This Thesis research project aims to design a Line-tracking algorithm for a low-cost mini drone through Vision-based control with image processing techniques. The design process is the application of the principles of Model-based software design, which is a modern technique to design control systems, based on the development of a model of the plant and the controller with enough detail to have a realistic representation of its behavior to accomplish the specifications. The designed model is tested in a simulation environment (Model-in-the-loop phase). Then, if it satisfies the requirements, it is tested in real-time, deploying the algorithm on the Hardware to evaluate if its performances are still acceptable or if it requires to be updated.