Design of a Fuzzy Logic Classification System for an Ocular Sun Protection Factor

Abstract

There is no reliable and universal method to assess and compare protective properties of lenses, which is generally communicated to the purchasers by sunglasses categories based on lenses only, classifying the entire sun transmission spectrum (ultraviolet, infrared and visible), without accounting the geometry of the frame, nor the back reflection of the lenses, which is a serious problem. The present work develops a fuzzy classification system whose purpose is to create a reliable method to rate and compare sunglasses through their sun protective properties. This system treats the pre-acquired data relative to the lenses, i.e. ultraviolet transmittance and back reflection, in addition to the frame coverage data through the fuzzification interface, followed by the fuzzy inference process and later by the defuzzification interface. The output is an alphabetic rate of the protective eyewear to inform consumers, in a simple way to understand, regarding the sun protective properties of the sunglasses they purchase. Through the results it was possible to prove the effectiveness of choosing a fuzzy system for this classification system, as it was able to translate, in mathematical terms, the linguistic rules, classifying each of the various possible combinations of the inputs to one of the six factors stipulated for the ocular sun protection factor (OSPF) proposed in this work.