Making light of poor lighting

March 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:

Securing Savannah Hills Estate
August 2019, Rhyco Risk Projects , CCTV, Surveillance & Remote Monitoring, Perimeter Security, Alarms & Intruder Detection
Savannah Hills Estate in Midrand planned a security upgrade which was awarded to Rhyco Risk Projects. The project started in March 2019 and was completed in May 2019.

Read more...
10 things to consider when shopping for a VMS
August 2019, Genetec , CCTV, Surveillance & Remote Monitoring, Integrated Solutions
Today’s video management systems (VMS) provide a wide range of tools and capabilities that help make security personnel more efficient by allowing them to focus on what really matters.

Read more...
How far are we really at with artificial intelligence?
August 2019, Axis Communications SA , Editor's Choice, CCTV, Surveillance & Remote Monitoring, IT infrastructure, Residential Estate (Industry)
Justin Ludik unpacks exactly how far AI has come and what it potentially can do for society and more importantly, surveillance.

Read more...
Enhancing security with AI
August 2019, Hikvision South Africa , CCTV, Surveillance & Remote Monitoring
Hikvision explains how residential estates can revolutionise their security strategies and outcomes with artificial intelligence.

Read more...
More than simply a camera
August 2019, Forbatt SA, Secutel Technologies , CCTV, Surveillance & Remote Monitoring, Residential Estate (Industry)
With the human element being the weakest link in all security solutions, Hi-Tech Security Solutions looks at the pros and cons of using body-worn cameras in estates.

Read more...
The importance of effective perimeter security
August 2019, Elf Rentals - Electronic Security Solutions, Stafix , Editor's Choice, CCTV, Surveillance & Remote Monitoring, Residential Estate (Industry)
Protecting the perimeter is critical for any residential estate; how does one go about making sure your perimeter is as secure as possible?

Read more...
Security playing speedcop
August 2019, Axis Communications SA, Hikvision South Africa , CCTV, Surveillance & Remote Monitoring, Residential Estate (Industry)
Estates now have a legal precedent to manage their traffic and fine people in the estate for violations of the rules; all they need do is find solutions that will support them.

Read more...
CathexisVision video management software
August 2019, Cathexis Technologies , Products, CCTV, Surveillance & Remote Monitoring
The CathexisVision IP video management software (VMS) helps clients get the most out of their surveillance investment and reap rewards for their companies.

Read more...
Capture every detail with Smart PIR kits
August 2019, Longse Distribution , Home Security, CCTV, Surveillance & Remote Monitoring, Residential Estate (Industry)
Longse Technology offers DIY smart security kits that are easy to install and offer a Wi-Fi range that can reach up to 300 metres.

Read more...
Future-facing cameras
August 2019, Bosch Building Technologies , Products, CCTV, Surveillance & Remote Monitoring
All FLEXIDOME IP starlight 8000i cameras feature built-in Intelligent Video Analytics, making them intuitive, and elevates their importance far beyond security alone.

Read more...