Color Transparency

Abstract

Observation suggests that the chromatic changes which elicit an impression of transparency include translations and convergences in color space. Neither rotations nor shears in color space lead to perceived transparency. Results of matching experiments show that equiluminous translations, which cannot be generated by episcotister or filter models, give rise to the perception of transparency. This implies that systematic luminance change is not needed for transparency to be perceived. These results were used for the development of a method for detecting a transparent overlay within a color image and for separating the overlay from the underlying surfaces. The method tests for the coherence of chromatic change along contours through X-junctions to help detect the contour of a transparent region. The algorithm tests locally for translation and convergence to detect a transparent region. It estimates globally the chromatic parameters of the transparent overlay in order to separate the overlay from the underlying surfaces.

Perceptual transparency in neon color spreading displays

“…Therefore, all possible settings for the chromaticity of the inner elements should have led to the impression of transparency, according to Anderson's model. 10 Our data clearly show that this is the case only for some combinations of chromaticities, which is to be expected from known models of color transparency (Chen & D'Zmura, 1998;Da Pos, 1989;D'Zmura et al, 1997;Faul, 1997). Furthermore, it is evident that a real subset of the color combinations that led to an impression of transparency had a special status, since the subjects reliably found a unique setting for each stimulus that led to an impression of transparency that was more compelling than the others.…”

“…is the primary determinant of scission," whereas we have been adopting the working hypothesis that chromatic properties also play an important role. This seemed natural to us, given the fact that this has already been found to be true by several authors (Chen & D'Zmura, 1998;Da Pos, 1989;D'Zmura, Colantoni, Knoblauch, & Laget, 1997;Faul, 1996Faul, , 1997 for four-region transparency displays, originally studied by Metelli (1970). Related to this is a further difference between our approaches.…”

“…It has been shown, however, that the perception of transparency does not depend only on the luminance relations of the stimuli, but also on chromatic relations (Chen & D'Zmura, 1998;Da Pos, 1989;D'Zmura et al, 1997;Faul, 1997). These relations may be modeled with the episcotister model, since it can easily be extended to tristimulus values.…”

“…Although the models of Chen andD'Zmura (1998), Da Pos (1989), D'Zmura et al (1997), andFaul (1997) differ in some respects, this natural extension of the episcotister model is a core element in all of them. This model, which we will refer to as the strict additive model, leads to more restrictive conditions for the perception of transparency than do Equations 4 and 5.…”

“…In contrast, we have chosen to think in terms of the episcotister model. An important reason for this is that it can easily be generalized and applied to three-dimensional color codes (Chen & D'Zmura, 1998;Da Pos, 1989;D'Zmura et al, 1997;Faul, 1997).…”