Some applications require IP cameras with a wide dynamic range (WDR). What is a wide dynamic range? It means that the video will look much better in situations where there are very wide light differences in the scene. You may have seen this type of problem, where you are viewing a person in front of a bright background. The background is clear, but the person is very dark and hard to see. The older IP (and analog) cameras used “Back Light” control to enhance the darker area (foreground) and ignore the background.
In this case, you can see the person but the background is lost in a bright haze. If there are people in the background you can’t see them. Today’s new IP cameras use a wide dynamic range to allow you to view both the foreground and background.
There are two ways to improve dynamic range. The first way is to use non-linear amplification of the video. This reduces the very bright areas and enhances the dark areas. It works, but the better method is to use multiple frames and average them together.
The latest cameras are fast enough to use the multiple frame technique so they have dramatically improved wide dynamic range (WDR).
We tested the WDR in the new Samsung, Sony, and Hikvision cameras. Wide dynamic range has been dramatically improved from about 50 dB to over 120 dB.
We tested each camera with WDR (Wide Dynamic Range) on and off. To do this test, we looked at objects positioned in front of a window looking at a bright sunlit scene. This was the ideal setting to test for WDR as the sun-light coming through the window was making it hard to see the color and detail of our objects in the foreground.
We tested the Sony SNC-VM630, Samsung SNV-6084R, and Hikvision DS-2CD7254FWD-EIZ. Here are the results:
The camera has a number of controls for getting the best picture. The camera specifications indicate that the camera has WDR equivalent to 90 dB with View-DR technology.
In some cases just turning on the Visibility Enhancer will brighten the image. The Visibility Enhancer uses non-linear amplification to adjust the dark and light portion of the video. The best image is achieved by turning on WDR which uses the multiple frame averaging technique.
Here’s what we observed. With WDR turned off the foreground looks dark and we can’t see the subtle differences in the green of each leaf of the tree clearly.
With WDR turned on, we could clearly see the different shades of green on the trees. Also, we can see the plant on the table is a lighter green at its root and progressively becomes darker toward its ends. Finally, we can see the shadows produced by the scale are less noticeable with WDR turned on. This difference is most apparent at the top of the scale by the numbers and where the scale meets the edge of the table.
The specifications for the Samsung camera say that it has 120 dB of WDR. Our testing showed that it met all our expectations. The difference between WDR on and off was dramatic with the Samsung camera.
With WDR off, the lower portion of the picture was shadowed in darkness. By turning WDR on, we can see this area in much higher clarity and brightness. The colors of each pen are hard to distinguish when WDR is off, but clearly recognizable with WDR on. The bookcase and the plant pot are black with WDR off, but appear brown with WDR on. The leaves on the trees can’t be distinguished when WDR is off, but with WDR turned on we can see the leaves, and the blue sky with white clouds.
The Samsung camera, like many other cameras with WDR averaging, exhibits bars on the image that are caused by the fluorescence lights. This can be removed by adjusting the lighting controls in the camera video set up. The Samsung camera demonstrated an excellent dynamic range.
Hikvision DS-2CD7254FWD-EIZ (Note we no longer sell Hikvision camera because of US government restrictions)
Even though this is an economic camera, the WDR works well. The specifications indicate the camera has 120 dB of WDR. We discovered that the default white balance settings should not be used. The video had a slight yellow tint with the white balance set to “natural light”. After a call to tech support (who was very helpful), we were able to correct the color by switching the white balance to “AWB1”. This points out the need to make sure all the camera adjustments are right for a specific application.
With the WDR off, the color of the toy truck is hard to see, and the clouds can’t be seen at all. It is also hard to see the scale clearly because of the shadow.
With the WDR on, we could see the blue sky and the white clouds. The color of the toy truck becomes more apparent and the scale numbers are easy to read. With WDR off, the leaves on the trees are not clear, but with WDR on they have a light-lively green look and can be seen clearly.
The wide dynamic range has been dramatically improved in the latest IP cameras. Samsung, Sony, and Hikvision all demonstrated very good performance. The Sony camera provided the best image but required some additional adjustments. The Samsung camera was the best without requiring any adjustments. We liked this camera the best for situations that require WDR.
The Sony camera provided the best image but only after we turned on the “image enhancer”.
The Hikvision camera also showed great improvement in its image once WDR was activated. When using the nominal camera settings, the Hikvision image had a yellow tint, which was corrected by making the adjustment in white balance.
If you need some assistance selecting the right megapixel IP camera for your application, please don’t hesitate to contact us. We can be reached at 914-944-3425 or use our contact form.