Can't create CSV file

edit

No need to loop:

#include <fstream>

void saveMatToCsv(Mat &matrix, string filename){
    ofstream outputFile(filename);
    outputFile << format(matrix, "CSV") << endl;
    outputFile.close();
}

If using OpenCV 3.0, then format(matrix, "CSV") should be replaced with format(matrix, Formatter::FMT_CSV)

@LorenaGdL, perfect!!! I was not aware of that at all, thanks. Though it seems that in version 3.x, format() no longer takes a string, but an enumeration from the ones below:

FMT_DEFAULT
FMT_MATLAB
FMT_CSV
FMT_PYTHON
FMT_NUMPY
FMT_C

so writing part in your code should be outputFile << cv::format(matrix, cv::Formatter::FMT_CSV) << endl;, but still thanks for the info ;-)

you've been faster than me :-p...

haha yep, just after writing I remembered the change in 3.0 :P

can you tell me how I can use the function by an example code:

void saveMatToCsv(Mat &matrix, string filename)

@theodore@LorenaGdL I faced this error could you plz solve it?I captured my error.please look at it: error pic

and this is my main funtion that I call it: main fun pic

@Mehdi.Am 1) seems you're using the incorrect version of the function. Take a careful look at @theodore explanation once again; 2) saving a 3-channel images as it is may not be the best option. It's probably better to reshape to 1-channel, so you know how to undo the operation once you load back the data

@theodore: edited the answer, reading method in 2.x is valid. And just for your info, though what you post is perfectly working, you can do this too in 3.x reading:

cv::Ptr<cv::ml::TrainData> raw_data = cv::ml::TrainData::loadFromCSV("test.csv", 0, -2, 0);
cv::Mat data = raw_data->getSamples();

(no need for hconcat)

@LorenaGdL May I ask you to edit my code?

int _tmain(int argc, _TCHAR* argv[])
{
    Mat img = imread("f.jpg",CV_LOAD_IMAGE_GRAYSCALE);
    saveMatToCsv(img,"mycsv.csv");
    //fisherFaceTrainer();
    return 0;
}

//------------------

void saveMatToCsv(Mat &matrix, string filename){
    ofstream outputFile(filename);
    outputFile << format(matrix, "CSV") << endl;
    outputFile.close();
}

I use OpenCV 2.4

@Mehdi.Am it seems correct to me. Are you sure you're correctly loading your image?