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Scientific Reports Dec 2022Light Field (LF) imaging empowers many attractive applications by simultaneously recording spatial and angular information of light rays. In order to meet the challenges...
Light Field (LF) imaging empowers many attractive applications by simultaneously recording spatial and angular information of light rays. In order to meet the challenges of LF storage and transmission, many view reconstruction-based LF compression methods are put forward. However, occlusion issue and under-exploitation of LF rich structure information limit the view reconstruction qualities, which further influence LF compression efficiency. In order to alleviate these problems, in this paper, we propose a geometry-aware view reconstruction network for LF compression. In our method, only sparsely-sampled LF views are encoded, which are further used as priors to reconstruct the un-sampled LF views at the decoder side. The proposed reconstruction process contains two stages including geometry-aware reconstruction and texture refinement. The geometry-aware reconstruction stage utilizes a multi-stream framework, which can fully explore LF spatial-angular, location and geometry information. The texture refinement stage can adequately fuse such rich LF information to further improve LF reconstruction quality. Comprehensive experimental results validate the superiority of the proposed method. The rate-distortion performance and the perceptual quality of reconstructed views further demonstrate that the proposed method can save more bitrate while increasing LF reconstruction quality.
Topics: Data Compression; Algorithms; Imaging, Three-Dimensional; Image Processing, Computer-Assisted
PubMed: 36564515
DOI: 10.1038/s41598-022-26887-4 -
Scientific Reports Dec 2022Precisely estimating event timing is essential for survival, yet temporal distortions are ubiquitous in our daily sensory experience. Here, we tested whether the...
Precisely estimating event timing is essential for survival, yet temporal distortions are ubiquitous in our daily sensory experience. Here, we tested whether the relative position, duration, and distance in time of two sequentially-organized events-standard S, with constant duration, and comparison C, with duration varying trial-by-trial-are causal factors in generating temporal distortions. We found that temporal distortions emerge when the first event is shorter than the second event. Importantly, a significant interaction suggests that a longer inter-stimulus interval (ISI) helps to counteract such serial distortion effect only when the constant S is in the first position, but not if the unpredictable C is in the first position. These results imply the existence of a perceptual bias in perceiving ordered event durations, mechanistically contributing to distortion in time perception. We simulated our behavioral results with a Bayesian model and replicated the finding that participants disproportionately expand first-position dynamic (unpredictable) short events. Our results clarify the mechanisms generating time distortions by identifying a hitherto unknown duration-dependent encoding inefficiency in human serial temporal perception, something akin to a strong prior that can be overridden for highly predictable sensory events but unfolds for unpredictable ones.
Topics: Humans; Bayes Theorem; Perception
PubMed: 36473982
DOI: 10.1038/s41598-022-25573-9 -
Journal of Family & Reproductive Health Jun 2022Psychological perceptions are concerned with how a person perceives and psychologically frames life with an illness. The current study sought to examine the...
Psychological perceptions are concerned with how a person perceives and psychologically frames life with an illness. The current study sought to examine the psychological perceptions of women suffering from Female Sexual Interest/Arousal Disorder in the setting of Isfahan, Iran. The study was done according a qualitative design, and it was conducted in Isfahan, Iran, from July 2018 to February 2019. Twenty in-depth interviews were performed with 20 patients who were recruited on the purposeful method. The thematic analysis approach was used to analyze the data. The data were organized using MAXQDA software (version 12). The following four themes were extracted: (i) Dysfunctional cognition, which includes five sub-themes: attention bias, belief bias, memory bias, perceptual bias, and cognitive distortion; and (ii) Relationship and partner factors, which include four sub-themes: psychological maltreatment, aggression, deception, and betrayal.; (iii) lack of life skills, which includes four sub-themes: poor problem-solving, poor sexual knowledge, poor understanding and intimate relationships, and immature defense mechanisms; and (iv) lack of motivation and genuine interest, which includes two sub-themes: forced marriage and lack of initial affection and attraction to the husband. Internal and interpersonal factors were shown to have a role in the creation of sexual arousal disorder in Iranian women, according to the study. As a result, designing scenarios for cognitive bias modification and educational programs for improving interpersonal skills would be beneficial.
PubMed: 36457662
DOI: 10.18502/jfrh.v16i2.9478 -
JASA Express Letters Nov 2022When the ear is stimulated by two tones presented at frequencies f and f, nonlinearity in the cochlea's vibratory response leads to the generation of distortion products...
When the ear is stimulated by two tones presented at frequencies f and f, nonlinearity in the cochlea's vibratory response leads to the generation of distortion products (DPs), with the cubic 2f-f DP commonly viewed as the most prominent. While the quadratic f-f DP is also evident in numerous physiological and perceptual studies, its presence in the cochlea's mechanical response has been less well documented. Here, examination of vibratory DPs within the mouse cochlea confirmed that f-f was a significant and sometimes dominant component, whether DPs were measured near their generation site, or after having propagated from more basal locations.
Topics: Mice; Animals; Vibration; Cochlea; Caffeine; Niacinamide
PubMed: 36456371
DOI: 10.1121/10.0015244 -
Psychopharmacology Jan 2023Preclinical studies indicate that high-frequency oscillations, above 100 Hz (HFO:100-170 Hz), are a potential translatable biomarker for pharmacological studies, with...
RATIONALE
Preclinical studies indicate that high-frequency oscillations, above 100 Hz (HFO:100-170 Hz), are a potential translatable biomarker for pharmacological studies, with the rapid acting antidepressant ketamine increasing both gamma (40-100 Hz) and HFO.
OBJECTIVES
To assess the effect of the uncompetitive NMDA antagonist ketamine, and of D-cycloserine (DCS), which acts at the glycine site on NMDA receptors on HFO in humans.
METHODS
We carried out a partially double-blind, 4-way crossover study in 24 healthy male volunteers. Each participant received an oral tablet and an intravenous infusion on each of four study days. The oral treatment was either DCS (250 mg or 1000 mg) or placebo. The infusion contained 0.5 mg/kg ketamine or saline placebo. The four study conditions were therefore placebo-placebo, 250 mg DCS-placebo, 1000 mg DCS-placebo, or placebo-ketamine.
RESULTS
Compared with placebo, frontal midline HFO magnitude was increased by ketamine (p = 0.00014) and 1000 mg DCS (p = 0.013). Frontal gamma magnitude was also increased by both these treatments. However, at a midline parietal location, only HFO were increased by DCS, and not gamma, whilst ketamine increased both gamma and HFO at this location. Ketamine induced psychomimetic effects, as measured by the PSI scale, whereas DCS did not increase the total PSI score. The perceptual distortion subscale scores correlated with the posterior low gamma to frontal high beta ratio.
CONCLUSIONS
Our results suggest that, at high doses, a partial NMDA agonist (DCS) has similar effects on fast neural oscillations as an NMDA antagonist (ketamine). As HFO were induced without psychomimetic effects, they may prove a useful drug development target.
Topics: Humans; Male; Cross-Over Studies; Cycloserine; Double-Blind Method; Electroencephalography; Ketamine; N-Methylaspartate; Receptors, N-Methyl-D-Aspartate
PubMed: 36401646
DOI: 10.1007/s00213-022-06272-9 -
Sensors (Basel, Switzerland) Oct 2022Recently, deep learning-based image quality enhancement models have been proposed to improve the perceptual quality of distorted synthesized views impaired by...
Recently, deep learning-based image quality enhancement models have been proposed to improve the perceptual quality of distorted synthesized views impaired by compression and the Depth Image-Based Rendering (DIBR) process in a multi-view video system. However, due to the lack of Multi-view Video plus Depth (MVD) data, the training data for quality enhancement models is small, which limits the performance and progress of these models. Augmenting the training data to enhance the synthesized view quality enhancement (SVQE) models is a feasible solution. In this paper, a deep learning-based SVQE model using more synthetic synthesized view images (SVIs) is suggested. To simulate the irregular geometric displacement of DIBR distortion, a random irregular polygon-based SVI synthesis method is proposed based on existing massive RGB/RGBD data, and a synthetic synthesized view database is constructed, which includes synthetic SVIs and the DIBR distortion mask. Moreover, to further guide the SVQE models to focus more precisely on DIBR distortion, a DIBR distortion mask prediction network which could predict the position and variance of DIBR distortion is embedded into the SVQE models. The experimental results on public MVD sequences demonstrate that the PSNR performance of the existing SVQE models, e.g., DnCNN, NAFNet, and TSAN, pre-trained on NYU-based synthetic SVIs could be greatly promoted by 0.51-, 0.36-, and 0.26 dB on average, respectively, while the MPPSNRr performance could also be elevated by 0.86, 0.25, and 0.24 on average, respectively. In addition, by introducing the DIBR distortion mask prediction network, the SVI quality obtained by the DnCNN and NAFNet pre-trained on NYU-based synthetic SVIs could be further enhanced by 0.02- and 0.03 dB on average in terms of the PSNR and 0.004 and 0.121 on average in terms of the MPPSNRr.
Topics: Deep Learning; Image Enhancement; Data Compression
PubMed: 36365828
DOI: 10.3390/s22218127 -
NeuroImage Dec 2022Time is as pervasive as it is elusive to study, and how the brain keeps track of millisecond time is still unclear. Here we addressed the mechanisms underlying duration...
Time is as pervasive as it is elusive to study, and how the brain keeps track of millisecond time is still unclear. Here we addressed the mechanisms underlying duration perception by looking for a neural signature of subjective time distortion induced by motion adaptation. We recorded electroencephalographic signals in human participants while they were asked to discriminate the duration of visual stimuli after different types of translational motion adaptation. Our results show that perceived duration can be predicted by the amplitude of the N200 event-related potential evoked by the adapted stimulus. Moreover, we show that the distortion of subjective time can be predicted by the activity in the Beta band frequency spectrum, at the offset of the adaptor and during the presentation of the subsequent adapted stimulus. Both effects were observed from posterior electrodes contralateral to the adapted stimulus. Overall, our findings suggest that local and low-level perceptual processes are involved in generating a subjective sense of time.
Topics: Humans; Motion Perception; Visual Perception; Electroencephalography; Evoked Potentials; Adaptation, Physiological; Photic Stimulation
PubMed: 36341952
DOI: 10.1016/j.neuroimage.2022.119707 -
Frontiers in Psychology 2022Moderate physical activity can influence cognitive functions and visual cortical activity. However, little is known about the effects of exercise on fundamental...
Moderate physical activity can influence cognitive functions and visual cortical activity. However, little is known about the effects of exercise on fundamental perceptual domains, such as spatial and temporal representation. Here we tackled this issue by testing the impact of physical activity on a temporal estimation task in a group of adult volunteers in three different conditions: (1) in a resting condition (baseline), (2) during moderate physical activity (cycling in place - PA), and (3) approximately 15 to 20 min following the physical activity phase, in which participants were seated and returned to a regular heart rate (POST). We show that physical activity specifically impacts time perception, inducing a consistent overestimation for durations in the range of milliseconds. Notably, the effect persisted in the POST session, ruling out the main contribution of either heart rate or cycling rhythmicity. In a control experiment, we found that spatial perception (distance estimation) was unaffected by physical activity, ruling out a major contribution of arousal and fatigue to the observed temporal distortion. We speculate that physical exercise might alter temporal estimation either by up-regulating the dopaminergic system or modulating GABAergic inhibition.
PubMed: 36275247
DOI: 10.3389/fpsyg.2022.1004504 -
Optics Express Jul 2022Single image dehazing is a challenging task because of the hue and brightness distortion problems due to the atmospheric scattering. These problems limit the perceptual...
Single image dehazing is a challenging task because of the hue and brightness distortion problems due to the atmospheric scattering. These problems limit the perceptual fidelity, as well as information integrity, of a given image. In this paper, we propose an image dehazing method based on the optical neural networks dehazing by simulating optical diffraction. The algorithm is trained from a large number of hazy images and their corresponding clean images. The experimental results demonstrate that the proposed method has reached an advanced level in both PSNR and SSIM dehazing performance indicators, and the amount of calculation is less than most artificial neural networks.
PubMed: 36236995
DOI: 10.1364/OE.458610 -
Hearing Research Dec 2022Alterations of the speech signal, including additive noise and nonlinear distortion, can reduce speech intelligibility and quality. Hearing aids present an especially... (Review)
Review
Alterations of the speech signal, including additive noise and nonlinear distortion, can reduce speech intelligibility and quality. Hearing aids present an especially complicated situation since these devices may implement nonlinear processing designed to compensate for the hearing loss. Hearing-aid processing is often realized as time-varying multichannel gain adjustments, and may also include frequency reassignment. The challenge in designing metrics for hearing aids and hearing-impaired listeners is to accurately model the perceptual trade-offs between speech audibility and the nonlinear distortion introduced by hearing-aid processing. This paper focuses on the Hearing Aid Speech Perception Index (HASPI) and the Hearing Aid Speech Quality Index (HASQI) as representative metrics for predicting intelligibility and quality. These indices start with a model of the auditory periphery that can be adjusted to represent hearing loss. The peripheral model, the speech features computed from the model outputs, and the procedures used to fit the features to subject data are described. Examples are then presented for using the metrics to measure the effects of additive noise, evaluate noise-suppression processing, and to measure the differences among commercial hearing aids. Open questions and considerations in using these and related metrics are then discussed.
Topics: Humans; Hearing Aids; Speech Intelligibility; Speech Perception; Benchmarking; Hearing Loss; Deafness; Hearing; Hearing Loss, Sensorineural
PubMed: 36137862
DOI: 10.1016/j.heares.2022.108608