qccimgimagecomponentmse.3

spiht for linux this is used to decod and encode vedio i wich all enjoy

.TH QCCIMGIMAGECOMPONENTMSE 3 "QCCPACK" ""
.SH NAME
QccIMGImageComponentMSE,
QccIMGImageComponentShapeAdaptiveMSE,
QccIMGImageComponentMAE,
QccIMGImageComponentShapeAdaptiveMAE
\- 
mean squared error and maximum absolute error between image components
.SH SYNOPSIS
.B #include "libQccPack.h"
.sp
.BI "double QccIMGImageComponentMSE(const QccIMGImageComponent *" image_component1 ", const QccIMGImageComponent *" image_component2 );
.br
.BI "double QccIMGImageComponentShapeAdaptiveMSE(const QccIMGImageComponent *" image_component1 ", const QccIMGImageComponent *" image_component2 ", const QccIMGImageComponent *" alpha_mask );
.br
.sp
.BI "double QccIMGImageComponentMAE(const QccIMGImageComponent *" image_component1 ", const QccIMGImageComponent *" image_component2 );
.br
.BI "double QccIMGImageComponentShapeAdaptiveMAE(const QccIMGImageComponent *" image_component1 ", const QccIMGImageComponent *" image_component2 ", const QccIMGImageComponent *" alpha_mask );
.SH DESCRIPTION
.BR QccIMGImageComponentMSE()
returns the mean squared error (MSE) between
.IR image_component1
and
.IR image_component2 .
The MSE is calculated by taking the difference between a pixel in
.IR image_component1
and its corresponding pixel in
.IR image_component2 ,
squaring this difference, and finally averaging all the squared differences
over the entire image component.
.IR image_component1
and
.IR image_component2
must have the same size.
.LP
.BR QccIMGImageComponentShapeAdaptiveMSE()
performs an MSE calculation similar to that of
.BR QccIMGImageComponentMSE() ,
except that
.IR alpha_mask
is assumed to denote regions that are "transparent" in
both
.IR image_component1
and
.IR image_component2
and thus contain no valid pixel data.
That is,
.BR QccIMGImageComponentShapeAdaptiveMSE()
skips over pixels in the MSE calculation for which
.BR QccAlphaTransparent (3)
returns non-zero when applied to
.IR alpha_mask
at the current pixel location.
If
.IR alpha_mask
is
.BR NULL ,
the usual, full-image MSE is calculated via
.BR QccIMGImageComponentMSE() .
.IR image_component1 ,
.IR image_component2 ,
and
.IR alpha_mask
(if it is
.RB non- NULL )
must all have the same size.
.LP
.BR QccIMGImageComponentMAE()
returns the maximum absolute error (MAE) between
.IR image_component1
and
.IR image_component2 .
The MAE is calculated by taking the difference between a pixel in
.IR image_component1
and its corresponding pixel in
.IR image_component2 ,
and then calculating the absolute value of this difference using
.BR fabs (3).
The largest absolute value encountered in this fashion
over the entire image component is returned by
.BR QccIMGImageComponentMAE() .
.IR image_component1
and
.IR image_component2
must have the same size.
.LP
.BR QccIMGImageComponentShapeAdaptiveMAE()
performs an MAE calculation similar to that of
.BR QccIMGImageComponentMAE() ,
except that
.IR alpha_mask
is assumed to denote regions that are "transparent" in
both
.IR image_component1
and
.IR image_component2
and thus contain no valid pixel data.
.IR alpha_mask
is
.BR NULL ,
the usual, full-image MAE is calculated via
.BR QccIMGImageComponentMAE() .
.IR image_component1 ,
.IR image_component2 ,
and
.IR alpha_mask
(if it is
.RB non- NULL )
must all have the same size.
.SH "RETURN VALUES"
These routines return the value of the MSE or MAE quantity they calculate;
in the case of an error, these routines return 0.0.
.SH "SEE ALSO"
.BR fabs (3),
.BR QccAlphaTransparent (3),
.BR QccIMGImageComponent (3),
.BR QccPackIMG (3),
.BR QccPack (3)

.SH AUTHOR
Copyright (C) 1997-2009  James E. Fowler
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