Making light of poor lighting

CCTV Handbook 2009 CCTV, Surveillance & Remote Monitoring

Jacques Botha, manager of Norbain SA’s technical division throws some light on WDR technology.

WDR (wide dynamic range) technology was developed for use on imaging devices ie, cameras. It is related to BLC (backlight compensation) and its primary area of address or concern is the efficient reproduction of highlights and shadows as encountered in many images.

We often find these stark contrasts alongside one another in a single image and while BLC was initially developed to combat image washout or similar problems it is more often than not insufficient.

A real life example would be a camera facing a door that leads out of a dark hallway to the outside of a building (in other words, plenty of light, and as it is outside, expect sunlight). If we place an object in front of this closed door we may find that (assuming the camera specification is sufficient and the device was setup correctly) the camera will be able to reproduce images where a user can discern individual features such as buttons on a shirt and facial features, to name but two. This is the status quo as long as the door remains closed and lighting conditions are unchanged.

In the next instance we assume that the door opens and a person enters the hallway. The door is still open behind this person and there is a lot of bright light entering the hallway from behind our subject.

The camera (akin to the performance of the human eye) now has too much light to contend with and reproduces images that appear overly bright or washed out. Detail such as facial features and the aforementioned buttons are now mostly in the dark with this object (the person) being back lit.

The camera now needs to reproduce this as true as possible and due to dark and bright areas, struggle to find a median. The result is a very bright doorframe and a shadowy figure approaching the camera through it. No detail, or very little is discernable.

Enter WDR. The camera will use a technology such as APS (active pixel system) to accentuate the differences between individual pixels (picture elements) and detail can be seen again despite the fact that it is not the part of the object bathed in light.

The Samsung Techwin SHC-735P employs digital pixel system and active pixel system type technologies known to CCTV users as WDR. This ensures the ability of the image sensor to quantify and subsequently represent highlights and shadows in the same image. The end result then, quite simply, is a camera with better video reproduction under such adverse conditions as stated above.



Credit(s)




Share this article:
Share via emailShare via LinkedInPrint this page



Further reading:

Drones and cybersecurity?
October 2019 , CCTV, Surveillance & Remote Monitoring
Hacker drones can eavesdrop electronically on conversations, can perform network attacks, or can create fake wireless access points.

Read more...
Body-worn cameras transforming security
October 2019 , CCTV, Surveillance & Remote Monitoring, Security Services & Risk Management
Police Service Northern Ireland now has over 7 000 officers using 2 500 cameras covering approximately 173 000 incidents each year.

Read more...
Camera Selection Guide 2019
CCTV Handbook 2019 , CCTV, Surveillance & Remote Monitoring
The Camera Selection Guide 2019 includes a range of IP, analogue, thermal and speciality cameras aimed at a broad range of surveillance functions.

Read more...
Intelligent analytics and the brains to match
September 2019, Bosch Building Technologies , CCTV, Surveillance & Remote Monitoring, Integrated Solutions
What if the brains behind our security cameras could be trained to improve their cognitive ability to pay attention, learn, and problem-solve according to specific rules and situations?

Read more...
AI-powered autonomous Drone-in-a-Box
September 2019 , CCTV, Surveillance & Remote Monitoring, Integrated Solutions
Organisations in the mining, energy and industrial, oil and gas, ports and terminals sectors can optimise security and business operations, whilst reducing risks and operational costs

Read more...
Cybersecurity for video surveillance systems
September 2019, Mobotix , Cyber Security, CCTV, Surveillance & Remote Monitoring
Video surveillance systems are increasingly accessible over any IP network, which has led to the rise of potential cyberattack.

Read more...
What are the cybersecurity issues in video surveillance?
November 2019, Axis Communications SA , Editor's Choice, CCTV, Surveillance & Remote Monitoring, Cyber Security
he importance of the data captured by surveillance cameras – and what can be done with it – has led to a new breed of cybercriminals, looking for insights to steal and sell.

Read more...
The safe city and its need for interoperability
November 2019 , Integrated Solutions, CCTV, Surveillance & Remote Monitoring
Interoperability continues to present one of the greatest challenges, particularly with video management systems, video recording devices and cameras.

Read more...
A platform approach to safer and smarter cities
November 2019, Milestone Systems , CCTV, Surveillance & Remote Monitoring
Selecting the right platform to manage the vast data collected from smart and safe cities is critical to the ultimate success of the project.

Read more...
Creating safe cities with smart technology
November 2019, Secutel Technologies , CCTV, Surveillance & Remote Monitoring
In a digital age, where resilience and responsiveness are paramount to fighting crime and creating a safer world, CCTV systems are becoming part of every city’s infrastructure.

Read more...