Information technology and visual impairment: New developments

No abstract available

Constructing sonified haptic line graphs for the blind student: first steps

Line graphs stand as an established information visualisation and analysis technique taught at various levels of difficulty according to standard Mathematics curricula. It has been argued that blind individuals cannot use line graphs as a visualisation and analytic tool because they currently primarily exist in the visual medium. The research described in this paper aims at making line graphs accessible to blind students through auditory and haptic media. We describe (1) our design space for representing line graphs, (2) the technology we use to develop our prototypes and (3) the insights from our preliminary work

Studies of mechano-chemical interactions in the tribological behavior of materials

Mechano-chemical interaction studies can contribute to the understanding of wear and friction of materials. Specific examples of experimental results relative to the subject are discussed. There are two parts: one describes the synergistic effect of corrosion and wear of iron sliding on sapphire in sulfuric acid, and the other describes the effect of surface films on the wear and friction of plasma-deposited diamondlike carbon (amorphous hydrogenated carbon) films in sliding contact with silicon nitride. The concentration of acid (pH) is an important factor in controlling the iron loss caused by wear-corrosion processes in sulfuric acid. The mechanical action can cause chemical reactions to proceed much faster than they would otherwise. The diamondlike carbon (DLC) films are shown to behave tribologically much like bulk diamond. In a dry nitrogen environment, a mechano-chemical reaction produces a substance which greatly decreases the coefficient of friction. In a moist air environment, mechano-chemical interactions drastically reduce the wear life of DLC films and water vapor greatly increases friction

A high-speed OLED monitor for precise stimulation in vision, eye-tracking, and EEG research

The recent introduction of organic light-emitting diode (OLED) monitors with refresh rates of 240 Hz or more opens new possibilities for their use as precise stimulation devices in vision research, experimental psychology, and electrophysiology. These affordable high-speed monitors, targeted at video gamers, promise several advantages over the cathode ray tube (CRT) and liquid crystal display (LCD) monitors commonly used in these fields. Unlike LCDs, OLED displays have self-emitting pixels that can show true black, resulting in superior contrast ratios, a broad color gamut, and good viewing angles. More importantly, the latest gaming OLEDs promise excellent timing properties with minimal input lags and rapid transition times. However, OLED technology also has potential drawbacks, notably Auto-Brightness Limiting (ABL) behavior, where the local luminance of a stimulus can change with the number of currently illuminated pixels. This study characterized a 240 Hz OLED monitor, the ASUS PG27AQDM, in terms of its timing properties, spatial uniformity, viewing angles, warm-up times, and ABL behavior. We also compared its responses to those of CRTs and LCDs. Results confirm the monitor’s excellent temporal properties with CRT-like transition times (around 0.3 ms), wide viewing angles, and decent spatial uniformity. Additionally, we found that ABL could be prevented with appropriate settings. We illustrate the monitor’s benefits in two time-critical paradigms: Rapid “invisible” flicker stimulation and the gaze-contingent presentation of stimuli during eye movements. Ourfindings suggest that the newest gaming OLEDs are precise and cost-effective stimulation devices for visual experiments that have several key advantages over CRTs and LCDs

(Micro)saccade-related potentials during face recognition:A study combining EEG, eye-tracking, and deconvolution modeling

Under natural viewing conditions, complex stimuli such as human faces are typically looked at several times in succession, implying that their recognition may unfold across multiple eye fixations. Although electrophysiological (EEG) experiments on face recognition typically prohibit eye movements, participants still execute frequent (micro)saccades on the face, each of which generates its own visuocortical response. This finding raises the question of whether the fixation-related potentials (FRPs) evoked by these tiny gaze shifts also contain psychologically valuable information about face processing. Here we investigated this question by co-recording EEG and eye movements in an experiment with emotional faces (happy, angry, neutral). Deconvolution modeling was used to separate the stimulus-ERPs to face onset from the FRPs generated by subsequent microsaccades-induced refixations on the face. As expected, stimulus-ERPs exhibited typical emotion effects, with a larger early posterior negativity (EPN) for happy/angry compared to neutral faces. Eye-tracking confirmed that participants made small saccades within the face in 98% of the trials. However, while each saccade produced a strong response over visual areas, this response was unaffected by the face’s emotional expression, both for the first and for subsequent (micro)saccades. This finding suggests that the face’s affective content is rapidly evaluated after stimulus onset, leading to only a short-lived sensory enhancement by arousing stimuli that does not repeat itself during immediate refixations. Methodologically, our work demonstrates how eye-tracking and deconvolution modeling can be used to extract several brain responses from each EEG trial, providing insights into neural processing at different latencies after stimulus onset

Comparison of magnetic resonance imaging and computed tomography for breast target volume delineation in prone and supine positions

Purpose To\ua0determine whether T2-weighted MRI improves seroma cavity (SC) and whole breast (WB) interobserver conformity for radiation therapy purposes, compared with the gold standard of CT, both in the prone and supine positions. Methods and Materials Eleven observers (2 radiologists and 9 radiation oncologists) delineated SC and WB clinical target volumes (CTVs) on T2-weighted MRI and CT supine and prone scans (4 scans per patient) for 33 patient datasets. Individual observer's volumes were compared using the Dice similarity coefficient, volume overlap index, center of mass shift, and Hausdorff distances. An average cavity visualization score was also determined. Results Imaging modality did not affect interobserver variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than supine CTVs (on both MRI and CT). Seroma cavity volumes were larger on CT than on MRI. Seroma cavity volumes proved to be comparable in interobserver conformity in both modalities (volume overlap index of 0.57\ua0(95% Confidence Interval (CI) 0.54-0.60) for CT supine and 0.52\ua0(95% CI 0.48-0.56) for MRI supine, 0.56\ua0(95% CI 0.53-0.59) for CT prone and 0.55\ua0(95% CI 0.51-0.59) for MRI prone); however, after registering modalities together the intermodality variation (Dice similarity coefficient of 0.41\ua0(95% CI 0.36-0.46) for supine and 0.38\ua0(0.34-0.42) for prone) was larger than the interobserver variability for SC, despite the location typically remaining constant. Conclusions Magnetic resonance imaging interobserver variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Although the cavity visualization score and interobserver concordance was not significantly higher for MRI than for CT, the SCs were smaller on MRI, potentially owing to clearer SC definition, especially on T2-weighted MR images

A screen reader solution for accessing SPSS 9.0 without sight

No abstract available

Self-recognition generates characteristic responses in pupil dynamics and microsaccade rate

Visual fixation is an active process with pupil dynamics as well as fixational eye movements and microsaccades that support perception. Measures of both pupil contraction and microsaccades are known to be sensitive to ongoing cognition and emotional processing. Here we present experimental results from a visual fixation task demonstrating that pupil size and microsaccade rate respond differently during self-recognition (when seeing one's own face) than when seeing familiar or unfamiliar faces. First, the pupil response is characterized by an immediate pupil-constriction followed by later dilation in response to stimulus onsets. For one's own face, we observe muted constriction and greater dilation compared to other faces. Second, microsaccades, which generally show an inhibitory response to incoming stimuli, are more strongly inhibited in response to one's own face compared to other faces. Our results lend support to the idea that eye-related physiological measures could contribute to biometric identification procedures

Self-recognition generates characteristic responses in pupil dynamics and microsaccade rate

Visual fixation is an active process with pupil dynamics as well as fixational eye movements and microsaccades that support perception. Measures of both pupil contraction and microsaccades are known to be sensitive to ongoing cognition and emotional processing. Here we present experimental results from a visual fixation task demonstrating that pupil size and microsaccade rate respond differently during self-recognition (when seeing one's own face) than when seeing familiar or unfamiliar faces. First, the pupil response is characterized by an immediate pupil-constriction followed by later dilation in response to stimulus onsets. For one's own face, we observe muted constriction and greater dilation compared to other faces. Second, microsaccades, which generally show an inhibitory response to incoming stimuli, are more strongly inhibited in response to one's own face compared to other faces. Our results lend support to the idea that eye-related physiological measures could contribute to biometric identification procedures.Comment: 22 pages, 5 figures, 3 table