scaler
Scalers are image format converters. They convert one image format to another and improve image resolution for projection and screen display by scaling image formats with lower image resolution to those with higher and vice versa.
Video scalers work with video processors and can convert analogvideo signals into digital ones, they can convert interlaced television signals into those for progressive scan, and they can also convert digital video with a low image resolution into one with a higher image resolution. For example, an image resolution of 720 x 576 pixels can be converted to one with HDTV resolution of 1,280 x 720 or even to full HD with 1,920 x 1,080 pixels. However, scaling not only refers to video formats, but also to display formats of personalcomputers(PCs), from VGA to Super-VGA ( SVGA), XGA to Super-XGA( SXGA).
A scaler can be an integral part of a projector or a stand-alone device. They are used in home theaters where they improve projection quality.