OBJECTIVE To determine if blind people have heightened tactile spatial acuity. BACKGROUND Recently, studies using magnetic source imaging and somatosensory evoked potentials have shown that the cortical representation of the reading fingers of blind Braille readers is expanded compared to that of fingers of sighted subjects. Furthermore, the visual cortex is activated during certain tactile t...

Stereo thresholds for 84% correct detection of sinusoidal disparity corrugations depicted by narrow-band-filtered random dot stereograms were determined for surfaces as a function of (i) luminance center spatial frequency and (ii) disparity modulation frequency. In addition, supra-threshold depth matching functions for two amplitudes of peak-to-trough depth were determined using similar stimuli...

Extreme value theory focuses on the study of rare events and uses asymptotic properties to estimate their associated probabilities. Easy availability of georeferenced data has prompted a growing interest in the analysis of spatial extremes. Most of the work so far has focused on models that can handle block maxima, with few examples of spatial models for exceedances over a threshold. Using a hi...

Address Event Representation (AER) is an emergent technology for assembling modular multi-blocks bio-inspired sensory and processing systems. Visual sensors (retinae) are among the first AER modules to be reported since the introduction of the technology. Spatial contrast AER retinae are of special interest since they provide highly compressed data flow without reducing the relevant information...

Some researchers suggested that one central mechanism is responsible for temporal order judgments (TOJ), within and across sensory channels. This suggestion is supported by findings of similar TOJ thresholds in same modality and cross-modality TOJ tasks. In the present study, we challenge this idea by analyzing and comparing the threshold distributions of the spectral and spatial TOJ tasks. In ...

We have measured the spread of contrast adaptation across the dimension of spatial frequency. Threshold elevation was tightly tuned to the adapting spatial frequency but became much broader as test contrast was increased. This means that, for a given test frequency, there are some frequencies which do not raise threshold but do result in a loss of perceived contrast. The contrast dependence, re...

To clarify the role of lateral interaction and uncertainty reduction in collinear flanker facilitation of contrast discrimination, we investigated the effect of flankers and spatial cueing on the contrast discrimination threshold. The task of the observers was to detect a 1.3 cyc/deg vertical Gabor target superimposed on one of the Gabor pedestals presented at 3 degrees to the left and right of...

We used Gaussian blurred stimuli to explore the effect of blur on three tasks: (i) 2-line "resolution"; (ii) line detection; and (iii) spatial interval discrimination, in both central and peripheral vision. The results of our experiments can be summarized as follows. (i) 2-Line "resolution": thresholds for pairs of unblurred, low contrast, stimuli are approx. 0.5 min arc in the fovea. When the ...

Non-invasive spatial activity recognition is a difficult task, complicated by variation in how the same activities are conducted and furthermore by noise introduced by video tracking procedures. In this paper we propose an algorithm based on dynamic time warping (DTW) as a viable method with which to quantify segmented spatial activity sequences from a video tracking system. DTW is a widely use...

Objective: In processing high dimensional clinical data, choosing the optimal subset of features is important, not only for reduce the computational complexity but also to improve the value of the model constructed from the given data. This study proposes an efficient feature selection method with a variable threshold. Methods: In the proposed method, the spatial distribution of labeled data, w...