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pyramid.cxx

Reduce image size by mean of a Gaussian pyramid
Usage: example_pyramid infile outfile

/************************************************************************/
/* */
/* Copyright 1998-2002 by Ullrich Koethe */
/* */
/* This file is part of the VIGRA computer vision library. */
/* The VIGRA Website is */
/* http://hci.iwr.uni-heidelberg.de/vigra/ */
/* Please direct questions, bug reports, and contributions to */
/* ullrich.koethe@iwr.uni-heidelberg.de or */
/* vigra@informatik.uni-hamburg.de */
/* */
/* Permission is hereby granted, free of charge, to any person */
/* obtaining a copy of this software and associated documentation */
/* files (the "Software"), to deal in the Software without */
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/* sell copies of the Software, and to permit persons to whom the */
/* Software is furnished to do so, subject to the following */
/* conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the */
/* Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES */
/* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND */
/* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT */
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/* */
/************************************************************************/
#include <iostream>
#include <stdio.h>
#include "vigra/stdimage.hxx"
#include "vigra/convolution.hxx"
#include "vigra/resizeimage.hxx"
#include "vigra/impex.hxx"
using namespace vigra;
// Gaussian reduction to next pyramid level
template <class Image>
void reduceToNextLevel(Image & in, Image & out)
{
// image size at current level
int width = in.width();
int height = in.height();
// image size at next smaller level
int newwidth = (width + 1) / 2;
int newheight = (height + 1) / 2;
// resize result image to appropriate size
out.resize(newwidth, newheight);
// define a Gaussian kernel (size 5x1)
vigra::Kernel1D<double> filter;
filter.initExplicitly(-2, 2) = 0.05, 0.25, 0.4, 0.25, 0.05;
vigra::BasicImage<typename Image::value_type> tmpimage1(width, height);
vigra::BasicImage<typename Image::value_type> tmpimage2(width, height);
// smooth (band limit) input image
separableConvolveX(srcImageRange(in),
destImage(tmpimage1), kernel1d(filter));
separableConvolveY(srcImageRange(tmpimage1),
destImage(tmpimage2), kernel1d(filter));
// downsample smoothed image
resizeImageNoInterpolation(srcImageRange(tmpimage2), destImageRange(out));
}
int main(int argc, char ** argv)
{
if(argc != 3)
{
std::cout << "Usage: " << argv[0] << " infile outfile" << std::endl;
std::cout << "(supported formats: " << vigra::impexListFormats() << ")" << std::endl;
return 1;
}
try
{
vigra::ImageImportInfo info(argv[1]);
if(info.isGrayscale())
{
vigra::BImage levels[4];
levels[0].resize(info.width(), info.height());
importImage(info, destImage(levels[0]));
for(int i=1; i<4; ++i)
{
// reduce gray image 3 times
reduceToNextLevel(levels[i-1], levels[i]);
}
exportImage(srcImageRange(levels[3]), vigra::ImageExportInfo(argv[2]));
}
else
{
vigra::BRGBImage levels[4];
levels[0].resize(info.width(), info.height());
importImage(info, destImage(levels[0]));
for(int i=1; i<4; ++i)
{
// reduce color image 3 times
reduceToNextLevel(levels[i-1], levels[i]);
}
exportImage(srcImageRange(levels[3]), vigra::ImageExportInfo(argv[2]));
}
}
catch (vigra::StdException & e)
{
std::cout << e.what() << std::endl;
return 1;
}
return 0;
}
vigra::BasicImage
Fundamental class template for images.
Definition basicimage.hxx:476
vigra::BasicImage::resize
void resize(std::ptrdiff_t width, std::ptrdiff_t height)
Definition basicimage.hxx:778
vigra::ImageExportInfo
Argument object for the function exportImage().
Definition imageinfo.hxx:134
vigra::ImageImportInfo
Argument object for the function importImage().
Definition imageinfo.hxx:391
vigra::Kernel1D
Generic 1 dimensional convolution kernel.
Definition separableconvolution.hxx:1372
vigra::Kernel1D::initExplicitly
Kernel1D & initExplicitly(int left, int right)
Definition separableconvolution.hxx:2105
vigra::exportImage
void exportImage(...)
Write an image to a file.
vigra::importImage
void importImage(...)
Read an image from a file.
impex.hxx
image import and export functions
vigra
vigra::separableConvolveX
void separableConvolveX(...)
Performs a 1 dimensional convolution in x direction.
vigra::BRGBImage
BasicImage< RGBValue< UInt8 > > BRGBImage
Definition stdimage.hxx:164
vigra::impexListFormats
std::string impexListFormats()
List the image formats VIGRA can read and write.
vigra::separableConvolveY
void separableConvolveY(...)
Performs a 1 dimensional convolution in y direction.
vigra::resizeImageNoInterpolation
void resizeImageNoInterpolation(...)
Resize image by repeating the nearest pixel values.
vigra::BImage
BasicImage< UInt8 > BImage
Definition stdimage.hxx:62

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python vigra 1.12.4