expand_edge

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Name

expand_edge - Expand image by edge mirroring.

Syntax

expand_edge [-0] [-e] [-o] [-z <value>] [-p <size>] <inimage> <outimage>

Description

expand_edge is used on an image to aviod some types of edge difficulties.

Expands inimage by size pixels on all four edges, and writes the result to outimage. If the dimensions of inimage is n x m, then the dimensions of outimage will be (n + 2*size) x (m + 2*size).

Imagine placing mirrors on the edges of inimage. These mirror images are mapped to outimage. Using the default setting, which is equivalent to specifying -e -p 3, the result will be like this: 

       inimage                          outimage

ihg|ghi xyz|zyx fed|def . . . uvw|wvu cba|abc rst|tsr +------- - - - -------+ ---+------- - - - -------+--- 
abc               rst|      cba|abc               rst|tsr
def     . . .     uvw|      fed|def     . . .     uvw|wvu
ghi               xyz|      ihg|ghi               xyz|zyx
                     |         |                     |
. . . . . . . . . . . .

Options

-0
The new pixels are set to 0 instead of being mirror images.

-z value
The new pixels are set to -value instead of being mirror images.

-e
Even expansion.

-o
Odd expansion. The pixels closest to the edge are not mirrored.

-p size
size specifies the width in pixels of the expanded edge.

Restrictions

inimage must have pixel type unsigned byte. size must not exceed the smallest of the X dimension and the Y dimension of inimage. If both -e and -o options are specified, -e (the default) is chosen.

See also

expand_edge(3)

Author

Řivind Due Trier, BLAB, Ifi, UiO

Examples

expand_edge mona.img mona_expand.img expand_edge -0 -o -p 2 mona.img mona_zeroexpand.img expand_edge -z -255 -p 1 5.binary.img 5.binary_expand.img

Id

$Id: expand_edge.c,v 1.19 1997/01/14 15:47:01 svein Exp $