Masking Properties Research Articles

Color and masking properties of translucent monolithic zirconia before and after glazing.

Purpose 1. to assess the ability of four brands of translucent monolithic zirconia with different thicknesses to mask discolored substrates; 2. to assess the influence of glazing upon their color coordinates and masking properties.Methods Sixty samples of shade A1 (0.8, 1.5, and 2.0 mm thickness) from: ZirCAD/MT, Katana/HT, Vita YZ/HT, Cercon/HT were fabricated and glazed using a standardized laboratory procedure. CIE L*a*b* parameters were recorded on composite substrates, (IPS Natural Die Material Kit) (ND1=reference; ND2, ND3, ND4, ND5=test backgrounds), before and after glazing. The color changes of zirconia samples induced by glazing were analyzed. Masking properties was calculated as the color difference between CIE L*a*b* parameters of the samples placed on reference and test substrates with CIEDE2000(1:1:1) formula. The effect of material, thickness, substrate, and glazing on the color of monolithic zirconia was analyzed with ANOVA test and the multiple comparisons were analyzed with Tukey HSD tests (α=0.05).Results After glazing, lightness L* significantly increased, while chromatic coordinates a* and b* decreased (p<0.05). Significant differences in the masking properties of the four materials (p<0.001) were found, with IPS e.max ZirCAD/MT having the lowest masking effect (p<0.001). Thickness, substrate and glazing had a significant effect on the color masking properties of monolithic zirconia (p<0.001).Conclusions Masking properties of translucent zirconia were significantly influenced by the materials, the thickness and the color of the substrate; moreover, glazing improved the masking ability for all zirconia samples.

Reversible Watermarking in Medical Images Using Sub-Sample and Multiple Histogram Modification

This paper proposed a reversible medical image watermarking scheme using multiple histogram modification (MHM) and redundant discrete wavelet transform (RDWT). The MHM was introduced to the proposed scheme to enhance the embedding capacity. By embedding the watermark in the RDWT coefficients, the proposed scheme exploited the visual masking property of RDWT to guarantee the visual quality. Also, the proposed scheme has better performance on embedding capacity because the RDWT has several sub-band coefficients for embedding. The experimental results on medical images suggests that the proposed scheme could meet the demand of perceptional quality with better embedding capacity than former schemes.

Masking flavours for plant proteins

Masking flavours for plant proteins

Application of textile waste derived biochars onto cotton fabric for improved performance and functional properties

Abstract This study investigated the use of textile waste based biochars as fabric additives to improve the clothing performance and impart functional properties to textile materials. For this purpose, cotton, cotton/polyester and acrylic textile wastes were carbonized at low temperature and derived biochars were applied onto cotton fabrics by conventional printing method Moisture transfer, drying properties, water vapor and air permeability and odor adsorption capability of biochar printed fabrics were investigated by using of several methods. Biochar finishing provided a slight hydrophobic effect on the printed face of the cotton fabrics; therefore, a double-face textile structure could be obtained in terms of hydrophilic/hydrophobic behavior. With this feature, it was revealed that the addition of biochars improved the moisture transfer, accelerated the drying and increased the water vapor permeability. In addition, the obtained data showed that cotton/polyester fabric derived biochar printed fabrics had odor masking properties. As a result, it was shown that odor masking functional textile materials with high thermophysiological comfort can be produced by the recycling of textile wastes into biochar and application onto textile fabrics.

Retina-inspired neuromorphic edge enhancing and edge detection

In this paper, a novel analog retinomorphic block performing the edge enhancing and edge detection caused by lateral inhibition phenomenon is proposed. This phenomenon, which occurs in human retina, causes the visual acuity to improve in the edge regions of the object. In contrast to the negative meaning of the word “inhibition”, this type of behavior causes the human eye to act as an analogue image processing chip. The reason for that is the edges of object are enhanced and the contrast ratios in the edge regions of an object are increased owing to the lateral inhibition. We adapt the process of convolution and the concept of image masking used in digital image signal processing method to analog image signal processing method. Our proposed circuit, which exhibits edge enhancing behavior thanks to lateral inhibition, consists of only current mirrors and current subtractor circuits. We obtain the analysis results via a simple circuit design having lateral inhibition feature and the results are quite similar to that occurring in human retina. In addition to the ability of lateral inhibition, we utilize from the masking property of the lateral inhibition circuit and change the coefficients of the mask in order to obtain an edge detecting circuit. For this purpose, we use a mask whose sum of the coefficients is equal to zero. Two different 500 × 500 pixel silicon networks are designed for both edge enhancement and edge detection circuits. We have analyzed an image with the helped of both edge enhancement and edge detection circuits. Analyses results reveal that our suggested block, which is set up using only MOS transistors, can enable edge enhancement and edge detection in grayscale image and lateral inhibition behavior of the human retina can be provided using a simple electronic circuit design which has the ability of performing convolution operation. TSMC CMOS 0.18 μm process model is utilized to simulate proposed two analog circuit networks.

Design, evaluation and optimization of taste masked clarithromycin powder.

Clarithromycin (CLA) is an extremely bitter macrolide antibiotic used to treat paediatric and adult infections. The bitter taste affects patient adherence and may compromise therapy. This research developed a taste masked CLA resinate using Indion® 234, a weak acidic cation exchange resin. The factors affecting formation of the CLA-resin complex were assessed. Design of experiments was used to optimize response while evaluating input variables such as temperature, CLA-resin ratio,stirring time and pH. CLA loading efficiency was determined spectrophotometrically and CLA release using USP Apparatus II. Differential Scanning Calorimetry (DSC), Scanning Electron Microscop (SEM), Fourier Transform Infrared (FT-IR) Spectroscopy and X-ray Diffraction (XRD) were used to confirm complex formation. A spectrophotometric method was used to assess taste evaluation. The optimum CLA-resin ratio, temperature, and stirring time were 1:4, 80 °C, 3 hours, respectively, at pH 8. Characterization techniques revealed that CLA was crystalline and the complex amorphous in nature. FT-IR spectra of resinate revealed the absence of resonance due to the tertiary amine functional group that is responsible for the bitter taste of CLA. CLA was stable in simulated salivary fluid and was released within 3 hours in gastric fluid. All CLAresin batches revealed complete taste masking. Taste analysis highlighted the improvement of taste masking properties of the resinate as the CLA to resin ratio, increased.

Patterning solar cell metal grids on transparent conductive oxides using self-assembled phosphonic acid monolayers

We present a novel, simple and cost-effective method for patterning transparent conductive oxides (TCO) in order to form solar cell's metal grid by electro-plating. Self-assembled monolayers (SAMs) are prepared by dipping substrates in or spraying TCO with perfluorinated and alkylated phosphonic acid solutions. The investigated chemistry and explored deposition parameters on indium tin oxide have resulted in highly hydrophobic surfaces with exceptional coverage of the TCO by the SAMs. The resistance of the deposited layers to acidic plating conditions has been challenging but SAMs at optimized processing conditions have demonstrated masking properties for nickel electroplating.

Development and Evaluation of Acetaminophen Orodispersible Disc with Taste-Masking Property

Orodispersible tablet (ODT) provides rapid disintegration in the oral cavity. ODT improves the efficacy of using medicines especially in term of compliance in a patient with dysphagia. The major challenge of ODT is a bitter taste of active pharmaceutical ingredient (API); they can lead the patients to refuse medication. This study focused on the developing of the orodispersible disc (ODD) with a taste masking property by preparation of API particle that was taste-masked by polymers. The co-precipitation technique was used for the taste masking. Acetaminophen (APAP) taste-masked particles prepared with different grades of crospovidone were investigated for the taste-masking property. Kollidon® CL-SF exhibited the lowest drug release. An increasing amount of Kollidon® CL-SF caused increasing of APAP release. Particles consisted of APAP:crospovidone at ratio 3:1 showed the lowest drug release. It was probably due to the complexation which was shown by the FT-IR and DSC. Taste-masked particles were compressed as ODD by a hydraulic press machine. The disintegrating time of ODD was at the range of 12.62-17.35 s. The dissolution of ODD was focused on the taste-masking zone (drug release in 1 min). The ODD with ratio 3:1 particle (APAP: Kollidon® CL-SF) showed the highest taste-masking performance, the lowest drug release. All disc formulations completely released APAP after 30 min. Therefore, the preparation of ODD contains taste-masked particles was promising to improve patient compliance of bitter APIs.

IMPROVEMENT OF NOISE SILENCER ARMORED VEHICLE KRAZ “BASTION” APPLICATION OF THE GAS SCREEN

Ukraine has been fighting for five years in the east with the Northern Neighbor and for much more time striving for NATO membership. Under these circumstances, the ongoing improvement of military technology. Creation of modern armored cars is topical. One of the important requirements for them – high masking properties. In addition to visual masking there is also sound. In this case, it means reducing the external noise of armored cars. The source of noise and ways to reduce them is a lot. One of the most powerful sources of armored car noise is the noise of the release system, the noise of the bedroom. This type of noise is reduced by means of silencers. The latter are diverse in terms of designs, principles of operation, frequency characteristics and acoustic efficiency. The increase of the acoustic efficiency of silencer noise of the car internal combustion engines was proposed using a gas screen, which until now was used only in aircraft engineering. The essence of the proposal is to create around the outlet branch muffler gas flow, the speed of which is higher than the speed of the outflow of bedrooms. Due to this, the sound waves contained in the sleeping bags will not be able to go into the environment, passing through an additional gas stream, and they will fall onto a special sound absorbing plate. Correspondingly, the sponges will be reflected from this plate and will go to the environment. In this work, for example, the KrAZ Armored Vehicle “Bastion” shows the projected increase in the acoustic efficiency of the existing silencer through the use of a gas screen for the speed of the armored vehicle 45, 50, 75 and 85 km / h. At the same time, the dependence of the difference in speeds of artificially created gas flow and the beds in the muffler of noise from the angle of incidence of sound waves in the flow of bedrooms was calculated. Also shown is the dependence of the angle of incidence of sound waves on the frequency of the latter. Improvement of the existing muffler noise of the internal combustion engines through the use of a gas screen is projected to reduce the external noise of the KrAZ “Bastion” car at 4-6 dB in the range of 45-85 km / h. Keywords: armored vehicle, internal combustion engine, silencer, exhaust gases, noise, noise source, acoustic efficiency, gas screen.

Framework for audio reversible watermarking robust against content replacement with signal restoration capabilities

In the literature, there are robust Reversible Watermarking Schemes (RWS) that allow the extraction of watermarks after the signals have suffered attacks, however the modified carrier signals cannot be restored. On the other hand, self-recovery schemes allow the restoration of the attacked regions of the signals, but the embedding capacity is used for control information, and secret messages cannot be inserted in these type of schemes. In this manuscript a framework for robust reversible watermarking with signal restoration capabilities is proposed. This framework is a general construction that can be followed to implement schemes for different type of media. Previous works that propose a RWS and a self-recovery scheme, both for audio signals, have been taken to construct an implementation of the framework for audio signals. These schemes use the auditory masking properties of audio segments to insert the secret message and the control information required for restoration in a transparent manner. Results obtained with this implementation demonstrate that this construction fulfills a transparency constraint of −2 Objective Difference Grade (ODG) for practical applications, and it reaches payload capacities up to 13 kilobits per second (kbps) with acceptable robustness and adequate quality for the restored signals.

No-Reference Quality Assessment Method for Blurriness of SEM Micrographs with Multiple Texture.

Scanning electron microscopy (SEM) plays an important role in the intuitive understanding of microstructures because it can provide ultrahigh magnification. Tens or hundreds of images are regularly generated and saved during a typical microscopy imaging process. Given the subjectivity of a microscopist's focusing operation, blurriness is an important distortion that debases the quality of micrographs. The selection of high-quality micrographs using subjective methods is expensive and time-consuming. This study proposes a new no-reference quality assessment method for evaluating the blurriness of SEM micrographs. The human visual system is more sensitive to the distortions of cartoon components than to those of redundant textured components according to the Gestalt perception psychology and the entropy masking property. Micrographs are initially decomposed into cartoon and textured components. Then, the spectral and spatial sharpness maps of the cartoon components are extracted. One metric is calculated by combining the spatial and spectral sharpness maps of the cartoon components. The other metric is calculated on the basis of the edge of the maximum local variation map of the cartoon components. Finally, the two metrics are combined as the final metric. The objective scores generated using this method exhibit high correlation and consistency with the subjective scores.

AN IMPROVED ARMORED VEHICLE KRAZ “FIONA” NOISE SILENCER

Ecological requirements for cars grow from year to year, both in the world as a whole, and in Ukraine in particular. This is especially true of noise pollution. Additionally, noise reduction becomes relevant, taking into account the conduct of military operations during the last 5 years on the territory of Ukraine. The war has caused a special need for military vehicles for which masking properties are vital. Noise is a serious disincentive factor. Therefore, its reduction for a military vehicle, apart from the environmental aspect, is of a purely military nature, that is, it is extremely important. The car has many sources of noise there are many ways to deal with them. One of the most powerful source of noise is the sleeping bag. This kind of noise is reduced by means of silencers of noise. The vast majority of silencer data in the basis of its design has a reactive (or resonant) muffler. To calculate the jet silencer you must know the speed of sound in the sleeping bags. In order to increase the acoustic efficiency of reactive and resonant mufflers of exhaust gases noise of the ICE of cars, an experimental method was proposed for determining the speed of sound in the sleighs. Implementation of the method is carried out by measuring the attenuation of acoustic waves. The noise level of the bedrooms is measured without silencer and silencer. Based on the data obtained, the noise reduction performance of the residual is established. From the well-known formula, based on the calculation of the efficiency of the silencing of a jet muffler, a formula is obtained for calculating the speed of sound in the sleeping quays. In this formula, all parameters are known: the level of silencer efficiency, the noise level of the sleeping, the ratio of areas of cross sections of the muffler and the inlet pipe and the length of the muffler. The sound speed thus established can continue to be used not only for engines of the type for which measurements and calculations were made, but also with a certain approximation for some other types of engines. This method provides high accuracy for determining the required parameter. In the given work on the example of the armored car KrAZ “Fiona” the calculation of efficiency increase of the reactive silencer is made due to the above-mentioned method. Also, the projected decrease in the external noise level of the KrAZ Armored Vehicle “Fiona” is considered by determining the speed of sound in the recesses on the trunk cycle on the road with acceleration up to speed of 50 km/h (75 km/h) and the movement with this speed, as well as when driving at a speed of 45 km/h. Keywords: transport, armored car, internal combustion engine, exhaust, exhaust gases, noise, source, acoustic efficiency, acoustic efficiency, speed of sound, jet muffler.

Masking Properties of Structures Based on a Triacrylamide Derivative of Polyfluorochalcone at Wet and Reactive Ion Etching

The masking properties are studied for polymeric structures based on a triacrylamide derivative of polyfluorochalcone at wet etching in aqueous acidic (H2SO4, H3PO4) and alkaline (NaOH) environments, as well as at reactive ion etching (CF4). The kinetic curves are obtained and the etching rates inherent in the photoresists are estimated. A comparison with commercially available photoresists AZ4562 and SU-8 is performed.

Oblique Projection and Cepstral Subtraction in Signal Subspace Speech Enhancement for Colored Noise Reduction

In this paper, a subspace speech enhancement method handling the case of colored noise using oblique projection in the cepstral domain is proposed. Perceptual features and variance normalization are used to reduce the residual noise and improve the intelligibility of the output speech. Initially, the additive noise present in the noisy speech is removed by removing the orthogonal noise subspace from the noisy speech subspace to obtain the speech subspace. Then, the oblique projection of the noise subspace on the speech subspace along the additive noise subspace is used to determine the colored noise that remains. Colored noise removal is performed by power spectral subtraction in the cepstral domain. The spectral domain constrained estimator that incorporates the combined masking property of the human auditory system is employed to estimate the clean speech signal using the variance of the colored noise. To avoid the occurrence of any abrupt spikes in the output, variance normalization is performed by adaptively changing the control parameter of the estimator's gain matrix. The spectrograms, the objective measures and the subjective intelligibility test show the superior performance of the proposed method over the other existing speech enhancement methods.

Self-recovery scheme for audio restoration using auditory masking.

Self-recovery schemes identify and restore tampering, using as a reference a compressed representation of a signal embedded into itself. In addition, audio self-recovery must comply with a transparency threshold, adequate for applications such as on-line music distribution or speech transmission. In this manuscript, an audio self-recovery scheme is proposed. Auditory masking properties of the signals are used to determine the frequencies that better mask the embedding distortion. Frequencies in the Fourier domain are mapped to the intDCT domain for embedding and extraction of reference bits for signal restoration. The contribution of this work is the use of auditory masking properties for the frequency selection and the mapping to the intDCT domain. Experimental results demonstrate that the proposed scheme satisfies a threshold of -2 ODG, suitable for audio applications. The efficacy of the scheme, in terms of its restoration capabilities, is also shown.

Visual Saliency Based Just Noticeable Difference Estimation in DWT Domain

It has been known that human visual systems (HVSs) can be applied to describe the underlying masking properties for the image processing. In general, HVS can only perceive small changes in a scene when they are greater than the just noticeable distortion (JND) threshold. Recently, the cognitive resources of huma visual attention mechanisms are limited, which can not concentrate on all stimuli. To be specific, only more important stimuli will react from the mechanisms. When it comes to visual attention mechanisms, we need to introduce the visual saliency to model the human perception more accurately. In this paper, we presents a new wavelet-based JND estimation method that takes into account the interrelationship between visual saliency and JND threshold. In the experimental part, we verify it from both subjective and objective aspects. In addition, the experimental results show that extracting the saliency map of the image in the discrete wavelet transform (DWT) domain and then modulating its JND threshold is better than the non-modulated JND effect.

Automated Subjective Assessment of Speech Intelligibility in Various Listening Modes

In this paper, the results of automated subjective assessment of Ukrainian speech intelligibility are presented. Speech monosyllables of the consonant-vowel-consonant (CVC) type were listened in two modes: through headphones and through acoustic monitors. The assessment was carried out with the help of specially developed software that allowed automating of articulation tests. Speech listening was done for four situations: pure language; speech distorted by noise; speech distorted by reverberation; speech distorted by the combined effect of noise and reverberation. In the first case, speech monosyllables of 3 articulation tables were listened, each of which contained 50 monosyllables. In the second case, speech distorted by the additive noise with the signal-to-noise ratios (SNR) varied in the range ‑15…+10 dB was listened. In this case, models of white, pink and brown noises were used, the masking properties of which are rather well-studied. In the third case, the reverberant speech for reverberation times in the range 0.3…2.7 s was modeled by convolution of pure speech signals with room impulse responces (RIRs) of various rooms, and in the fourth case the joint action of pink noise and reverberation was considered. It turned out that the masking ability of white noise exceeds one for brown noise for SNR less than minus 5 dB, which is not entirely consistent with preliminary predictive estimates. In addition, it turned out that listening to speech distorted by noise through acoustic monitors could lead to a significant increase in the speech intelligibility, compared to the case of listening through headphones. The analysis of possible causes of abnormal increase in speech intelligibility has been carried out. Early reflections, presence of two loudspeakers, binaural listening, psychophysical features of listeners, as well as peculiarities of software and articulatory testing organization were considered as possible reasons of the phenomenon. After correction of the software and some features of articulation tests it turned out that the results of the speech intelligibility estimation almost coincide when listening to the signals through the headphones and through acoustic monitors, if the distance between the listener and acoustic monitors does not exceed 0.6-0.8 meters. At the same time, these corrections did not differ in the behavior of the dependencies of speech intelligibility on the SNR for small (less minus 5 dB) SNR values The general conclusion may be that listening to speech signals distorted by noise and reverberation interferences, performed with the application of the proposed automated system of articulation tests, indicates the performance and high quality of the developed system.Ref. 13, fig. 7.

Subjective Evaluation of the Speech Intelligibility on the Background of Noise and Reverberation

In this paper, the results of speech intelligibility subjective assessment of Ukrainian speech monosyllabic sound combinations against background noise and reverberation through articulation tests are presented. The evaluation was carried out with the help of specially developed software that allowed automating and thus greatly facilitating and accelerating the procedure of articulation tests. Special text and sound tables of the Ukrainian speech monosyllables of the consonant-vowel-consonant (CVC) type were developed for the tests. The recordings of pure signals were made in the muffled room of the Acoustics and Acoustoelectronics Department of the National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute". The recording was performed at a frequency of 22050 Hz and a bit depth of 16 bits. Speech monosyllables were read using a verbal environment. Listening was done for four situations: pure language; speech distorted by noise; speech distorted by reverberation; speech distorted by the combined effect of noise and reverberation. In the first case, speech monosyllables of 3 articulation tables were listened, each of which contained 50 monosyllables. In the second case, speech distorted by the additive noise with the signal-to-noise ratios minus 10 dB, 0 dB and plus 10 dB was listened. In this case, models of white, pink and brown noises were used, the masking property of which is rather well-studied. In the third case, the reverberant speech for reverberation times from 0.3 to 2.7 s was modeled by convolution of pure speech signals with impulse characteristics of various rooms, and in the fourth case the joint action of pink noise and reverberation was considered. It turned out that the masking ability of white noise exceeds one for brown noise for signal-to-noise ratios (SNR) less than minus 5 dB, which is not entirely consistent with previous preliminary predictive estimates. Signals listening had been made by two ways, namely through the headphones and by means of acoustic monitors. The SNR varied in the range ‑10…+10 dB, and the reverberation time varied in the range 0.3…2.7 s. In addition, it turned out that listening to speech distorted by noise through acoustic monitors could lead to a significant increase in the intelligibility of speech, compared to the case of listening through headphones. With a signal-to-noise ratio of minus 10 dB, the values of speech intelligibility scores increased from 0.1-0.3 to 0.85-0.93. Similar results were obtained for the reverberation action: the speech intelligibility increased from 0.65 to 0.94 for the reverberation time of 2.7 s. This speech intelligibility growth can be explained, firstly, by the action of early reflections. Secondly, usage of two loudspeakers as sound sources and also binaural listening can be also considered as reasons of speech intelligibility increase. Nevertheless, these reasons for increasing the intelligibility of speech are hardly the only ones. Therefore, it is necessary to further study the causes of the revealed significant increase in speech intelligibility. Among such reasons can be both features of the developed automated system of articulation tests, and features of the psychophysical state of listeners.Ref. 13, fig. 5.

Reversible Watermarking in Digital Image Using PVO and RDWT

This article proposed a reversible digital image watermarking scheme using PVO and Redundant Discrete Wavelet Transform (RDWT). The PVO was introduce to the proposed scheme to enhance the embedding capacity. By embedding the watermark in the RDWT coefficients, the proposed scheme exploited the visual masking property of RDWT to achieve better visual quality. Also, the proposed scheme has better performance on embedding capacity because the RDWT has several sub-band coefficients for embedding. The experimental results on natural and medical images suggests that the proposed scheme could meet the demand of perceptional quality with better embedding capacity than former schemes.

Translucency and masking properties of two ceramic materials for heat-press technology.

To assess the translucency of two pressable ceramics and to analyze their masking property when placed on different tooth-shaded backgrounds. Thirty discs (1-mm thickness) were fabricated using two pressable ceramics (shade/translucency): 1M1T/HT, 1M2T/HT, 2M2T (VITA PM9), and A1LT/HT, B1LT/HT, A2LT (e.max Press). Color measurements of discs were performed with a dental spectrophotometer on tooth-colored backgrounds (A1/A2/A3/A3.5/A4), and black and white backings. The masking property was calculated as the color difference (CIEDE2000) between parameters of discs on control (A1, A2) and test backgrounds (A3, A3.5, A4). One-way ANOVA was used for assessing differences in translucency parameter (TP) between ceramics. Two-way ANOVA was used for detecting differences among groups when measured over tooth-shaded backgrounds (α = 0.05, Bonferroni correction). TP ranged between 14.96 (B1LT) and 25.18 (1M1HT). A significant difference in TP was found between tested ceramics (F = 949.949, P < .001). However, TP did not vary significantly between 1M1HT and 1M2HT (P > .05), 1M1T, A1HT and B1HT (P > .05), 1M2T, 2M2T, and A2HT (P > .05). A significant interaction effect of underlying background on color of ceramic discs was found (F = 107.994, P < .001). VITA PM9 demonstrated higher translucency than e.max Press ceramics. Except A1LT, all ceramic materials evaluated showed poor masking properties on A4 background. Highly translucent ceramics should be wisely used for restoring the appearance of dental structures since background color has a large effect upon these materials. The more recently introduced pressable ceramics showed high levels of translucency.