A Local-Global Graph Approach for Facial Expression Recognition

In this article, we present a local global graph (LGG) method for recognizing facial expressions from static images irrespective of different illumination conditions, shadows and cluttered backgrounds. First, a neural color constancy based skin detection procedure to detect skin in complex real world images is presented. Second, the LGG method for detecting faces and facial expressions with a maximum confidence from skin segmented images is presented. The LGG approach presented here emulates the human visual perception for face and expression detection. In general, humans first extract the most important facial features such as eyes, nose, mouth, etc. and then inter-relate them for face and facial expression representations. The LG Graph embeds both the local information (the shape of facial feature is stored within the local graph at each node) and the global information (the topology of the face). Facial expression recognition from the detected face images is obtained by comparing the LG Expression Graphs with the existing the LG expression models present in the LGG database. Experimental results on the AR database and real-world images suggest the robustness of the proposed approach for facial expression recognition