i.histo.match

Calculate histogram matching of several images.

Command linePython (grass.script)

i.histo.match input=name [,name,...] [suffix=string] [output=name] [database=name] [max=integer] [nprocs=integer] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

i.histo.match input=name

grass.script.run_command("i.histo.match", input, suffix="match", output=None, database=None, max=255, nprocs=1, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("i.histo.match", input="name")

Parameters

Command linePython (grass.script)

input=name [,name,...] [required]
    Name of raster maps to be analyzed
suffix=string
    Suffix for output maps
    Default: match
output=name
    Name for mosaic output map
database=name
    DEPRECATED, do not use
max=integer
    Number of the maximum value for raster maps
    Default: 255
nprocs=integer
    Number of threads for parallel computing
    Default: 1
--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 | list[str], required
    Name of raster maps to be analyzed
    Used as: input, raster, name
suffix : str, optional
    Suffix for output maps
    Used as: 1
    Default: match
output : str, optional
    Name for mosaic output map
    Used as: output, raster, name
database : str, optional
    DEPRECATED, do not use
    Used as: input, dbname, name
max : int, optional
    Number of the maximum value for raster maps
    Used as:
    Default: 255
nprocs : int, optional
    Number of threads for parallel computing
    Default: 1
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

i.histo.match performs histogram matching on the given input images.

NOTES

The histogram matching method is based on the method Cumulative Distribution Function (CDF) of two or more histograms. Each value of original CDF is compared with the target histogram in order to obtain the target CDF value closest to the original value.

EXAMPLE

This example is based the North Carolina GRASS sample data set (complete GRASS dataset).

# create the output with histogram matching
i.histo.match input=lsat5_1987_10,lsat7_2000_10

# set grey color to the new maps
r.colors map=lsat5_1987_10.match color=grey
r.colors map=lsat7_2000_10.match color=grey

# visualize and compare the results

Original data

Matched data

SEE ALSO

i.ortho.photo, i.rectify

AUTHORS

Laura Zampa 2004, student of Dipartimento di Informatica e Telecomunicazioni, Facolta' di Ingegneria, University of Trento and ITC-irst, Trento (Italy); original PERL code

Luca Delucchi, Fondazione E. Mach (Italy); implementation with Python / SQLite

Stefan Blumentrath (Norway); current, parallelized implementation with Numpy

SOURCE CODE

Available at: i.histo.match source code (history)
Latest change: Friday Feb 21 12:27:42 2025 in commit 8fce680