CCTV WDR: What Is It and Is It Right For You?

CCTV WDR Cameras 

 

As CCTV technology continues to advance, more and more high-tech features are becoming readily available.

WDR is a prime example of this, helping security cameras pick up better image quality, record in low light and bright light and ultimately provide a very high-quality monitoring experience. 

In this article, Eclipse (IP) will walk you through everything you need to know about WDR and help you decide if a WDR technology is the right choice for your surveillance cameras. 

 

What is WDR?

WDR stands for Wide Dynamic Range. Having a wide dynamic range on your camera lens essentially means that your security camera can better process images from high contrast scenes. WDR technology helps balance brightness and shaded areas simultaneously so that the image is neither overly bright and completely blown out nor too dark and impossible to make out. 

By having security cameras with a wide dynamic range, you will be assured of better image quality no matter the scene. 

When measuring WDR cameras, the value used is in Decibels (dB). Generally, a range of 60 dB and upwards counts as a wide dynamic range, but with advancements in this area, you can now find security cameras with an impressive range of 120 dB. Bear in mind that manufacturers determine dB in slightly different ways, so don't automatically assume that a camera with a higher dB from one manufacturer produces a better quality image than a camera with a lower dB from another manufacturer.

As confusing as this is, it's always best to find out more information and view the wide dynamic range in action to ensure quality. 

 

Why use WDR cameras?

Imagine the scene. You've spent months researching the best security systems for your property. You've installed a whole host of CCTV cameras. You feel confident that each and every one of your security cameras is up and running perfectly. 

You take your first look at your monitoring station, and the camera you installed facing your large windows is entirely white. There seems to be far too much light coming through. Worse still, the outdoor CCTV camera tucked around the side is almost pitch black. "What was the point in all that hassle if my security cameras can't even pick up the image!?" you ask yourself. 

This is where WDR technology comes in to save the day. 

If you have one or more high contrast areas in and around your property, such as conservatories, open plan rooms, glass doors and other naturally bright areas, WDR cameras will be an excellent fit for you. 

Similarly, if you have a lot of dark areas around your property where little light can get to, WDR cameras placed in these vulnerable positions would allow you to view the scene without compromise. 

 

How WDR works

WDR cameras work with two different, all-be-it similar programs. These are True WDR and Digital WDR (DWDR).

Both help lighten dark images and reduce brightness on light images. Still, they do so in slightly different ways, impacting the final image quality. Let's break down each one individually.

 

True Wide Dynamic Range

Security cameras with true WDR technology work by using advanced image sensors in conjunction with a Digital Signal Processor to produce a balanced image. The technology provides even illumination to every part of the image for optimal results. 

The sensors from True WDR Cameras take two scans of each frame of video at different shutter speeds. The first scan is taken at a low shutter speed to capture lots of light, and the second scan is taken at a high shutter speed, meaning the sensor's exposure picks up less light. 

The Digital Signal Processor then combines these two images, resulting in a single, well-balanced and properly illuminated clear image. This processing is done constantly, allowing you to view your video surveillance footage in real-time without poor light exposure levels affecting your view.

 

Digital Wide Dynamic Range

Digital WDR works by using algorithms to digitally enhance dark and bright areas of the image. If the image is overexposed, with far too much light being picked up, DWDR cameras will automatically darken the brighter areas. In the same fashion, if the image is too dark, DWDR technology will add more light to the darker areas. 

The DSP chip works to adjust every pixel of the image and calculates the exposure accordingly. Although this sounds highly technical and advanced, it does have a major downside. This intense manipulation of the images' pixels results in a poorer quality image, with video footage often appearing grainy or low quality, 

However, despite this drawback, digital wide dynamic range cameras have no need for the expensive image sensors needed for True WDR cameras, meaning DWDR can be a cheaper option when purchasing a security camera with WDR technology. 

 

What to do if you don't have WDR Cameras

Perhaps you're reading this article with the alarming realisation that you have a full set of CCTV cameras installed that are all lacking in WDR technology, or perhaps WDR is simply not a viable option for you. Fortunately, a few alternatives are available that can help with your security camera lighting issues. 

We've outlined some of the best options below:

• Backlight Compensation (BLC) - BLC helps to brighten the backlight of the image to allow you to view the dark areas better. It also used DSPS to increase the exposure levels but does so for the entire image; where WDP technology will balance the over and underexposed parts and blend them together, BLC will simply brighten the entire image. Not ideal, but it gets the job done for cameras in dark areas.
• Highlight compensation (HLC) - HLC is another software compensation technique that works to darken bright highlights found in your image. HLC is an appropriate tool to use in darkly lit areas where bright lighting will appear, causing overexposed highlights to compromise the overall image quality. Common examples would be streets or parking lots, where bright hot spots such as street lights and headlights appear regularly. These bright light sources can make the rest of the image overly dark as the sensors attempt to process the hot spot. HLC helps to automatically dim and suppress the bright light source, giving adequate exposure to the rest of the image. 

Although these alternatives are good options, the image quality will not be the same as a true WDR camera. However, WDR cameras aren't necessary for everyone, so it's important to consider all your options thoroughly before making a decision. 

 

Get in touch

To find out more about WDR technology or to get your own WDR cameras installed professionally by Eclipse (IP), get in touch with our team today.