Fitting psychometric functions to achromatic brightness matching data

Abstract

In asymmetric brightness matching procedure, one of two target regions is set by the experimenter at a fixed luminance (the reference}. This reference, with its fixed luminance and fixed relationship to the surrounding context will be perceived by the participant at some brightness. The participant then adjusts another target region (the match), until it is perceived as equally bright. If the context has no influence on the perception of brightness of either the reference and the matching target, then the only way to match the two target regions would be to set the match at the same physical luminance as the reference. Any difference in physical luminance of the two targets at match, is a measure of the magnitude of the brightness induction effect of the surrounding context. However, this induction magnitude seems to be depend on the luminance relationships not just between the targets, but also between the target luminance and the surround context luminances. The current investigation aims to develop descriptive models of asymmetric matching data, that can adequately summarize the induction magnitude over a range of target luminance values.