Wide dynamic range (WDR) how to check ?

[musfir 0]

Hi all

 

I saw in lot of data sheet vendor is highlighting WDR function example Samsung SNB3000 offering up to 52dB, my question is as an End-user how we can check WDR level? There is any testing software for this?

 

 

 

 

thanks in advance

musfir mohideen

[buellwinkle 0]

Just a personal preference, set it sort of like a contrast setting to overcome very contrary situations like being able to see in shadows better, better able to see in overblown light situations. From what I've seen from most manufacturers is there's a trade off between using WDR and noise at night.

[MaxIcon 0]

It's not an easy thing to test objectively, but you can get an idea of what to expect by googling wdr demo video. There's even one for the SNB3000:

 

Some vendors have very good WDR, while with others it's barely different from contrast adjustments. With an image that has areas both too bright and too dark, good WDR will bring out the details in both areas at the same time.

[jhonovich 0]

WDR specs (in dBs) like minimum illumination ones are mostly worthless, primarily because they are incomparable and not based on a uniform standard.

 

I've seen many manufacturers rate their WDR as 100dB+ only to have our tests show poor performance.

 

If a manufacturer lists their camera as being ~50dB or ~60dB, for sure it's poor WDR.

 

If a manufacturers lists their camera as being 100dB+, it might be strong WDR but you still need to test to verify that they are not lying / fudging / wrong.

 

Short of testing, the best way to check is to ask whether the camera's WDR uses multiple exposures. Outside of Pixim (who is SD only), all the 'true'/good WDR implementations combine multiple exposures (one long for dark areas, one short for bright areas).

 

Beware that a lot of manufacturers have created crazy categories like 'basic', 'pro', 'advanced', 'enhanced', etc. for describing their WDR. If it's not multi-exposure, it most likely makes very little difference.

[buellwinkle 0]

John,

 

Wouldn't multiple-exposures at different settings, sort of what photographers call HDR, be affected by moving objects and cause trails or ghosting?

 

They way I look it is this, I'm a photographer and in newer versions of Photoshop, I can make a Shadows/Highlights adjustment that brings out detail in dark shadows, and overblown areas. It's not perfect, but I would equate that to "digital WDR" or "basic WDR" where the frame is enhanced through an algorithm. Then I've used cameras with "Dynamic Capture" or "Advanced WDR" and while they are better, it's not dramatically better, at least to me.

 

I guess in a perfect world, a camera would have at least 3 sensors, each one calibrated by maybe an F-stop apart and the camera would use the results from the 3 sensors to make one perfect picture for WDR and to reduce noise, etc.

[jhonovich 0]

We have done tests of multi-exposure WDR with cars going 50 miles an hour. None had any ghosting / blurring / trailing issues except for the Sony 6th gen at max WDR, which Sony later informed us uses 4 exposures. Reducing it to 2 exposures eliminated that.

 

Beyond that, WDR is typically used in entrances, very commonly with people. In those scenarios, objects are moving fairly slow anyway.

 

In our tests, we aim for a 5x+ lux variance between a dark and bright spot (e.g., the bright area is 2000 lux, the dark area a few feet away is 300 lux). This is typical for entrances / openings to the outdoors and multi-exposure is much better than digital / basic WDR here.

 

In easier / lower light variance scenes, the difference in WDR performance is less significant since there's less of a light variance that needs to be handled.

[musfir 0]

Big thanks for you all " title="Applause" /> " title="Applause" /> " title="Applause" /> " title="Applause" /> " title="Applause" />