Rough membership function based illumination classifier for illumination invariant face recognition

•We make use of rough set as a decision maker for illumination classification.•Efficient for any type of illumination.•Normalization of illumination can be done with efficient illumination normalization technique.•Evaluated the efficiency for real time images also.

This paper proposes a face recognition system to overcome the problem due to illumination variation. The propose system first classifies the image's illumination into dark, normal or shadow and then based on the illumination type; an appropriate technique is applied for illumination normalization. Propose system ensures that there is no loss of features from the image due to a proper selection of illumination normalization technique for illumination compensation. Moreover, it also saves the processing time for illumination normalization process when an image is classified as normal. This makes the approach computationally efficient. Rough Set Theory is used to build rmf illumination classifier for illumination classification. The results obtained as high as 96% in terms of accuracy of correct classification of images as dark, normal or shadow.