vlt.math.mod_ellipse_on_mvnpdf

  MOD_ELLIPSE_ON_MVNPDF - Calcluate 'response' of an ellipse on multivariate normal, modulated by surround region

   Y=vlt.math.mod_ellipse_on_mvnpdf(XMESH,YMESH,ELLIPSE_PARAMS,MU,SIGMA)

   Computes the overlap of an ellipse on a multivariate normal distribution.

   Inputs:
     XMESH = The X coordinates over which to calculate the response
     YMESH = The Y coordinates over which to calculate the response
     ELLIPSE_PARAMS = a list of column vectors; each column describes 1 ellipse
         the first row has the X_Ctr position, the second row has the Y_Ctr
         position, the third row has the X axis vertex, the fourth row has the
         Y axis vertex, and the fifth row has the rotation (in radians)
     MU - The mean for the multivariate normal pdf; can be a column vector or row vector (see MVNPDF)
     SIGMA - the covariance matrix for the multivariate normal pdf (must be 2x2, see MVNPDF)
     MOD_AMP - the amplitude by which the response in the "surround" modulates the center"
     MOD_SIGMA - the multiplier to SIGMA that defines the "surround" region; the region and intensity
                 that corresponds to the surround is the rectified difference between a mvn distribution with mean
                 MU and covariance SIGMA*MOD_SIGMA and a mvn distribution with mean MU and covariance 
                 SIGMA (so only the surround is positive and contributes).
   Outputs:
     Y - The response, in a column vector, for each ellipse

   See also: vlt.image.inside_ellipse, MVNPDF