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Results 201 - 250 of 828
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Schepers Paul - - 2011
The number of single-bicycle crash victims is substantial in countries with high levels of cycling. To study the role of visual characteristics of the infrastructure, such as pavement markings, in single-bicycle crashes, a study in two steps was conducted. In Study 1, a questionnaire study was conducted among bicycle crash ...
Tombu Michael M Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN 37203, - - 2011
People can attend to and track multiple moving objects over time. Cognitive theories of this ability emphasize location information and differ on the importance of motion information. Results from several experiments have shown that increasing object speed impairs performance, although speed was confounded with other properties such as proximity of ...
Gur M Berke - - 2011
Approximately a quarter of all West Indian manatee (Trichechus manatus latirostris) mortalities are attributed to collisions with watercraft. A boater warning system based on the passive acoustic detection of manatee vocalizations is one possible solution to reduce manatee-watercraft collisions. The success of such a warning system depends on effective enhancement ...
Karanovic Olivera - - 2011
Flickering light is strongly aversive to many individuals with migraine. This study was designed to evaluate other abnormalities in the processing of temporally modulating visual stimulation. We measured psychophysical thresholds for detection of a flickering target and for the discrimination of suprathreshold flicker contrasts (increment thresholds) in 14 migraineurs and ...
Carle Corinne F - - 2011
To investigate the neural basis of contraction anisocoria and any implications for assessments using pupillary responses, through analysis of topographic variation in amplitudes of direct and consensual pupil responses. Direct and consensual pupillary contraction amplitudes were analyzed from six studies in which 120 normal subjects were tested with 24 different ...
Kim Jun-Sik - - 2011
We present a telecentric lens that is able to gain 3D information. The proposed lens system has multiple aperture stops, which enable it to capture multidirectional parallel light rays, while a conventional telecentric lens has only one aperture stop and can capture only light rays that are perpendicular to the ...
Onat Selim - - 2011
Neurons in primary visual cortex have been characterized by their selectivity to orientation, spatiotemporal frequencies, and motion direction, among others all essential parameters to decompose complex image structure. However, their concerted functioning upon real-world visual dynamics remained unobserved since most studies tested these parameters in isolation rather than in rich ...
Paltoglou Aspasia E AE MRC Institute of Hearing Research, University Park, Nottingham, - - 2011
Feature-specific enhancement refers to the process by which selectively attending to a particular stimulus feature specifically increases the response in the same region of the brain that codes that stimulus property. Whereas there are many demonstrations of this mechanism in the visual system, the evidence is less clear in the ...
Collet Catherine - - 2011
Forest tree saplings that grow in the understorey undergo frequent changes in their light environment to which they must adapt to ensure their survival and growth. Crown architecture, which plays a critical role in light capture and mechanical stability, is a major component of sapling adaptation to canopy disturbance. Shade-adapted ...
Takeda H - - 2011
Although spatial deblurring is relatively wellunderstood by assuming that the blur kernel is shift-invariant, motion blur is not so when we attempt to deconvolve this motion blur on a frame-by-frame basis: this is because, in general, videos include complex, multi-layer transitions. Indeed, we face an exceedingly difficult problem in motion ...
Hansen Bruce C - - 2011
The contrast response function of early visual evoked potentials elicited by sinusoidal gratings is known to exhibit characteristic potentials closely associated with the processes of parvocellular and magnocellular pathways. Specifically, the N1 component has been linked with parvocellular processes, while the P1 component has been linked with magnocellular processes. However, ...
Weigelt Sarah - - 2011
The processing of orientations is at the core of our visual experience. Orientation selectivity in human visual cortex has been inferred from psychophysical experiments and more recently demonstrated with functional magnetic resonance imaging (fMRI). One method to identify orientation-selective responses is fMRI adaptation, in which two stimuli-either with the same ...
Kim Jong S - - 2011
Abstract Objective: The effects of asymmetric directional microphone fittings (i.e., an omnidirectional microphone on one ear and a directional microphone on the other) on speech understanding in noise and acceptance of background noise were investigated in 15 full-time hearing aid users. Design: Subjects were fitted binaurally with four directional microphone ...
Murd Carolina - - 2011
In searching for the target-afterimage patch among spatially separate alternatives of color afterimages the target fades from awareness before its competitors (Bachmann, T., Murd, C., 2010. Covert spatial attention in search for the location of a color-afterimage patch speeds up its decay from awareness: Introducing a method useful for the ...
Delso G - - 2011
The evaluation of coronary plaque vulnerability could be of great diagnostic value in cardiology. Positron emission tomography (PET) is a good candidate due to its ability to quantify micromolar concentrations of targeted drugs. However, the detectability of sub-voxel targets such as coronary plaque is limited by partial volume effects and ...
Purves Dale - - 2011
This article considers visual perception, the nature of the information on which perceptions seem to be based, and the implications of a wholly empirical concept of perception and sensory processing for vision science. Evidence from studies of lightness, brightness, color, form, and motion all indicate that, because the visual system ...
Maier Florian F Medical Physics in Radiology (E020), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany. - - 2012
Proton resonance frequency shift thermometry is sensitive to breathing motion that leads to incorrect phase differences. In this work, a novel velocity-sensitive navigator technique for triggering MR thermometry image acquisition is presented. A segmented echo planar imaging pulse sequence was modified for velocity-triggered temperature mapping. Trigger events were generated when ...
Yang Shu-Ju - - 2011
We investigated whether the impact of an object's orientation on a perceiver's actions (an orientation effect) is moderated by the perceiver's ability to act on the object in question. To do this, we manipulated the physical location of presented objects (Experiment 1) and the perceiver's action capacity (Experiment 2). Regardless ...
McGovern David P - - 2011
Temporal information in a scene is thought to be an important cue for visual grouping of local image features into a single object. The majority of studies on this topic have attempted to determine the conditions that facilitate segregation of a figure from a cluttered background. Here we examine the ...
Woodhead Zoe Victoria Joan ZV MRC Clinical Sciences Centre, Imperial College, Hammersmith Hospital, London W12 0NN, UK. - - 2011
Different cortical regions within the ventral occipitotemporal junction have been reported to show preferential responses to particular objects. Thus, it is argued that there is evidence for a left-lateralized visual word form area and a right-lateralized fusiform face area, but the unique specialization of these areas remains controversial. Words are ...
Brants Marijke - - 2011
Object knowledge is hierarchical. Several hypotheses have proposed that this property might be reflected in the spatial organization of ventral visual cortex. For example, all exemplars of a category might activate the same patches of cortex, but with a slightly different position of the peak of activation in each patch. ...
Ma Jianfen - - 2011
Most of the existing intelligibility measures do not account for the distortions present in processed speech, such as those introduced by speech-enhancement algorithms. In the present study, we propose three new objective measures that can be used for prediction of intelligibility of processed (e.g., via an enhancement algorithm) speech in ...
Di Luca Massimiliano - - 2011
Handling a compliant object using a pinch grasp provides sensory information about deformation and resistive force from both index finger and thumb. In this paper, an object with rigid surfaces and composed of two compliant materials fixed on a central position is used to address how information from the two ...
Barbot Antoine A Department of Psychology, New York University, New York, NY 10003, United States. - - 2011
Natural scenes contain a rich variety of contours that the visual system extracts to segregate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. ...
Aguirre Geoffrey Karl GK Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA. - - 2011
Stimulus counterbalance is critical for studies of neural habituation, bias, anticipation, and (more generally) the effect of stimulus history and context. We introduce de Bruijn cycles, a class of combinatorial objects, as the ideal source of pseudo-random stimulus sequences with arbitrary levels of counterbalance. Neuro-vascular imaging studies (such as BOLD ...
Yoshida Eiji - - 2011
Conventionally, block detectors, which consist of a two-dimensionally segmented scintillator array with inserted reflectors, are often used for PET. On the other hand, PET detectors with a monolithic block have been investigated because they are expected to offer higher resolution than do segmented crystal arrays. However, previous reports focused on ...
Grossberg Stephen - - 2011
How do spatially disjoint and ambiguous local motion signals in multiple directions generate coherent and unambiguous representations of object motion? Various motion percepts, starting with those of Duncker (Induced motion, 1929/1938) and Johansson (Configurations in event perception, 1950), obey a rule of vector decomposition, in which global motion appears to ...
Tan Ping - - 2011
Different materials reflect light in different ways, and this reflectance interacts with shape, lighting, and viewpoint to determine an object's image. Common materials exhibit diverse reflectance effects, and this is a significant source of difficulty for image analysis. One strategy for dealing with this diversity is to build computational tools ...
Su Wei-Hung - - 2011
An approach using a liquid-crystal spatial light modulator (LC-SLM) to enlarge the depth measuring range of the projected fringe profilometry is presented. This approach is especially applicable to detect dynamic objects with micro-scale sizes. Compared with a typical 2D image system, the LC-SLM provides a better performance for a 3D ...
- - 2011
Video retargeting from a full-resolution video to a lower-resolution display will inevitably cause information loss. Content-aware video retargeting techniques have been studied to avoid critical visual information loss while resizing a video. Maintaining the spatio-temporal coherence of a retargeted video is very critical on visual quality. Camera motions and object ...
Calabro F J FJ Brain and Vision Research Laboratory, Department of Biomedical Engineering, Boston, MA 02215, - - 2011
In humans, as well as most animal species, perception of object motion is critical to successful interaction with the surrounding environment. Yet, as the observer also moves, the retinal projections of the various motion components add to each other and extracting accurate object motion becomes computationally challenging. Recent psychophysical studies ...
Lister Jennifer J - - 2011
Abstract Objective: Several methods exist to measure temporal resolution in a clinical setting. The Adaptive Tests of Temporal Resolution (ATTR?) are unique in that they incorporate an adaptive psychophysical procedure to present stimuli via computer sound card. The purpose of this study was to determine if ATTR gap detection thresholds ...
Renninger Sabine L - - 2011
Vision of high temporal resolution depends on careful regulation of photoresponse kinetics, beginning with the lifetime of activated photopigment. The activity of rhodopsin is quenched by high-affinity binding of arrestin to photoexcited phosphorylated photopigment, which effectively terminates the visual transduction cascade. This regulation mechanism is well established for rod photoreceptors, ...
Sęk Aleksander A Institute of Acoustics, Adam Mickiewicz University, Poznań, Poland. - - 2011
To implement a fast method for measuring psychophysical tuning curves (PTCs) for use in clinical applications, such as assessment of frequency selectivity and detection of dead regions in the cochlea. The method is based on that described by Sek et al (2005) and has been implemented in software that can ...
Bradley Julie A - - 2011
PURPOSE: To quantify swallowing frequency and tumor and normal structure displacements during deglutition using dynamic magnetic resonance imaging (MRI) and to determine planning target volume (PTV) margins to account for resting and deglutition-induced displacements in patients with head-and-neck cancer (HNC). METHODS AND MATERIALS: Twenty-two patients with HNC were imaged in ...
Thompson Benjamin - - 2011
Amblyopia is characterised by visual deficits in both spatial vision and motion perception. While the spatial deficits are thought to result from deficient processing at both low and higher level stages of visual processing, the deficits in motion perception appear to result primarily from deficits involving higher level processing. Specifically, ...
Hu L - - 2011
OBJECTIVE: To develop an effective approach for enhancing the signal-to-noise ratio (SNR) and identifying single-trial short-latency somatosensory evoked potentials (SEPs) from multi-channel electroencephalography (EEG). METHODS: 128-channel SEPs elicited by electrical stimuli of the left posterior tibial nerve were recorded from 11 healthy subjects. Probabilistic independent component analysis (PICA) was used ...
Badri Rohima - - 2011
Some individuals complain of hearing difficulties in the presence of background noise even in the absence of clinically significant hearing loss (obscure auditory dysfunction). Previous evidence suggests that these listeners have impaired frequency resolution, but there has been no thorough characterization of auditory filter shapes in this population. Here, the ...
Chang Enson - - 2011
Conventional synthetic aperture processing uses motion of the sonar to increase aperture size and bearing resolution. Two recent papers discussed a different application in which synthetic elements are used to fill in an otherwise sparse passive array. This paper points out that ambiguities persist, even with synthetic elements, in the ...
Liu Le - - 2011
We describe a two-dimensional polarization interferometry based parallel scan angular surface plasmon resonance (SPR) biosensing technique. The method of line-shaped light illumination and parallel scan offers a high throughput. The simultaneous record of SPR angular spectrum enables the system to be unaffected by the time-dependent variation of the light source. ...
Chung Susana T L ST School of Optometry, University of California, Berkeley, Berkeley, California, - - 2011
In persons with infantile nystagmus (IN), visual acuity correlates with the duration of the foveation period of the nystagmus waveform, i.e., when the retinal image is on or near the fovea and moves with low velocity. In this study, we asked how acuity is affected by the non-foveating phases of ...
Mehboob Zareen - - 2011
The empirical mode decomposition (EMD) method can adaptively decompose a non-stationary time series into a number of amplitude or frequency modulated functions known as intrinsic mode functions. This paper combines the EMD method with information analysis and presents a framework of information-preserving EMD. The enhanced EMD method has been exploited ...
Buss Emily - - 2011
The present study sought to clarify the role of non-simultaneous masking in the binaural masking level difference for maskers that fluctuate in level. In the first experiment the signal was a brief 500-Hz tone, and the masker was a bandpass noise (100-2000 Hz), with the initial and final 200-ms bursts ...
Meyer O - - 2011
Charge exchange spectroscopy is one of the standard plasma diagnostic techniques used in tokamak research to determine ion temperature, rotation speed, particle density, and radial electric field. Configuring a charge coupled device (CCD) camera to serve as a detector in such a system requires a trade-off between the competing desires ...
Bruns Patrick P Biological Psychology and Neuropsychology, University of Hamburg, Von-Melle-Park 11, 20146 Hamburg, Germany. - - 2011
In the well-known spatial ventriloquism effect, auditory stimuli are mislocalized towards the location of synchronous but spatially disparate visual stimuli. Recent studies have demonstrated a similar influence of tactile stimuli on auditory localization, which predominantly operates in an external coordinate system. Here, we investigated whether this audio-tactile ventriloquist illusion leads ...
Jonke Erwin - - 2011
The aim of the present investigation was to study the variation in interdental forces between mandibular canines and lateral incisors of 19 volunteers (9 males and 10 females) aged 20-26 years for four configurations (mandible open/closed and left/right side). These forces were derived by pulling a stainless steel matrix strip ...
Inaba Naoko - - 2011
When tracking a moving target in the natural world with pursuit eye movement, our visual system must compensate for the self-induced retinal slip of the visual features in the background to enable us to perceive their actual motion. We previously reported that the speed of the background stimulus in space ...
Bishop Christopher W CW Center for Mind and Brain, University of California, Davis, Davis, CA 95618, USA. - - 2011
Locating sounds in realistic scenes is challenging because of distracting echoes and coarse spatial acoustic estimates. Fortunately, listeners can improve performance through several compensatory mechanisms. For instance, their brains perceptually suppress short latency (1-10 ms) echoes by constructing a representation of the acoustic environment in a process called the precedence ...
Tadin Duje D Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA. - - 2011
As stimulus size increases, motion direction of high-contrast patterns becomes increasingly harder to perceive. This counterintuitive behavioral result, termed "spatial suppression," is hypothesized to reflect center-surround antagonism-a receptive field property ubiquitous in sensory systems. Prior research proposed that spatial suppression of motion signals is a direct correlate of center-surround antagonism ...
Skoe Erika E Auditory Neuroscience Laboratory, Northwestern University, 2240 Campus Drive, Evanston, IL 60208, - - 2011
We introduce a new approach, the cross-phaseogram, that captures the brain's ability to discriminate between spectrotemporally dynamic speech sounds, such as stop consonants. The goal was to develop an analysis technique for auditory brainstem responses (ABRs) that taps into the sub-millisecond temporal precision of the response but does not rely ...
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