Modulation frequency and orientation tuning of second-order mechanisms underlying the detection of modulation in local spatial-frequency information are assessed by using an oblique-masking paradigm. Stimuli were Gabor-filtered noise patterns in which the local carrier spatial frequency was modulated about an average value of 4.7 cycles per degree (cpd) according to sinusoidal function. Thresho...

In human vision, the response to luminance contrast at each small region in the image is controlled by a more global process where suppressive signals are pooled over spatial frequency and orientation bands. But what rules govern summation among stimulus components within the suppressive pool? We addressed this question by extending a pedestal plus pattern mask paradigm to use a stimulus with u...

The application of high energy ion implantation is restricted by an asymmetric doping profile at the mask edges. As a result, buried interconnect cannot easily be formed. Moreover, the holding voltage and threshold voltage of CMOS-processes with retrograde wells may be strongly affected by this asymmetry. It arises from the 7" wafer tilt, which is frequently used to avoid channeling, even in th...

We consider the role of nonlinear inhibition in physiologically realistic multineuronal models of V1 to predict the dipper functions from contrast discrimination experiments with sinusoidal gratings of different geometries. The dip in dipper functions has been attributed to an expansive transducer function, which itself is attributed to two nonlinear inhibitory mechanisms: contrast normalizatio...

Computerized segmentation of retinal vessels can help doctors discover diabetic retinopathy, Retinal Tear and Detachment. Because the anatomy is complicated changing, automated vessel still a difficult task. The Expectation-Maximization approach for vascular proposed in this paper, which uses matched filter (MF) that combines Mask based Blood Vessels Extraction with global image threshold to ex...

We use the term \Blue Noise Mask" to mean a halftone threshold array that has been constructed to produce pleasing, unstructured (but not white noise) binary patterns. An eecient way to produce a Blue Noise Mask is to construct a set of binary patterns that are constrained by neighboring levels. These binary patterns are appropriate for diierent grey levels, and can be summed to form a single t...

This paper presents an approach for a real-time region-based motion segmentation and tracking using an adaptive thresholding and k-means clustering in a scene, with focus on a video monitoring system. In order to reduce the computational load to the motion segmentation, the presented approach is based on the variation regions application of a weighted k-means clustering algorithm, followed by a...

A class of shift-variant reduction operations is introduced, that is useful for performing efficient and controllable shape and texture transformations between resolution levels. In their most general form, the operations proceed in three steps: (a) convolve a binary image with a kernel of arbitrary size; (b) threshold the result; (c) subsample to produce the reduced image. Taking a binary stru...

Interactions between filters tuned to different orientations and gpatial Iocatiom were investigated with a masking paradigm. Targets were masked by pairs of Gabor signals presented either at a different orientation (*A(I)or at a different spatial location (&Ay).The two mask components were either of equal phase or of opposite phase to each other. Detection thresholds of the target were measured...

A blind (non-ideal) time-frequency (T-F) masking technique is proposed for suppressing reverberation. A binary mask is estimated at each T-F unit by extracting a single variance-based feature from the reverberant signal and comparing its value against an adaptive threshold. The performance of the estimated binary mask is evaluated using intelligibility listening tests with hearing impaired list...