Progressive Scan is a video process to improve the definition and fluidity of an image broadcast by a video projector, a flat screen or, less often, a television by doubling the signal lines. Normally, the lines making up the image are sent in two frames: the first with the odd lines, the second with the even lines. With progressive scan the signal is "un-interleaved", i.e. all the lines are displayed at the same time by extrapolating the missing image frame from the one that is sent. This system is either directly built into the DVD player or into the image display device.