CS663

Video Monitor/Display Types

Computer monitors, laptops, televisions, tablets, and mobile devices use digital display technologies to present text, images, graphics, and video. A display is commonly described by its resolution, which specifies the number of pixels displayed horizontally and vertically. For example, a Full HD display has a resolution of 1920 × 1080 pixels.

Display technology has changed significantly over time. Early computer displays supported relatively low resolutions and a limited number of colors. Modern displays can support millions or billions of colors, very high resolutions, high refresh rates, and technologies such as LCD, LED-backlit LCD, OLED, and Mini-LED.

The following table shows several important display resolutions, including historical computer display standards and resolutions commonly used today.

Display Standard	Resolution	Aspect Ratio	Typical Use / Notes
VGA (Video Graphics Array)	640 × 480	4:3	Historical PC display standard
SVGA (Super VGA)	800 × 600	4:3	Older computer monitors and projectors
XGA (Extended Graphics Array)	1024 × 768	4:3	Older monitors, laptops, and projectors
SXGA (Super XGA)	1280 × 1024	5:4	Older LCD computer monitors
WXGA (Wide XGA)	1280 × 800	16:10	Older widescreen laptops and displays
HD / 720p	1280 × 720	16:9	Entry-level video and displays
Full HD / 1080p	1920 × 1080	16:9	Common monitors, laptops, televisions, and video
WUXGA	1920 × 1200	16:10	Computer monitors and productivity displays
QHD / 1440p	2560 × 1440	16:9	Higher-resolution monitors and gaming displays
WQXGA	2560 × 1600	16:10	High-resolution laptops and monitors
4K UHD	3840 × 2160	16:9	High-resolution monitors, televisions, video, and gaming
DCI 4K	4096 × 2160	≈1.90:1	Digital cinema and professional video
5K	5120 × 2880	16:9	High-resolution professional displays
8K UHD	7680 × 4320	16:9	Very-high-resolution televisions and specialized displays

Resolution and Pixels

A pixel is the smallest individually addressable picture element in a digital image or display. Resolution describes the dimensions of a display in pixels.

For example:

1920 × 1080 = 2,073,600 pixels

A 4K UHD display contains:

3840 × 2160 = 8,294,400 pixels

Therefore, a 4K UHD display contains four times as many pixels as a Full HD display.

A higher resolution can provide greater image detail, but perceived sharpness also depends on the physical size of the display and the viewing distance.

Pixel Density

Resolution alone does not determine how sharp an image appears. Pixel density, commonly measured in pixels per inch (PPI), describes how closely pixels are packed together.

For example, a 1920 × 1080 image displayed on a small smartphone screen has a much higher pixel density than the same resolution displayed on a large television. Higher pixel density generally produces finer detail and makes individual pixels more difficult to distinguish.

Aspect Ratio

The aspect ratio describes the proportional relationship between the width and height of a display.

Older computer monitors commonly used a 4:3 aspect ratio. Most modern televisions and many computer monitors use 16:9, while 16:10 is also common on productivity-oriented laptops and monitors.

Ultrawide monitors may use aspect ratios such as 21:9 or 32:9, providing substantially more horizontal screen space.

Color Depth

Modern displays are also characterized by color depth, or the number of bits used to represent color.

A typical display uses 8 bits for each red, green, and blue (RGB) color channel, resulting in 24 bits per pixel:

8 bits red + 8 bits green + 8 bits blue = 24 bits

This allows approximately:

2²⁴ = 16.7 million colors

Higher-end displays may support 10 bits per color channel, allowing more than one billion possible RGB color combinations and smoother color gradients. Such displays are particularly useful for photography, video production, visualization, and other applications requiring accurate color reproduction.

Refresh Rate

Another important characteristic is the refresh rate, measured in hertz (Hz). Refresh rate indicates how many times per second a display can update the image.

Common refresh rates include:

60 Hz — common for general-purpose displays
75–100 Hz — increasingly common for smoother desktop interaction
120–144 Hz — common for gaming and high-motion applications
165 Hz, 240 Hz, and higher — available on high-performance gaming displays

A higher refresh rate can make motion appear smoother, although the computer's graphics hardware must be capable of producing frames quickly enough to take advantage of it.

Current Display Technologies

Most modern computer displays use one of several related technologies.

LCD (Liquid Crystal Display) uses liquid crystals to control light passing through individual pixels. Most modern LCD monitors use LED backlighting, so displays marketed as "LED monitors" are generally LCD panels illuminated by LEDs rather than a fundamentally different display technology.

OLED (Organic Light-Emitting Diode) displays use pixels that generate their own light. Because individual pixels can be turned completely off, OLED displays can provide excellent black levels and high contrast.

Mini-LED displays are LCD displays that use large numbers of very small LEDs in the backlight. Multiple local-dimming zones allow better control of brightness and contrast than conventional LED-backlit LCD displays.

High Dynamic Range (HDR)

Modern displays may also support High Dynamic Range (HDR). HDR displays are designed to reproduce a wider range between dark and bright portions of an image and, depending on the display and content, a wider range of colors.

HDR capability depends on several factors, including display brightness, contrast, color gamut, color depth, and support for HDR formats. Simply having a high screen resolution does not necessarily mean that a display provides high-quality HDR.

Display Resolution vs. Image Resolution

It is important in computer vision and image processing to distinguish between display resolution and image resolution.

An image may contain more or fewer pixels than the display on which it is viewed. Software can scale an image to fit a display, but scaling does not create the same information that would have been captured at the higher resolution.

For example, a 640 × 480 image displayed full-screen on a 4K monitor still contains only 307,200 original image pixels. Enlarging it to fill the screen does not turn it into a true 4K image.

This distinction is particularly important when working with computer vision, where the resolution of the input image can directly affect the amount of visual information available for tasks such as object detection, segmentation, feature extraction, and image recognition.