Both video and photographic film capture a series of frames (still images) in rapid succession; however, television systems read the captured image by serially scanning the image sensor by lines (rows). In analog television, each frame is divided into two consecutive fields, one containing all even lines, another with the odd lines. The fields are captured in succession at a rate twice that of the nominal frame rate. For instance, PAL and SECAM systems have a rate of 25 frames/s or 50 fields/s, while the NTSC system delivers 29.97 frames/s or 59.94 fields/s. This process of dividing frames into half-resolution fields at double the frame rate is known as interlacing.
Since the interlaced signal contains the two fields of a video frame shot at two different times, it enhances motion perception to the viewer and reduces flicker by taking advantage of the persistence of vision effect. This results in an effective doubling of time resolution as compared with non-interlaced footage (for frame rates equal to field rates). However, interlaced signal requires a display that is natively capable to show the individual fields in a sequential order, and only traditional CRT-based TV sets are capable of displaying interlaced signal, due to the electronic scanning and lack of apparent fixed resolution.
Most modern displays, such as LCD, DLP and plasma displays, are not able to work in interlaced mode, because they are fixed-resolution displays and only support progressive scanning. In order to display interlaced signal on such displays, the two interlaced fields must be converted to one progressive frame with a process known as de-interlacing. However, when the two fields taken at different points in time are re-combined to a full frame displayed at once, visual defects called interlace artifacts or combing occur with moving objects in the image. A good deinterlacing algorithm should try to avoid interlacing artifacts as much as possible and not sacrifice image quality in the process, which is hard to achieve consistently. There are several techniques available that extrapolate the missing picture information, however they rather fall into the category of intelligent frame creation and require complex algorithms and substantial processing power.
Deinterlacing techniques require complex processing and thus can introduce a delay into the video feed. While not generally noticeable, this can result in the display of older video games lagging behind controller input. Many TVs thus have a "game mode" in which minimal processing is done in order to maximize speed at the expense of image quality. Deinterlacing is only partly responsible for such lag; scaling also involves complex algorithms that take precious milliseconds to run.
Read more about this topic: Deinterlacing
Other articles related to "background":
... Organ, Electric piano Billy Preston - Organ Sammy Turner - Background Vocals Hubert Laws - Alto Flute Chuck Rainey - Bass J.R ... Bailey - Background Vocals Carolyn Franklin - Background Vocals Erma Franklin - Background Vocals The Memphis Horns - Ensemble The Sweet Inspirations - Background Vocals Jack Adams - Engineer Howard Albert ... Clark - Background Vocals Cornell Dupree - Guitar Jimmy Douglass - Engineer Tom Dowd - Arranger, Producer Chuck Kirkpatrick - Engineer Eric Gale - Bass Lewis Hahn - Engineer Dan Hersch ...
... Well along into his criminal career he was arrested in Scotland and charged with blowing up the safe of the headquarters of the Edinburgh Co-operative Society ... Let out on bail, he fled to Jersey in the Channel Islands where he attempted unsuccessfully to continue his crooked ways ...
... White is an administrative nickname for a background check given in the United States of America for Department of Defense personnel and contractor employees ... clearance requires, in part, a Single Scope Background Investigation (SSBI) which is conducted under the manuals of the U.S ... Individuals having Yankee White clearances undergo extensive background investigation ...
512 Colors onscreen Maximum of 482 (241 background, 241 sprite) Palettes Maximum of 32 (16 for background tiles, 16 for sprites) Colors per palette 16 per background palette (color entry #0 of each background palette ...
... In 1985, a liquormart brought a suit against the liquor control commissioner, arguing, among other things, that the first regulation, which prevented the liquormart from advertising its prices, was unconstitutional ... The Rhode Island Supreme Court, however, held that the regulation did not violate the First Amendment, the Commerce Clause, the Equal Protection Clause, or the Sherman Anti-Trust Act ...
Famous quotes containing the word background:
“In the true sense ones native land, with its background of tradition, early impressions, reminiscences and other things dear to one, is not enough to make sensitive human beings feel at home.”
—Emma Goldman (18691940)
“... every experience in life enriches ones background and should teach valuable lessons.”
—Mary Barnett Gilson (1877?)
“I had many problems in my conduct of the office being contrasted with President Kennedys conduct in the office, with my manner of dealing with things and his manner, with my accent and his accent, with my background and his background. He was a great public hero, and anything I did that someone didnt approve of, they would always feel that President Kennedy wouldnt have done that.”
—Lyndon Baines Johnson (19081973)