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Author Otsuka, Takahiro ♦ Ohya, Juan
Source CiteSeerX
Content type Text
File Format PDF
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Two-dimensional Fourier Transform ♦ Significant Frame ♦ Feature Vector ♦ Facial Exp ♦ Velocity Vector Field ♦ Automatic Extraction ♦ Image Sequence ♦ Facial Expression ♦ Facial Expression Using Hmm ♦ Facial Motion ♦ Velocity Vector ♦ Successive Frame ♦ Hidden State ♦ Facial Muscle ♦ Multiple Person ♦ Image Processing ♦ New Sequence ♦ Output Probability ♦ Hmm Computation ♦ Mixture Density ♦ Optical Flow Algorithm
Description A method that can be used for for recognizing facial expressions of multiple persons is proposed. In this method, the condition of facial muscles is assigned to a hidden state of a HMM for each expression. Then, the probability of the state is updated according to a feature vector obtained from image processing. Image processing is performed in two steps. First, a velocity vector is estimated from every two successive frames by using an optical flow algorithm. Then, a two-dimensional Fourier transform is applied to a velocity vector field at the regions around an eye and the mouth. The coefficients for lower frequencies are selected to form a feature vector. A mixture density is used for approximating the output probability of the HMM so as to represent a variation in facial expressions among persons. To cope with the case when two expressions are displayed contiguously, the HMM computation is modified such that when the peak of a facial motion is detected, a new sequence of facial exp...
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Learning Resource Type Article
Publisher Date 1997-01-01
Publisher Institution In Proc. Int. Conf. on Image Processing (ICIP-97