OpenCVFITS

OpenCVFITS is a single header file C++ library designed to write and read FITS files with cv::Mat objects. It has basic functionality to write keys to images, and read image keys. It can write multiple images to a single FITS file, and read multiple images from a single FITS file.

Installation

Install the following packages:

• libopencv-dev
• libcfitsio-dev

Then place the header file in your project. An example on how to build a project using OpenCVFITS with cmake is available. This library has been tested on Ubuntu 22.04 LTS, but should work on other distributions.

Building and running the example

mkdir build
cd build
cmake ..
cmake --build .
./example

The example creates a FITS file with three images inside. It opens each image, displays it, and prints the keys on the console. Do not run the example from a VSCode terminal, the images will not display.

Usage

Create, add images, add keys, and close

/* Assume this is actually full of data */
cv::Mat image1;
cv::Mat image2;
cv::Mat image3;
/* Use false for second argument if you do not wish to overwrite existing files */
fits.createFITS("testfits.fit", true);
fits.addMat2FITS(image1);
fits.addKey2FITS("TestDouble", 14.3);
fits.addKey2FITS("testsigned", (int64_t)-8461292);
fits.addMat2FITS(image2);
fits.addKey2FITS("TestDouble", 7.3);
fits.addKey2FITS("testsigned", (int64_t)-234292);
fits.addMat2FITS(image3);
fits.addKey2FITS("TestDouble", 3.3);
fits.addKey2FITS("testsigned", (int64_t)5231292);
fits.closeFITS();

Open, get images and keys, and close

cv::Mat image;
std::string key;
std::string value;
fits.openFITS("testfits.fit");
while(true == fits.getNextImage(image))
{
    /* Image got successfully */
    /* Read some keys */
    while(true == fits.getNextKey(key, value))
    {
        std::cout << key << ": " << value << std::endl;
    }
}
fits.closeFITS();

Limitations

At the moment it only works with CV_8U and CV_16U data. Help me add other types!