What Is WDR Security Cameras & How Does It Work

Last Updated on November 27, 2022

Maybe you will find that the part of the image taken by the CCTV / IP security camera is very dark, but the other part is too bright and you can’t see any details.
Here are the technologies about Wide Dynamic Range (WDR) applied to security cameras, called WDR cameras, to solve this problem.

What Is The WDR Camera

Dynamic Range is the difference in light levels in an image, between the darkest and the brightest areas.

On an overcast day with little sun and few shadows, there will be a fairly low dynamic range, i.e. there will be no areas of deep black and no extreme bright spots. On a sunny day, however, in a scene with distinct shadows, there will be a greater difference between the brightest and darkest areas, and this is what we call a wide dynamic range or WDR (also known as High Dynamic Range, or HDR).

There are also dynamic ranges that extend further than the camera or the human eye can perceive. One example is when you take a photo of a person in front of a bright window. The camera will either expose the person properly, rendering the scene through the window “washed out”, or it might give priority to the scene through the window, thus leaving the person underexposed and hard to see. In this case, the dynamic range of the scene is wider than the camera can handle.

WDR – Dynamic Contrast

WDR mode is a technology that extends the camera’s range, to cover a greater span between the bright and the dark areas in the image.

There are several ways to increase the dynamic range, and many solutions are used in combination to achieve the best result.

The simplest method of combatting WDR is what Axis calls Dynamic Contrast, a capability built-in to most of our cameras. In this method, the camera’s sensor captures an image with a higher bit depth (an internal property that translates to dynamic range) than what the camera can actually deliver.

The camera then performs advanced tone mapping, in which some brightness levels are dropped, to decrease the bit depth to a format that a computer screen can handle. Both the darkest and the brightest parts are taken into account, resulting in more details at both ends of the scale.

There are two types of tone mapping. In Global Tone mapping, all pixels are handled the same way, meaning that the same levels are removed everywhere in the image. With Local Tone mapping, decisions are made per region in the image, to determine which levels to remove. Local Tone mapping requires much more processor power but gives a superior result.

WDR – Dynamic Capture

Another, completely different technology used to increase the range is called Dynamic Capture, in which the camera takes several images in a rapid sequence, using a different exposure level for each image. These images are then combined into a composite, with both the brightest and the darkest parts being retained.

This image has a much higher bit depth than can be displayed on a computer screen, so tone mapping must be applied here too, as with Dynamic Contrast.

Saving several images in the time normally used for one image requires an extremely fast and sensitive sensor to provide this superior WDR output. This technology is available today in some Axis cameras.

WDR – Forensic Capture

Many years of research and development also gave us WDR – Forensic Capture, which is available in many of our most advanced cameras. This method uses a set of advanced algorithms to lower noise levels and increase the image signal, in an effort to display every single detail in the best possible way.

The result is a video that is highly optimized for forensic purposes, ensuring all details are captured in both dark and bright areas at the same time – even in scenes with very complex lighting conditions.

Furthermore, Axis cameras with WDR – Forensic Capture provide the ability to seamlessly transition between WDR and low-light mode. Compared to other currently available WDR technology, this method makes it easier to detect and identify important details in a scene.

For a better understanding, compare the level of detail in the two images below.

How Does a Wide Dynamic Range Works in Security Cameras?

A Camera with WDR technology has an advanced sensor that produces a wide range of light hence enables the camera to record a high light depth.
After recording large rages of light in an accurate manner, it speeds a camera in balancing light in two ways. This happens as the tone mapping allows the software to automatically brighten dark areas and darken light areas at the same time.
On the other hand, the camera captures several shots in the scene at different exposure levels. This brings about overexposed and underexposed images that are identical and the camera combines them. Moreover, it takes the most balanced side of the two images thereby forming the visible images. However, this happens with only an extremely fast and a sensor that is light-sensitive and is only available in an advanced professional camera.

In order to use the WDR features, the camera shuttles work as follows;
Firstly, it is subjected to a high speed of exposure of the sensor to the lighting within a short time. It also uses low velocity in exposing the sensor light for a long time and finally, it is responsible for merging all captured images and exposing them to different light.
All the same, when the WDR is activated on the camera, the shuttered automatically exposes the camera to light in a quick and double rapid succession and gives an exemplary result after merging the pictures.

What Are The Differences Between HDR and WDR?

HDR is an abbreviation for High Dynamic Range. Its description falls under the category of photography with post-processing technology. HDR reaches the shooting outcome in which the normal combination of shutter and aperture may not compose different photos of various exposure as well as conduct tone mapping. The advantage bit about HDR photography is its ability to keep the original information to the highest level and show the vibrant colors that appeared originally.
On the other hand. WDR is a short form for a wide dynamic range and it’s a technology used in observing images smoothly with a severe light contrast condition. It can be used in place of a possible range of a changing object or in an area where the minimum and maximum value span is clearly visible. WDR ensures that the imaging systems correct the intense backlight around a subject thereby giving power in distinguishing definite shape and characteristics of that subject.
The main difference between an HDR and WDR is brought about by their implementation method. WDR applies most of its effort to hardware while the HDR makes much of its effort on software. However, their function is similar such that they turn dark and bright information clearer under high contrast lighting conditions. This reveals that there are two distinguished processing technologies.

Another difference is that the WDR is relatively low in purchasing price and also it has a low installation cost as compared to HDR.
Again, the WDR is convenient in installing CCTV especially in dark areas since it can capture images that are both in dark places and in lighting places unlike in the case of the HDR.
A WDR camera produces a high-quality image that is revolutionized as compared to that of HDR.

Click here to learn what’s WDR, BLC or HLC in CCTV/IP cameras.

Reasons Why I Would Choose WDR Camera

To begin with, the WDR camera is cheap in installation as well as in the purchasing price hence its overall cost together with maintenance is friendly.
Again the WDR camera can capture the images in dark places and illuminate them clearly hence tightening the security even with low power or no power at all. say. a blackout.
A WDR produces a high-quality image that is revolutionized as compared to an HDR camera. The image produced by this kind of camera is exceptionally sharp and with clarity with much details and information in tone mapping.
A WDR camera is suitable for a dashcam because it can allow capturing images in both a dark and a bright scene at the same time and clearly. Dashcams are becoming popular and their brands are also coming up and are installed even in business premises for security purposes.

Best WDR Security Camera/System Recommends

1. Best WDR Outdoor Security Camera – C190 Pro

2. Best WDR PTZ Security Camera – C289

3. Best WDR Wireless Security System – W4 Pro

Conclusion

All cameras cannot be made equally. They differ in resolutions, their features and also their field of view. The camera to be used should fit the expectations and the needs of the customer. On the same note. There are dynamic ranges that go beyond the perception of the human eye and the camera. For instance, if one takes a photo of an object in front of a transparent window, the camera may expose the object property and render the scene via the window or else give the priority to the scene via the window. Thereby leaving the object underexposed or totally unexposed. It is therefore clear that in such a case, the dynamic range of the specified scene is wider or beyond the camera’s ability to handle. Regardless of the type of camera used, the images’ results vary due to the complexity and the movements made in the scene.