Figure 3.

The generative model: the generative model employed in this paper models illuminance as a discrete cosine function and reflectance as a Harr wavelet function with peripheral high frequency wavelets removed. In addition, illumination is allowed to change quickly over time, whereas reflectance varies more slowly. This is achieved by making the coefficients on the reflectance basis functions hidden states, which accumulate hidden causes to generate changes in reflectance. Inversion of the model provides conditional estimates of the hidden causes and states responsible for sensory input as a function of time. See main text for an explanation of the variables in this figure.