Scan conversion
Scan conversion or scan rate converting is a video processing technique for changing the vertical / horizontal scan frequency of video signal for different purposes and applications. The device which performs this conversion is called a scan converter.
The application of scan conversion is wide and covers video projectors, cinema equipment, TV and video capture cards, standard and HDTV televisions, LCD monitors, radar displays and many different aspects of picture processing.
Mechanisms and methods
Scan conversion involves changing the picture information data rate and wrapping the new picture in appropriate synchronization signals.
There are two distinct methods for changing a picture's data rate:
This conversion is done using large numbers of delay cells and is appropriate for analog video. It may also be performed using a specialized scan converter vacuum tube. In this case polar coordinates (angle and distance) data from a source such as a radar receiver, so that it can be displayed on a raster scan (TV type) display.