Many problems in metrology and optical tomography have to recover information from the wrapping phase. In most of the cases, phase, that is associate to a physical magnitude, is continuous and generally, varies smoothly. Therefore, we can say that the problem in these cases is reduced to find a continuous phase. Considering this, many solutions to this kind of problems have been proposed, from the use of local planes to the implementation of most robust algorithms. However, these methods are also very slow. That is why the unwrapping problem is an open subject research in optics. We propose a phase unwrapping method based on finite differences that is fast and robust. In addition, it is easy to program.