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total_variation.cxx

Smooth an image with Total Variation (TV) regularization (standard ROF model, anisotropic, second order)
Usage: `example_total_variation` reads a given parameter file (see tv.par, aniso_tv.par, secondo_oder_tv.par in the examples subfolder) and performs a smoothing with TV regularization with the parameters given in this file.

/************************************************************************/
/* */
/* Copyright 2012 by Frank Lenzen & */
/* 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 */
/* restriction, including without limitation the rights to use, */
/* copy, modify, merge, publish, distribute, sublicense, and/or */
/* 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 */
/* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, */
/* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING */
/* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR */
/* OTHER DEALINGS IN THE SOFTWARE. */
/* */
/************************************************************************/
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <vigra/multi_array.hxx>
#include <vigra/stdimagefunctions.hxx>
#include <vigra/impex.hxx>
#include <vigra/tv_filter.hxx>
#ifdef _MSC_VER
#define strcasecmp _stricmp
#endif
using namespace vigra;
// Read a string from file <file>.
void read_string(FILE *file,const char *name, char* out){
char dummy[80];
int s=fscanf(file,"%s %s ",dummy,out);
if (s==EOF || s<2){
std::cout<<"Could not read from file.\n";
exit(0);
}
else if (strcasecmp(name,dummy)!=0){
std::cout<<"Found parameter "<<dummy<<" instead of "<<name<<"\n";
exit(0);
}
else
std::cout<<"Parameter "<<name<<" = "<<out<<std::endl;
}
// read a flota-value from file <file>
float read_value(FILE *file,const char *name){
char dummy[80];
char dummy2[80];
float f=0;
int s=fscanf(file,"%s %s ",dummy,dummy2);
if (s==EOF || s<2){
std::cout<<"Could not read from file.\n";
exit(0);
}
else if (strcasecmp(name,dummy)!=0){
std::cout<<"Found parameter "<<dummy<<" instead of "<<name<<"\n";
exit(0);
}
else{
f=atof(dummy2);
std::cout<<"Parameter "<<name<<" = "<<f<<std::endl;
}
return f;
}
int main(int argc, char ** argv)
{
using namespace multi_math;
if(argc <2)
{
std::cout << "Usage: " << argv[0] << " parameterfile" << std::endl;
std::cout << "(supported formats for images: " << impexListFormats() << ")" << std::endl;
return 1;
}
try
{
char infile[80],outfile[80];
double alpha0=0.01*sqrt(255.0),beta0=0.1*sqrt(255.0),sigma=0.1,rho=.5,K=10,eps=0,gamma0=0;
int mode,inner_steps=200,outer_steps=5,write_steps=0;
FILE *file=fopen(argv[1],"r"); // open parameter file
if (!file){
std::cout<<"Cannot open file "<<argv[1]<<std::endl;
return 1;
}
read_string(file,"input_file",infile); // read name of input file (an image)
read_string(file,"output_file",outfile); // read name of output file (an image)
mode=(int)read_value(file,"mode"); // read mode: 1- standard Total Variation
// 2- Anisotropic Total Variation
// 3- Anisotropic Total Variation with Higher Order term
// further parameters depend on mode
switch(mode){
case 1:
case 2:
inner_steps=1000; // read number of iteration steps
alpha0=read_value(file,"alpha"); // read alpha
eps=read_value(file,"epsilon"); // read eps
break;
case 3:
outer_steps=(int)read_value(file,"outer_steps"); // read number of outer iteration steps
inner_steps=(int)read_value(file,"inner_steps"); // read number of inner iteration steps
alpha0=read_value(file,"alpha"); // read alpha
beta0=read_value(file,"beta"); // read beta
sigma=read_value(file,"sigma"); // read sigma
rho=read_value(file,"rho"); // read rho
K=read_value(file,"edge_factor"); // read parameter K (edge sensitivity)
write_steps=(int)read_value(file,"write_outer_steps"); //read flag for writing intermediate result after each outer iteration
break;
case 4:
outer_steps=(int)read_value(file,"outer_steps"); // read number of outer iteration steps
inner_steps=(int)read_value(file,"inner_steps"); // read number of inner iteration steps
alpha0=read_value(file,"alpha"); // read alpha
beta0=read_value(file,"beta"); // read beta
gamma0=read_value(file,"gamma"); // read gamma
sigma=read_value(file,"sigma"); // read sigma
rho=read_value(file,"rho"); // read rho
K=read_value(file,"edge_factor");// read parameter K (edge sensitivity)
write_steps=(int)read_value(file,"write_outer_steps");//read flag for writing intermediate result after each outer iteration
break;
default:
std::cout<<"Unknown mode "<<mode<<std::endl;
}
int stretch=(int)read_value(file,"histogram_stretch"); // flag for histogram stretching: 0 -no, 1 -yes
ImageImportInfo info(infile); // get information about input image
if(info.isGrayscale())
{
MultiArray<2,double> data(info.shape());
MultiArray<2,double> out(info.shape());
MultiArray<2,double> weight(info.shape());
for (int y=0;y<data.shape(1);y++){
for (int x=0;x<data.shape(0);x++){
weight(x,y)=1; // set weight to 1 (needed for anisotropicTotalVariationFilter and
// higherOrderTotalVariationFilter
}
}
importImage(info, destImage(data)); // read image data
data=data*(1/255.); // scale to [0,1] (smoothing parameters are tuned to this scaling)
//------------------------------------
// Choose specific TV Filter
//------------------------------------
switch(mode){
case 1:
std::cout<<"Standard TV filter"<<std::endl;
totalVariationFilter(data,out,alpha0,inner_steps,eps);
break;
case 2:
std::cout<<"Weighted TV filter"<<std::endl;
totalVariationFilter(data,out,weight,alpha0,inner_steps,eps);
break;
case 3:{
std::cout<<"Anisotropic TV filter"<<std::endl;
MultiArray<2,double> phi(info.shape());
MultiArray<2,double> alpha(info.shape());
MultiArray<2,double> beta(info.shape());
out=data; //'data' serves as initial value
for (int i=0;i<outer_steps;i++){ // Outer loop to update anisotropic data
std::cout<<"outer step "<<i<<"\n";
getAnisotropy(out,phi,alpha,beta,alpha0,beta0,sigma,rho,K); // get anisotropic data
anisotropicTotalVariationFilter(data,weight,phi,alpha,beta,out,inner_steps); //perform smoothing
if(write_steps){
char dummy[80];
sprintf(dummy,"output_step_%03d.png",i);
std::cout<<"Writing temp file\n";
if (stretch)
exportImage(out, ImageExportInfo(dummy)); //exportImage performes histogramm stretching
else{
MultiArray<2,unsigned char> buffer(info.shape());
buffer=max(min(out*255+0.5,0.),255.); //scaling back to [0,255], clipping, cast to uint8
exportImage(buffer, ImageExportInfo(dummy));
}
}
}
break;
}
case 4:{
std::cout<<"Second order TV filter"<<std::endl;
MultiArray<2,double> phi(info.shape());
MultiArray<2,double> alpha(info.shape());
MultiArray<2,double> beta(info.shape());
MultiArray<2,double> gamma(info.shape());
MultiArray<2,double> xedges(info.shape());
MultiArray<2,double> yedges(info.shape());
for (int y=0;y<data.shape(1);y++){ // set data needed for second order term
for (int x=0;x<data.shape(0);x++){
gamma(x,y)=gamma0;
xedges(x,y)=1;
yedges(x,y)=1;
}
}
out=data; //'data' serves as initial value
for (int i=0;i<outer_steps;i++){// Outer loop to update anisotropic data
std::cout<<"outer step "<<i<<"\n";
getAnisotropy(out,phi,alpha,beta,alpha0,beta0,sigma,rho,K); // get anisotropic data
secondOrderTotalVariationFilter(data,weight,phi,alpha,beta,gamma,xedges,yedges,out,inner_steps);//perform smoothing
if(write_steps){
char dummy[80];
sprintf(dummy,"output_step_%03d.png",i);
std::cout<<"Writing temp file\n";
if (stretch)
exportImage(out, ImageExportInfo(dummy));
else{
MultiArray<2,unsigned char> buffer(info.shape());
buffer=max(min(out*255+0.5,0.),255.); //scaling back to [0,255], clipping, cast to uint8
exportImage(buffer, ImageExportInfo(dummy));
}
}
}
}
}
//-------------------------------------
if (stretch)
exportImage(out, ImageExportInfo(outfile)); //write result to file
else{
MultiArray<2,unsigned char> buffer(info.shape());
buffer=min(max(out*255.+0.5,0.),255.); //scaling back to [0,255], clipping, cast to uint8
exportImage(buffer, ImageExportInfo(outfile));
}
}
else
{
std::cout<<"Color images are currently not supported !\n";
}
}
catch (std::exception & e)
{
std::cout << e.what() << std::endl;
return 1;
}
return 0;
}
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::RGBValue
Class for a single RGB value.
Definition rgbvalue.hxx:128
impex.hxx
image import and export functions
vigra
vigra::totalVariationFilter
void totalVariationFilter(...)
Performs standard Total Variation Regularization.
vigra::gamma
double gamma(double x)
The gamma function.
Definition mathutil.hxx:1587
vigra::impexListFormats
std::string impexListFormats()
List the image formats VIGRA can read and write.
vigra::anisotropicTotalVariationFilter
void anisotropicTotalVariationFilter(...)
Performs Anisotropic Total Variation Regularization.
vigra::secondOrderTotalVariationFilter
void secondOrderTotalVariationFilter(...)
Performs Anisotropic Total Variation Regularization.
vigra::getAnisotropy
void getAnisotropy(...)
Sets up directional data for anisotropic regularization.

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python vigra 1.12.2