BRIGHTNESS INDUCTION FROM UNIFORM AND COMPLEX SURROUNDS - A GENERAL-MODEL

We studied the brightness induced from complex non-figural achromatic surrounds, A spatially uniform test field was surrounded by a random t exture composed of two sets of dots. The luminance of each set of dots was modulated sinusoidally at 0.5 Hz. The mean luminance, phase and a mplitude of modulation of each set were controlled independently so as to modulate the luminance and/or the contrast of the surround. Bright ness induction was measured by a modulation nulling technique. The res ults were fit by a model in which the total brightness induced by a su rround is equal to a weighted spatial summation of the induced effects from each point in the surround. The model incorporates local luminan ce gain controls in the test and surround fields and assumes that the magnitude of induction from each surround element is gain controlled b y the difference between the mean luminance of the test and the indivi dual surround elements. Copyright (C) 1996 Elsevier Science Ltd.