The processing of spatial frequency and orientation information

Abstract

Three identification experiments were completed to disambiguate the associations between spatial frequency and orientation information at the sensory, decisional, and response levels. The stimuli were gratings generated by crossing four levels each of spatial frequency and orientation. In Experiment 1, the subjects made a single identification response to the stimuli. In Experiment 2, two identification responses were made, one for the spatial frequency component and the other for the orientation component. In Experiment 3, the subjects identified either the spatial frequency or the orientation component in any block of trials. The data were confusion matrices, and an information-transmission approach was used to investigate the interactions in the system. The results show that although there were sensory associations, there were no interactions at the decisional level. Performance parity was found: there was no significant difference between the single-and double-judgment paradigms in terms of information transmitted. Overall, the results suggest that although spatial frequency and orientation information is coded jointly at the sensory level, subsequent processing is independent, with each dimension drawing upon different attentional resources.

Stimulus information contaminates summation tests of independent neural representations of features

“…These studies found that, in general, discriminations along one dimension for two simple gratings are not affected by variations along the other dimension. Chua (1990) came to a similar conclusion using an identification/discrimination task requiring judgments of both spatial frequency and orientation (dual judgments). Chua performed analyses of judgments of 16 stimuli varying across four levels of both spatial frequency and orientation using the confusion matrices along with an information transmission approach (roughly, analyzing the correlation of the errors with the stimulus values and the responses for each dimension).…”

“…A common aspect in the modeling of visual processing, particularly in the field of attention, proposes that different types of visual information are analyzed by separate retinotopic "feature" maps with, for example, color and motion as representative features (Neisser, 1967;Treisman & Gelade, 1980;Livingstone & Hubel, 1988;Wolfe, Cave, & Franzel, 1989). Within the domain of spatial vision, in particular, it has been speculated that orientation and spatial frequency are separable and independent features of visual analysis (Burbeck & Regan, 1983;Morgan, 1992;Heeley, Buchanan-Smith, & Heywood, 1993;Heeley & Buchanan-Smith, 1994;Vincent & Regan, 1995;Olzak & Thomas, 1991, 1992Thomas & Olzak, 1990Chua, 1990).…”

The psychophysics of perceptual memory

“…When subjects are required to judge two dimensions of a single stimulus simultaneously, they can do the task without impairment in accuracy, compared to the single-judgment condition for contrast and spatial frequency (Greenlee & Thomas, 1993;Magnussen, Greenlee, & Thomas, 1996;Magnussen & Greenlee, 1997) and spatial frequency and orientation (Vogels, Eeckhout, & Orban, 1988;Chua, 1990), and they can even perform triple judgments of contrast, spatial frequency, and orientation without reduction in accuracy (Vincent & Regan, 1995). However, when subjects are required to judge two spatial frequencies or two contrast components, discrimination thresholds rise by a factor of four to six (Magnussen & Greenlee, 1997).…”

Using visual texture for information display

“…There is some . 5 evidence for a higher level of processing that separates adjacent areas filled by different textures [Chua 1990;Sagi 19901. The basic neural detectors are broadly tuned with respect to orientation and size.…”

“…Mathematical models of these have been developed [Garner and Felfoldy 1970;Heeley 1991]. A mathematical model based on the Gabor function accounts for a variety of experimental results [Chua 1990;Jones and Palmer 1987;Marcelja 1980;Nothdurft 1991;Porat and Zeevi 1989].…”