  We consider the evolution model proposed in [9, 6] to describe illusory
contrast perception phenomena induced by surrounding orientations. Firstly, we
highlight its analogies and differences with the widely used Wilson-Cowan
equations [48], mainly in terms of efficient representation properties. Then,
in order to explicitly encode local directional information, we exploit the
model of the primary visual cortex (V1) proposed in [20] and largely used over
the last years for several image processing problems [24,38,28]. The resulting
model is thus defined in the space of positions and orientation and it is
capable to describe assimilation and contrast visual bias at the same time. We
report several numerical tests showing the ability of the model to reproduce,
in particular, orientation-dependent phenomena such as grating induction and a
modified version of the Poggendorff illusion. For this latter example, we
empirically show the existence of a set of threshold parameters differentiating
from inpainting to perception-type reconstructions and describing long-range
connectivity between different hypercolumns in V1.
