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NAME

i.histo.match - Calculate histogram matching of several images.

KEYWORDS

imagery, histogram matching

SYNOPSIS

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

Flags:

--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog

Parameters:

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

Table of contents

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 location].
# 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: Sunday Jan 07 13:42:55 2024 in commit: 986ae4dc69ae870fc9f02ffb09cd81079f73aff5


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