The perception of a visual stimulus is affected by the presence of other stimuli in its surround region. The perceived central contrast can be suppressed or enhanced by the surrounds. Our previous psychophysical results showed that both surround suppression and enhancement existed in the foveal vision while only suppression existed in the peripheral vision. Moreover, the suppression in the periphery was much stronger than that in the fovea. In this report, we built an image processing model for the vision system with lateral connections embedded. We first adjusted model parameters to make the model have the same performance as human subjects had in contrast perception experiments in fovea and periphery respectively. With those parameters, we then analyzed the functions of lateral connections in image perception. We found that: 1) With foveal parameters, lateral interactions served the purpose of gain control and image regularization. The contrast response in the fovea was modulated by the global image through lateral connections. 2) With peripheral parameters, lateral interactions resulted in image boundary segmentation. The response to a uniform image region was suppressed while the response to the boundary regions remained. The results suggest that a visual image be encoded differently by foveal and peripheral vision. The possible impacts of this feature on image compression were discussed.
Jing Xing, Jing Xing,
"Functional roles of center-surround interactions in visual image processing", Proc. SPIE 4662, Human Vision and Electronic Imaging VII, (30 May 2002); doi: 10.1117/12.469506; https://doi.org/10.1117/12.469506