Comparações de tamanhos sob informações pictóricas de profundidade provenientes de gradientes de textura e horizonte em exposições breves / Size comparisons under effects of pictorial depth cues from texture gradient and horizon in brief exposures.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The aim of this study was to investigate the effects of the duration of pictorial depth cue exposures on perceived sizes of stimuli. For this, 120 volunteers distributed randomly in 12 groups compared two vertical bars, one the test and other the standard, in to order to report which one was bigger. Using the method of constant stimuli, these bars could be presented simultaneously for 50, 100 or 200ms in four background conditions: (1) without depth cues, (2) with only the horizon, (3) with the horizon and compression line gradient, and (4) with the horizon and perspective line gradient. The slope of the psychometric curves, the points of subjectivity equality (PSE) and relative errors were calculated. The analysis of relative errors indicated a significant difference among the perspective gradient and other two conditions (without texture and horizon). Although exposure time had not presented significant differences among them, it was observed size overestimation during the 100ms exposure in depth cues conditions (compression and perspective). The analysis of slopes psychometric function showed a greater sensibility in the participants who made comparisons with 200ms than the ones who made with 50ms, independently of depth cue background. Pronounced relative errors in comparisons with perspective gradient tend to agree with previous studies, which demonstrate higher influence of this cue in perceived size modulation. Besides, this efficiency seems to be maximized when stimuli exposure time was 100ms.

ASSUNTO(S)

depth cues brief exposure. informações pictóricas de profundidade size perception percepção de tamanho exposição breve

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