M. Li Evin

Publications (3)0 Total impact

• Article: A Hierarchical Segmentation Algorithm For Face Analysis. Application To Lipreading

  M. Li Evin, F. Luthon
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  ABSTRACT: A hierarchical algorithm for face analysis is presented in this paper. A color video sequence of speaker's face is acquired, under natural lighting conditions and without any particular make-up. The application aims at providing geometrical features of the face for scalable video transmission when no specific model of the speaker face is assumed. First, a logarithmic hue transform is performed from RGB to HI (hue, intensity) color space. Next, a Markov random field modeling regularizes motion and hue information within a spatiotemporal neighborhood. The hierarchical segmentation labels the different areas of the face. Results are shown on the lower part of the face and compared with standard color segmentation algorithm (fuzzy c-means). A speaker's lip shape with inner and outer borders is extracted from the final labeling and used to initialize an active contours stage.
  12/2000;
• Article: Automatic Lip Tracking: Bayesian Segmentation and Active Contours in a Cooperative Scheme

  M. Li Evin, P. Delmas, P.Y. Coulon, F. Luthon, V. Fristot
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  ABSTRACT: An algorithm for speaker's lip contour extraction is presented in this paper. A color video sequence of speaker's face is acquired, under natural lighting conditions and without any particular make-up. First, a logarithmic color transform is performed from RGB to HI (hue, intensity) color space. A bayesian approach segments the mouth area using Markov random field modelling. Motion is combined with red hue lip information into a spatiotemporal neighbourhood. Simultaneously, a Region Of Interest and relevant boundaries points are automatically extracted. Next, an active contour using spatially varying coefficients is initialised with the results of the preprocessing stage. Finally, an accurate lip shape with inner and outer borders is obtained with good quality results in this challenging situation. 1. Introduction It is commonly observed that visual information provides a precious help to the listener under degraded acoustical conditions [1]. The motivation of the present work is to e...
  05/1999;
• Article: Unsupervised Lip Segmentation Under Natural Conditions

  M. Li Evin, F. Luthon
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  ABSTRACT: An unsupervised algorithm for speaker's lip segmentation is presented in this paper. A color video sequence of speaker's face is acquired, under natural lighting conditions and without any particular make-up. First, a logarithmic color transform is performed from RGB to HI (hue, intensity) color space and sequence dependant parameters are evaluated. Second, a statistical approach using Markov random field modeling segment mouth shape using red hue predominant region and motion in a spatiotemporal neighborhood. Simultaneously, a Region Of Interest (ROI) is automatically extracted. Third, the speaker's lip shape is extracted from the final hue field with good quality results in this challenging situation. 1.
  03/1999;