Vol. 23, No. 3, pp. 159-168
We consider a method of measurement of apparent illumination using the perceptual phenomenon of fluorescence to which we give a psychophysical explanation based on the hypothesis of direct relation of perception of self-luminosity to the apparent illumination of the scene observed by the viewer. We report results of three experimental studies: (1) measurements of apparent illumination when a flat mondrian in the darkness is observed; (2) measurements of apparent illumination in a ‘‘rich’’ 3D scene; (3) testing linearity of the subjective illumination space. Based on the obtained data, we confirm the basic hypothesis of a relation between the self luminosity phenomenon and the perceived illumination, and show that the suggested method of measurement of apparent illumination gives reliable and accurate (errors were in the range 4–10%) values of its chromatic components. Apparent illumination in the case of a mondrian observed in the darkness is found unstable, which can be expected given that the context of such a scene is insufficient for obtaining a unique solution for all the components of the photometric problem. In the second experiment, we show that the measurement results remain constant when the context of a ‘‘rich’’ 3D scene is changed and that they follow the changes in illumination conditions.
In the third experiment, we study the composition of different illuminations and show that the simple relation f = f1 + f2 holds for the measurement of the illumination ( f ) when two other illuminations ( f1 , f2 ) are applied simultaneously.
We consider a method of measurement of apparent illumination using the perceptual phenomenon of fluorescence to which we give a psychophysical explanation based on the hypothesis of direct relation of perception of self-luminosity to the apparent illumination of the scene observed by the viewer. We report results of three experimental studies: (1) measurements of apparent illumination when a flat mondrian in the darkness is observed; (2) measurements of apparent illumination in a ‘‘rich’’ 3D scene; (3) testing linearity of the subjective illumination space. Based on the obtained data, we confirm the basic hypothesis of a relation between the self luminosity phenomenon and the perceived illumination, and show that the suggested method of measurement of apparent illumination gives reliable and accurate (errors were in the range 4–10%) values of its chromatic components. Apparent illumination in the case of a mondrian observed in the darkness is found unstable, which can be expected given that the context of such a scene is insufficient for obtaining a unique solution for all the components of the photometric problem. In the second experiment, we show that the measurement results remain constant when the context of a ‘‘rich’’ 3D scene is changed and that they follow the changes in illumination conditions.
In the third experiment, we study the composition of different illuminations and show that the simple relation f = f1 + f2 holds for the measurement of the illumination ( f ) when two other illuminations ( f1 , f2 ) are applied simultaneously.