Display Resolutions

The Display Resolution of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT), Flat panel display which includes Liquid crystal displays, or projection displays using fixed picture-element (pixel) arrays.

It is usually quoted as width × height, with the units in pixels: for example, "1024x768" means the width is 1024 pixels and the height is 768 pixels. This example would normally be spoken as "ten twenty-four by seven sixty-eight" or "ten twenty-four by seven six eight".

One use of the term “display resolution” applies to fixed-pixel-array displays such as plasma display panels (PDPs), liquid crystal displays (LCDs), digital light processing (DLP) projectors, or similar technologies, and is simply the physical number of columns and rows of pixels creating the display (e.g., 1920x1080). A consequence of having a fixed-grid display is that, for multi-format video inputs, all displays need a "scaling engine" (a digital video processor that includes a memory array) to match the incoming picture format to the display.

Note that for broadcast television standards the use of the word resolution here is a misnomer, though common. The term “display resolution” is usually used to mean pixel dimensions, the number of pixels in each dimension (e.g., 1920x1080), which does not tell anything about the pixel density of the display on which the image is actually formed: broadcast television resolution properly refers to the pixel density, the number of pixels per unit distance or area, not total number of pixels. In digital measurement, the display resolution would be given in pixels per inch. In analog measurement, if the screen is 10 inches high, then the horizontal resolution is measured across a square 10 inches wide. This is typically stated as "lines horizontal resolution, per picture height;" for example, analog  NTSC TVs can typically display about 340 lines of "per picture height" horizontal resolution from over-the-air sources, which is equivalent to about 440 total lines of actual picture information from left edge to right edge.



Some commentators also use display resolution to indicate a range of input formats that the display`s input electronics will accept and often include formats greater than the screen`s native grid size even though they have to be down-scaled to match the screen`s parameters (e.g., accepting a1920x1080 input on a display with a native 1366x768 pixel array). In the case of television inputs, many manufacturers will take the input and zoom it out to "overscan" the display by as much as 5% so input resolution is not necessarily display resolution.

The eye`s perception of display resolution can be affected by a number of factors – see image resolution and optical resolution. One factor is the display screen`s rectangular shape, which is expressed as the ratio of the physical picture width to the physical picture height. This is known as the aspect ratio. A screen`s physical aspect ratio and the individual pixels` aspect ratio may not necessarily be the same. An array of 1280x720 on a 16:9 display has square pixels, but an array of 1024x768 on a 16:9 display has rectangular pixels.

An example of pixel shape affecting "resolution" or perceived sharpness: displaying more information in a smaller area using a higher resolution makes the image much clearer or "sharper". However, most recent screen technologies are fixed at a certain resolution; making the resolution lower on these kinds of screens will greatly decrease sharpness, as an interpolation process is used to "fix" the non-native resolution input into the display`s native resolution output.

While some CRT-based displays may use digital video processing that involves image scaling using memory arrays, ultimately "display resolution" in CRT-type displays is affected by different parameters such as spot size and focus, astigmatic effects in the display corners, the color phosphor pitch shadow mask (such as Trinitron) in colour displays, and the video bandwidth.


Overscan and underscan

Most television display manufacturers "overscan" the pictures on their displays (CRTs and PDPs, LCDs etc.), so that the effective on-screen picture may be reduced from 720x576(480) to 680x550(450), for example. The size of the invisible area somewhat depends on the display device. HD televisions do this as well, to a similar extent.

Computer displays including projectors generally do not overscan although many models (particularly CRT displays) allow it. CRT displays tend to be underscanned in stock configurations, to compensate for the increasing distortions at the corners.


Current standards


Televisions are of the following resolutions:

·         Standard-definition television (SDTV):

·         480i (NTSC standard uses an analog system of 486i split into two interlaced fields of 243 lines)

·         576i (PAL, 720x576 split into two interlaced fields of 288 lines)

·         Enhanced-definition television (EDTV):

·         480p (720x480 progressive scan)

·         576p (720x576 progressive scan)

·         High-definition television (HDTV):

·         720p (1280x720 progressive scan)

·         1080i (1920x1080 split into two interlaced fields of 540 lines)

·         1080p (1920x1080 progressive scan)

·         Ultra-high-definition television (UHDTV)

·         2160p (3840x2160 progressive scan)

·         4320p (7680x4320 progressive scan)

·         8640p (15360x8640 progressive scan)


Cinema projection

·         2K Digital Cinema (2048x1080)

·         4K Digital Cinema (4096x2160)

·         8K Digital Cinema (8192x4608)

Computer monitors

Computer monitors have higher resolutions than most televisions. As of July 2002, 1024x768 Extended Graphics Array was the most common display resolution. Many web sites and multimedia products were re-designed from the previous 800x600 format to the layouts optimized for 1024x768.

The availability of inexpensive LCD monitors has made the 5:4 aspect ratio resolution of 1280x1024 more popular for desktop usage. Many computer users including CAD users, graphic artists and video game players run their computers at 1600x1200 resolution (UXGA) or higher if they have the necessary equipment. 

Other recently available resolutions include oversize aspects like 1400x1050 SXGA+ and wide aspects like 1280x800 WXGA, 1440x900 WXGA+, 1680x1050 WSXGA+, and 1920x1200 WUXGA. 

A new more-than-HD resolution of 2560x1600 WQXGA was released in 30-inch LCD monitors in 2007. In 2010, 27-inch LCD monitors with the resolution 2560x1440 were released by multiple manufacturers including Apple,and in 2012 Apple introduced a 2880x1800 display on the MacBook Pro. 

Panels for professional environments, such as medical use and air traffic control, support resolutions up to 4096x2160.


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