pamdeinterlace(1) General Commands Manual pamdeinterlace(1)NAME
pamdeinterlace - remove ever other row from a PAM/PNM image
SYNOPSIS
pamdeinterlace [-takeodd] [-takeeven] N [infile]
You can use the minimum unique abbreviation of the options. You can use two hyphens instead of one. You can separate an option name from
its value with white space instead of an equals sign.
DESCRIPTION
pamdeinterlace Removes all the even-numbered or odd-numbered rows from the input PNM or PAM image. Specify which with the -takeeven and
-takeodd options.
This can be useful if the image is a video capture from an interlaced video source. In that case, each row shows the subject 1/60 second
before or after the two rows that surround it. If the subject is moving, this can detract from the quality of the image.
Because the resulting image is half the height of the input image, you will then want to use pamstretch or pnmscale to restore it to its
normal height:
pamdeinterlace myimage.ppm | pamstretch -yscale=2 >newimage.ppm
OPTIONS -takeodd
Take the odd-numbered rows from the input and put them in the output. The rows are numbered starting at zero, so the first row in
the output is the second row from the input. You cannot specify both -takeeven and -takeodd.
-takeeven
Take the even-numbered rows from the input and put them in the output. The rows are numbered starting at zero, so the first row in
the output is the first row from the input. This is the default. You cannot specify both -takeeven and -takeodd.
SEE ALSO pamstretch(1), pnmscale(1)AUTHOR
put by Bryan Henderson in the public domain in 2001
11 November 2001 pamdeinterlace(1)
Check Out this Related Man Page
pamstretch(1) General Commands Manual pamstretch(1)NAME
pamstretch - scale up a PNM or PAM image by interpolating between pixels
SYNOPSIS
pamstretch [-xscale=X] [-yscale=Y]
[-blackedge] [-dropedge] N [infile]
You can use the minimum unique abbreviation of the options. You can use two hyphens instead of one. You can separate an option name from
its value with white space instead of an equals sign.
DESCRIPTION
pamstretch scales up pictures by integer values, either vertically, horizontally, or both. pamstretch differs from pnmscale and pnmenlarge
in that when it inserts the additional rows and columns, instead of making the new row or column a copy of its neighbor, pamstretch makes
the new row or column an interpolation between its neighbors. In some images, this produces better looking output.
To scale up to non-integer pixel sizes, e.g. 2.5, try pamstretch-gen(1) instead.
Options let you select alternative methods of dealing with the right/bottom edges of the picture. Since the interpolation is done between
the top-left corners of the scaled-up pixels, it's not obvious what to do with the right/bottom edges. The default behaviour is to scale
those up without interpolation (more precisely, the right edge is only interpolated vertically, and the bottom edge is only interpolated
horizontally), but there are two other possibilities, selected by the blackedge and dropedge options.
PARAMETERS
The N parameter is the scale factor. It is valid only if you don't specify -xscale or -yscale. In that case, pamstretch scales in both
dimensions and by the scale factor N.
OPTIONS -xscale=X
This is the horizontal scale factor. If you don't specify this, but do specify a vertical scale factor, the horizontal scale factor
is 1.
-yscale=Y
This is the vertical scale factor. If you don't specify this, but do specify a horizontal scale factor, the vertical scale factor
is 1.
-blackedge
interpolate to black at right/bottom edges.
-dropedge
drop one (source) pixel at right/bottom edges. This is arguably more logical than the default behaviour, but it means producing out-
put which is a slightly odd size.
BUGS
Usually produces fairly ugly output for PBMs. For most PBM input you'll probably want to reduce the `noise' first using something like
pnmnlfilt(1).
SEE ALSO pamstretch-gen(1), pnmenlarge(1), pnmscale(1), pnmnlfilt(1)AUTHOR
Russell Marks (russell.marks@ntlworld.com).
11 November 2001 pamstretch(1)