Space vs. Time Digital Noise Reduction Levels in new Hikvision Firmware

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FastCamMan

Getting the hang of it
Oct 1, 2015
45
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In some of the newer Hikvision firmware for their Value Plus Line of 4MP Cameras an "Expert" mode has been added under "Image Enhancement" Digital Noise Reduction.

Prior we use to just have a 0 - 100 scale to set Digital Noise Reduction and for which the configuration was obvious.

Now you can set Digital Noise Reduction to "Expert" and then has the following that can be adjusted:

Space DNR Level [Range 0 - 100]

Time DNR Level [Range 0 - 100]

Can anyone who is familiar with digital signal processing provide an explanation as to what the differences are of the Space and Time DNR and how each might be affect the video as well as how each may be utilized and for what purpose? For example, should one handle motion where by the other handles pixel noise?
Just getting ready to start playing around with these but wanted to see if any DSP experts might provide some preliminary guidance.

The Expert DNR was added in WDR Cameras DS-2x22,2x42 Firmware v5.4.0 (build 160401)

Thanks in advance.
 
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As far as I can tell:

Space DNR:
- When set too high this will soften the image, I used it to eliminate weird artifacts that used to be shown when people where walking by. (I have it set on 10)

Time DNR:
- This works more like the DNR settings we used to know, when set too high you'll notice motion blur and lots of delay in the footage. (I have it set on 20)
 
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so, in low light situations without using IR, what would be the best combination for these time and space DVR settings? Anyone?

Ok, i will set it to what @Kroegtijgertje suggests. Hope it fixes my issue with blur and noice at night.
 
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It won't. Or more correctly it will trade off a great looking static picture for one useless for any motion. You either need more light or a better camera. It is exactly as described by kroegtijgerte and pointed to by fenderman. Spatial is blur in the frame and time is blur over sucessive frames. Without enough light it will always be a balance between noise and utility. Can you identify that smeared blurry moving block of pixels?
 
Brad_C said:
It won't. Or more correctly it will trade off a great looking static picture for one useless for any motion. You either need more light or a better camera. It is exactly as described by kroegtijgerte and pointed to by fenderman. Spatial is blur in the frame and time is blur over sucessive frames. Without enough light it will always be a balance between noise and utility. Can you identify that smeared blurry moving block of pixels?
Click to expand...

Hi Brad, problem is i can only see the difference during night time. So i will play with these settings tonight to see the effects. What i want basically is to identify any moving object in an area that is lit up by an external LED floodlight about 15m away. I can see that area clearly when the floodlight lights up, but then i see the amount of blur, noice and artifacts is too high to be able to see faces.

These are samples taken last night with both cams:

192.168.1.201_Camera1_192.168.1.201_20160803223441_182287.jpg192.168.1.202_Camera1_192.168.1.202_20160803223348_129231.jpg


By the way, this is the reaction from Hikvision support regarding this matter:

If you don’t use IR in low night, I can only recommend you

1. Increase the exposition time from 1/25 to 1/3 or higher
2. Set DNR to expert mode and increase the DVR level

For the firmware download, sorry it is not possible to downgrade from V5.4.0 to V5.3.8
 
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Those images are pretty nice given the camera, but as you say I suspect they are integrating to such an extent as you'll just see skid marks instead of features.

Manually wind the shutter speed up to something useful. A good test is to put someone out there with an A4 page with a single black line down the middle and have them wave it side to side, you can use that to actually quantify the smear. I built a similar machine with a moving test chart that I could use to compare multiple cameras side by side. The test chart also allows you to get your contrast, gamma, resolution and colour rendition at the same time.

One of the things that will help you with those images is to trim the views so you're not looking directly at the light sources. The camera won't be able to give you the contrast you require to adjust for those bright spots and still see into the darker areas of the image.

Frank van der Heide said:
By the way, this is the reaction from Hikvision support regarding this matter:

If you don’t use IR in low night, I can only recommend you

1. Increase the exposition time from 1/25 to 1/3 or higher
2. Set DNR to expert mode and increase the DVR level
Click to expand...

Yeah, the first one will make it *completely* useless for you and the second one will just smear more the further you wind it up.
At some point you might have to admit that this camera is just not up to the task you are asking of it. Your options will be a better camera, more light or adjust your expectations. You can have a good play though and make incremental improvements. It depends entirely on your expectations.
 
Also, 2.8mm cams are not that great for facial recognition.
 
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