1. A non-transitory computer readable medium storing a computer program that when executed by at least one processor implements a graphical user interface (GUI) for removing distortion from an image, the GUI comprising: a display area for displaying the image; and a distortion removal tool for (i) allowing a user of the GUI to identify, in the image, a first curvilinear line representing the distortion that should appear straight by drawing, on the image, a second curvilinear line over or near the first curvilinear line, (ii) determining a set of transformations based on the identification, and (iii) applying the set of transformations to the image in order to remove the distortion from the image.