1,720,993 research outputs found
A phenomenological instead of psychophysical definition of visual illusions.
No full textThe traditional definition of perceptual illusion is critically discussed. To avoid the theoretical limitations of a definition which includes the opposition of the physical versus perceptual domain, a phenomenological definition is proposed which seems to include all possible cases of what usually is intended for perceptual illusions. Some relevant theories about object identity are mentioned and the concept of illusion is confronted with that of phenomenal reality (Michotte). Few examples are given of the different kinds of illusion which can be perceived as a function of the object identit
Explanation and reductionism in experimental phenomenology
No full textPhenomenology was born inside a philosophical milieu (Brentano, Husserl), but at its very beginning it appeared as a sound theoretical and methodological approach for a scientific psychology, which could become independent from philosophy by keeping at the same time the fundamental interest to the subjective human experience. A short survey of the first founders of experimental phenomenology shows how this approach was satisfying the deep needs of the researchers, and contributed to the characterization of psychology not only as an independent science, but keeping it essentially phenomenal soul. The analysis of some paradigmatic positions enlightens the critical issues dealing with the relationships between phenomenology and philosophy, psychology, neurophysiology, experimentation, natural sciences. The problem of which kind of scientific explanation can suit the salient traits of experimental phenomenology is explored by annotating some considerable positions of authors who gave significant contributes to the still open debate
Unique hues: A possible base for the evaluation of colour appearance quality
No full textThe first results of a novel visual experiment for the analysis of the appearance of colours under different lights is presented. It could be the basis for the improvement of the Colour Rendering Index, starting from the concept of unique hues. The constancy or variations of unique hues could be used to analyse colour distortion introduced by different contents in the spectral density power of the light source under test. Among the sources analysed in the experiment are incandescent lamp, a simple realization of D65 and white LEDs
Factorial constraints of transparency
No full textThe present paper reports the results of an experiment designed to determine the constraints of the factorial pattern of data that a valid model for the perceived extent of achromatic transparency, rated, must predict. Consider a transparent achromatic disk in the middle of two adjoining achromatic rectangles with the common border of the rectangles dividing the disk in half. Let a and b be the l-minances of the left and right rectangles, respectively, and let p and q be the lu-minances of the left and right halves of the disk, respectively. By varying p and q factorially for different pairs of a and b and plotting mean rated as a function of p, we have found that a valid model of transparency must meet the constraints that (i) the rated extent of transparency of the disk varies essentially linearly with p, (ii) that factorial curves converge upward as p increases, and (iii) that the mean slope of factorial curves increases as the difference between a and b decreases. A new model of transparency is proposed which satisfies these constraints
Communications and Comments - Column in "Cultura e Scienza del Colore - Color Culture and Science" N. 10 /2018 - ISSN: 2384-9568 - ANCE: E227716
No full textChromatic induction in neon colour spreading
No full textAbstractNeon colour spreading occurs when sections of a lattice are replaced by segments of a different colour. This colour appears to diffuse out of the segments, and produce a slightly tinted transparent surface floating above the lattice. In two of the four experiments reported here, observers varied the colour of an area in a test display, until it matched the neon colour perceived in a corresponding (illusory) area in a comparison display. We found that the neon colour is an additive mixture of the colour of the segments and the colour complementary to the lattice, as suggested by Bressan (Vision Research 35 (1995) 375). In the other two experiments, we separately manipulated the presence and alignment of lattice and segments, to test whether the neon effect is fully predicted by a combination of colour diffusion and simultaneous colour contrast. We found that the colour induced in a neon figure is more saturated than the colour induced in a comparable non-neon figure. We discuss the implications of these results on our current understanding of the mechanisms of neon colour spreading
Facial Expressions, Colours and Basic Emotions
No full textWe investigated whether the pairing of facial expressions of emotion with colours is consistent among different cultures, in particular between Australian and European people. Two groups, one consisting mainly of younger and the other of older people, participated in two experiments: For each of six faces, which expressed basic emotions, single colours and combinations of three colours were selected for the best visual ‘fit’ with the faces. The performance by the two groups was essentially identical. The different emotions appear well characterised by the paired colours in a similar way with the European results by Oberascher & Gallmetzer (2003), da Pos & Valentini (2005), but also with some interesting difference
Semantic resonance to light sources of different correlated colour temperature
No full textNew light sources are nowadays used as a consequence of energy saving problems and developments of illumination technology. Their quality is evaluated in terms of their rendering capabilities and of people preferences. The research is focused on the psychological reaction of young participants to the environmental lighting of three rooms expressed by subjective measures of a list of associable qualities. We then describe how observers can distinguish different qualities of interior lightings. One room was lighted by a halogen lamp, and two other rooms by LED lamps. Walls were white and a rather large coloured Mondrian was hung at a wall. A group of 370 high school students volunteered in the experiment. Their task was to evaluate the quality of the three illuminations by using a semantic differential. Evaluations were performed in small groups or individually, and data were collected for each participant. Many students left the experiment after performing their task in one or two rooms only. Therefore, data from 197 students who completed the task in all the three rooms were considered. An ANOVA shows that the halogen lamp receives evaluations significantly different from the other two light sources. The two LEDs received equal evaluations in seven scales and significantly different in other three scale. A factorial analysis identifies three factors; in relation to all of them the halogen lamp significantly differs from the LEDs, while the two LEDs differ one from the other only in two factors. In conclusion naive young participants can consistently evaluate personal psychological reactions to lights and discern the qualitative features of the lightings; evaluations are not consistent with the differences in CCT of the three sources but seem affected by other lighting characteristics; some evaluations seem to depend on participants’ psychological context
CONDITIONS FOR PERCEPTUAL TRANSPARENCY
No full textWe review the conditions that are necessary for the perception of transparency and describe the spatio chromatic constraints for achromatic and chromatic transparent displays. These constraints can be represented by the convergence model and are supported by psychophysical data. We present an alternative representation of the constraints necessary for transparency perception that is based on an analogy with a model of colour constancy and the invariance of cone-excitation ratios. Recent psychophysical experiments are described that suggest that displays where the cone-excitation ratios are invariant produce a stronger impression of transparency than displays where the cone excitations are convergent. We argue that the spatial relations in an image are preserved when a Mondrian-like surface is partially covered by a transparent filter and therefore show an intriguing link between transparency perception and colour constancy. Finally, we describe experiments to relate the strength of the transparency percept with the number of unique patches in the image display. We find that the greater the number of surfaces in the display that are partially covered by a transparent filter the stronger the impression of transparenc
The effect of illumination on gray color
Full text linkThe lightness of 3D real objects has been evaluated in three experiments through a matching procedure in different conditions of spatial arrangement (1 - one object alone vs a group of objects, 2 - different spatial sequences of objects, 3 - different illuminations levels) with substantial lightness constancy deviations, which is nevertheless smaller for light objects
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