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Biomedical subjects

G Moraglia

Publications and source records attributed to G Moraglia.

21 records · Page 2Linked to original sources
PubMed1987

The concept of spatial frequency channels cannot explain some visual masking effects.

Visual masking is assumed to be predictable by the degree to which mask and signal spatial frequency amplitudes are similar. In this masking experiment we have clearly shown this not to be the case by studying the effects of factorial combinations of signal-mask amplitude and phase spectra. Results show that the amplitude spectra characteristics do not predict masking, and a better predictor of these results appears to be the correlations between the mask and signal's luminance profiles. These results, therefore, show that the spatial similarity between two images, as may be processed by "spatial frequency channels" cannot be determined by the similarities between these channel outputs as defined by the (output) modulated amplitudes.

Humans↗
PubMed1985

On the detection of Gabor signals and discrimination of Gabor textures.

We have explored the detection and discrimination of Gabor signals in two different paradigms in order to determine the signals' relative importance for spatial vision. In the first experiment we determined the "detection efficiency" of five such signals presented in isolation, and our results support the conclusion that, for optimal detection, the Gaussian profile should only span (to 1/e decay values) approximately two cycles. In three subsequent experiments we have observed the discriminability of textures composed of such signals over a range of spatial frequencies, Gaussian windows and orientation differences. Our results are consistent with the detection data only insofar as the discrimination thresholds vary in a predictable way with the Gaussian window parameters. Finally, we have determined the degree to which texture discrimination, in terms of differences in both orientation and spatial frequency, can be predicted from the independent manipulations of both codes within a given Gaussian window size.

Discrimination, Psychological↗