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GDAL-RASTER-CLEAN-COLLAR(1) |
GDAL |
GDAL-RASTER-CLEAN-COLLAR(1) |
gdal-raster-clean-collar - Clean the collar of a raster dataset,
removing noise
Added in version 3.11.
Usage: gdal raster clean-collar [OPTIONS] <INPUT> [<OUTPUT>]
Clean the collar of a raster dataset, removing noise.
Positional arguments:
-i, --input <INPUT> Input raster dataset [required]
-o, --output <OUTPUT> Output raster dataset
Common Options:
-h, --help Display help message and exit
--json-usage Display usage as JSON document and exit
--config <KEY>=<VALUE> Configuration option [may be repeated]
--progress Display progress bar
Options:
-f, --of, --format, --output-format <OUTPUT-FORMAT> Output format
--co, --creation-option <KEY>=<VALUE> Creation option [may be repeated]
--overwrite Whether overwriting existing output is allowed
--update Whether to open existing dataset in update mode
--color <COLOR> Transparent color(s): tuple of integer (like 'r,g,b'), 'black', 'white' (default: black) [may be repeated]
--color-threshold <COLOR-THRESHOLD> Select how far from specified transparent colors the pixel values are considered transparent. (default: 15)
--pixel-distance <PIXEL-DISTANCE> Number of consecutive transparent pixels that can be encountered before the giving up search inwards. (default: 2)
--add-alpha Adds an alpha band to the output dataset.
Mutually exclusive with --add-mask
--add-mask Adds a mask band to the output dataset.
Mutually exclusive with --add-alpha
--algorithm <ALGORITHM> Algorithm to apply. ALGORITHM=floodfill|twopasses (default: floodfill)
Advanced Options:
--oo, --open-option <KEY>=<VALUE> Open options [may be repeated]
--if, --input-format <INPUT-FORMAT> Input formats [may be repeated]
gdal raster clean-collar scans a (8-bit) image and sets all
pixels that are nearly or exactly black (the default), white or one or more
custom colors around the collar to black or white. This is often used to
"fix up" lossy compressed air photos so that color pixels can be
treated as transparent when mosaicing. The output format must use lossless
compression if either alpha band or mask band is not set.
- --co
<NAME>=<VALUE>
- Many formats have one or more optional creation options that can be used
to control particulars about the file created. For instance, the GeoTIFF
driver supports creation options to control compression, and whether the
file should be tiled.
May be repeated.
The creation options available vary by format driver, and some
simple formats have no creation options at all. A list of options
supported for a format can be listed with the --formats command
line option but the documentation for the format is the definitive
source of information on driver creation options. See Raster
drivers format specific documentation for legal creation options for
each format.
- --overwrite
- Allow program to overwrite existing target file or dataset. Otherwise, by
default, gdal errors out if the target file or dataset already
exists.
- --update
- If only an input dataset is specified, ask for it to be opened in update
mode If an output dataset is specified, ask for it to be opened in update
mode (this implies that it already exists). Note that updating an existing
dataset may lead to file size increase if the dataset is compressed,
and/or quality loss if lossy compression is used.
- --color
<c1>,<c2>,<c3>...<cn>|black|white
- Search for pixels near the specified color. May be specified multiple
times. When this option is specified, the pixels that are considered as
the collar are set to 0, unless only white is specified, in which case
there are set to 255.
- --color-threshold
<val>
- Select how far from black, white or custom colors the pixel values can be
and still considered near black, white or custom color. Defaults to
15.
- --pixel-distance
<val>
- Number of consecutive transparent pixels that can be encountered before
the giving up search inwards. Said otherwise, the collar will be extended
by this number of pixels. Defaults to 2.
- --addalpha
- Adds an alpha band to the output file. The alpha band is set to 0 in the
image collar and to 255 elsewhere. This option is mutually exclusive with
--addmask.
- --addmask
- Adds a mask band to the output file, The mask band is set to 0 in the
image collar and to 255 elsewhere. This option is mutually exclusive with
--addalpha.
- --algorithm
floodfill|twopasses
- Selects the algorithm to apply.
twopasses uses a top-to-bottom pass followed by a
bottom-to-top pass. It may miss with concave areas. The algorithm
processes the image one scanline at a time. A scan "in" is
done from either end setting pixels to black or white until at least
"non_black_pixels" pixels that are more than "dist"
gray levels away from black, white or custom colors have been
encountered at which point the scan stops. The nearly black, white or
custom color pixels are set to black or white. The algorithm also scans
from top to bottom and from bottom to top to identify indentations in
the top or bottom.
floodfill (default) uses the Flood Fill
algorithm and will work with concave areas. It requires creating a
temporary dataset and is slower than twopasses. When a non-zero
value for --pixel-distance is used, twopasses is actually
called as an initial step of floodfill.
$ gdal raster clean-collar --update my.tif
$ gdal raster clean-collar --addalpha --color=black --color=white --color-threshold=5 in.tif out.tif
Even Rouault <even.rouault@spatialys.com>
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