WDR Vs Digital WDR

[killingwb 0]

Hello i am new at this forum; i just started working as installer.

My customer's are asking question. i am not technical enough to answer.

i was hopping you guys might be able to help me

What is difference between WDR and D-WDR?

How about performance, are they about same?

i need to get some data for customer to see, do you have some link i can ref?

Thank you for your help in advance

[koolmer 0]

I actually never heard about D-WDR or Digital WDR. I googled for it and only found some fishy Asian cams with D-WDR. Could be a cheap "enhancement" of the dynamic range.

 

I wouldn't touch it. Buy real WDR cams from Pelco, Samsung, Bosch, etc.

 

koolmer

[Baylab 0]

a real WDR is achieved by double exposure: one exposure with longer exposure time to get the detail in dark area, another is taken with shorter exposure time to get the detail in very bright area, then the two pictures is combinen in the DSP of camera to a single frame ( actually one field).

 

the Digital WDR, to my understanding, should be just some kind manipulation of digitized picture in the camera, it may make the output of camera looks better ( if it does work). but won't provide any extra detail.

[Dongwonsecurity 0]

Hello i am new at this forum; i just started working as installer.

My customer's are asking question. i am not technical enough to answer.

i was hopping you guys might be able to help me

What is difference between WDR and D-WDR?

How about performance, are they about same?

i need to get some data for customer to see, do you have some link i can ref?

Thank you for your help in advance

 

D-WDR - digital WDR.

the DSP will be Hawk from Nextchip.

Edited October 20, 2010 by Guest

[Pearlwu 0]

The real WDR are made by 213BK, will be more expensive than D-WDR (639+Hawk 2170), D-WDR just adjusted the GAMA, as you know, this will lead to a lot of noise in the dark side and cann't get the clear picture in foreground and background at the same time, also it will be exposure in the light side.

[Huviron 0]

Sorry to bring up the old post back.

While I was testing Sony Effio and Huviron Gen2 DSP, I did a quick WDR test for you guys. Since Huviron Gen2 DSP support Both DWDR and WDR.

I took a few pictures with each on/off

 

Both WDR off

 

DWDR ON High

 

LWDR ON (True Mechnical/Low-Frame WDR)

 

You can clearly see the difference.

[cglaeser 0]

the Digital WDR, to my understanding, should be just some kind manipulation of digitized picture in the camera, it may make the output of camera looks better ( if it does work). but won't provide any extra detail.

 

I don't know how they implement Digital WDR in CCTV cameras, but it digital photography, HDR (high dynamic range) images are made by combining two or more images of the same scene that are taken at different exposure settings. So, some of the pixels in one image may be overexposed, and some other pixels in another image may be underexposed. The HDR application discards the under and over exposed pixels and selects pixels that are properly exposed. Using this technique, it's possible to create images that would otherwise span far more stops than can be recorded by the sensor in one shot.

 

It would be possible, for example, for a CCTV camera to take two consecutive images, one at 1/60 sec and another at 1/120 sec, and combine them. Don't know if that's how it is actually done, but something like that is possible, and would significantly increase detail for scenes with wide dynamic range.

 

Best,

Christopher

[Huviron 0]

the Digital WDR, to my understanding, should be just some kind manipulation of digitized picture in the camera, it may make the output of camera looks better ( if it does work). but won't provide any extra detail.

 

I don't know how they implement Digital WDR in CCTV cameras, but it digital photography, HDR (high dynamic range) images are made by combining two or more images of the same scene that are taken at different exposure settings. So, some of the pixels in one image may be overexposed, and some other pixels in another image may be underexposed. The HDR application discards the under and over exposed pixels and selects pixels that are properly exposed. Using this technique, it's possible to create images that would otherwise span far more stops than can be recorded by the sensor in one shot.

 

It would be possible, for example, for a CCTV camera to take two consecutive images, one at 1/60 sec and another at 1/120 sec, and combine them. Don't know if that's how it is actually done, but something like that is possible, and would significantly increase detail for scenes with wide dynamic range.

 

Best,

Christopher

 

That is exactly what our LWDR do. With single scan CCD, it cuts one frame into half so first half the frame it takes one exposure in dark area and correct gamma value, and next half the frame it takes one exposure with bright area and correct gamma value, then the two exposures are combined in the nex frame. Basically this is why we call it LWDR (Low-Frame WDR) and obviously frame rate drops to 1/2 of the normal frame rate.

 

There's more advanced way but more expensive solution. We can use dual scan CCD like the one from Sony Effio so it take two long and short exposures at the same time basically saves 1/4 frame rate from single scan CCD WDR and total frame rate only drops to 3/4 of the normal frame rate. A bit smoother pictures. We call this SWDR.

 

DWDR, however, is manipulation of digitized picture in the camera. "It may make the output of camera looks better ( if it does work). but won't provide any extra detail." This is totally true, but there are more good things about DWDR so manufacturers can't totally ignore DWDR.

Most important thing is, DWDR does not drop any frame rate so pictures still look smooth and DWDR can be used with DIS function while real WDR can't use them at the same time.

 

Hope this help you guys.

[rory 0]

Thanks for the info.

I was wondering what that was, saw it in the KT&C camera specs but could only find a review of it on a japanese site, and the review was in an image so could not translate it.

[sichuan 0]

I actually never heard about D-WDR or Digital WDR. I googled for it and only found some fishy Asian cams with D-WDR. Could be a cheap "enhancement" of the dynamic range.

 

I wouldn't touch it. Buy real WDR cams from Pelco, Samsung, Bosch, etc.

 

koolmer

 

"I actually never heard about D-WDR or Digital WDR."

 

A little research goes a long way and your research was not complete. Digital WDR , or D-WDR, is a software based technology (software based technique) that optimizes image quality by adjusting the gamma value of an image to enhance dark areas. This technique leaves a lot to be desired. True WDR is a sensor-based technology (hardware based technique) that can capture several images with short and long exposures, then combining them into a single frame. True WDR will give you much better images with much better contrast of the light and dark areas of the images, but only if the WDR setting is appropriate. Setting the WDR level too low, such as 25db, may not produce a satisfying image, while setting the WDR level too high, such as 100db or 120db, may lead to washed out images.

 

"fishy Asian cams"

 

I believe the vast majority of security cameras are manufactured in Asia, most notably China. Most products are manufactured in Asian countries because that's where the cheapest labor can be exploited, thereby guaranteeing the highest profits. As far as "quality" is concerned these products are manufactured to the specifications of the companies that have them manufactured, regardless of which nation they are manufactured in. Don't blame the factory employees for the "cheapness" of the product. Put the blame where it belongs, which is squarely on the companies writing the specifications. As far as "fishy cams" is concerned, you get what you pay for. Do you want to pay very little for your security cameras? If so, you will get very little in the way of the product.

 

Your list of "real WDR cams" is very short and doesn't include other high quality camera manufacturers, such as Sony and most notably Hikvision and Dahua. Hikvision and Dahua manufacture the majority of security cameras.

 

Bosch Security & Communications System opened its largest manufacturing facility worldwide in Zhuhai, China in January 2008. Does this mean that Bosch security cameras are "fishy" and that they should be avoided? I don't think so.

 

Please don't misunderstand my post. It's not really a criticism of your post but rather a correction of the information provided in your post.

[sichuan 0]

In an ideal world, there should be no CCTV (either Closed Circuit Television or China Central Television)!

 

England and the U.S. are no better than China when it comes to surveillance of citizens, whether that surveillance is audio or video.