A computational model of the spatial‐frequency filtering processes at the level of 4Cβ layer of the visual striate cortex is being proposed. The model does not interfere with the filtering performed by the cortical receptive fields itself, and the focus of attention is restricted to the cortical input. The model is based on the literature data concerning the conformal mapping of the visual field representation at the primary visual cortex and uniformity of short‐range horizontal connections of cortical neurons. To test the model, the illusory figures were used as input stimuli, responses to which were computed and the output patterns constructed. The psychophysical experiments employing the same illusory figures were performed. A rather good correspondence between the model predictions and the experimental measurements of perceived size distortions was observed. In practice, the neurophysiological model provides a simplified and relatively fast algorithm of evaluation of distortions caused by filtering.