Line doubler
A line doubler (Engl. Line doubler ) is a device or module for deinterlacing of video signals before displaying it and is therefore Deinterlacer called.
The main function of a line doubler is to take a field video source and create a full screen output from it. CRT -based display devices (also known as projection devices) can display reverb and full-screen video directly and therefore the line doubling process is an optional step to improve image quality. Most types of displays , including LCD , plasma and DLP , do not usually accept a field signal directly and therefore line doublers must be used. This is usually built in and transparent for the user. Progressive scan - DVD players also have a line doubler.
The easiest and most literal way to double lines is to repeat each scan line, although most of the time the result looks very crude. Most line doublers use digital interpolation to restore the missing lines in a field signal, and the resulting quality depends on the technique used. Most of the time a line doubler only interpolates within a single field and does not merge the information from two neighboring fields, which would keep the movements fluid. Some line doublers can use the former technique in moving areas and the second in static areas, which increases overall sharpness.
Line doublers are increasingly being replaced by video processors , which combine several processing functions in one module and then also, for example, master 3: 2 pulldown and video scaling .