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/*
% Copyright (C) 2003 - 2009 GraphicsMagick Group
% Copyright (C) 2003 ImageMagick Studio
% Copyright 1991-1999 E. I. du Pont de Nemours and Company
%
% This program is covered by multiple licenses, which are described in
% Copyright.txt. You should have received a copy of Copyright.txt with this
% package; otherwise see http://www.graphicsmagick.org/www/Copyright.html.
%
% GraphicsMagick Image Statistics Methods.
%
*/
/*
Include declarations.
*/
#include "magick/studio.h"
#include "magick/pixel_iterator.h"
#include "magick/statistics.h"
#include "magick/utility.h"
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% G e t I m a g e S t a t i s t i c s %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% GetImageStatistics computes common statistics (currently maximum, minimum,
% mean and standard deviation) for the available image channels. The
% per-channel values are returned in an ImageStatistics structure. Statistics
% are normalized to the range 0.0 to 1.0. Multiply values by MaxRGB to obtain
% the statistics in quantum units. Statistics for non-existent channels are
% set to zero.
%
% The format of the GetImageStatistics method is:
%
% MagickPassFail GetImageStatistics(const Image *image,
% ImageStatistics *statistics
% ExceptionInfo *exception)
%
% A description of each parameter follows:
%
% o image: The image.
%
% o statistics: An ImageStatistics structure to update with statistics.
%
% o exception: Any errors are reported here.
%
*/
typedef struct _StatisticsContext {
double samples;
double variance_divisor;
} StatisticsContext;
static MagickPassFail GetImageStatisticsMean(void *mutable_data,
const void *immutable_data,
const Image *image,
const PixelPacket *pixel,
const IndexPacket *indexes,
const long npixels,
ExceptionInfo *exception)
{
ImageStatistics
lstatistics,
*statistics=(ImageStatistics *) mutable_data;
const StatisticsContext
*context=(const StatisticsContext *) immutable_data;
double
normalized;
register long
i;
ARG_NOT_USED(indexes);
ARG_NOT_USED(exception);
(void) memset(&lstatistics, 0, sizeof(ImageStatistics));
lstatistics.red.minimum=1.0;
lstatistics.green.minimum=1.0;
lstatistics.blue.minimum=1.0;
if (image->matte)
lstatistics.opacity.minimum=1.0;
for (i=0; i < npixels; i++)
{
normalized=(double) pixel[i].red/MaxRGB;
lstatistics.red.mean += normalized/context->samples;
if (normalized > lstatistics.red.maximum)
lstatistics.red.maximum=normalized;
if (normalized < lstatistics.red.minimum)
lstatistics.red.minimum=normalized;
normalized=(double) pixel[i].green/MaxRGB;
lstatistics.green.mean += normalized/context->samples;
if (normalized > lstatistics.green.maximum)
lstatistics.green.maximum=normalized;
if (normalized < lstatistics.green.minimum)
lstatistics.green.minimum=normalized;
normalized=(double) pixel[i].blue/MaxRGB;
lstatistics.blue.mean += normalized/context->samples;
if (normalized > lstatistics.blue.maximum)
lstatistics.blue.maximum=normalized;
if (normalized < lstatistics.blue.minimum)
lstatistics.blue.minimum=normalized;
if (image->matte)
{
normalized=(double) pixel[i].opacity/MaxRGB;
lstatistics.opacity.mean += normalized/context->samples;
if (normalized > lstatistics.opacity.maximum)
lstatistics.opacity.maximum=normalized;
if (normalized < lstatistics.opacity.minimum)
lstatistics.opacity.minimum=normalized;
}
}
#if defined(HAVE_OPENMP)
# pragma omp critical (GM_GetImageStatisticsMean)
#endif
{
statistics->red.mean += lstatistics.red.mean;
if (lstatistics.red.maximum > statistics->red.maximum)
statistics->red.maximum=lstatistics.red.maximum;
if (lstatistics.red.minimum < statistics->red.minimum)
statistics->red.minimum=lstatistics.red.minimum;
statistics->green.mean += lstatistics.green.mean;
if (lstatistics.green.maximum > statistics->green.maximum)
statistics->green.maximum=lstatistics.green.maximum;
if (lstatistics.green.minimum < statistics->green.minimum)
statistics->green.minimum=lstatistics.green.minimum;
statistics->blue.mean += lstatistics.blue.mean;
if (lstatistics.blue.maximum > statistics->blue.maximum)
statistics->blue.maximum=lstatistics.blue.maximum;
if (lstatistics.blue.minimum < statistics->blue.minimum)
statistics->blue.minimum=lstatistics.blue.minimum;
if (image->matte)
{
statistics->opacity.mean += lstatistics.opacity.mean;
if (lstatistics.opacity.maximum > statistics->opacity.maximum)
statistics->opacity.maximum=lstatistics.opacity.maximum;
if (lstatistics.opacity.minimum < statistics->opacity.minimum)
statistics->opacity.minimum=lstatistics.opacity.minimum;
}
}
return MagickPass;
}
#define Square(x) ((x)*(x))
static MagickPassFail GetImageStatisticsVariance(void *mutable_data,
const void *immutable_data,
const Image *image,
const PixelPacket *pixel,
const IndexPacket *indexes,
const long npixels,
ExceptionInfo *exception)
{
ImageStatistics
lstatistics,
*statistics=(ImageStatistics *) mutable_data;
const StatisticsContext
*context=(const StatisticsContext *) immutable_data;
double
normalized;
register long
i;
ARG_NOT_USED(indexes);
ARG_NOT_USED(exception);
(void) memset(&lstatistics, 0, sizeof(ImageStatistics));
#if defined(HAVE_OPENMP)
# pragma omp critical (GM_GetImageStatisticsVariance)
#endif
{
lstatistics.red.mean=statistics->red.mean;
lstatistics.green.mean=statistics->green.mean;
lstatistics.blue.mean=statistics->blue.mean;
lstatistics.opacity.mean=statistics->opacity.mean;
}
for (i=0; i < npixels; i++)
{
normalized=(double) pixel[i].red/MaxRGB;
lstatistics.red.variance +=
Square(normalized-lstatistics.red.mean)/context->variance_divisor;
normalized=(double) pixel[i].green/MaxRGB;
lstatistics.green.variance +=
Square(normalized-lstatistics.green.mean)/context->variance_divisor;
normalized=(double) pixel[i].blue/MaxRGB;
lstatistics.blue.variance +=
Square(normalized-lstatistics.blue.mean)/context->variance_divisor;
if (image->matte)
{
normalized=(double) pixel[i].opacity/MaxRGB;
lstatistics.opacity.variance +=
Square(normalized-lstatistics.opacity.mean)/context->variance_divisor;
}
}
#if defined(HAVE_OPENMP)
# pragma omp critical (GM_GetImageStatisticsVariance)
#endif
{
statistics->red.variance += lstatistics.red.variance;
statistics->green.variance += lstatistics.green.variance;
statistics->blue.variance += lstatistics.blue.variance;
statistics->opacity.variance += lstatistics.opacity.variance;
}
return MagickPass;
}
MagickExport MagickPassFail GetImageStatistics(const Image *image,
ImageStatistics *statistics,
ExceptionInfo *exception)
{
StatisticsContext
context;
MagickPassFail
status=MagickPass;
double
samples;
(void) memset((void *) statistics, 0, sizeof(ImageStatistics));
statistics->red.minimum=1.0;
statistics->green.minimum=1.0;
statistics->blue.minimum=1.0;
if (image->matte)
statistics->opacity.minimum=1.0;
samples=(double) image->rows*image->columns;
context.samples=samples;
context.variance_divisor=samples-1;
/*
Compute Mean, Max, and Min
*/
status = PixelIterateMonoRead(GetImageStatisticsMean,
NULL,
"[%s] Compute image mean, max, min...",
statistics,&context,0,0,image->columns,
image->rows,image,exception);
/*
Compute Variance
*/
if (status == MagickPass)
status = PixelIterateMonoRead(GetImageStatisticsVariance,
NULL,
"[%s] Compute image variance...",
statistics,&context,0,0,image->columns,
image->rows,image,exception);
/*
Compute Standard Deviation
*/
if (status == MagickPass)
{
statistics->red.standard_deviation=sqrt(statistics->red.variance);
statistics->green.standard_deviation=sqrt(statistics->green.variance);
statistics->blue.standard_deviation=sqrt(statistics->blue.variance);
if (image->matte)
statistics->opacity.standard_deviation=sqrt(statistics->opacity.variance);
}
return status;
}
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