1. A computer-implemented process for selectively applying image processing to a selected region of a target image provided by an image source, the process being carried out in a computer system coupled to the image source, comprising the steps of: obtaining a key frame image from an image provided by an image source; in response to user commands, defining a key from the key frame image, the key corresponding to the selected region of interest for applying image processing to the target image; automatically vectorizing the region of interest in the key to derive a user defined window; and applying image processing within the region of the target image corresponding to the user defined window of the key.