International Journal of Signal Processing, Image Processin International Journal of Signal Processing, Image Processin International Journal of Signal Processing, Image Processin International Journal of Signal Processing, Image Processing and Pattern Recognition g and Pattern Recognition g and Pattern Recognition g and Pattern Recognition Vol. 4, No. 1, Vol. 4, No. 1, Vol. 4, No. 1, Vol. 4, No. 1, March 2011 March 2011 March 2011 March 2011                                            !" "# !    "  !  $  ! %&    !   "            !" "# ! ’(’             )’          ’         &    #        ’ *      ’        +       ’ *         #  ’      #&   ’        +        )      ,  ’   &      )    ,     ++       ++ ’          ++   -$.        )’ /       &  0  & &      #  )’  ,   *   *  1 $++   $++    &’          !  "  #!   $%& ’ (’ ! !  ")     ’" #  "’  *         #’  "    #!  ’" ’   #’  +,-     !    #  ’ .!    / "  ,0 ’ ! +12-  .    ,’,   ’ ’, / ’!3 ! (453)," /   