AVS Modules							maskgen (6)

NAME
		maskgen - circlular and elliptical mask generator

AUTHOR INFO:	David E. Harris, Georgia Tech Research Institute

SOURCE FILE:	maskgen.c

TYPE:		data

INPUTS:		none

OUTPUTS:	field 2D uniform scalar byte

PARAMETERS:     Name		Type	Default Min		Max
		X Size		dial	64	2		1024
		Y Size		dial	64	2		1024
		X Radius	dial	4.0	0.1		unbounded
		Y Radius	dial	4.0	0.1		unbounded
		X Position	dial	32	unbounded	unbounded
		Y Position	dial	32	unbounded	unbounded
		Center		oneshot	-	-		-
		Invert BG	toggle	off	-		-
		Mask Value	typein	255	0		255

DESCRIPTION:
	This module generates a field that is intended to be interpreted as a
	binary mask for filtering FFTs, a gray scale image, or a structuring
	element for various morphological operations.  The field can be any
	size from 2x2 pixels on up and an ellipse of any size major and minor
	axes from one pixel on up.  The background can be either black or white
	and the intensity value of the ellipse can be any gray level.  The
	position of the ellipse within the field is arbitrary and can intersect
	the edges of the field or be outside the field entirely.

PARAMETERS:

   X Size	- Horizontal and vertical dimensions of the field being
   Y Size	  generated.  2x2 pixels minimum, 1024x1024 pixels maximum.

   X Radius	- Major and minor axes of the elliptical mask.  Floating point
   Y Radius	  values are used to give better control over the size of the
		  ellipse.

   X Position	- Position of the center of the ellipse.  Values outside the
   Y Position	  field boundaries are allowed giving partial ellipses.

   Center	- Brings the center of the ellipse to the center of the field.

   Invert BG	- Toggles the background between black and white.

   Mask Value	- Gray scale value given to the pixels in the ellipse.


EXAMPLE: This network demonstrates the mask generator module.
	
                          MASK GENERATOR
                                |
                            COLORIZER
                                |
                          DISPLAY IMAGE


EXAMPLE2:  This network shows the mask generator used with a companion module
	   called dilate.

                                     (image)
                                    READ FIELD
                                        |
            MASK GENERATOR        FIELD TO BYTE
                   |___________  _______|
                              |  |
                            DILATE
                               |
                           COLORIZER
                               |
                         DISPLAY IMAGE


See also:  FFT2D, IFFT2D, DILATE, ERODE, CLOSEING, OPENING