Posted by Arowosegbe Olawale in General

Display screens are used to play back videos for the audience. In the imaging chain, the choice of monitor is on par with that of camera and lens in terms of impact on final image quality. There are a wide variety of video monitors available on the market today. 

These monitors can have anything from liquid crystal displays (LCDs) to LED displays, as well as a wide range of screen sizes and other customization options. The specifications of each system will dictate the specifications of the monitor to be used. In this section, we'll go over some of the options and factors that go into choosing a monitor.

3.4.1 Pixels

A monitor's display resolution is measured in pixels. The best possible picture can only be displayed on a screen with at least as many pixels as the cameras can capture. The width and height of an image, in terms of pixels, are typically used to describe its quality. On a 17–19-inch screen, for instance, a resolution of 800 x 600 pixels will yield a respectable video quality. 

Wide screen images on TVs and computer monitors are typically presented in a 16:9 aspect ratio (width:16, height:9). The use of 16:9 monitors in CCTV systems that only use digital or IP network components is something to consider.

3.4.2 Size

A monitor's size, expressed as a diagonal, is a key specification to keep in mind when shopping for a display. Using a monitor with a screen size of less than 9 inches can make it tough to focus a camera. If the operator is sitting directly in front of the screen, a 9-inch monitor should be fine; otherwise, a 15-inch monitor is the bare minimum for displaying multiple images at once.

3.4.3 Monitors

In this section, we'll take a look at the various commercially available monitors and discuss how they can be used to meet an organization's specific CCTV requirements. 

Televisions - In some situations, such as when conducting an investigation from a safe room, high-definition televisions can be useful for watching videos. It is possible to save money by using televisions for the dual purpose of watching network broadcasts and internal CCTV feeds. However, televisions lack the durability of monitors, making them an unsuitable option for applications requiring constant surveillance.

PC Monitors - Recording Devices (DVRs) can be hooked up to a PC display. These devices' inputs and outputs must be matched using industry-standard connectors, adapters, or converters.

Monochrome Monitors - Differences in technology mean that monochrome monitors have the potential to display more detail than their color counterparts. Though the resolution gap between color and monochrome monitors is closing, the potential loss of visual detail with a color monitor must be weighed against the cost and benefits of its display. Both monochrome and color video signals can be displayed on either type of screen.

CCTV Monitors - If multiple monitors and cameras are to be used in the system, or if the monitor is to be left on at all times, the best option is a CCTV monitor. There are many different types of monitor technologies available today, such as the cathode ray tube (CRT), liquid crystal display (LCD), organic light-emitting diode (OLED), and plasma.

CRT Monitors - The cathode ray tube (CRT) analog monitor is an antiquated method of CCTV monitoring. There is a wide range of sizes for CRT screens. Magnetic tape recorder (MTR) screens should have EMI shielding. Electromagnetic interference (EMI) can alter the path of the electron beams, degrading image quality. Because of their heft, CRT displays are almost never found in mobile applications these days.

LCD Monitor - LCD monitors come in a wide variety of sizes, colors, and resolutions. As a result of the higher resolution at which they process CCTV signals, the picture on these screens is noticeably clearer and brighter than that of CRT monitors. LCD monitors are more space and energy efficient because they are thinner front to back than CRT monitor of the same resolution. Many are lightweight and portable because of their small size. Large sizes for use with multiple cameras are also a possibility. LCD monitor don't get damaged by magnetic interference, which is a major drawback of CRT screens. In many governments, industrial, and corporate installations, LCD monitors are replacing banks of CRT monitors because of the greater viewing flexibility they offer.

OLED Monitors - The OLEDs in LED/OLED monitors are responsible for the direct emission of light, so no backlight is necessary. In contrast to liquid crystal displays (LCDs), which require the backlight source to be covered to produce blacks, each diode in an LED monitor can be turned on or off independently of the others. When compared to LCD screens, OLED displays have superior contrast while also using less power. OLED display technology is more expensive, more difficult to produce, and has a shorter lifespan than LCD screens.

Plasma Monitors - Like LCD displays, plasma screens are flat panels with independent pixel control. Each pixel in a plasma display contains a unique gas. Light is emitted from the pixel elements in response to incoming electrical signals. Although plasma screens come in a wide range of sizes, the majority of them are designed with a 16:9 aspect ratio. The superior visibility at off-axis viewing angles is the primary benefit of plasma displays over LCD ones. Improvements in LCD display capabilities have caused plasma displays to lose favor in CCTV applications.

3.4.4 Video Walls

Video, maps, facility diagrams, alarm points, access control, event logs, third party applications, and internet websites can all be displayed on a wall of closely spaced screens in a monitoring facility. As early as possible in the process, it is crucial to understand and identify all requirements for use if the monitoring center will be used for other purposes, such as an emergency operations center or for training, presentations, or video conferencing. Back projection screens, thin film transistor (TFT)-LCD screens, front projection LED tiles, and high definition (HD) LCD screens are all viable options for video walls. A video wall processor, a special kind of video switcher, is responsible for managing the content that is displayed on a video wall's many screens at once.

Rear Projection Monitors: Rear-projection monitors can use either cathode ray tube (CRT) or micro-display technology for their displays. Digital light processors (DLPs), liquid crystal on silicon (LCoS), and LCD-driven displays are the three major types of micro-displays. Analog and digital inputs of varying image sizes are supported by rear projection devices. In order to create an image using projection technology, lamps are needed. The heat produced by the lamps necessitates the use of fans, which in turn necessitate clean air to function properly. Consequently, you should budget for the price of filters and light bulbs, as well as their regular upkeep and eventual replacement. 

TFT-LCD Monitors: These modern flat video screens outperform their predecessors, traditional LCDs. They help produce high-quality video images because of the accuracy of their colors, the swiftness of their response, and the clarity of their resolution. A TFT-LCD wall can function as a single massive screen or be partitioned into multiple smaller screens to show multiple images at once.

 Front Projection Monitors: LED Tiles: Displays for control rooms can now be made using cutting-edge tech like LED tiles. To better manage video images that span multiple screens with displays offering fine details, LED tiles offer minimal gaps between panels. Tiles can be displayed with or without borders, depending on the user's preferences. With an estimated 65,000 hours of use at 50% brightness, the lifespan of LED components is significantly longer, extending the time between replacements to 7 years or more. When compared to TFT displays, LED monitors typically have advantages in terms of weight, sharpness, brightness, energy efficiency, and cost. With an LED tile wall, you can display different content on each individual tile, or wrap content from a single source across multiple tiles for more display options. While LED tile monitors are currently more expensive, they typically require less upkeep than older monitor technologies.

HD LCD Displays: High-definition liquid crystal display (LCD) screens can be configured into multiple displays by arranging multiple screens in a grid pattern. Historically, burn-in has been the most common issue with HD LCD screens. In order to avoid burn-in, modern technology employs a technique in which the image is shifted so subtly that it is undetectable to the naked eye.