Dispelling the myths of IP video: Myth #10: Networked video image quality is not as good as analogue

December 2007 Surveillance

In this series, Roy Alves, country manager of Axis Communications South Africa, examines 10 myths about IP video.

The basis of this myth originates from the fact that CCTV cameras have been on the market for a longer period of time, as opposed to network video cameras, which made their grand entrance in 1984. It is assumed that because of this timelapse that network video image quality is lagging behind the CCTV offering.

Quite the contrary, network cameras have the same, in some cases even better, high-quality image sensors (CCDs) and optics as analogue security cameras. In a recent discussion with the South African Police Service a detective mentioned that they do not even look at CCTV surveillance footage in the investigation of a crime - simply because of the poor image quality.

Image quality is clearly one of the most important features of any camera, if not the most important. This is especially true of security surveillance and remote monitoring applications, where lives and property may be at stake. Unlike traditional analogue cameras, network cameras are equipped with the processing power not only to capture and present images, but also to manage and compress them digitally for network transport.

Image quality can vary considerably and is dependent on several factors such as the choice of optics and image sensor, the available processing power and the level of algorithms in the processing chip.

Today, two different techniques are available to render video; interlaced scanning and progressive scanning. The technique selected will depend on the application and purpose of the video system and particularly whether the system is required to capture moving objects and to allow viewing of detail within a moving image.

Interlaced scan-based images use techniques developed for cathode ray tube (CRT)-based TV monitor displays, made up of 75 PAL (phase alternating line)/480 NTSC (National Television System Committee) visible vertical lines across a standard television screen. Interlacing divides these into odd and even lines and then alternately refreshes them at 25/30 frames per second. The slight delay between odd and even line refreshes creates some distortion or 'jaggedness'. This is because only half the lines keep up with the moving image while the other half wait to be refreshed.

Interlaced scanning has served the analogue camera, television and VHS video world very well for many years, and is still the most suitable for certain applications. However, now that display technology is changing with the advent of liquid crystal display (LCD), thin film transistor (TFT)-based monitors, DVDs and digital cameras, an alternative method of bringing the image to the screen, known as progressive scanning, has been created.

Progressive scanning, as opposed to interlaced, scans the entire image line by line every 25/30 of a second. In other words, captured images are not split into separate fields like in interlaced scanning. Computer monitors do not need to interlace to show the picture on the screen. It puts them on one line at a time in perfect order. So there is virtually no 'flickering' effect. As such, in a video surveillance application it can be critical in viewing detail within a moving image such as a person running away.

Furthermore, by employing video servers, an analogue specialty camera or those that are already installed can be incorporated into an IP-surveillance system. In comparing network and analogue cameras, we must emphasise 'good' quality network cameras built for professional use. These high quality professional network cameras should not be confused with lower-end network or PC Webcam cameras used for 'Web attraction'. These cameras cannot deliver the same capabilities as a full-function network camera.

Network cameras and IP-Surveillance technology are delivering superior image quality by means of mega-pixel resolution. Analogue cameras are limited by the 0,4 Megapixel resolution of NTSC/PAL standards, which network cameras are not.



Credit(s)




Share this article:
Share via emailShare via LinkedInPrint this page



Further reading:

Safer spaces through smart surveillance
NEC XON Surveillance
Advances in facial recognition technology are transforming surveillance from a mere recording tool into an intelligent, integrated system that enhances real-time safety, moving beyond the traditional expansion of CCTV efforts.

Read more...
Next generation of AI-powered video telematics
IoT & Automation Surveillance Transport (Industry)
Webfleet, Bridgestone’s fleet management solution in South Africa, has launched Webfleet Video 2.0, an AI-powered solution designed to enhance fleet safety, security, compliance with local regulations and operational efficiency through real-time video insights.

Read more...
Key design considerations for a control room
Leaderware Editor's Choice Surveillance Training & Education
If you are designing or upgrading a control room, or even reviewing or auditing an existing control room, there are a number of design factors that one would need to consider.

Read more...
Smart cities and the role of video security
Surveillance Integrated Solutions
As cities around the world continue to embrace smart technology, including IoT that not only connects to people, but also the surrounding activity, the integration of advanced video security systems is crucial to ensure safety and efficiency in environments.

Read more...
How intrusion protection helps secure O&G operations
Surveillance Perimeter Security, Alarms & Intruder Detection Industrial (Industry)
For O&G operators in Africa, physical security remains one of the biggest considerations, particularly when it comes to perimeter protection and the ability to mitigate intruder-related incidents.

Read more...
Axis secures the Waterfront
Surveillance Entertainment and Hospitality (Industry) Retail (Industry)
Axis Communications shares insight into its longstanding partnership with the V&A Waterfront, one of Africa’s premier retail and mixed-use precincts, through its latest, updated customer success story.

Read more...
Advanced surveillance storage from ASBIS
Infrastructure Surveillance Products & Solutions
From a video storage solutions perspective, SkyHawk drives, designed for DVRs and NVRs, offer high capacity, optimised firmware, and a reliability workload rating of hundreds of terabytes per year.

Read more...
Open and collaborative logistics systems
Hikvision South Africa Surveillance Logistics (Industry) AI & Data Analytics
E-commerce and other high-volume logistics operations need open and collaborative technology ecosystems that drive efficiencies, throughput and digital transformation. Hikvision discusses the benefits of harnessing open and collaborative systems in the logistics market.

Read more...
4K HDR camera for mobility
Surveillance Transport (Industry)
e-con Systems has introduced a 4K HDR front-view camera, engineered to deliver reliable, long-range imaging for mobility applications such as delivery robots, autonomous vehicles, and off-road vehicles.

Read more...
The future of the surveillance channel
Duxbury Networking Technews Publishing Elvey Security Technologies SMART Security Solutions Surveillance
The video surveillance market has evolved from camera-based specifications to integrated solutions that solve customers’ problems. Moreover, the growth of AI and cloud has changed the channel even more, with more to come.

Read more...