scholarly journals Glyph guessing for ‘oo’ and ‘ee’: spatial frequency information in sound symbolic matching for ancient and unfamiliar scripts

2017 ◽  
Vol 4 (9) ◽  
pp. 170882 ◽  
Author(s):  
Nora Turoman ◽  
Suzy J. Styles
Keyword(s):  
Spatial Frequency ◽  
Historical Time ◽  
Adult Readers ◽  
Visual Spatial ◽  
Internet Users ◽  
Spatial Frequencies ◽  
The Difference ◽  
Diverse Groups ◽  
Geographical Space ◽  
Larger Sample

In three experiments, we asked whether diverse scripts contain interpretable information about the speech sounds they represent. When presented with a pair of unfamiliar letters, adult readers correctly guess which is /i/ (the ‘ee’ sound in ‘feet’), and which is /u/ (the ‘oo’ sound in ‘shoe’) at rates higher than expected by chance, as shown in a large sample of Singaporean university students (Experiment 1) and replicated in a larger sample of international Internet users (Experiment 2). To uncover what properties of the letters contribute to different scripts' ‘guessability,’ we analysed the visual spatial frequencies in each letter (Experiment 3). We predicted that the lower spectral frequencies in the formants of the vowel /u/ would pattern with lower spatial frequencies in the corresponding letters. Instead, we found that across all spatial frequencies, the letter with more black/white cycles (i.e. more ink) was more likely to be guessed as /u/, and the larger the difference between the glyphs in a pair, the higher the script's guessability. We propose that diverse groups of humans across historical time and geographical space tend to employ similar iconic strategies for representing speech in visual form, and provide norms for letter pairs from 56 diverse scripts.

Natural scenes have matched amplitude-modulated sounds that systematically influence visual scanning

2012 ◽  
Vol 25 (0) ◽  
pp. 121
Author(s):  
Marcia Grabowecky ◽  
Aleksandra Sherman ◽  
Satoru Suzuki
Keyword(s):  
Eye Movements ◽  
Spatial Frequency ◽  
Memory Task ◽  
High Spatial Frequency ◽  
Visual Object ◽  
Natural Scenes ◽  
Scale Invariant ◽  
Visual Coding ◽  
Visual Spatial ◽  
Spatial Frequencies

We have previously demonstrated a linear perceptual relationship between auditory amplitude-modulation (AM) rate and visual spatial-frequency using gabors as the visual stimuli. Can this frequency-based auditory–visual association influence perception of natural scenes? Participants consistently matched specific auditory AM rates to diverse visual scenes (nature, urban, and indoor). A correlation analysis indicated that higher subjective density ratings were associated with faster AM-rate matches. Furthermore, both the density ratings and AM-rate matches were relatively scale invariant, suggesting that the underlying crossmodal association is between visual coding of object-based density and auditory coding of AM rate. Based on these results, we hypothesized that concurrently presented fast (7 Hz) or slow (2 Hz) AM-rates might influence how visual attention is allocated to dense or sparse regions within a scene. We tested this hypothesis by monitoring eye movements while participants examined scenes for a subsequent memory task. To determine whether fast or slow sounds guided eye movements to specific spatial frequencies, we computed the maximum contrast energy at each fixation across 12 spatial frequency bands ranging from 0.06–10.16 cycles/degree. We found that the fast sound significantly guided eye movements toward regions of high spatial frequency, whereas the slow sound guided eye movements away from regions of high spatial frequency. This suggests that faster sounds may promote a local scene scanning strategy, acting as a ‘filter’ to individuate objects within dense regions. Our results suggest that auditory AM rate and visual object density are crossmodally associated, and that this association can modulate visual inspection of scenes.

Velocity Threshold for Relative and Uniform Motion

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 353-353
Author(s):  
S Shioiri ◽  
S Ito ◽  
H Yaguchi
Keyword(s):  
Spatial Frequency ◽  
Relative Motion ◽  
Threshold Function ◽  
Uniform Motion ◽  
Measured Velocity ◽  
Velocity Threshold ◽  
Spatial Frequencies ◽  
Motion Condition ◽  
The Difference ◽  
The Right

We measured velocity thresholds for relative and uniform motion as functions of spatial frequency and contrast. Stimuli were two horizontal bands on top of each other, both filled with vertical sinusoidal gratings. The gratings drifted either to the right or to the left, in opposite directions in the relative-motion condition but in the same direction in the uniform-motion condition. Observers had to report the direction of motion, and the velocity was varied until a velocity threshold was obtained. The results showed that the shapes of the threshold function plotted against spatial frequency are quite different for uniform and relative motion. The threshold for relative motion had a minimum at around 5 cycles deg−1, whereas the threshold for uniform motion had no such minimum, at least at higher contrasts (10% or higher). The difference was unclear for lower-contrast stimuli, however. The threshold profile as a function of contrast was also different between relative and uniform motion. Although the threshold decreased with increasing contrast in both cases, this dependence saturated at around 10% contrast for uniform motion, while it continued up to the highest contrast (85%) for relative motion. This difference held for all the spatial frequencies examined (from 0.75 to 12.1 cycles deg−1). The results suggest that the detection mechanisms for relative motion and uniform motion are different.

The Perceived Duration of Gratings

Perception ◽  
1992 ◽  
Vol 21 (2) ◽  
pp. 161-166 ◽  
Author(s):  
John A Baro ◽  
Lynda J Brzezicki ◽  
Stephen Lehmkuhle ◽  
Howard C Hughes
Keyword(s):  
Spatial Frequency ◽  
Reaction Times ◽  
Visible Persistence ◽  
Subjective Duration ◽  
Spatial Frequencies ◽  
The Difference ◽  
Perceived Duration

Since visible persistence of grating patterns increases with spatial frequency, it is often inferred that the perceived duration of a grating is also longer at higher spatial frequencies. However, other work has demonstrated that the perceived onset of a grating is also delayed at higher spatial frequencies. Thus it is impossible to infer the subjective duration from the results of visible persistence studies alone. In order to estimate perceived duration in the present study, reaction times (RTs) to grating onsets and offsets were measured for a range of spatial frequencies. The results indicate that although the perceived duration (ie the difference between offset and onset RTs) was consistently longer than the physical duration, the estimates of perceived duration did not vary with changes in spatial frequency. Differences between the present results and earlier findings are interpreted in the context of the different methods used to measure perceived offset.

Multisensory Integration Is Modulated by Auditory Sound Frequency and Visual Spatial Frequency

2019 ◽  
Vol 32 (7) ◽  
pp. 589-611
Author(s):  
Jessica J. Green ◽  
Allison M. Pierce ◽  
Spencer L. Mac Adams
Keyword(s):  
Spatial Frequency ◽  
Frequency Spectrum ◽  
Visual Information ◽  
Sound Frequency ◽  
Audiovisual Speech ◽  
Low Level ◽  
Speech Stimuli ◽  
Visual Spatial ◽  
Spatial Frequencies ◽  
Stimulus Features

Abstract Accurate integration of auditory and visual information is essential for our ability to communicate with others. Previous studies have shown that the temporal discrepancies over which audiovisual speech stimuli will be integrated into a coherent percept are much wider than those typically observed for simple stimuli like beeps and flashes of light. However, our sensitivity to the low-level features of simple stimuli is not constant. We hypothesized that part of the enhanced integration of audiovisual speech may be due to it consisting predominantly of the sound frequencies and visual spatial frequencies that humans are most sensitive to. Here, we examined integration behaviors for pure tones across the sound frequency spectrum and visual gratings across the spatial frequency spectrum to examine how these low-level features modulate integration. The temporal window of integration was modulated by both sound frequency and visual spatial frequency, with the widest integration window occurring when both stimuli fell within their respective peak sensitivity ranges. These results suggest that part of the increased tolerance for temporal asynchrony typically observed for audiovisual speech may be due to the differential integration of low-level stimulus features that are dominant within complex audiovisual speech.

scholarly journals Transformation from local image contrast to location-independent numerosity tuning in human extrastriate cortex

2021 ◽  
Author(s):  
Jacob M Paul ◽  
Martijn van Ackooij ◽  
Tuomas C ten Cate ◽  
Benjamin M Harvey
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Computational Modelling ◽  
Occipital Cortex ◽  
Extrastriate Cortex ◽  
Visual Responses ◽  
Fourier Decomposition ◽  
Visual Spatial ◽  
Spatial Frequencies ◽  
Item Size

Many animals use visual numerosity, the number of items in a group, to guide behavior. Neurons in human association cortices show numerosity-tuned responses, decreasing amplitude with distance from a specific numerosity. How are such responses derived from early visual responses? Recent studies show aggregate response amplitudes in human early visual cortex monotonically increase with numerosity, regardless of object size and spacing. This is surprising because numerosity is typically considered a high-level visual or cognitive feature. Here we first use computational modelling of 7T fMRI data to show these monotonic responses originate at the stimulus's retinotopic location in primary visual cortex (V1). Given this location, we then ask whether these monotonic responses can be better described by V1's established response properties. We characterize the Fourier decomposition (into contrast at specific orientations and spatial frequencies) of laboratory numerosity stimuli. This demonstrates that aggregate Fourier power (at all orientations and spatial frequencies) nonlinearly follows numerosity with little effect of item size, spacing or shape: it is proportional to numerosity at a fixed contrast. This nonlinear relationship lets us distinguish predictions of responses to Fourier power and numerosity. Monotonic responses are better predicted by Fourier power, later tuned responses are better predicted by numerosity. Tuned responses emerge after lateral occipital cortex and are independent of retinotopic location. We propose that numerosity's straightforward perception and neural responses reflect its straightforward estimation from early visual spatial frequency domain image representations. Our numerical vision may have built on behaviorally beneficial analysis of spatial frequency in simpler animals.

Understanding Customers' Continuance Intention

2021 ◽  
Vol 52 (2) ◽  
pp. 68-93
Author(s):  
Bangaly Kaba
Keyword(s):  
Information And Communication Technologies ◽  
Structural Equation ◽  
Service Providers ◽  
Equation Modeling ◽  
Continuance Intention ◽  
Internet Service ◽  
Digital Inequality ◽  
Internet Users ◽  
The Difference ◽  
Use Behavior

The purpose of this study is to understand the difference between Internet users' continuing use behavior in the context of digital inequality. Data were collected through a survey of Internet users in the Ivory Coast. The structural equation modeling technique was used to test the research hypothesis. This study showed empirically that concern over information and communication technologies (ICT) access as an explanation for digital inequality should be toned down. This research suggests emphasizing alternative factors to explain Internet sustained use intention by underprivileged individuals, including normative beliefs. The results will help internet service providers, governments, and international aid agencies to better understand users' behaviors or reactions to ICT available to them. This understanding provides a foundational platform upon which viable and effective information technology-enabled solutions and policies can be conceptualized and implemented. This study is one of the few that integrate three salient beliefs to differentiate ICT use continuance intention in the context of digital inequality.

scholarly journals Numerical Simulation on Spatial-Frequency Domain Imaging for Estimating Optical Absorption and Scattering Properties of Two-Layered Horticultural Products

2021 ◽  
Vol 11 (2) ◽  
pp. 617
Author(s):  
Dong Hu ◽  
Yuping Huang ◽  
Qiang Zhang ◽  
Lijian Yao ◽  
Zidong Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Property ◽  
Optical Absorption ◽  
Spatial Frequency ◽  
Estimation Accuracy ◽  
Property Estimation ◽  
Spatial Frequencies ◽  
Stepwise Method ◽  
Horticultural Products ◽  
Layered Samples

Spatial-frequency domain imaging (SFDI) is a wide-field, noncontact, and label-free imaging modality that is currently being explored as a new means for estimating optical absorption and scattering properties of two-layered turbid materials. The accuracy of SFDI for optical property estimation, however, depends on light transfer model and inverse algorithm. This study was therefore aimed at providing theoretical analyses of the diffusion model and inverse algorithm through numerical simulation, so as to evaluate the potential for estimating optical absorption and reduced scattering coefficients of two-layered horticultural products. The effect of varying optical properties on reflectance prediction was first simulated, which indicated that there is good separation in diffuse reflectance over a large range of spatial frequencies for different reduced scattering values in the top layer, whereas there is less separation in diffuse reflectance for different values of absorption in the top layer, and even less separation for optical properties in the bottom layer. To implement the nonlinear least-square method for extracting the optical properties of two-layered samples from Monte Carlo-generated reflectance, five curve fitting strategies with different constrained parameters were conducted and compared. The results confirmed that estimation accuracy improved as fewer variables were to be estimated each time. A stepwise method was thus suggested for estimating optical properties of two-layered samples. Four factors influencing optical property estimation of the top layer, which is the basis for accurately implementing the stepwise method, were investigated by generating absolute error contour maps. Finally, the relationship between light penetration depth and spatial frequency was studied. The results showed that penetration depth decreased with the increased spatial frequency and also optical properties, suggesting that appropriate selection of spatial frequencies for a stepwise method to estimate optical properties from two-layered samples provides potential for estimation accuracy improvement. This work lays a foundation for improving optical property estimation of two-layered horticultural products using SFDI.

Harmonic basis functions for spatial coding in the cat striate cortex

1989 ◽  
Vol 3 (4) ◽  
pp. 351-363 ◽  
Author(s):  
V. D. Glezer ◽  
V. V. Yakovlev ◽  
V. E. Gauzelman
Keyword(s):  
Spatial Frequency ◽  
Striate Cortex ◽  
Weighting Function ◽  
Discrete Distribution ◽  
Basis Functions ◽  
Spatial Coding ◽  
Central Visual Field ◽  
Spatial Frequencies ◽  
The Absolute ◽  
Number Of Cycles

AbstractThe number of subregions in the activity profiles of simple cells varies in different cells from 2–8; that is, the number of cycles in the weighting function varies from 1–4. The distribution of receptive-field (RF) sizes at eccentricities of 0-6 deg are clustered at half-octave intervals and form a discrete distribution with maxima at 0.62, 0.9, 1.24, 1.8, 2.48, and 3.4 deg. The spatial frequencies to which the cells are tuned are also clustered at half-octave intervals, forming a discrete distribution peaking at 0.45, 0.69, 0.9, 1.35, 1.88, 2.7, 3.8, and 5.6 cycles/deg. If we divide the RF sizes by the size of the period of the subregions, then the average indices of complexity (really existing) or the number of cycles in the weighting function form (after normalization) the sequences: 1, 1.41, 2.0, 2.9, 4.15.The relation between the bandwidth of the spatial-frequency characteristic and the optimal spatial frequency is in accordance with predictions of the Fourier hypothesis. The absolute bandwidth does not change with the number of cycles/module. This means that inside the module the absolute bandwidth does not change with the number of the harmonic. The results allow us to suggest the following. A module of the striate cortex, which is a group of cells with RFs of equal size projected onto the same area of central visual field, accounts for the Fourier description of the image. The basis functions of the module are composed of four harmonics only, irrespective of size and position of the module.Besides linear cells (sinusoidal and cosinusoidal elements), the module contains nonlinear cells, performing a nonlinear summation of the responses of sinusoidal and cosinusoidal elements. Such cells are characterized by an index of complexity which is more than the number of cycles in the weighting function and by marked overlap of ON and OFF zones. The analysis of organization suggests that the cells can measure the amplitude and phase of the stimulus.

Spatial-frequency and orientation tuning in psychophysical end-stopping

1998 ◽  
Vol 15 (4) ◽  
pp. 585-595 ◽  
Author(s):  
CONG YU ◽  
DENNIS M. LEVI
Keyword(s):  
Spatial Frequency ◽  
Frequency Tuning ◽  
Spatial Filter ◽  
Orientation Tuning ◽  
Maximal Strength ◽  
Facilitation Effect ◽  
Spatial Filters ◽  
Spatial Frequency Tuning ◽  
Spatial Frequencies ◽  
Wide Range

A psychophysical analog to cortical receptive-field end-stopping has been demonstrated previously in spatial filters tuned to a wide range of spatial frequencies (Yu & Levi, 1997a). The current study investigated tuning characteristics in psychophysical spatial filter end-stopping. When a D6 (the sixth derivative of a Gaussian) target is masked by a center mask (placed in the putative spatial filter center), two end-zone masks (placed in the filter end-zones) reduce thresholds. This “end-stopping” effect (the reduction of masking induced by end-zone masks) was measured at various spatial frequencies and orientations of end-zone masks. End-stopping reached its maximal strength when the spatial frequency and/or orientation of the end-zone masks matched the spatial frequency and/or orientation of the target and center mask, showing spatial-frequency tuning and orientation tuning. The bandwidths of spatial-frequency and orientation tuning functions decreased with increasing target spatial frequency. At larger orientation differences, however, end-zone masks induced a secondary facilitation effect, which was maximal when the spatial frequency of end-zone masks equated the target spatial frequency. This facilitation effect might be related to certain types of contour and texture perception, such as perceptual pop-out.

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