73 lines
2.2 KiB
Groff
73 lines
2.2 KiB
Groff
|
.TH IM_DILATE 3 "14 May 1991"
|
||
|
|
.SH NAME
|
||
|
|
im_dilate, im_dilate_raw, im_erode, im_erode_raw \- perform morphological operations on a white object against a black background
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.B #include <vips/vips.h>
|
||
|
|
|
||
|
|
.B int im_dilate(in, out, m)
|
||
|
|
.br
|
||
|
|
.B IMAGE *in, *out;
|
||
|
|
.br
|
||
|
|
.B INTMASK *m;
|
||
|
|
|
||
|
|
.B int im_erode(in, out, m)
|
||
|
|
.br
|
||
|
|
.B IMAGE *in, *out;
|
||
|
|
.br
|
||
|
|
.B INTMASK *m;
|
||
|
|
|
||
|
|
.B int im_dilate_raw(in, out, m)
|
||
|
|
.br
|
||
|
|
.B IMAGE *in, *out;
|
||
|
|
.br
|
||
|
|
.B INTMASK *m;
|
||
|
|
|
||
|
|
.B int im_erode_raw(in, out, m)
|
||
|
|
.br
|
||
|
|
.B IMAGE *in, *out;
|
||
|
|
.br
|
||
|
|
.B INTMASK *m;
|
||
|
|
|
||
|
|
.SH DESCRIPTION
|
||
|
|
The above functions are applications of morphological operations on one
|
||
|
|
channel binary images ie. images with pixels that are either 0 (black) or 255
|
||
|
|
(white). All functions assume that input images contain white objects against
|
||
|
|
a black background.
|
||
|
|
|
||
|
|
Mask coefficients can be either 0 (for object) or 255 (for background) or 128
|
||
|
|
(for do not care).
|
||
|
|
|
||
|
|
The mask should have odd length sides and the origin of the mask is at location
|
||
|
|
(m-\>xsize/2,m-\>ysize/2) integer division. All algorithms have been based on
|
||
|
|
the book "Fundamentals of Digital Image Processing" by A. Jain, pp 384-388,
|
||
|
|
Prentice-Hall, 1989. Essentially, im_dilate(3) sets pixels in the output if
|
||
|
|
*any* part of the mask matches, whereas im_erode(3) sets pixels only if *all*
|
||
|
|
of the mask matches.
|
||
|
|
|
||
|
|
im_dilate(3)
|
||
|
|
dilates the image pointed by in, according to the mask pointed by m and writes
|
||
|
|
the result in the location pointed by the IMAGE descriptor out. The output
|
||
|
|
image is the same size as the input, with a black border in the manner of
|
||
|
|
im_conv(3).
|
||
|
|
|
||
|
|
im_dilate_raw(3)
|
||
|
|
works as im_dilate(3), but does not add a black border.
|
||
|
|
|
||
|
|
im_erode(3)
|
||
|
|
erodes the image pointed by in, according to the mask pointed by m and writes
|
||
|
|
the result in the location pointed by the IMAGE descriptor out. Again, the
|
||
|
|
output image is forced to have the same size as the input.
|
||
|
|
|
||
|
|
im_erode_raw(3)
|
||
|
|
works as im_erode(3), but does not add a black border.
|
||
|
|
|
||
|
|
See the boolean operations im_and(3), im_or(3) and im_eor(3) for analogues
|
||
|
|
of the usual set difference and set union operations.
|
||
|
|
|
||
|
|
.SH RETURN VALUE
|
||
|
|
All functions returns 0 on success and -1 on error.
|
||
|
|
.SH SEE ALSO
|
||
|
|
im_read_imask(3), im_conv(3), im_and(3), im_rotate_imask(3).
|
||
|
|
.SH COPYRIGHT
|
||
|
|
1991-1995, Birkbeck College and the National Gallery
|