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Visual stimuli can be kept from awareness using various methods. The extent of processing that a given stimulus receives in the absence of awareness is typically used to make claims about the role of consciousness more generally. The neural processing elicited by a stimulus, however, may also depend on the method used to keep it from awareness, and not only on whether the stimulus reaches awareness. Here we report that the method used to render an image invisible has a dramatic effect on how category information about the unseen stimulus is encoded across the human brain. We collected fMRI data while subjects viewed images of faces and tools, that were rendered invisible using either continuous flash suppression (CFS) or chromatic flicker fusion (CFF). In a third condition, we presented the same images under normal fully visible viewing conditions. We found that category information about visible images could be extracted from patterns of fMRI responses throughout areas of neocortex known to be involved in face or tool processing. However, category information about stimuli kept from awareness using CFS could be recovered exclusively within occipital cortex, whereas information about stimuli kept from awareness using CFF was also decodable within temporal and frontal regions. We conclude that unconsciously presented objects are processed differently depending on how they are rendered subjectively invisible. Caution should therefore be used in making generalizations on the basis of any one method about the neural basis of consciousness or the extent of information processing without consciousness.

The critical flicker fusion frequency (cFFF) refers to the frequency at which a regularly recurring change of light stimuli is perceived as steady. The cFFF threshold is often assessed in clinics to evaluate the temporal characteristics of the visual system, making it a common test for eye diseases. Additionally, it serves as a helpful diagnostic tool for various neurological and internal diseases. In the field of diving/hyperbaric medicine, cFFF has been utilized to determine alertness and cognitive functions. Changes in the cFFF threshold have been linked to the influence of increased respiratory gas partial pressures, although there exist inconsistent results regarding this effect. Moreover, the use of flicker devices has produced mixed outcomes in previous studies. This narrative review aims to explore confounding factors that may affect the accuracy of cFFF threshold measurements, particularly in open-field studies. We identify five broad categories of such factors, including (1) participant characteristics, (2) optical factors, (3) smoking/drug use, (4) environmental aspects, and (5) breathing gases and partial pressures. We also discuss the application of cFFF measurements in the field of diving and hyperbaric medicine. In addition, we provide recommendations for interpreting changes in the cFFF threshold and how they are reported in research studies.

Purpose: Critical flicker-fusion frequency (CFF) has been used in clinical studies as a measure of visual fatigue. We examine the correlation between CFF and subjective reports of visual fatigue in a group of symptomatic computer users, to consider whether CFF may be used as a surrogate measure of visual fatigue symptoms., Methods: We analysed data from a previous randomised controlled trial. One hundred and twenty adults, diagnosed with computer vision syndrome, had CFF and visual fatigue symptoms quantified before and after a visually demanding 2-h computer task. Symptoms were assessed using a questionnaire with nine subcomponents that summed to a total score of 900. CFF was measured using a two-interval forced-choice method, with the flicker rate altered by a computer-controlled staircase procedure. For our primary analysis, we determined Spearman correlation coefficients between post-task symptom scores and CFF, and between change from baseline symptom scores and CFF. We also used a bootstrap procedure to consider whether symptom score subcomponents were significantly (Bonferroni-corrected) different from overall scores with regard to their correlations with CFF., Results: Although visual fatigue symptom scores altered significantly post-task (mean change: 92 units; 95% confidence interval [CI]: 11 to 122), CFF did not (mean change -0.7 Hz; 95% CI: -1.7 to 0.3). There was no significant correlation between overall symptom scores and CFF, either for the post-task (r = -0.13; 95% CI: -0.31 to 0.05) or the change from baseline (r = -0.18; 95% CI: -0.35 to 0.01) analysis. Subcomponents of the symptom questionnaire did not show a significant correlation with CFF, either for the post-task or the change from baseline analysis., Conclusions: We find that CFF is not a useful surrogate for symptoms of visual fatigue, given its low correlation with scores on a visual fatigue symptom questionnaire., (© 2022 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

Strings of dots can be used to construct easily identifiable letters, and these in turn can be used to write words and sentences. Prior work found that respondents could identify individual letters when all the dots were simultaneously flashed for an ultra-brief duration. Four of the experiments reported here constructed five-letter words with these dot-letters and a fifth experiment used them to write complete sentences. Respondents were able to recognize individual words that were displayed with a single, simultaneous ultra-brief flash of all the letters. Further, sentences could be efficiently read with a sequence of simultaneous flashes at a frequency that produced perceptual fusion. One experiment determined the frequency range that would produce flicker-fusion. Two experiments established the relation of intensity to probability of recognition with single flashes and with fused-flicker frequencies. Another established the intensities at which flicker-fused and steady displays were judged to be equal in brightness. The final experiment used those flicker-fused and steady intensities to display sentences. The two display conditions were read with equal efficiency, even though the flicker-fused displays provided light stimulation only 0.003% of the time. [ABSTRACT FROM AUTHOR]

Online object tracking is a challenging problem as it entails learning an effective model to account for appearance change caused by intrinsic and extrinsic factors. In this paper, we propose a novel online object tracking with guided image filter for accurate and robust night fusion image tracking. Firstly, frame difference is applied to produce the coarse target, which helps to generate observation models. Under the restriction of these models and local source image, guided filter generates sufficient and accurate foreground target. Then accurate boundaries of the target can be extracted from detection results. Finally timely updating for observation models help to avoid tracking shift. Both qualitative and quantitative evaluations on challenging image sequences demonstrate that the proposed tracking algorithm performs favorably against several state-of-art methods. [ABSTRACT FROM AUTHOR]

Aim. Vision may be the most variable and selective of all the senses. Attempting to observe fast movements that occur in sport places great demands on human vision. The eyes send information to the brain where it is integrated and interpreted as a three-dimensional (3D) phenomenon. The integration of visual information from both eyes into a 3D image called fusion. Without a conscious effort to attend to something, the eyes will continuously move throughout the visual field. When something gets our visual attention, we may focus both eyes on the object. This pause is called a fixation. The aim of this study was to determine the differences between Egyptian handball players and Kuwaiti handball players in eye movements and dynamic balance. Methods. Eleven elite Egyptian handball players and Ten Kuwaiti handball players were participated in the study (mean age. 22.55 ± 2.34). , test results were obtained for eye movements. All participants were professional players and members in national teams. Eye movements of participants were recorded via Videonystagmograpy (VNG). In addition, star test to measure the dynamic balance. Results. There was no significantly differences between Egyptian handball players and Kuwaiti handball players in eye movements except gaze test. In addition, relationship only between gaze behavioral and balance test forEgyptian handball players. Conclusions. Future research should consider these results, and determines the vision tests that strong connect with handball game. [ABSTRACT FROM AUTHOR]

The pathogenesis of hepatic encephalopathy (HE) is not fully understood yet. Hyperammonemia due to liver failure and subsequent disturbance of cerebral osmolytic balance is thought to play a pivotal role in the emergence of HE. The aim of this in-vivo MR spectroscopy study was to investigate the levels of γ-aminobutyric acid (GABA) and its correlations with clinical symptoms of HE, blood ammonia, critical flicker frequency, and osmolytic levels. Thirty patients with minimal HE or HE1 and 16 age-matched healthy controls underwent graduation of HE according to the West-Haven criteria and including the critical flicker frequency (CFF), neuropsychometric testing and blood testing. Edited proton magnetic resonance spectroscopy (H MRS) was used to non-invasively measure the concentrations of GABA, glutamate (Glu), glutamine (Gln), and myo-inositol (mI) - all normalized to creatine (Cr) - in visual and sensorimotor cortex. GABA/Cr in the visual area was significantly decreased in mHE and HE1 patients and correlated both to the CFF ( r = 0.401, P = 0.013) and blood ammonia levels ( r = −0.434, P = 0.006). Visual GABA/Cr was also strongly linked to mI/Cr ( r = 0.720, P < 0.001) and Gln/Cr ( r = −0.699, P < 0.001). No group differences or correlations were found for GABA/Cr in the sensorimotor area. Hepatic encephalopathy is associated with a regional specific decrease of GABA levels in the visual cortex, while no changes were revealed for the sensorimotor cortex. Correlations of visual GABA/Cr with CFF, blood ammonia, and osmolytic regulators mI and Gln indicate that decreased visual GABA levels might contribute to HE symptoms, most likely as a consequence of hyperammonemia. [ABSTRACT FROM AUTHOR]

Critical flicker fusion (CFF), a measure of visual processing speed, has often been regarded as a basic metric underlying a number of higher cognitive functions. To test this, we measured CFF, global cognition, and several cognitive subdomains. Because age is a strong covariate for most of these variables, both younger (n = 72) and older (n = 57) subjects were measured. Consistent with expectations, age was inversely related to CFF and performance on all of the cognitive measures except for visual memory. In contrast, age-adjusted CFF thresholds were only positively related to executive function. Results showed that CFF predicted executive function across both age groups and accounted for unique variance in performance above and beyond age and global cognitive status. The current findings suggest that CFF may be a unique predictor of executive dysfunction. [ABSTRACT FROM AUTHOR]

The study aims to test whether impaired conduction velocities following optic neuritis (ON) serve as a limiting factor on various temporal, as compared to static, aspects of vision. Critical Flicker fusion frequency (CFFF), two motion perception tasks (object and number-from-motion extraction tasks), high and low contrast acuities, and visual evoked potentials (VEPs) were assessed in 23 ON patients. Strong correlations were found between the various dynamic visual function scores. Furthermore, regression models revealed that each of the dynamic visual functions significantly predicted VEP latencies. These findings were specific to patients' affected eyes and were not evident for static visual functions. Fellow eyes' VEP latencies were best predicted by the VEP latencies of the affected eyes. The similar impact of VEP latencies on various dynamic visual functions suggests conduction velocity to be the common limiting factor for temporal-related visual perceptual abilities. The specificity of these findings to the patients' affected eyes and to dynamic visual functions highlights the precision of dynamic visual functions for identifying demyelinative attack. Prolonged VEP latencies in the fellow eyes seem to stem from different patho-physiological processes. The hypothesis that inter-eye synchronization in conduction latencies is important to accomplish visual processing (binocular vision) is further discussed. [ABSTRACT FROM AUTHOR]

Interharmonics and flickers have an interrelationship between each other. Based on International Electrotechnical Commission (IEC) flicker standard, the critical flicker frequency for a human eye is located at 8.8 Hz. Additionally, eye strains, headaches, and in the worst case seizures may happen due to the critical flicker. Therefore, this paper introduces a worthwhile research gap on the investigation of interrelationship between the amplitudes of the interharmonics and the critical flicker for 50 Hz power system. Consequently, the significant findings obtained in this paper are the amplitudes of two particular interharmonics are able to detect the critical flicker. In this paper, the aforementioned amplitudes are detected by adaptive linear neuron (ADALINE). After that, the critical flicker is detected by substituting the aforesaid amplitudes to the formulas that have been generated in this paper accordingly. Simulation and experimental works are conducted and the accuracy of the proposed algorithm which utilizes ADALINE is similar, as compared to typical Fluke power analyzer. In a nutshell, this simple predictive method for critical flicker detection has strong potential to be applied in any human crowded places (such as offices, shopping complexes, and stadiums) for human healthy precaution purpose due to its simplicity. [ABSTRACT FROM AUTHOR]

To improve the effectiveness and robustness of fatigue driving recognition, a self-adaptive dynamic recognition model is proposed that incorporates information from multiple sources and involves two sequential levels of fusion, constructed at the feature level and the decision level. Compared with existing models, the proposed model introduces a dynamic basic probability assignment (BPA) to the decision-level fusion such that the weight of each feature source can change dynamically with the real-time fatigue feature measurements. Further, the proposed model can combine the fatigue state at the previous time step in the decision-level fusion to improve the robustness of the fatigue driving recognition. An improved correction strategy of the BPA is also proposed to accommodate the decision conflict caused by external disturbances. Results from field experiments demonstrate that the effectiveness and robustness of the proposed model are better than those of models based on a single fatigue feature and/or single-source information fusion, especially when the most effective fatigue features are used in the proposed model. [ABSTRACT FROM AUTHOR]

Background Hepatic encephalopathy ( HE) is a serious complication of liver cirrhosis. Recently, a microsatellite in the promoter region of the phosphate-activated glutaminase ( GLS ) gene was associated with the risk of HE. The aim of the present study was to investigate, using the critical flicker frequency ( CFF) test, whether the described GLS variant increases the risk of developing HE in patients with cirrhosis. Methods We recruited 158 patients (66% men; mean age 59 years, range 23-86) with liver cirrhosis. Mean model for end-stage liver disease score was 13.8 (range 5-35); 48% of patients presented with Child-Pugh score B or C. The presence and severity of HE were determined by the CFF test, with frequencies ≤39 Hz denoting cases. GLS variants were genotyped by sequencing the microsatellite in the promoter region and were classified as short, long or short-long forms (depending on the length of the macrosatellite alleles). Results In total, 53% of patients had abnormal CFF results (i.e. ≤39 Hz; range for entire cohort 26-57). The GLS microsatellite distribution amongst patients was short form (20%), long form (32%) and short-long form (48%) and was consistent with Hardy-Weinberg equilibrium. CFF values differed significantly between groups ( P = 0.043). Carriers of the GLS long microsatellite had a significantly higher risk of HE according to multivariate analyses (odds ratio 3.23, 95% confidence interval 1.46-7.13, P = 0.004). Conclusion CFF results were significantly lower amongst carriers of the GLS long microsatellite. Our findings support the role of the GLS long microsatellite in the development of HE; this could be important for identifying susceptible patients and for the prevention of this condition. [ABSTRACT FROM AUTHOR]

Purpose: To compare the amplitudes and implicit times of the flicker electroretinograms before and after an intravitreal injection of ranibizumab (IVR) in eyes with a central retinal vein occlusion (CRVO). Methods: We reviewed the medical records of 15 consecutive patients who had macular oedema secondary to CRVO and had received an IVR at the Nagoya University Hospital from November 2013 to July 2014. Flicker ERGs were recorded with both the RETeval™ system and a conventional ERG system before the IVR. One month after the IVR, recordings were repeated with only the RETeval™ system. Results: The mean implicit times of the flicker ERGs of the affected eyes recorded with the RETeval™ system were significantly longer than that of the fellow eyes (32.2 ± 2.6 msec versus 28.1 ± 1.2 msec, p < 0.001). One month after the IVR, the implicit times of the flicker ERGs of affected eyes were significantly shortened from 32.2 ± 2.6 to 30.6 ± 2.2 msec (p < 0.001). Conclusions: The shortening of the implicit times of the flicker ERGs after the IVR indicates an improvement of retinal function after anti-VEGF therapy for CRVO eyes. [ABSTRACT FROM AUTHOR]

This paper proposes a novel technique based on feature fusion using multiple linear regression analysis, and the least-square estimation method is employed to estimate the parameters. The given input query image is segmented into various regions according to the structure of the image. The color and texture features are extracted on each region of the query image, and the features are fused together using the multiple linear regression model. The estimated parameters of the model, which is modeled based on the features, are formed as a vector called a feature vector. The Canberra distance measure is adopted to compare the feature vectors of the query and target images. The F-measure is applied to evaluate the performance of the proposed technique. The obtained results expose that the proposed technique is comparable to the other existing techniques. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was (1) to further explore the heart rate dynamics and assess a potential cardiovascular risk in response to 4000 m jumps in experienced skydivers; (2) to assess whether there is an impact of such jumps on skydivers' cortical arousal or not, which may impact their decision making processes. Method: 18 experienced skydivers performed successive jumps from a plane at 4000 m of height. Heart rate dynamics and cortical arousal were assessed by the use of heart rate variability and Critical Flicker Fusion Frequency (CFFF), respectively. Results: CFFF did not differ between the three measurement time points ( p > 0.05). Mean heart rate increased during the jump ( p < 0.001) and came back to pre-jump values after the jump ( p < 0.001). Percentage of the differences of successive NN intervals greater than 50 ms (pNN50) decreased during the jump ( p < 0.001) and kept lower values after the jump compared to pre-jump ( p < 0.05). High-frequency power (HF) did not differ during the jump ( p > 0.05) but decreased after the jump compared to both pre-jump ( p < 0.01) and jump ( p < 0.05). Sample entropy decreased during the jump ( p < 0.001) and came back to pre-jump values after the jump ( p > 0.05). Conclusion: These results confirm a vagal input reduction associated with a rise of the sympathetic tone during the jump and suggests that the experienced skydiver is not exposed to a high cardiovascular risk. This study also shows that environmental stresses induced by free fall could not hamper the perceptual vigilance of experienced skydivers. [ABSTRACT FROM AUTHOR]

In most stereo-matching algorithms, stereo similarity measures are used to determine which image patches in a left–right image pair correspond to each other. Different similarity measures may behave very differently on different kinds of image structures, for instance, some may be more robust to noise whilst others are more susceptible to small texture variations. As a result, it may be beneficial to use different similarity measures in different image regions. We present an adaptive stereo similarity measure that achieves this via a weighted combination of measures, in which the weights depend on the local image structure. Specifically, the weights are defined as a function of a confidence measure on the stereo similarities: similarity measures with a higher confidence at a particular image location are given higher weight. We evaluate the performance of our adaptive stereo similarity measure in both local and global stereo algorithms on standard benchmarks such as the Middlebury and KITTI data sets. The results of our experiments demonstrate the potential merits of our adaptive stereo similarity measure. [ABSTRACT FROM AUTHOR]

Spatio-temporal saliency detection has attracted lots of research interests due to its competitive performance on wide multimedia applications. For spatio-temporal saliency detection, existing bottom-up algorithms often over-simplify the fusion strategy, which results in the inferior performance than the human vision system. In this paper, a novel bottom-up spatio-temporal saliency model is proposed to improve the accuracy of attentional region estimation in videos through fully exploiting the merit of fusion. In order to represent the space constructed by several types of features such as location, appearance and temporal cues extracted from video, kernel regression in mixed feature spaces (KR-MFS) including three approximation entity-models is proposed. Using KR-MFS, a hybrid fusion strategy which considers the combination of spatial and temporal saliency of each individual unit and incorporates the impacts from the neighboring units is presented and embedded into the spatio-temporal saliency model. The proposed model has been evaluated on the publicly available dataset. Experimental results show that the proposed spatio-temporal saliency model can achieve better performance than the state-of-the-art approaches. [ABSTRACT FROM AUTHOR]

In this study, a wave park is analysed from the economic and electrical points of view. The system under consideration goes from each wave energy unit up to the point of common connection with the main grid. Time series are obtained from simulation models for a scaled prototype and include data for mild, medium and strong sea states. The simulation models have been validated against the small scale tank testing of a prime mover, a wave rider buoy and a scaled testing of the power take-off in a land-based test rig. The design of the proposed wave park layout aims to minimise its cost and power losses. A life-cycle analysis of the park is performed showing that around 30 €/MWh will be the share of the electricity price required to install and operate the wave park grid. The power quality of the wave park and its compliance with regulations are also analysed. Special emphasis is put in the study of flicker emissions concluding that the proposed wave park is within the grid code limitations and even a reduction of a 66% in the flicker coefficients is reported when considering the aggregation of several units in one model. [ABSTRACT FROM AUTHOR]

Four experiments examined the ability of respondents to identify letters that were displayed on an LED array with flashes lasting little more than a microsecond. The first experiment displayed each letter with a single, simultaneous flash of all the dots forming the letter and established the relation of flash intensity to the probability of letter identification. The second experiment displayed the letters with multiple flashes at different frequencies to determine the probability that the sequence of flashes would be perceived as fused. The third experiment displayed the letters at a frequency that was above the flicker-fusion frequency, varying flash intensity to establish the amount needed to elicit a given probability of letter identification. The fourth experiment displayed each letter twice, once at a frequency where no flicker was perceived and also with steady light emission. The intensity of each flash was fixed and the steady intensity was varied; respondents were asked to judge whether the fused-flicker display and the steady display appeared to be the same brightness. Steady intensity was about double the average flash intensity where the two conditions were perceived as being equal in brightness. This is at odds with Talbot-Plateau law, which predicts that these two values should be equal. The law was formulated relative to a flash lasting half of each period, so it is surprising that it comes this close to being correct where the flash occupies only a millionth of the total period. [ABSTRACT FROM AUTHOR]

A simple and cost-efficient method for extending a projector's depth-of-field (DOF) is proposed. By leveraging liquid lens technology, we can periodically modulate the focal length of a projector at a frequency that is higher than the critical flicker fusion (CFF) frequency. Fast periodic focal length modulation results in forward and backward sweeping of focusing distance. Fast focal sweep projection makes the point spread function (PSF) of each projected pixel integrated over a sweep period (IPSF; integrated PSF) nearly invariant to the distance from the projector to the projection surface as long as it is positioned within sweep range. This modulation is not perceivable by human observers. Once we compensate projection images for the IPSF, the projected results can be focused at any point within the range. Consequently, the proposed method requires only a single offline PSF measurement; thus, it is an open-loop process. We have proved the approximate invariance of the projector's IPSF both numerically and experimentally. Through experiments using a prototype system, we have confirmed that the image quality of the proposed method is superior to that of normal projection with fixed focal length. In addition, we demonstrate that a structured light pattern projection technique using the proposed method can measure the shape of an object with large depth variances more accurately than normal projection techniques. [ABSTRACT FROM AUTHOR]

Background/Aims To investigate the effect of increased CO2 levels on flicker defined stimuli. Methods The sensitivity of two flicker defined tasks was measured in nine healthy, trained observers using the Flicker Defined Form (FDF) stimulus of the Heidelberg Edge Perimeter (HEP; Heidelberg Engineering) and Frequency Doubling Technology (FDT) stimulus of the Matrix perimeter (Carl Zeiss Meditec) during normoxia and 15% hypercapnia (end-tidal CO2 increased by 15% relative to baseline). HEP-FDF and Matrix-FDT sensitivities were analysed for the global field, superior and inferior hemifields and at specific matched eccentricities, using repeated measures analysis of variance. The main effect of hypercapnia on flicker sensitivity was analysed using regression models. Results Higher flicker sensitivity outcomes with increasing CO2 values were found for HEP-FDF and Matrix-FDT with a statistically significant main effect for HEP-FDF global, superior and inferior hemifields (p<0.01 for all) as well as 6°, 18°, 12° and 24° eccentricities (p=0.03, 0.04, 0.01, 0.05, respectively). When comparing mean sensitivity values between normocapnia and hypercapnia conditions, no statistically significantly different results were found for HEP-FDF and Matrix-FDT (p>0.05). Conclusions As CO2 levels were increased in healthy young individuals, there was an associated increase in visual sensitivity that was only significant for HEP-FDF stimuli, highlighting the different mechanisms involved in processing each of HEP-FDF and Matrix-FDT stimuli. Mean visual sensitivity outcomes were found to be similar for normocapnia and hypercapnia suggesting that a capability to compensate for a mild and stable increase in systemic CO2 levels may exist. [ABSTRACT FROM AUTHOR]

Illumination variation is among the several bottlenecks in a practical face recognition system. Extracting illumination-invariant features, such as the gradient-based descriptor, is an effective method to deal with this problem and shows outstanding performance. In this paper, a novel illumination-invariant, histogram-based descriptor, namely local Gradientface XOR and binary pattern (LGXBP), is proposed to enhance the recognition performance of gradient-based method under varying lighting conditions. To this end, first, this approach transforms a face image into the logarithm domain and obtains a pair of illumination-insensitive components. Then the two components are encoded further by local XOR patterns and local binary patterns, respectively, to get compact descriptors and histogram representations, which not only preserve illumination invariance but also gain more discriminating power. Finally, the complementary histograms are integrated for face recognition. Comparative experimental results verify the effectiveness of our approach and show that LGXBP achieves superior recognition rates and a high degree of stability under varying illumination conditions, outperforming most of the state-of-the-art methods. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Superior local at the expense of global perception characterises vision in autism spectrum disorders (ASD). However, progress towards discovering a neural mechanism has been slow. Here we used known differences in magnocellular and parvocellular receptive field properties to assess the temporal encoding of information, via flicker fusion paradigms, in those high and low in self-reported autistic tendency (Autism Spectrum Quotient – AQ). A Low AQ group (AQ≤13, n =22), and a High AQ group (AQ≥18, n =17) undertook a 4AFC luminance flicker fusion (FF) with 5 temporal contrasts from 5% to 100%, and a 2AFC isoluminant red–green colour fusion task. Both groups showed an increase in fusion thresholds with temporal achromatic contrast. The High AQ group displayed diminished flicker fusion thresholds compared to the Low AQ at the lowest contrasts. For the red–green colour fusion task, the High AQ group displayed mean fusion frequency slightly greater than the Low AQ group. A significant interaction between 5% luminance contrast and the red–green fusion frequencies demonstrated that the differences in thresholds were not simply due to variations in overall attentional capacity between groups. These differences in flicker fusion thresholds are in accordance with reported differences in cortical visual evoked potential nonlinearities, particularly relating to the neural efficiency of the magnocellular pathway. [ABSTRACT FROM AUTHOR]

Independent channels respond to both the spatial and temporal characteristics of visual stimuli. Gratings <3 cycles per degree (cpd) are sensed by transient channels that prefer intermittent stimulation, while gratings >3 cpd are sensed by sustained channels that prefer steady stimulation. From this we predict that adaptation to a spatially uniform flickering field will selectively adapt the transient channels and raise the apparent spatial frequency of coarse sinusoidal gratings. Observers adapted to a spatially uniform field whose upper or lower half was steady and whose other half was flickering. They then adjusted the spatial frequency of a stationary test (matching) grating on the previously unmodulated half field until it matched the apparent spatial frequency of a grating falling on the previously flickering half field. The adapting field flickered at 8 Hz and the spatial frequency of the gratings was varied in octave steps from 0.25 to 16 cpd. As predicted, adapting to flicker raised the apparent spatial frequency of the test gratings. The aftereffect reached a peak of 11% between 0.5 and 1 cpd and disappeared above 4 cpd. We also observed that superimposed 10 Hz luminance flicker raised the apparent spatial frequency of 0.5 cpd test gratings. The effect was not seen with slower flicker or finer test gratings. Altogether, our study suggests that apparent spatial frequency is determined by the balance between transient and sustained channels and that an imbalance between the channels caused by flicker can alter spatial frequency perception. [ABSTRACT FROM AUTHOR]

• A new block called fusion block is proposed to solve the artifact phenomenon. • ACGAN has better performance in the pose transfer and attribute control tasks. • Faster image generation speed and fewer parameters while obtaining higher score. At present, pose transfer and attribute control tasks are still the challenges for image synthesis network. At the same time, there are often artifacts in the images generated by the image synthesis network when the above two tasks are completed. The existence of artifacts causes the loss of the generated image details or introduces some wrong image information, which leads to the decline of the overall performance of the existing work. In this paper, a generative adversarial network (GAN) named ACGAN is proposed to accomplish the above two tasks and effectively eliminate artifacts in generated images. The proposed network was compared quantitatively and qualitatively with previous works on the DeepFashion dataset and better results are obtained. Moreover, the overall network has advantages over the previous works in speed and number of parameters. [ABSTRACT FROM AUTHOR]

The cinematic illusion of movement always requires a number of images. In this regard, the present article poses the question as to how far one can narrow this down, and still consider such a manifestation a meaningful cinematic experience that communicates a concise idea. Demonstrating the impact of a flicker or an electronically alternating sequence of visual impulses that arrest our attention, a thaumatrope or an animated GIF can already generate such significance. Within both the art world and avant-garde cinema, artists have found ways to maximize the ­potential of such a minimalist approach to the moving image. The discussion of what the minimal duration for filmic experience of any cultural significance could be, is approached here from a media-archaeological perspective. [ABSTRACT FROM AUTHOR]

Focus-context techniques provide visual guidance in visualizations by giving strong visual prominence to elements of interest while the context is suppressed. However, finding a visual feature to enhance for the focus to pop out from its context in a large dynamic scene, while leading to minimal visual deformation and subjective disturbance, is challenging. This paper proposes Attractive Flicker, a novel technique for visual guidance in dynamic narrative visualizations. We first show that flicker is a strong visual attractor in the entire visual field, without distorting, suppressing, or adding any scene elements. The novel aspect of our Attractive Flicker technique is that it consists of two signal stages: The first “orientation stage” is a short but intensive flicker stimulus to attract the attention to elements of interest. Subsequently, the intensive flicker is reduced to a minimally disturbing luminance oscillation (“engagement stage”) as visual support to keep track of the focus elements. To find a good trade-off between attraction effectiveness and subjective annoyance caused by flicker, we conducted two perceptual studies to find suitable signal parameters. We showcase Attractive Flicker with the parameters obtained from the perceptual statistics in a study of molecular interactions. With Attractive Flicker, users were able to easily follow the narrative of the visualization on a large display, while the flickering of focus elements was not disturbing when observing the context. [ABSTRACT FROM PUBLISHER]

In reflective liquid crystal devices that have an asymmetric electrode structure, an internal cell voltage is often present that interferes with the proper functioning of the device. Contrary to transmissive devices, this internal voltage cannot be attributed solely to ionic charges in the liquid crystal. On the basis of extensive measurements, an electro-chemical model is developed and validated, providing a complete explanation for the generation and the dynamic behavior of the internal voltage in asymmetric liquid crystal devices. A possible solution for eliminating the occurrence of the internal voltage is also provided. [ABSTRACT FROM AUTHOR]

The measurement of the Critical Flicker Frequency threshold is used to study the visual temporal resolution in healthy subjects and in pathological conditions. To better understand the role played by different cortical areas in the Critical Flicker Frequency threshold perception we used continuous Theta Burst Stimulation (cTBS), an inhibitory plasticity-inducing protocol based on repetitive transcranial magnetic stimulation. The Critical Flicker Frequency threshold was measured in twelve healthy subjects before and after cTBS applied over different cortical areas in separate sessions. cTBS over the left inferior parietal lobule altered the Critical Flicker Frequency threshold, whereas cTBS over the left mediotemporal cortex, primary visual cortex and right inferior parietal lobule left the Critical Flicker Frequency threshold unchanged. No statistical difference was found when the red or blue lights were used. Our findings show that left inferior parietal lobule is causally involved in the conscious perception of Critical Flicker Frequency and that Critical Flicker Frequency threshold can be modulated by plasticity-inducing protocols. [ABSTRACT FROM AUTHOR]

Vibration training has become a popular method used in professional sports and recreation. In this study, we examined the effect of whole-body vibration training on the central nervous system and muscle excitability in a group of 28 active men. Subjects were assigned randomly to one of two experimental groups with different variables of vibrations. The chronaximetry method was used to evaluate the effect of a single session of whole-body vibration training on the excitability of the rectus femoris and brachioradialis muscles. The examination of the fusing and flickering frequencies of the light stimulus was performed. An increase in the excitability of the quadriceps femoris muscle due to low intensity vibrations (20 Hz frequency, 2 mm amplitude) was noted, and a return to the initial values was observed 30 min after the application of vibration. High intensity vibrations (60 Hz frequency, 4 mm amplitude) caused elongations of the chronaxy time; however, these differences were not statistically significant. Neither a low intensity vibration amplitude of 2 mm (frequency of 20 Hz) nor a high intensity vibration amplitude of 4 mm (frequency of 60 Hz) caused a change in the excitability of the central nervous system, as revealed by the average frequency of the fusing and flickering of the light stimulus. A single session of high intensity whole-body vibration did not significantly decrease the excitability of the peripheral nervous system while the central nervous system did not seem to be affected. [ABSTRACT FROM AUTHOR]

Organisms have evolved under stable natural lighting regimes, employing cues from these to govern key ecological processes. However, the extent and density of artificial lighting within the environment has increased recently, causing widespread alteration of these regimes. Indeed, night-time electric lighting is known significantly to disrupt phenology, behaviour, and reproductive success, and thence community composition and ecosystem functioning. Until now, most attention has focussed on effects of the occurrence, timing, and spectral composition of artificial lighting. Little considered is that many types of lamp do not produce a constant stream of light but a series of pulses. This flickering light has been shown to have detrimental effects in humans and other species. Whether a species is likely to be affected will largely be determined by its visual temporal resolution, measured as the critical fusion frequency. That is the frequency at which a series of light pulses are perceived as a constant stream. Here we use the largest collation to date of critical fusion frequencies, across a broad range of taxa, to demonstrate that a significant proportion of species can detect such flicker in widely used lamps. Flickering artificial light thus has marked potential to produce ecological effects that have not previously been considered. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies have demonstrated that establishing figure–ground organization influences other perceptual processes. Specifically, figures undergo perceptual processing earlier than ground regions (Lester, Hecht, & Vecera, 2009), and they are processed for longer durations relative to ground regions (Hecht & Vecera, 2011). One potential consequence of figures' extended processing is degraded temporal resolution compared to ground regions. To test this hypothesis, observers completed a modified flicker-fusion task while viewing either displays that contained well-defined figures and grounds or displays that were ambiguous. As evidenced by increased sensitivity for flickering targets on the ground regions, the current results support the claim that figures have poorer temporal resolution than ground regions. [Copyright &y& Elsevier]

Bitemporal hemianopic visual field impairment frequently leads to binocular vision difficulties. Patients with bitemporal hemianopia with pre-existing exophoria complain of horizontal diplopia, sometimes combined with vertical deviation (with pre-existing hyperphoria). The symptoms are a result of the phoria decompensating into a tropia (hemi-slide) due to the lack of retinal correspondence between the remaining nasal fields of both eyes. We measured these effects using a dichoptic perimeter. We showed that aligning the eyes with prisms could prevent diplopia if the bitemporal hemianopia is incomplete. We also describe the successful use of a novel fusion aid - the 'stereo-typoscope' - that utilizes midline stereopsis to prevent diplopia resulting from hemi-sliding in patients with complete bitemporal hemianopia. [ABSTRACT FROM AUTHOR]

Purpose (1) To devise a model-based method for estimating the probabilities of binocular fusion, interocular suppression and diplopia from psychophysical judgements, (2) To map out the way fusion, suppression and diplopia vary with binocular disparity and blur of single edges shown to each eye, (3) To compare the binocular interactions found for edges of the same vs opposite contrast polarity. Methods Test images were single, horizontal, Gaussian-blurred edges, with blur B = 1-32 min arc, and vertical disparity 0-8.B, shown for 200 ms. In the main experiment, observers reported whether they saw one central edge, one offset edge, or two edges. We argue that the relation between these three response categories and the three perceptual states (fusion, suppression, diplopia) is indirect and likely to be distorted by positional noise and criterion effects, and so we developed a descriptive, probabilistic model to estimate both the perceptual states and the noise/criterion parameters from the data. Results (1) Using simulated data, we validated the model-based method by showing that it recovered fairly accurately the disparity ranges for fusion and suppression, (2) The disparity range for fusion (Panum's limit) increased greatly with blur, in line with previous studies. The disparity range for suppression was similar to the fusion limit at large blurs, but two or three times the fusion limit at small blurs. This meant that diplopia was much more prevalent at larger blurs, (3) Diplopia was much more frequent when the two edges had opposite contrast polarity. A formal comparison of models indicated that fusion occurs for same, but not opposite, polarities. Probability of suppression was greater for unequal contrasts, and it was always the lower-contrast edge that was suppressed. Conclusions Our model-based data analysis offers a useful tool for probing binocular fusion and suppression psychophysically. The disparity range for fusion increased with edge blur but fell short of complete scale-invariance. The disparity range for suppression also increased with blur but was not close to scale-invariance. Single vision occurs through fusion, but also beyond the fusion range, through suppression. Thus suppression can serve as a mechanism for extending single vision to larger disparities, but mainly for sharper edges where the fusion range is small (5-10 min arc). For large blurs the fusion range is so much larger that no such extension may be needed. [ABSTRACT FROM AUTHOR]