Progressive scanning refers to a way of displaying, storing or
transmitting moving images in which all the lines of each frame are drawn in
sequence. It is also known as noninterlaced scanning alternatively. In
comparison with interlaced video, progressive scanning is a way distinguished
from interlaced scanning. Interlaced video is usually adopted in traditional
analog television systems in which only the odd lines, then the even lines of
each frame (each image called a video field) are drawn one after another. As a
result, only half of the number of actual image frames are utilized to produce
video.
As a matter of fact, progressive scanning is known as “sequential
scanning” in the first place when it was adopted in the Baird 240 line
television transmissions from Alexandra Palace, United Kingdom in 1936. Nowadays,
progressive scanning has been universally adopted in computing.
Progressive scanning is applied in the scanning and storing of
film-based material on DVDs. It was agreed that all film transmissions by HDTV
would be broadcast with progressive scan in the US
Progressive scanning has been applied on most Cathode ray tube (CRT) computer monitors,
all LCD computer monitors, and most HDTVs for the display resolutions are
progressive by nature. Other CRT-type displays, such as SDTVs, will only
display interlaced video.
Generally speaking, some TVs and most video projectors have one or
more progressive scan inputs. Before HDTV became well received, some high end
displays supported 480p. Under such conditions, these displays were able to be
used with devices outputting progressive scan. For instance, some progressive
scan DVD players and certain video game consoles are included. HDTVs support
the 480p and 720p resolutions which have been progressively scanned. Compared
with lower resolution HDTV models, the 1080p displays are usually more expensive.
