I need to implement a function that receives a string containing the bytes of an image (received via boost socket connection) and converts the info into an OpenCV cv::Mat.
I also know the width and height of the image and its size in bytes. My function looks like this:
void createImageFromBytes(const std::string& name, std::pair<int,int> dimensions, const std::string& data)
{
int width,height;
width = dimensions.first;
height = dimensions.second;
//convert data to cv::Mat image
std::string filepng = DATA_PATH"/" + name +".png";
imwrite(filepng, image);
}
Which is the best method for doing this? Does OpenCV has a constructor for Mat from a string?
OpenCV Mat has a constructor from vector<byte>
, but this is not so intuitive. You need to convert from string to vector this way first:
std::vector<byte> vectordata(data.begin(),data.end());
Then you can create a cv::Mat from the vector:
cv::Mat data_mat(vectordata,true);
You also need to decode the image (check documentation for which types are allowed, png, jpg, depending on the OpenCV version)
cv::Mat image(cv::imdecode(data_mat,1)); //put 0 if you want greyscale
Now you can check if the resulting size of the image is the same as the one you sent:
cout<<"Height: " << image.rows <<" Width: "<<image.cols<<endl;