BRIGHTNESS CONTRAST AND THE PERCEPTUAL SCALE

A model for brightness contrast is presented which assumes two processes: an initial ‘perceptual’ transformation of visual intensity information, followed by lateral inhibitory interactions which can be represented linearly. The model has been applied to appropriate data and it appears to provide a satisfactory account of both brightness enhancement and brightness depression for homogeneous areas under stable conditions of viewing. This application of the model also provides evidence on the form of the function relating the relevant perceptual correlate of stimulus intensity to the physical values. This appears to be consistent with previous evidence that this relation is a power function with an exponent lying within a range about unity.