OpenCV: extract images from .vec file

In OpenCV haartraining, .vec files are given as input as the positive training examples. We can view the images inside the vec file using opencv-createsamples, but I wanted to extract images out of it. This is what is did.

I edited the file <opencvfolder>/apps/haartraining/src/cvsamples.cpp

first, include the following headers

#include <stdio.h>
#include <iostream>
#include <sstream>
#include <string>

function edited is cvShowVecSamples, in the for-loop for showing the images, edit as following

std::ostringstream stm;       //added
icvGetHaarTraininDataFromVecCallback( sample, &file );
stm<<”/temp/vecextracted/”;       //added folder in which to extract images
stm << i;            //added filename which will be given to save image, integer to string conversion
stm << “.pgm”; //added
std::cout<<”\n”; //added
std::cout<<stm.str(); //added
const char *filename = stm.str().c_str(); //added
std::cout<<filename; //added
cvSaveImage(filename, sample); //added
if( scale != 1.0 ) cvResize( sample, scaled_sample, CV_INTER_LINEAR);
cvShowImage(“Sample”, scaled_sample );
cvWaitKey(50);

//added == these are the lines that i have added, other lines are the default of OpenCV

Now, you have to rebuild the files. So, in the command line type

make all

Now, when you execute opencv-createsample -vec vecfile.vec, the images are extracted too.

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