NAME
Math::PSNR - Calculate PSNR (Peak Signal-to-Noise Ratio) and MSE (Mean
Square Error).
VERSION
This document describes Math::PSNR version 0.02
SYNOPSIS
use Math::PSNR;
my $psnr = Math::PSNR->new(
{
bpp => 8,
x => [ 1.1, 2.2, 3.3, 4.4, 5.5 ],
y => [ 9.9, 8.8, 7.7, 6.6, 5.5 ],
}
);
# Calculate MSE
$psnr->mse;
# Calculate PSNR
$psnr->psnr;
# Access to member variable of x
$psnr->x(
{
r => [ 1.1, 2.2, 3.3, 4.4, 5.5 ],
g => [ 1.1, 2.2, 3.3, 4.4, 5.5 ],
b => [ 1.1, 2.2, 3.3, 4.4, 5.5 ],
}
);
# Access to member variable of y
$psnr->y(
{
r => [ 9.9, 8.8, 7.7, 6.6, 5.5 ],
g => [ 9.9, 8.8, 7.7, 6.6, 5.5 ],
b => [ 9.9, 8.8, 7.7, 6.6, 5.5 ],
}
);
# Calculate MSE of three components signal (e.g. RGB image)
$psnr->msr_rgb;
# Calculate PSNR of three components signal (e.g. RGB image)
$psnr->psnr_rgb;
DESCRIPTION
This module calculates PSNR (Peak Signal-to-Noise Ration) and MSE (Mean
Square Error).
PSNR and MSE are the index of measuring quality between different
signals. They are commonly used to evaluate quality of images.
This module can deal with single component signals (e.g. monochrome
image) and three components signals (e.g. color (RGB) image).
More examples are in my GitHub repository.
INTERFACES
"Math::PSNR->new( bpp => $bpp, x => $x, y => $y )"
Creates an instance. Attributes are as follows:
"bpp"
Specify the bpp (bit per pixel). It sets 2^(bpp) - 1 to maximum power
("maximum power" means maximum allowable value of signal).
"is : rw"
This attribute is rewritable. Default accessor to this attribute is
provided.
"isa : Int"
Please specify value of this attribute as integer.
"default : 8"
This attribute has default value. If *bpp* is not specified, it will
be set 8 (bit).
"required : 0"
You do not have to set value of this attribute at constructor.
"x"
One side of signal for calculate PSNR and MSE.
"is : rw"
This attribute is rewritable. Default accessor to this attribute is
provided.
"isa : ArrayRef|HashRef"
Please specify value of this attribute as numerical array reference
or hash reference.
"required : 1"
You must set value of this attribute at constructor.
"y"
Another signal for calculate PSNR or MSE.
"is : rw"
This attribute is rewritable. Default accessor to this attribute is
provided.
"isa : ArrayRef|HashRef"
Please specify value of this attribute as numerical array reference
or hash reference.
"required : 1"
You must set value of this attribute at constructor.
METHODS
"mse"
This function calculates and returns MSE of single component signal.
This function requires values of attribute *x* and *y* that is
numerical array reference. Signal (array) length of *x* and *y* must
be the same.
This function can use cache. If instance is immutable, this function
returns previous calculated result.
"psnr"
This function calculates and returns PSNR of single component
signal. This function requires values of attribute *x* and *y* that
is numerical array reference. Signal (array) length of *x* and *y*
must be the same.
This function can use cache. If instance is immutable, this function
returns previous calculated result. And this function uses cache of
MSE if it is available.
"mse_rgb"
This function calculates and returns MSE of three components (RGB)
signal. This function requires values of attribute *x* and *y* that
is hash reference. Those hash references must have three components
(keys of hash are 'r', 'g', and 'b'). Signal length of each
components (keys) of *x* and *y* must be the same.
This function can use cache like above-functions.
"psnr_rgb"
This function calculates and returns PSNR of three components
signal. This function requires values of attribute *x* and *y* that
is hash reference. Those hash references must have three components
(keys of hash are 'r', 'g', and 'b'). Signal length of each
components (keys) of *x* and *y* must be the same.
This function can use cache like above-functions.
CONFIGURATION AND ENVIRONMENT
Math::PSNR requires no configuration files or environment variables.
DEPENDENCIES
Mouse (version 1.02 or later)
Test::Exception (version 0.31 or later)
Test::Warn (version 0.24 or later)
INCOMPATIBILITIES
None reported.
BUGS AND LIMITATIONS
No bugs have been reported.
Please report any bugs or feature requests to
"bug-math-psnr@rt.cpan.org", or through the web interface at
.
AUTHOR
moznion ""
LICENCE AND COPYRIGHT
Copyright (c) 2012, moznion "". All rights reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See perlartistic.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR, OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.