mask_ellipse

PURPOSE ^

Creates a binary image of an ellipse.

SYNOPSIS ^

function mask = mask_ellipse( mrows, ncols, varargin )

DESCRIPTION ^

 Creates a binary image of an ellipse.

 Creats a binary image of size (mrows x ncols), with all pixels off except inside of the
 specified ellipse.  The ellipse is given by 5 parameters,  a semimajor axis of ra, a
 semminor axis of radius rb, angle phi (in radians), centered at (crow,ccol).

 An alternative method of specifying the ellipse parameters is in terms of the parameters
 of a 2d gaussian.  For more information on how a gaussian relates to an ellipse see
 gauss2ellipse.
 
 USAGE
   mask = mask_ellipse( mrows, ncols, crow, ccol, ra, rb, phi )
   mask = mask_ellipse( mrows, ncols, mu, C, d )

 INPUTS
   % version 1
   mrows   - number of rows in mask
   ncols   - number of columns in mask
   crow    - the row location of the center of the ellipse
   ccol    - the column location of the center of the ellipse
   ra      - semi-major axis length (in pixels) of the ellipse
   rb      - semi-minor axis length (in pixels) of the ellipse
   phi     - rotation angle (in radians) of the semimajor axis from the x-axis
   % version 2
   mrows   - number of rows in mask
   ncols   - number of columns in mask
   mu      - 1x2 vector representing the center of the ellipse
   C       - 2x2 cov matrix
   d       - [optional] Number of std to create the ellipse to (2 is default)

 OUTPUTS
   mask    - created image mask

 EXAMPLE
   mask = mask_ellipse(  200, 200, 40, 100,  20, 15, pi/4 );
   figure(1); im(mask); [mu,C] = imageMLG( mask, 0, 2 );

 DATESTAMP
   29-Sep-2005  2:00pm

 See also PLOT_ELLIPSE, GAUSS2ELLIPSE, MASK_CIRCLE, MASK_GAUSSIANS, IMAGEMLG

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:
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