Search results
Results From The WOW.Com Content Network
A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode-ray tube (CRT) display of a television set or computer monitor. [1] On CRT screens the horizontal scan lines are visually discernible, even when viewed from a distance, as alternating colored lines and black lines, especially when ...
However, this does not apply to LCD monitors. The closest equivalent to a refresh rate on an LCD monitor is its frame rate, which is often locked at 60 fps. But this is rarely a problem, because the only part of an LCD monitor that could produce CRT-like flicker—its backlight—typically operates at around a minimum of 200 Hz.
External flicker fixer. A flicker fixer or scan doubler is a piece of computer hardware that de-interlaces an output video signal. The flicker fixer accomplishes this by adjusting the timing of the natively interlaced video signal to suit the needs of a progressive display for example a CRT computer monitor.
During video motion, screen tearing creates a torn look as the edges of objects (such as a wall or a tree) fail to line up. Tearing can occur with most common display technologies and video cards and is most noticeable in horizontally-moving visuals, such as in slow camera pans in a movie or classic side-scrolling video games.
The flicker of a CRT monitor can cause various symptoms in those sensitive to it such as eye strain, headaches [9] in migraine sufferers, and seizures in epileptics. [10]As the flicker is most clearly seen at the edge of our vision there is no obvious risk in using a CRT, but prolonged use can cause a sort of retinal shock where the flickering is seen even when looking away from the monitor.
This part of the line display process is the Horizontal Blank. [1] [2] In detail, the Horizontal blanking interval consists of: front porch – blank while still moving right, past the end of the scanline, sync pulse – blank while rapidly moving left; in terms of amplitude, "blacker than black".
However, this intermediate image is seen by the user as flickering. In addition, computer monitors constantly redraw the visible video page (traditionally at around 60 times a second), so even a perfect update may be visible momentarily as a horizontal divider between the "new" image and the un-redrawn "old" image, known as tearing.
Progressive scan is used for all LCD computer monitors and most HDTVs. Most cathode-ray tube (CRT) computer monitors and CRT-type displays, such as SDTVs , needed to use interlace to achieve full vertical resolution, but could display progressive video at the cost of halving the vertical resolution.