1. A method for enhancing stent visibility in a set of image frames, comprising: acquiring a set of image frames including multiple test frames; defining a set of measurement points uniformly distributed within an image of a stent in each of the multiple test frames; defining a local image context around each measurement point of each of the multiple test frames; calculating a non-rigid deformation field that relates the local image contexts of each of the multiple test frames to local image contexts of a reference image; optimizing the non-rigid deformation field by maximizing a similarity function between the local image contexts of each of the multiple test frames and the local image contexts of the reference image; using the optimized non-rigid deformation field to damn images of a stent in each of the multiple test frames and combine the non-rigidly deformed images of the stent from each of the multiple test frames; and displaying an image frame of the set of image frames with the combined image of the stents superimposed thereon.