic features) were adaptive DMs and gain-reduction NR with fewer channels. In contrast, the DM/NR features of the premium HAs (i.e., premium features) included adaptive DMs and gain-reduction NR with more channels, bilateral beamformers, speech-seeking DMs, pinna-simulation directivity, reverberation reduction, impulse NR, wind NR, and spatial NR. The trial consisted of four conditions, which were factorial combinations of HA model (premium versus basic) and DM/NR feature status (on versus off). To blind participants regarding the HA technology, no technology details were disclosed and minimal training on how to use the features was provided. In each condition, participants wore bilateral HAs for 5 weeks. Outcomes regarding speech understanding, listening effort, sound quality, localization, and HA satisfaction were measured using laboratory tests, retrospective self-reports (i.e., standardized questionnaires), and in-situ self-reports (i.e., self-reports completed in the real world in real time). A smartphone-based ecological momentary assessment system was used to collect in-situ self-reports. Laboratory efficacy data generally supported the benefit of premium DM/NR features relative to basic DM/NR, premium HAs relative to basic HAs, and DM/NR features relative to no DM/NR in improving speech understanding and localization performance. Laboratory data also indicated that DM/NR features could improve listening effort and sound quality compared with no features for both basic- and premium-level HAs. For real-world effectiveness, in-situ self-reports first indicated that noisy or very noisy situations did not occur very often in participants' daily lives (10.9% of the time). Although both retrospective and in-situ self-reports indicated that participants were more satisfied with HAs equipped with DM/NR features than without, there was no strong evidence to support the benefit of premium DM/NR features and premium HAs over basic DM/NR features and basic HAs, respectively. Although premium DM/NR features and premium HAs outperformed their basic-level counterparts in well-controlled laboratory test conditions, the benefits were not observed in the real world. In contrast, the effect of DM/NR features relative to no features was robust both in the laboratory and in the real world. Therefore, the present study suggests that although both premium and basic DM/NR technologies evaluated in the study have the potential to improve HA outcomes, older adults with mild-to-moderate hearing loss are unlikely to perceive the additional benefits provided by the premium DM/NR features in their daily lives. Limitations concerning the study's generalizability (e.g., participant's lifestyle) are discussed.

The Effect of Digital Noise Reduction on Annoyance and Speech Perception in Low and High Acceptable Noise Level Groups.

Introduction Studies have reported that although speech perception in noise was unaltered with and without digital noise reduction (DNR), the annoyance toward noise measured by acceptable noise level (ANL) was significantly improved by DNR with the range between 2.5 and 4.5 dB. It is unclear whether a similar improvement would be observed in those individuals who have an ANL ≥ 14 dB (predictive of poor hearing aid user) often rejects their aid because of annoyance toward noise. Objectives (a) To determine the effect of activation of DNR on the improvement in the aided ANL from low- and high-ANL groups; and (b) to predict the change in ANL when DNR was activated. Method Ten bilateral mild to severe sloping sensorineural hearing loss (SNHL) participants in each of the low- and high-ANL groups were involved. These participants were bilaterally fitted with receiver in canal (RIC) hearing aids (Oticon, Smorum, Egedal, Denmark) with a DNR processor. Both SNR-50% (Signal to noise ratio (in dB) required to achieve 50 % speech recognition) and ANL were assessed in DNR-on and DNR-off listening conditions. Results Digital noise reduction has no effect on SNR-50 in each group. The annoyance level was significantly reduced in the DNR-on than DNR-off condition in the low-ANL group. In the high-ANL group, a strong negative correlation was observed between the ANL in DNR off and a change in ANL after DNR was employed in the hearing aid (benefit). The benefit of DNR on annoyance can be effectively predicted by baseline-aided ANL by linear regression. Conclusion Digital noise reduction reduced the annoyance level in the high-ANL group, and the amount of improvement was related to the baseline-aided ANL value.

Empirical Investigation of Noise Reduction Filter for a Flow-Based Spirometer Accuracy Improvement

A turbine spirometer with an IR rotary encoder is designed and fabricated for performing Respiratory Function Tests (RFT). The system includes a hardware for gathering breath inspiratory flow rate and a user software which represents analysed data of patients' breath flow and volume parameters in real-time. The purpose of the paper is evaluating the efficiency of three different types of digital noise reduction filters in term of increasing the accuracy of system in calculation of air volume passing through the spirometer turbine by use of data obtained by a flow sensor. Three distinct kinds of flow waves are experimented and the most sufficient filter for corresponding respiratory function tests are reported. Keywords: spirometer, respiratory function test, noise reduction, IR encoder DOI : 10.7176/CEIS/10-5-01 Publication date :June 30 th 2019