Masking Properties Research Articles

Разработка маршрута ресинтеза комбинационных логических схем с целью повышения маскирующих свойств

This paper is devoted to development of combinational circuits resynthesis flow aimed at soft error tolerance improvement. Sensitivity factor, i.e. average number of non-reliable elements, is used as fault-tolerance metric, as well as circuit's “sensitive area” which additionally considers areas of standard cells. Re-synthesis algorithm involves iterative replacement of some sections of circuit by functionally equivalent blocks with better masking properties. Result can be achieved by adding redundancy, or by implementing more optimal structure with respect to fault tolerance. When estimating masking properties, circuit section is considered to be separate circuit, which speeds up program performance. We use input test patterns for subcircuit in accordance with their probabilities and observability of subcircuit outputs at primary circuit outputs to take into account influence of surrounding gates during optimal structure selection. The algorithm was tested on circuits from ISCAS'85 and LGSynth'89 benchmarks synthesized with different optimization parameters using two different standard digital libraries.

Subjective evaluation of quality and intelligibility of speech distorted by synthesized noise

The distortion of the speech signal by noise interferences negative impacts on the perception of speech information by listeners, and a noise disturbance in the form of people conversations has the best masking ability. This phenomenon is usually used when the intelligibility of speech should be minimal. Therefore, there are nowadays many different acoustical systems generating acoustic noise in the form of stationary or non-stationary noise for active masking of speech information. Assessment of acoustic masking quality for systems generating stationary noise can be made by means of formant technique and speech intelligibility can be used as a measure of masking quality for such systems. Previously, it was theoretically shown that masking property of white noise is worst at low signal-to-noise ratio. However, this result was not tested by subjective testing. Moreover, masking ability of nonstationary noise was not tested too. In this paper, this gap has been eliminated and the results of subjective estimation of the effect of stationary and nonstationary synthesized noise on the quality and intelligibility of speech signals are presented. Degradation Mean Opinion Score (DMOS) measure of speech quality was used for the estimation. It was used the fact of high correlation (about 0.9) between speech quality and intelligibility upon results interpretation. For the case of stationary noise, it was shown that for signal-to-noise ratios below minus 5 dB white noise is inferior to pink and brown noise by masking ability. This result is in a good agreement with previously theoretically predicted one. Two simple, from the computational point of view, non-stationary noise generation algorithms were studied also. The first algorithm uses both spectrum inversion and reverberation simulation. Second algorithm is based on formation of nonstationary process as result of noise carrier amplitude modulation by envelope of speech signal. It was found that these nonstationary processes provide a better, in comparison with white noise, masking of speech signals. These nonstationary processes have the significant advantage compare to stationary ones because they provide less environmental pollution during speech pauses.Ref. 12, fig. 8.

Quaternion discrete fractional random transform for color image adaptive watermarking

As for the fractional transforms, to date only fractional Fourier transform (FrFT) has been applicable to color images in a holistic manner by using the quaternion algebra, yet, discrete fractional random transform (DFRNT) with the useful intrinsic randomness is still to be explored. This paper first defines quaternion DFRNT (QDFRNT) which generalizes DFRNT to efficiently process quaternion signals, and then applies QDFRNT to color image adaptive watermarking. For the QDFRNT, this paper also derives the relationship between QDFRNT of a quaternion signal and DFRNT of four components for this signal to efficiently compute QDFRNT. For the color image adaptive watermarking based on QDFRNT and SVM, in order to efficiently utilize the color information in the adaptive process, this paper also exploits the human vision system’s (HVS) masking properties of texture, edge and color tone directly from the color host image to adaptively adjust the watermark strength for each block. In addition, the constraints in watermark embedding are discussed to preserve the watermarking energy. Experimental results show that: (a) the proposed efficient computation method takes only half the computational time of the direct method; (b) the comparison of five color models (RGB, YUV, YIQ, CIEL*a*b* and YCbCr) shows that the proposed QDFRNT-based watermarking scheme using YCbCr color model has the overall best performance and can achieve a good balance between invisibility and robustness to the Checkmark attacks; (c) The proposed scheme is superior to the existing schemes respectively using DCT, DFRNT, discrete quaternion Fourier transform (DQFT), discrete fractional quaternion Fourier transform (DFrQFT), and quaternion radial moments (QRMs). Moreover, the fractional order and the random matrix of QDFRNT enhance the security of the proposed scheme.

A perceptually motivated LP residual estimator in noisy and reverberant environments

Both reverberation and additive noise can degrade the quality of recorded speech and thus should be suppressed simultaneously. Previous studies have shown that the generalized singular value decomposition (GSVD) has the capability of suppressing the additive noise effectively, but it is not often applied for speech dereverberation since reverberation is considered to be convolutive as well as colored noise. Recently, we revealed that late reverberation is also additive and relatively white interference component in the linear prediction (LP) residual domain. To suppress both late reverberation and additive noise, we have proposed an optimal filter for LP residual estimator (LPRE) based on a constrained minimum mean square error (CMMSE) by using GSVD in single channel speech enhancement, where the algorithm is referred as CMMSE-GSVD-LPRE. Experimental results have shown a better performance of the CMMSE-GSVD-LPRE than spectral subtraction methods, but some residual noise and reverberation components are still audible and annoying. To solve this problem, this paper incorporates the masking properties of the human auditory system in the LP residual domain to further suppress these residual noise and reverberation components while reducing speech distortion at the same time. Various simulation experiments are conducted, and the results show an improved performance of the proposed algorithm. Experimental results with speech recorded in noisy and reverberant environments further confirm the effectiveness of the proposed algorithm in real-world environments.

Enhancement of noise-suppressed speech by spectral processing implemented in a digital signal processor

This paper presents a noisy suppressed speech enhancement method by combining the basic spectral subtraction technique and spectral processing in the frequency domain to provide better noise suppression as well as better enhancement in the speech regions. In contrast to several previous approaches we do not try to achieve a complete removal of the noise, but instead our goal is to preserve a pre-defined amount of the original noise in the processed signal. This is accomplished by exploiting the masking properties of the human auditory system. The proposed algorithm is named PM “Proposed Method” which simulates properties of the human auditory system and applies it to the speech recognition system to enhance its robustness. The performance of the speech enhancement algorithm using the proposed masking model was compared with three other speech enhancement methods over 4 different noise types and five SNRs. The performances of the proposed approach are objectively and subjectively compared to the conventional approaches to highlight the aforementioned improvement. In this paper we discuss the design and development of a digital signal processor (DSP) implementation to achieve real-time performance of our filter. The target processor is a Texas Instruments TMS320C6713 floating point DSP.

Estimating just‐noticeable distortion for images/videos in pixel domain

Existing pixel-based just noticeable distortion (JND) models only take into account luminance adaptation and texture masking (TM). Similarly, existing discrete cosine transform (DCT) based models do not take into account foveal vision effects and do not estimate TM efficiently. As human visual system (HVS) is not sensitive to distortion below the JND threshold, estimation of the perceptual visibility threshold is widely used in digital and video processing applications. The authors propose a comprehensive and efficient pixel-based JND model incorporating all major factors which contribute to the JND estimation. The evaluation of contrast masking (CM) is done by distinguishing the edge and TM with respect to the entropy masking properties of the HVS. Similarly, the foveal vision effects are also taken into account for the comprehensive estimation of contrast sensitivity function (CSF). Hence, the proposed pixel-based JND model incorporates the spatio-temporal CSF, foveal vision effects, influence of eye-movement, luminance adaptation and CM to be more consistent with human perception. The incorporation of these important factors makes the proposed model the most comprehensive and efficient in the current literature. Psychophysical experiments were performed to test the proposed model. The results show the proposed model comprehensively outperforms other existing models proving its efficiency.

Inclusion complex of neohesperidin dihydrochalcone and glucosyl-β-cyclodextrin: Synthesis, characterization, and bitter masking properties in aqueous solutions

The objective of this study was to synthesize a new water-soluble bitterness inhibitor—neohesperidin dihydrochalcone (NHDC)/glucosyl-β-cyclodextrin (G-β-CD) inclusion complex via ultrasonic-assisted technique in the ethanol aqueous solution, and also assess its bitterness-masking effect on corn peptides (CPs) using descriptive sensory analysis. Under the optimal synthetic condition, the NHDC payload was 278mg/g and inclusion rate was 74.6%. The scanning electron microscopy (SEM) observation demonstrated that NHDC was inserted into the cavity of G-β-CD. The disposition of NHDC/G-β-CD inclusion complexes were affirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Furthermore, the molecular structures of the complexes were explored by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR). Results clearly indicated that the formation of a multicomponent complex was held together by hydrophobic interaction or hydrogen bond. The CP-debittering assessment showed that the prepared NHDC/G-β-CD inclusion complex possessed a more superior bitterness-masking effect on CP compared to single NHDC or G-β-CD, and other bitterness inhibitors, such as phosphatidic acid, protein-phosphatidic acid complexes, tannin, and neodiosmin. Therefore, this inclusion complex has a potential use for debittering of CP-based food and drugs.

Masking properties of ceramics for veneer restorations

Statement of problemThe translucency and opacity of ceramics play a significant role in emulating the natural color of teeth, but studies of the masking properties and limitations of dental ceramics when used as monolayer restorations are lacking. PurposeThe purpose of this in vitro study was to determine the translucency of 6 materials used for veneer restorations by assessing their translucency parameters (TPs), contrast ratios (CRs), and potential to mask dark tooth colors. Material and methodsTen square- or disk-shaped specimens (0.5-mm thickness, shade A2) were fabricated from Vitablocks Mark II (VMII; Vita Zahnfabrik), IPS e.max CAD LT (EMXC LT; Ivoclar Vivadent AG), IPS e.max CAD HT (EMXC HT; Ivoclar Vivadent AG), IPS Empress CAD LT (EMP LT; Ivoclar Vivadent AG), IPS e.max Press LT (EMXP LT; Ivoclar Vivadent AG), and CZR (CZR; Kuraray Noritake Dental Inc). Their luminance (Y) values over black and over white tiles were measured, followed by their color (CIELab) over black tiles and white tiles and shaded A2 (control group), A3.5, A4, and B4 acrylic resin blocks. All measurements were performed using a spectrophotometer in 2 different areas on each specimen. Then CRs, TPs, and color differences (over shaded backgrounds) were determined. Data were subjected to 1-way and 2-way ANOVA (α=.05) for analysis. ResultsMean CR values of EMXP LT were significantly higher than those of the other tested materials, whereas VMII and EMXC HT had the lowest values (P<.001). Mean TP values over black and over white backgrounds of VMII and EMXC HT were significantly higher than those of the other tested materials, while EMXP LT and EMXC LT revealed the lowest values (P<.001). Background shade A4 displayed the highest mean effect (expressed in ΔE* values) on the color of the ceramic materials, whereas shade B4 demonstrated the lowest mean background effect (P<.001). ConclusionsSignificant differences in translucency among the tested ceramics were revealed (P<.001). The EMXC LT and EMXP LT groups were the least translucent under the conditions of this study (P<.001). All tested ceramics exhibited poor masking properties against the A4 background. The color differences of most tested ceramics were more acceptable when tested against the B4 background (ΔE*≤3.3).

Exploring Use of the Coordinate Response Measure in a Multitalker Babble Paradigm.

Three experiments examined the use of competing coordinate response measure (CRM) sentences as a multitalker babble. In Experiment I, young adults with normal hearing listened to a CRM target sentence in the presence of 2, 4, or 6 competing CRM sentences with synchronous or asynchronous onsets. In Experiment II, the condition with 6 competing sentences was explored further. Three stimulus conditions (6 talkers saying same sentence, 1 talker producing 6 different sentences, and 6 talkers each saying a different sentence) were evaluated with different methods of presentation. Experiment III examined the performance of older adults with hearing impairment in a subset of conditions from Experiment II. In Experiment I, performance declined with increasing numbers of talkers and improved with asynchronous sentence onsets. Experiment II identified conditions under which an increase in the number of talkers led to better performance. In Experiment III, the relative effects of the number of talkers, messages, and onset asynchrony were the same for young and older listeners. Multitalker babble composed of CRM sentences has masking properties similar to other types of multitalker babble. However, when the number of different talkers and messages are varied independently, performance is best with more talkers and fewer messages.

Variance normalized perceptual subspace speech enhancement

In this paper, a perceptual subspace speech enhancement method using masking property of the human auditory system and variance normalization is presented. The simultaneous masking property of the human auditory system is used while deciding the gain parameters of the algorithm. Spectral Domain Constrained estimator was employed in determining the filter coefficients, and colored noise was handled by replacing the noise variance by Rayleigh quotient. Normalized variance was used as control parameter which adaptively decided the amount of filtering to be performed. Adaptively varying the control parameter enabled the proposed algorithm to perform better in non-stationary colored noise environments, compared to some of the other existing algorithms. The waveforms and spectrograms indicate that the proposed algorithm removes most of the noise without distorting the speech signal. The results obtained in terms of objective parameters (wcep,WSS,SNRLOSS and SNRLESC) and informal listening test support the claim.

A Watermarking Algorithm Based on DCT and JPEG Quantization Table

In this paper, we propose a scheme of watermark embedding and extracting based on DCT transform and JPEG quantization table. Firstly, the image is divided into non-overlapping 8 × 8 blocks, and each block is transformed by DCT. Then, a pair of points with the same quantization value is selected by the JPEG quantization table in order to embed one watermark bit, and the adjustment coefficients are adaptively selected by using the visual masking property of HVS. The experimental results presented in this paper showed that our proposed algorithm is robust to JPEG compression under different quality factors.

Joint 3-D Image Quality Assessment Metric by Using Image View and Depth Information Over the Networking in IoT

It is accepted that image compression and transmission are essential in the image processing system and that errors occurred may introduce the degradation on the quality of the received image over the wireless transmission for intelligent Internet of things (IoT). Image quality assessment metric (QAM) is of fundamental significance to various image processing systems, and the goal of studying the QAM is to design an algorithm that can automatically evaluate the quality of the received image at the terminal display equipment in a perceptible way under the ubiquitous network circumstances. In this paper, focusing on the image compression and transmission, a joint full-reference (FR) QAM ( JQAM ) for evaluating the quality of a 3-D image is proposed based on the state-of-the-art physiological and psychological properties of the human visual system (HVS) for image transmission under the wireless networks. The major technical contribution of this paper is that the binocular perception (depth perception) and local image properties are taken into consideration. First, the luminance masking property and local image content information are calculated to establish image QAM (IQAM) to improve the abilities of current quality evaluation algorithms. Meanwhile, the information abstracted from the depth map is also utilized as side information (SI) to evaluate the depth map on quality assessment. Finally, IQAM and SI are combined to construct the proposed JQAM. Experimental results show that the proposed metric could achieve better correlation with the subjective quality scores compared with the relevant existing IQAMs, and it could be used to evaluate the quality of the 3-D image signal of the intelligent equipment for multimedia communication systems in IoT.

A saliency-modulated just-noticeable-distortion model with non-linear saliency modulation functions

It is well-known that the human visual system (HVS) cannot sense small variations of visual signals below the so-called just-noticeable distortion (JND) thresholds due to their underlying spatial/temporal masking properties. It is also known that the visual attention mechanism of the human brain can enhance or reduce visual sensitivity. In other words, the visual attention has modulatory effects on JND thresholds. The current knowledge also states that the visual attention is mainly driven by visual saliency in an automatic and involuntary manner. In this paper we present a saliency-modulated JND (SJND) model for static images in the discrete cosine transform (DCT) domain. In the proposed model, the JND thresholds of each block in a given image are elevated by two non-linear modulation functions using the visual saliency of the block. The parameters of the saliency modulation functions are obtained through an optimization framework, which utilizes a state-of-the-art saliency-based objective image quality assessment method. To evaluate the proposed SJND model, two subjective experiments were conducted. The obtained experimental results demonstrated that the proposed method achieves a high accuracy in JND estimation, and also it provides a high distortion-hiding capacity.

Silica layers as masks in Ag+-Na+ ion exchange processes

The paper present the application of sol-gel derived silica layers as masks in selective ion exchange processes. These layers were deposited on soda-lime glass substrates, subjected then to the ion exchange processes using liquid source of admixture in the form of a AgNO3:NaNO3 solution with a molar fraction of silver κAg=0.0025. The concentration of silver in the masked and non-masked areas of the glass were examined with the use of Scanning Electron Microscope/Energy-Dispersive X-ray Spectroscopy (SEM/EDS). The resulting silver concentration profiles allowed to estimate the masking properties of silica layers. Using sol-gel silica films as masks for selective ion-exchange processes, the multimode strip waveguides were produced.

Reorganized DCT-based image representation for reduced reference stereoscopic image quality assessment

In this paper, a novel reduced reference (RR) stereoscopic image quality assessment (SIQA) is proposed by characterizing the statistical properties of the stereoscopic image in the reorganized discrete cosine transform (RDCT) domain. Firstly, the difference image between the left and right view images is computed. Afterwards, the left and right view images, as well as the difference image, are decomposed by block-based discrete cosine transform (DCT). The DCT coefficients are further reorganized into a three-level coefficient tree, resulting in ten RDCT subbands. For each RDCT subband, the statistical property of the coefficient distribution is modeled by the generalized Gaussian density (GGD) function. And the mutual information (MI) and energy distribution ratio (EDR) are employed to depict the statistical properties across different RDCT subbands. Moreover, EDR can further model the mutual masking property of the human visual system (HVS). By considering the GGD modeling behavior within each RDCT subband and MI together EDR characterizing behavior across RDCT subbands, the statistical properties of the stereoscopic image are fully exploited, including the left view, right view, and the difference image. Experimental results demonstrated that the statistical properties of the difference image can well represent the perceptual quality of the stereoscopic image, which outperforms the representative RR quality metrics for stereoscopic image and even some full reference (FR) quality metrics. By considering the left view, right view, and difference image together, the performances of the proposed RR SIQA can be further improved, which presenting a more closely relationship between the quality metric output and human visual perception.

Durations required to distinguish noise and tone: Effects of noise bandwidth and frequency

Perceptual audio coders exploit the masking properties of the human auditory system to reduce the bit rate in audio recording and transmission systems; it is intended that the quantization noise is just masked by the audio signal. The effectiveness of the audio signal as a masker depends on whether it is tone-like or noise-like. The determination of this, both physically and perceptually, depends on the duration of the stimuli. To gather information that might improve the efficiency of perceptual coders, the duration required to distinguish between a narrowband noise and a tone was measured as a function of center frequency and noise bandwidth. In experiment 1, duration thresholds were measured for isolated noise and tone bursts. In experiment 2, duration thresholds were measured for tone and noise segments embedded within longer tone pulses. In both experiments, center frequencies were 345, 754, 1456, and 2658 Hz and bandwidths were 0.25, 0.5, and 1 times the equivalent rectangular bandwidth of the auditory filter at each center frequency. The duration thresholds decreased with increasing bandwidth and with increasing center frequency up to 1456 Hz. It is argued that the duration thresholds depended mainly on the detection of amplitude fluctuations in the noise bursts.

Taste-masking properties of solid lipid based micropellets obtained by cold extrusion-spheronization

Taste-masked properties of micropellets based on hard fat and/or solid lipid mixtures (prepared by solvent-free cold extrusion/spheronization), containing metformin hydrochloride were investigated. An in-line and an on-line drug release profile evaluation of the pellets was performed and further correlated with an electronic tongue investigation. The pellets based on more than 30% of lipid binders showed metformin HCl releases below 10% after 30s of dissolution. Micropellets based on 20 and 30% of lipids showed immediate drug release profiles. Likewise, the electronic tongue assay showed a decrease in the sensor responses related to the increase of lipid amount in the formulations denoting a significant improvement in the taste masking properties of pellets based on more than 30% of lipid binders. A slight difference between pellets based on hard fat only and pellets based on ternary lipid mixtures was evidenced. Solvent-free cold extrusion/spheronization using solid lipids showed to be a robust method to obtain high drug loaded metformin HCl micropellets with adequate taste-masked properties and immediate drug release profile.

Forward masking in the superior paraolivary nucleus of the rat.

In natural acoustic environments, perception of acoustic stimuli depends on the recent contextual history. Forward masking describes a phenomenon whereby the detection threshold of a probe stimulus is markedly increased when it is preceded by a masking stimulus. The aim of this study was to characterize the offset response of single units in the superior paraolivary nucleus (SPON) to a forward masking paradigm. We observed two distinct response types to forward-masked stimuli, namely inhibited and facilitated responses. In the presence of a default masking stimulus, inhibited responses to probe stimuli were characterized by elevated thresholds and/or diminished spike counts, whereas facilitated responses were characterized by reduced thresholds and increased spike counts. In units with inhibited responses to the probe stimuli, probe thresholds increased and spike counts decreased as masker intensity was raised or the masker-to-probe delay was shortened. Conversely, in units with facilitated responses to the probe stimuli, probe thresholds decreased and spike counts increased as masker intensity was raised or the masker-to-probe delay was shortened. Neither inhibited nor facilitated responses to the forward masking paradigm were significantly dependent on masker frequency. These findings suggest that SPON responses are not themselves consistently subject to the same forward masking properties observed in other nuclei along the ascending auditory pathway. The potential neural mechanisms of the forward masking responses observed in the SPON are discussed.

A study of the effect of the structure of plasma-chemical silicon nitride on its masking properties

Dependence of the chemical composition of a film of plasma-chemical silicon nitride on the technological parameters of the deposition process is studied. The stages in which the process parameters are optimized in order to improve the masking properties of the film are described. A systematic study of the Fourier-transform infra-red (IR) spectra of plasma-chemical silicon-nitride films is carried out. It is found that the chemical resistance of a silicon-nitride film depends on the configuration in which hydrogen is incorporated into chemical bonds.

Simple outlier labeling based on quantile regression, with application to the steelmaking process

This paper introduces some methods for outlier identification in the regression setting, motivated by the analysis of steelmaking process data. The proposed methodology extends to the regression setting the boxplot rule, commonly used for outlier screening with univariate data. The focus here is on bivariate settings with a single covariate, but extensions are possible. The proposal is based on quantile regression, including an additional transformation parameter for selecting the best scale for linearity of the conditional quantiles. The resulting method is used to perform effective labeling of potential outliers, with a quite low computational complexity, allowing for simple implementation within statistical software as well as commonly used spreadsheets. Some simulation experiments have been carried out to study the swamping and masking properties of the proposal. The methodology is also illustrated by some real life examples, taking as the response variable the energy consumed in the melting process. Copyright © 2015 John Wiley &amp; Sons, Ltd.