How to write a Float Mat to a file in OpenCV

by

Using pure OpenCV API calls:

// Declare what you need
cv::FileStorage file("some_name.ext", cv::FileStorage::WRITE);
cv::Mat someMatrixOfAnyType;

// Write to file!
file << "matName" << someMatrixOfAnyType;

The file extension can be xml or yml.
In both cases you get a small header that you can easily remove/parse, then you have access to the data in a floating point format.
I used this approach successfully (with yml files) to get data into Matlab and Matplotlib

To get the data:

  1. open the file with any editor
  2. then suppress all the text and numbers except the content of the data tag (i.e., the pixel values).
  3. When done, save your file with a txt or csv extension and open it with matlab (drag-and-drop works).

Voilà. You may have to reshape the resulting matrix in matlab command line if it didn’t guess correctly the image size.

More Related Contents:

  1. Efficiently load a large Mat into memory in OpenCV
  2. cv::Mat to QImage and back
  3. C++ OpenCV image sending through socket
  4. load image with openCV Mat c++
  5. Transpose a 1D byte-wise array to a 2D array
  6. How do I take values from text file and input into a 2D array? c++
  7. Extracting text OpenCV
  8. OpenCV with Network Cameras
  9. What is a subnormal floating point number?
  10. Convert Mat to Array/Vector in OpenCV
  11. How to efficiently display OpenCV video in Qt?
  12. Change floating point rounding mode
  13. Emulate “double” using 2 “float”s
  14. C++: How to round a double to an int? [duplicate]
  15. Compare two float variables in C++
  16. Automatic perspective correction OpenCV
  17. Square detection doesn’t find squares
  18. A fast method to round a double to a 32-bit int explained
  19. checking for eof in string::getline
  20. Converting YUV into BGR or RGB in OpenCV
  21. Floating point Endianness?
  22. OpenCV threshold with mask
  23. Why can’t I open avi video in openCV?
  24. Matlab vs C++ Double Precision
  25. Is there a functional difference between “2.00” and “2.00f”?
  26. Convexity defects C++ OpenCv
  27. How to count lines of a file in C++?
  28. Does setprecision in c++ round? If so why am I seeing this?
  29. Displacement Map Filter in OpenCV
  30. Performance Difference Between C and C++ Style File IO

Leave a Comment