Abstract: Shortcomings of Tikhonov regularization model in Sobolev space for image zoom in are analyzed and a digital total variation model with image inpainting for noisy image zoom-in is presented. Described by a directed graph, a digital TV algorithm for noisy image zoom-in is implemented. For comparison, the digital Tikhonov zoom-in algorithm is also introduced. Tests show that the digital TV algorithm achieves better performance, it can zoom an image with arbitrary accuracy and keep the edges as clear and natural as possible. The algorithm is very suitable for non-texture medical image.