Mohammad Sadeghi Josef Kittler Kieron Messer Spatial Clustering of Pixels in the Mouth Area of Face Images. 36-41 2001 conf/iciap/2001 ICIAP http://doi.ieeecomputersociety.org/10.1109/ICIAP.2001.956982 db/conf/iciap/iciap2001.html#SadeghiKM01