RC models of the visual system: a review
Authors: Molesini G., Viliani G.
Autors Affiliation: Istituto Nazionale di Ottica
Abstract: Thw wish to describe, in the study of vision, eye’s behavior in a simple mathematical way, leads to the use of suitable models and to the introduction of a transfer function, in analogy to electronics’ procedure. It is just electronics which provides the simplest analogue of the visual process, that is, the RC low-pass filter. The main features of this device are recalled; then the well-known AC-curves are discussed in connection with system’s gain. Afterwards, looking at the historical evolution undergone by the basic ideas, we examine a model first introduced by Levinson, where the physical analogue is a mechanical filter, rather than an electric network, although the resulting transfer function turns out to be identical in the two cases. The transfer function has been interpreted by Levinson in statistical terms, this interpretation is presented. However, the physical analogue of the visual system which has been held in the major esteem is the electric one, in part because of the relative ease of its study. This analogue is presented along with the improvements due to Fuortes and Hodgkin; the detailed discussion of Matin is reported as well. Finally, we report and discuss the more sophisticated model of Sperling and Sondhi, dealing in some detail with the novelties introduced by these authors. We have left for the Appendices some mathematical developments relative to the RC filter and some simple applications of the resulting model.
Volume: 29 Pages from: 103 to: 148
KeyWords: vision; eye; physiological optics