A Note on the Masking of Pictures

Perception ◽  
1982 ◽  
Vol 11 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Peter M Forster
Keyword(s):  
Information Processing ◽  
High Frequency ◽  
Visual Information ◽  
Random Noise ◽  
Low Frequency ◽  
Pattern Mask ◽  
Type B ◽  
General Applicability ◽  
Everyday Objects ◽  
Different Types

An experiment is described in which photographs of everyday objects were masked by frequency-filtered random visual noise. The masking functions obtained were of the same type as those obtained by masking letters and words with random noise or a pattern mask. That is, the high-frequency mask produced a type A function while the low-frequency mask produced a type B function. This result is discussed in terms of the general applicability of models of visual information processing constructed on the basis of experiments with letter or word stimuli. It is suggested that spatial-frequency concepts may usefully be employed to describe the relevant features of different types of mask.

scholarly journals Low Frequency Noise Remove from EEG Signal

2020 ◽  
Vol 9 (1) ◽  
pp. 1510-1513
Keyword(s):  
Human Brain ◽  
Random Noise ◽  
Low Frequency ◽  
Frequency Noise ◽  
Eeg Signal ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Average Value ◽  
Different Types ◽  
The Brain

The electrical activity of the brain recorded by EEG which used to detect different types of diseases and disorders of the human brain. There is contained a large amount of random noise present during EEG recording, such as artifacts and baseline changes. These noises affect the low -frequency range of the EEG signal. These artifacts hiding some valuable information during analyzing of the EEG signal. In this paper we used the FIR filter for removing low -frequency noise(<1Hz) from the EEG signal. The performance is measured by calculating the SNR and the RMSE. We obtained RMSE average value from the test is 0.08 and the SNR value at frequency(<1Hz) is 0.0190.

Spatial Scale Interactions and Visual-Tracking Performance

Perception ◽  
1997 ◽  
Vol 26 (8) ◽  
pp. 1047-1058 ◽  
Author(s):  
Howard C Hughes ◽  
David M Aronchick ◽  
Michael D Nelson
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Visual Information ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Performance Measure ◽  
High Frequency Component ◽  
Stimulus Velocity ◽  
Spatial Frequencies ◽  
Wide Range

It has previously been observed that low spatial frequencies (≤ 1.0 cycles deg−1) tend to dominate high spatial frequencies (≥ 5.0 cycles deg−1) in several types of visual-information-processing tasks. This earlier work employed reaction times as the primary performance measure and the present experiments address the possibility of low-frequency dominance by evaluating visually guided performance of a completely different response system: the control of slow-pursuit eye movements. Slow-pursuit gains (eye velocity/stimulus velocity) were obtained while observers attempted to track the motion of a sine-wave grating. The drifting gratings were presented on three types of background: a uniform background, a background consisting of a stationary grating, or a flickering background. Low-frequency dominance was evident over a wide range of velocities, in that a stationary high-frequency component produced little disruption in the pursuit of a drifting low spatial frequency, but a stationary low frequency interfered substantially with the tracking of a moving high spatial frequency. Pursuit was unaffected by temporal modulation of the background, suggesting that these effects are due to the spatial characteristics of the stationary grating. Similar asymmetries were observed with respect to the stability of fixation: active fixation was less stable in the presence of a drifting low frequency than in the presence of a drifting high frequency.

scholarly journals Performance Evaluation of Scalar Multiplication in Elliptic Curve Cryptography Implementation using Different Multipliers Over Binary Field GF (2233)

2020 ◽  
Vol 26 (9) ◽  
pp. 45-64
Author(s):  
Alaa Mohammed Abdul-Hadi ◽  
Yousraa Abdul-sahib Saif-aldeen ◽  
Firas Ghanim Tawfeeq
Keyword(s):  
Elliptic Curve Cryptography ◽  
Performance Index ◽  
High Frequency ◽  
Low Frequency ◽  
Scalar Multiplication ◽  
Maximum Frequency ◽  
Binary Field ◽  
Point Multiplication ◽  
Additional Layer ◽  
Different Types

This paper presents a point multiplication processor over the binary field GF (2233) with internal registers integrated within the point-addition architecture to enhance the Performance Index (PI) of scalar multiplication. The proposed design uses one of two types of finite field multipliers, either the Montgomery multiplier or the interleaved multiplier supported by the additional layer of internal registers. Lopez Dahab coordinates are used for the computation of point multiplication on Koblitz Curve (K-233bit). In contrast, the metric used for comparison of the implementations of the design on different types of FPGA platforms is the Performance Index. The first approach attains a performance index of approximately 0.217610202 when its realization is over Virtex-6 (6vlx130tff1156-3). It uses an interleaved multiplier with 3077 register slices, 4064 lookup tables (LUTs), 2837 flip-flops (FFs) at a maximum frequency of 221.6Mhz. This makes it more suitable for high-frequency applications. The second approach, which uses the Montgomery multiplier, produces a PI of approximately 0.2228157 when its implementation is on Virtex-4 (6vlx130tff1156-3). This approach utilizes 3543 slices, 2985 LUTs, 3691 FFs at a maximum frequency of 190.47MHz. Thus, it is found that the implementation of the second approach on Virtex-4 is more suitable for applications with a low frequency of about 86.4Mhz and a total number of slices of about 12305.

Random Noise Reduction Based on Ensemble Empirical Mode Decomposition and Wavelet Threshold Filtering

2012 ◽  
Vol 518-523 ◽  
pp. 3887-3890 ◽  
Author(s):  
Wei Chen ◽  
Shang Xu Wang ◽  
Xiao Yu Chuai ◽  
Zhen Zhang
Keyword(s):  
Noise Reduction ◽  
Empirical Mode Decomposition ◽  
High Frequency ◽  
Reduction Method ◽  
Random Noise ◽  
Low Frequency ◽  
Ensemble Empirical Mode Decomposition ◽  
Intrinsic Mode Functions ◽  
Mode Decomposition ◽  
Eemd Method

This paper presents a random noise reduction method based on ensemble empirical mode decomposition (EEMD) and wavelet threshold filtering. Firstly, we have conducted spectrum analysis and analyzed the frequency band range of effective signals and noise. Secondly, we make use of EEMD method on seismic signals to obtain intrinsic mode functions (IMFs) of each trace. Then, wavelet threshold noise reduction method is used on the high frequency IMFs of each trace to obtain new high frequency IMFs. Finally, reconstruct the desired signal by adding the new high frequency IMFs on the low frequency IMFs and the trend item together. When applying our method on synthetic seismic record and field data we can get good results.

A Distinction Between Different Types of Stall in a Centrifugal Compressor Stage

1986 ◽  
Vol 108 (1) ◽  
pp. 83-92 ◽  
Author(s):  
N. Ka¨mmer ◽  
M. Rautenberg
Keyword(s):  
Energy Transfer ◽  
Centrifugal Compressor ◽  
High Frequency ◽  
Low Frequency ◽  
Rotating Stall ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Pressure Transducers ◽  
Different Types ◽  
Probe Measurements

The flow at the stall line of a centrifugal compressor with vaneless diffuser was investigated at different speeds. A distinction between three kinds of stall phenomena could be made. One type of stall with regurgitation of fluid at the impeller inlet was of a nonperiodic character, whereas two different types of periodic stall appeared at higher speeds. The rotating nature of these two types of stall was verified from a comparison of signals of peripherally spaced pressure transducers. The low-frequency rotating stall exhibited features of diffuser generated stall and a lobe number of three was measured. From a detailed investigation of the high-frequency rotating stall, which included unsteady probe measurements upstream and downstream of the impeller, it can be shown that this type of rotating stall is generated in the impeller by a periodic breakdown of energy transfer from the rotor to the flow. This conclusion is supported by the distribution of shroud static pressures.

Hue-Tone Sensory Interaction: A Negative Result

1971 ◽  
Vol 33 (3_suppl) ◽  
pp. 1327-1330 ◽  
Author(s):  
Ira H. Bernstein ◽  
Thomas R. Eason ◽  
D. L. Schurman
Keyword(s):  
Information Processing ◽  
High Frequency ◽  
Reaction Times ◽  
Low Frequency ◽  
Sensory Interaction ◽  
Tone Frequency ◽  
Processing Stage ◽  
Location Selection ◽  
Color Selection ◽  
Selective Effects

Choice reaction times (RT) were obtained from four trained Ss to red vs blue targets in four conditions. In three conditions, a noninformative tone occurred on half the trials and could be (a) low frequency, (b) high frequency, or (c) either high or low frequency. Tone never occurred in the fourth condition. As previously observed, tone occurrence produced a nonselective reduction in RT. Contrary to some studies where tone selectivity facilitated detection of blue as opposed to red targets, no such selective effects were obtained. As prior studies (Bernstein & Edelstein, 1971) have found tone frequency to interact with RT to targets differing in location (above vs below fixation), it was concluded that the information-processing stage for color selection is different from the stage for location selection.

Consciousness versus states of being conscious

1997 ◽  
Vol 20 (1) ◽  
pp. 155-156 ◽  
Author(s):  
Ernst Pöppel
Keyword(s):  
Information Processing ◽  
High Frequency ◽  
Temporal Integration ◽  
Low Frequency ◽  
Functional Connection ◽  
Temporal Information Processing ◽  
Neuronal Mechanisms ◽  
Integration Mechanism ◽  
System States ◽  
Temporal Windows

States of being conscious (S) can be defined on the basis of temporal information processing. A high-frequency mechanism provides atemporal system states with periods of approximately 30 msec to implement the functional connection of distributed activities allowing the construction of primordial events; a low frequency mechanism characterized by automatic temporal integration sets up temporal windows with approximately 3 seconds duration. This integration mechanism can be used to define S. P-consciousness and A-consciousness as conceived of by Block can be mapped onto these neuronal mechanisms.

scholarly journals Heart rhythm variation during affective pictures viewing in women in different phases of the menstrual cycle

2020 ◽  
Vol 80 (1) ◽  
pp. 35-40
Author(s):  
V. Kravchenko ◽  
K. Demidova
Keyword(s):  
Menstrual Cycle ◽  
High Frequency ◽  
Luteal Phase ◽  
Cardiac Rhythm ◽  
Low Frequency ◽  
Heart Rhythm ◽  
Follicular Phase ◽  
Activity Level ◽  
Spectral Indices ◽  
Different Types

The peculiarities of the dynamics of the spectral indices of cardiac rhythm variability in 32 women 17-23 years of age while viewing emotional IAPS (International affective picture system) images in different phases of the menstrual cycle were studied. It is shown that the differences in the regulation of the heart rhythm associated with viewing emotional images of different types are manifested mainly in the follicular phase of the menstrual cycle. During this period, significant differences in viewing emotional images of different types were found in the absolute and relative power of the very low-frequency (VLF) and high-frequency (HF) component of the spectrum. In the ovulation phase, emotion-sensitive markerwas a lowfrequency spectrum component (LF), reflecting the effect of the sympathetic nervous system on cardiac rhythm. This indicator was significantly higher when viewing unpleasant images compared to pleasant and erotic visual stimuli.The contribution of the sympathetic division to the regulation of cardiac rhythm was observed during viewing of negative and neutral images, and only the viewing of erotic images was characterized by an increase in parasympathetic activity, which was accompaniedwith the increased power of the high-frequency component of the spectrum (HF) reducing the proportion of LF/HF and respiratory rate. The study shows that during the menstrual cycle, the autonomic balance shifts toward the predominance of sympathetic regulation of the heart rhythm, which reaches a maximum in the luteal phase. In this regard, the activity level of the sympathetic link recorded by the power of the low-frequency (LF) component while viewing unpleasant images was the lowest in the follicular phase and the highest in the luteal one. No significant differences were found between the spectral indices of cardio-interval variability when viewing emotional images in the luteal phase, indicating that this period of the cycle was low informative to assess the characteristics of women's emotional response based on heart rate analysis.

Microparticle Trapping in Streaming Flows in Open Rectangular Chambers Undergoing Low Frequency Vertical Vibrations

2014 ◽  
Author(s):  
Prashant Agrawal ◽  
Prasanna S. Gandhi ◽  
Adrian Neild
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Mode Switching ◽  
Small Particles ◽  
Low Frequencies ◽  
Different Types ◽  
Frequency Regime ◽  
Vertical Vibrations ◽  
Rectangular Chamber ◽  
Streaming Flows

Microparticle collection in microfluidic systems via mechanical vibrations has been demonstrated in both low frequency systems (in the range of 100Hz) and in the high frequency regime (in the range of 1MHz). However, in most systems, collection of particles with lower inertia is hindered by second order time-averaged streaming flows. In our approach, we experimentally demonstrate collection of small particles (about 3 μm in diameter) by trapping them in streaming flows in a liquid filled open rectangular chamber undergoing vertical vibrations at low frequencies. The proposed method is then utilized to separate two different types of particles in distinct patterns through mode-switching.

Prediction of the sound reduction index of clay hollow brick walls

2020 ◽  
Vol 27 (2) ◽  
pp. 155-168 ◽  
Author(s):  
Nicola Granzotto ◽  
Antonino Di Bella ◽  
Edoardo Alessio Piana
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Sound Insulation ◽  
Frequency Range ◽  
Proposed Model ◽  
Different Types ◽  
Classic Approach ◽  
Hollow Brick ◽  
Sound Reduction ◽  
Reduction Index

Clay hollow brick walls are still popular in building industry, but the prediction of their sound insulation properties is not straightforward due to their inhomogeneous and anisotropic characteristics. In this article, a classic approach has been used to determine the sound transmission coefficient of brick walls, assuming an orthotropic behaviour and deriving the mechanical and dynamic characteristics from datasheet information. Different types of walls with horizontal and vertical mortar joints have been analysed. Experimental measurements of the sound reduction index carried out according to ISO 10140-2 standard have been performed, and the resulting values are compared with the predictions in the proposed model. It was found that the sound reduction index can be fairly predicted in the low-frequency range and it is correctly predicted in the mass law region, whereas in the high-frequency range the inner block structure is responsible for a loss of performance which is difficult to predict with the analytical methods.

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