Underwater noise, whether of natural or anthropogenic origin, has the ability to interfere with the way in which marine mammals receive acoustic signals (i.e., for communication, social interaction, foraging, navigation, etc.). This phenomenon, termed auditory masking, has been well studied in humans and terrestrial vertebrates (in particular birds), but less so in marine mammals. Anthropogenic...

The dynamic properties of a neural network model of visual perception, called the boundary contour system, explain characteristics of metacontrast visual masking. Computer simulations of the model, with a single set of parameters, demonstrate that it accounts for 9 key properties of metacontrast masking: Metacontrast masking is strongest at positive stimulus onset asynchronies (SOAs); decreasin...

We develop an objective, noninvasive method for determining the frequency selectivity of cochlear tuning at low and moderate sound levels. Applicable in humans at frequencies of 1 kHz and above, the method is based on the measurement of stimulus-frequency otoacoustic emissions and, unlike previous noninvasive physiological methods, does not depend on the frequency selectivity of masking or supp...

There are serious methodological problems in studies which report contralateral visual masking. Contralateral masking occurs when detection of a hemifield target stimulus is impaired by a pattern-masking stimulus presented to the opposite hemifield. We demonstrate that, in studies which used positive stimuli (i.e., black letters on a white field), contralateral masking may be an artifact. Altho...

Detection of a Gabor pattern is impaired in the presence of a similar pattern of orthogonal orientation, a phenomenon known as cross-orientation masking (XOM). Here we investigate the role of color in cross-orientation masking. We measured contrast detection thresholds to horizontally oriented Gabors overlaid by similar Gabors of a different orientation. Red-green chromatic masking was compared...

A new scheme of unsharp masking for image contrast enhancement is presented in this paper. An adaptive algorithm is introduced so that a sharpening action is performed only in locations where the image exhibits signiicant dynamics. Hence, the ampliication of noise in smooth areas is reduced. An adaptive directional l-tering is also performed so as to provide suitable emphasis to the diierent di...

In this paper, a novel approach to the transcription of polyphonic signals is investigated. The method makes use of top-down analysis and bottom-up reconstruction of the time-frequency contents of the signals. Time-frequency contents of the signals are obtained using a bank of narrow band filters with very sharp transition band. The filters are designed using the Frequency Response Masking tech...

The frequency-response-masking (FRM) technique proposed by Lim has proven effectiveness for the design of very sharp digital filters with reduced implementation complexity compared to other options. In this paper, we propose a constrained optimization method for the design of basic and multistage FRM filters where the prototype filters are of infinite-impulse response (IIR) with prescribed pole...