A BIOLOGICAL BASED MODEL OF THE HUMAN VISUAL SYSTEM INCORPORATING LATERAL SUBTRACTIVE INHIBITION WITH NON-UNIFORM SAMPLING AND MULTIPLE SPATIAL FREQUENCY FILTERS

The human visual system has been an interesting topic of scientific research for decades. It is known that the cone photo-receptors are arrayed in a non-linear fashion and that a lateral subtractive inhibitory process is occurring in the visual pathway. This thesis outlines for the first time how lateral subtractive inhibition manifests itself in the context of a non-uniform sensor distribution where the distance between cone photo-receptors, and size of the receptors, are varying in a log manner when moving radially away from the foveal area. Range limits on the parameters that control the non-uniform sampling and coupling coefficients are presented and optimal values are identified for specific image resolutions. The results of this analysis are then coupled to a proposed model of spatial frequency filtering to assist in subsequent studies of feature extraction and pattern analysis. The filters generated are based on three spatial-frequency channels that are designed to model the human eye contrast sensitivity curve. Simulated results are presented