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r.colors.contrastbrightness

Change the contrast/brightness of a raster.

r.colors.contrastbrightness input=name output=name minimum=value maximum=value contrast=value brightness=value [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.colors.contrastbrightness input=name output=name minimum=0.0 maximum=0.0 contrast=1.0 brightness=0.0

grass.script.run_command("r.colors.contrastbrightness", input, output, minimum, maximum, contrast=1.0, brightness=0.0, overwrite=None, verbose=None, quiet=None, superquiet=None)

Example:

gs.run_command("r.colors.contrastbrightness", input="name", output="name", minimum=0.0, maximum=0.0, contrast=1.0, brightness=0.0)

grass.tools.Tools.r_colors_contrastbrightness(input, output, minimum, maximum, contrast=1.0, brightness=0.0, overwrite=None, verbose=None, quiet=None, superquiet=None)

Example:

tools = Tools()
tools.r_colors_contrastbrightness(input="name", output="name", minimum=0.0, maximum=0.0, contrast=1.0, brightness=0.0)

This grass.tools API is experimental in version 8.5 and expected to be stable in version 8.6.

Parameters

input=name [required]
    Raster map to change the contrast of.
output=name [required]
    Name for output raster map
minimum=value [required]
    Minimum input/output data value
maximum=value [required]
    Maximum input/output data value
contrast=value [required]
    Contrast (gain, 8bit=>[1.0-3.0]
    Default: 1.0
brightness=value [required]
    Brightness (bias, 8bit=>[0.0-100.0])
    Default: 0.0
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str, required
    Raster map to change the contrast of.
    Used as: input, raster, name
output : str, required
    Name for output raster map
    Used as: output, raster, name
minimum : float, required
    Minimum input/output data value
    Used as: value
maximum : float, required
    Maximum input/output data value
    Used as: value
contrast : float, required
    Contrast (gain, 8bit=>[1.0-3.0]
    Used as: value
    Default: 1.0
brightness : float, required
    Brightness (bias, 8bit=>[0.0-100.0])
    Used as: value
    Default: 0.0
overwrite : bool, optional
    Allow output files to overwrite existing files
    Default: None
verbose : bool, optional
    Verbose module output
    Default: None
quiet : bool, optional
    Quiet module output
    Default: None
superquiet : bool, optional
    Very quiet module output
    Default: None

input : str | np.ndarray, required
    Raster map to change the contrast of.
    Used as: input, raster, name
output : str | type(np.ndarray) | type(np.array) | type(gs.array.array), required
    Name for output raster map
    Used as: output, raster, name
minimum : float, required
    Minimum input/output data value
    Used as: value
maximum : float, required
    Maximum input/output data value
    Used as: value
contrast : float, required
    Contrast (gain, 8bit=>[1.0-3.0]
    Used as: value
    Default: 1.0
brightness : float, required
    Brightness (bias, 8bit=>[0.0-100.0])
    Used as: value
    Default: 0.0
overwrite : bool, optional
    Allow output files to overwrite existing files
    Default: None
verbose : bool, optional
    Verbose module output
    Default: None
quiet : bool, optional
    Quiet module output
    Default: None
superquiet : bool, optional
    Very quiet module output
    Default: None

Returns:

result : grass.tools.support.ToolResult | np.ndarray | tuple[np.ndarray] | None
If the tool produces text as standard output, a ToolResult object will be returned. Otherwise, None will be returned. If an array type (e.g., np.ndarray) is used for one of the raster outputs, the result will be an array and will have the shape corresponding to the computational region. If an array type is used for more than one raster output, the result will be a tuple of arrays.

Raises:

grass.tools.ToolError: When the tool ended with an error.

DESCRIPTION

The r.colors.contrastbrightness module generates a contrasted version of the input raster map. The contrast is the gain of the affine transform, use values of 1.0-3.0 in case of an 8 bit image. The brightness is the bias of the affine transform, use values of 0.0-100.0 in case of an 8 bit image.

EXAMPLES

Contrast enhancement of an 8-bit raster band This does nothing to the image:

r.colors.contrastbrightness min=0.0 max=255.0 contrast=1.0 brightness=0.0 input=myinraster output=myoutraster

This does change the contrast of the image:

r.colors.contrastbrightness min=0.0 max=255.0 contrast=3.0 brightness=0.0 input=myinraster output=myoutraster

This does change the brightness of the image:

r.colors.contrastbrightness min=0.0 max=255.0 contrast=1.0 brightness=100.0 input=myinraster output=myoutraster

SEE ALSO

r.colors, v.colors, r3.colors, r.cpt2grass, r.colors.matplotlib

AUTHOR

Yann Chemin, JRC, Ispra, Italy

SOURCE CODE

Available at: r.colors.contrastbrightness source code (history)
Latest change: Thursday Feb 20 13:02:26 2025 in commit 53de819