About Line Doublers
In the quest to re-create the movie experience in the home, making the image appear more film-like is a high priority. And one of the main reasons normal video images don't look like film is because of the visible scan lines - if you look closely at a video screen, you can literally see the lines. A line doubler accumulates information from the image and paints twice as many lines on the screen in the same amount of time. This doesn't mean you see more lines, in fact, fewer lines are visible because the line doubler has drawn twice as many lines in the same space, basically filling in between the lines to create a solid image.
Read PlasmaTVBuyingGuide.com's review of the excellent DVDO iScan Pro Line Doubler.