The purpose is   - Distortion removal - removing distortion so straight lines stay   straight. The parameters of the lens distortion model are calculated   and a corrected form of the input image is output.   WORKINGS OF THE APPLICATION  The program is written in C++ using the Qt and OpenCV libraries. The application consists of a Qt-based GUI that allows the user to load images, select between various image processors, select parameters and peruse the results of the processing by zooming and panning on the output image. Furthermore, it is possible to select points of interest (POIs) by double clicking on the image, which can be used to select points for the calibration algorithm. The GUI also has a log output window for textual output from the algorithms.  Each processor is implemented as a class that specifies which parameters are available for this processor (the parameters can be set by the user with the help of the QPropertyEditor library), and does the actual processing. The processing is done in a separate thread, to keep the interface responsive, and make it possible for the user to cancel a long-running processor.