Low-light struggles / improving image quality.

[EagleEye7]

So I have 2x Hikvision IP cameras currently covering a specific area. 1 is a DS-2CD2325FWD-I, with the 2.8mm lens, and this is a great overview camera, but, as you would expect, and especially since it is mounted quite high, it is no good for anything beyond Observe or maybe Recognize in the DORI model.

I then later added another camera at a different angle, a DS-2CD2H43G1-IZ, pointing directly down the driveway. I will admit, I installed these cameras before I had a good enough understanding of sensor sizes, exposure times, and other parameters which are key to getting good images, especially at night. Also, both of these cameras were obtained 2nd hand at a great price, so it was a case of the camera being 'available' rather than 'optimal'.

The second camera is mounted quite high as well, but I was hoping that since it is a varifocal with a max. zoom of 12mm, this would make up for the height to some extent, and I think it has - during the day, I can get reasonable face-captures of people coming down the driveway, although not perfect - however ironic it may seem, I have blurred the faces in this image, but you should get a good idea from the rest of the image:


(Obviously only a snip of the whole frame)

However, at night the situation is far worse. I cannot expect great low-light performance, since this camera uses a 1/3" sensor, which for 4MP, is far too small (so I have learned). I will collect some captures to display, but in short, the nighttime image is dark, grainy, and face captures are pretty much useless. The settings in use are as follows:







I am pretty sure 1/25 shutter speed is too slow, and is causing motion blur - however, faster shutter speeds make the image even darker and more useless.

Interestingly though, the more I zoom out, the brighter the image becomes - less useful, as the lack of zoom means perps are too far away, but brighter all the same.

I will hopefully post some more details soon (distances, nighttime images), but I suppose my questions are as thus:
1. Why does lowering the zoom make the image appear brighter?
2. Are there any tweaks I can make to squeeze a little more useful performance out of this camera?
3. Does anyone have a recommendation for a replacement? (probably be easier to answer once I provide more detail). Budget is limited here unfortunately

 

[wittaj]

The faster the shutter, the more light that is needed. You need more light or have to accept the blur.

On a varifocal cams, the more you zoom in, the more light that is needed.

In terms of getting the most out of the camera, here is my "standard" post that many use as a start for dialing in day and night that helps get the clean captures and help the camera recognize people and cars.

Start with:

H264
8192 bitrate
CBR
15FPS
15 iframes

Every field of view is different, but I have found you need contrast to usually be 6-8 higher than the brightness number at night.

We want the ability to freeze frame capture a clean image from the video at night, and that is only done with a shutter of 1/60 or faster. At night, default/auto may be on 1/12s shutter or worse to make the image bright.

In my opinion, shutter (exposure) and gain are the two most important parameters and then base the others off of it. Shutter is more important than FPS. It is the shutter speed that prevents motion blur, not FPS. 15 FPS is more than enough for surveillance cameras as we are not producing Hollywood movies. Match iframes to FPS. 15FPS is all that is usually needed.

Many people do not realize there is manual shutter that lets you adjust shutter and gain and a shutter priority that only lets you adjust shutter speed but not gain. The higher the gain, the bigger the noise and see-through ghosting start to appear because the noise is amplified. Most people select shutter priority and run a faster shutter than they should because it is likely being done at 100 gain, so it is actually defeating their purpose of a faster shutter.

Go into shutter settings and change to manual shutter and start with custom shutter as ms and change to 0-8.3ms and gain 0-50 (night) and 0-4ms exposure and 0-30 gain (day)for starters. Auto could have a shutter speed of 100ms or more with a gain at 100 and shutter priority could result in gain up at 100 which will contribute to significant ghosting and that blinding white you will get from the infrared or white light.

Now what you will notice immediately at night is that your image gets A LOT darker. That faster the shutter, the more light that is needed. But it is a balance. The nice bright night static image results in Casper blur and ghost during motion LOL. What do we want, a nice static image or a clean image when there is motion introduced to the scene?

In the daytime, if it is still too bright, then drop the 4ms down to 3ms then 2ms, etc. You have to play with it for your field of view.

Then at night, if it is too dark, then start adding ms to the time. Go to 10ms, 12ms, etc. until you find what you feel is acceptable as an image. Then have someone walk around and see if you can get a clean shot. Try not to go above 16.67ms (but certainly not above 30ms) as that tends to be the point where blur starts to occur. Conversely, if it is still bright, then drop down in time to get a faster shutter.

You can also adjust brightness and contrast to improve the image. But try not to go above 70 for anything and try to have contrast be at least 7-10 digits higher than brightness.

You can also add some gain to brighten the image - but the higher the gain, the more ghosting you get. Some cameras can go to 70 or so before it is an issue and some can't go over 50.

But adjusting those two settings will have the biggest impact. The next one is noise reduction. Want to keep that as low as possible. Depending on the amount of light you have, you might be able to get down to 40 or so at night (again camera dependent) and 20-30 during the day, but take it as low as you can before it gets too noisy. Again this one is a balance as well. Too smooth and no noise can result in soft images and contribute to blur.

Do not use backlight features until you have exhausted every other parameter setting. And if you do have to use backlight, take it down as low as possible.

After every setting adjustment, have someone walk around outside and see if you can freeze-frame to get a clean image. If not, keep changing until you do. Clean motion pictures are what we are after, not a clean static image.

 

[bigredfish]

First impressions

1/3 sensor on 4MP is really so bad I would toss it and start over

Other

• Turn off Variable bitrate and use CBR (constant)
• turn off h.265 and use h.264 (or better h.264.h if it has it)
• increase bitrate from 4096 to at least 8192, better 10288
• exposure will need to be at least 1/50 preferably 1/100 or faster
• hopefully there's a Gain setting you can increase

 

[EagleEye7]

@wittaj, thanks for your detailed post. I have tried playing with a few settings, as suggested, but I am not sure I have made much improvement. I'm sure I could dial things in a little better, but this is of course a little tricky (can only really be evaluated properly in the dead of night, otherwise street lamps add extra light, etc), and I am not sure if it is worth it.

As @bigredfish pointed out, my sensor size:MP ratio is really bad, so I'm not sure I will ever get good results with this cam in this situation.

I am now looking into alternative camera options, to save me headache with this one. I found this interesting:

On a varifocal cams, the more you zoom in, the more light that is needed.

Is this the same with fixed lens cams? E.G comparing two fixed lens cams, one with a 2.8mm lens and one with a 12mm lens, will the 12mm require significantly more light?

Also, apologies if this sounds silly, but does a PTZ cam (focusing on the Z) use the same mechanism for Zoom as varifocal turrets etc do? Obviously some PTZ cams are able to zoom in quite significantly without losing too much low light performance - maybe they just have a huge aperture of beefier IR?

Finally, does anyone have a recommendation for a replacement, considering the following points?

• Currently running Hikvision, but would be willing to try a Dahua - they seem to be the most discussed here?
• Budget is somewhat limited in this case.
• The current cam is mounted quite high - not ideal, but mounting lower will be quite difficult, and I am hoping to be able to make up for this with an appropriate lens (maybe a 12mm). Is this feasible?

What about something like the 5442 (54IR) ZE? Have folks had good performance out of this in low-light whilst running near full zoom?

 

[Ri22o]

I recently found that even if you're on the correct MP for the sensor, it just doesn't always work. I struggled to get the triple lens camera to work in this location, but there just wasn't enough light, even with all of the onboard IR. I switched to a B54IR-Z4E and it was a huge difference. I am even able to run a much faster exposure on the Z4E.

Fixed 25mm. 2MP on 1/2.8 sensor. This is 0-16 exposure with gain at 20.


Here is a B54IR-Z4E. Full 32mm zoom. 4MP on 1/1.8 sensor. 0-3.33 exposure and gain at 40. (I am currently sorting out focus issues at night)



I run practically all of my T54IR-ZEs at full zoom, but also have supplemental IR floods around the house. This camera has no additional IR other than the couple other cameras over the deck.

 

[looney2ns]

The cam you linked is the go to cam for dark places.
It will blow that HIk out of the water.

If you are stuck with the current cam, you could improve it some by adding either white light or an IR illuminator.

 

[bigredfish]

On a varifocal cams, the more you zoom in, the more light that is needed.

Is this the same with fixed lens cams? E.G comparing two fixed lens cams, one with a 2.8mm lens and one with a 12mm lens, will the 12mm require significantly more light?

No. Other than getting IR or white light out there further. Same light same brightness on fixed lens cams generally if the FStop is the same
Generally Fixed lens will be brighter than VF's

 

[wittaj]

^and keep in mind his "getting light out there" above is important. If there isn't light out at that distance, it will perform poorly.

 

[EagleEye7]

OK, so looks like the 54IR-ZE might be a good choice then - price is not too bad either...

Would rather avoid a white light in this scenario - motion sensing maybe, but then we have issues with the cameras having to adjust when the light switches on, blowing out faces etc... I did consider using additional IR illumination, but illuminators are not simply £20, and by the time I have gone to the effort to wire and install, I will probably still be limited by my sensor size.

Generally Fixed lens will be brighter than VF's

@Ri22o looks like he is getting reasonable captures on a 54IR-ZE, even at full zoom. However, based on the above statement, would a 12mm fixed give a brighter image / be able to run faster shutter than the VF 54IR-ZE?

^and keep in mind his "getting light out there" above is important. If there isn't light out at that distance, it will perform poorly.

Yes, I guess this is called 'the laws of physics' - I suppose the only remedy to this would be additional IR, but I am optimistic a better cam might be OK without...

The area covered by my current 12mm VF cam is also visible on my DS-2CD2325FWD-I overview cam (which is 2MP on 1/2.8 sensor), and the area appears reasonably bright on this cam, although far away. However, since this is an overview cam, I haven't dialed it in for face captures or anything, so the shutter is probably a little slow etc...

 

[EagleEye7]

Here are a couple of examples from a few weeks ago, before I had tweaked the settings yesterday. Unfortunatley there is no motion to examine (nobody walking about at 12PM).

This is the 12mm Hik:

You can see how grainy the image is. And this was running 1/25 shutter, would only be worse at 1/50 or 1/60...

And this is the same area, but on the 2.8mm overview cam, again running 1/25:

Fuzzy, be keep in mind the overview cam is the other side of the property, and is only 2MP on 2.8mm...

 

[wittaj]

Not providing the whole image does us no good - when you cut out an area of a field of view, that essentially acts as a digital zoom when you paste it here.

What do those look like full field of view?

But those look horrible.

 

[bigredfish]

You need to post full res full size images

If you want good ID at distance I would go to the 5442 z4 8x32mm as @Ri22o showed

I’m not aware of a fixed 12mm

 

[EagleEye7]

Sorry, yes, attached is a full-size image from the Hik, at approx. 12mm, running 1/25 shutter.



Seems the two candidates are the 54IR-ZE (turret) or the B54IR-Z4E (bullet). The bullet is more expensive, and probably slightly less optimal from an aesthetics point of view (the turret sits quite nicely under the soffit), but may offer better performance?

I tried to measure the distance between people and the camera today, but could not find my measuring instrument .

EDIT: Apologies, seems the .bmp is not very easy to view. Have uploaded as a JPG as well.

 

[wittaj]

You should be able to pull your property up on Google Maps and get a rough idea on distance.

The bullet version benefits from additional IR, so it is really helpful in low/no light conditions.

 

[EagleEye7]

Good idea regarding the distance - I was hoping that by measuring, I could take into account the camera height and get the diagonal distance - I can still calculate this, perhaps will do so at some point.

The bullet version benefits from additional IR, so it is really helpful in low/no light conditions.

In that case, perhaps I will go with the bullet, as more IR is never a bad thing...

Does Andy ship to the UK from the website? I think I can order products on Amazon, but when I tried the website, the only shipping options were US or Canada...

 

[EagleEye7]

Looks like, very approximately, 40 feet + a bit for height. Actually slightly more than I thought!

The perp (or harmless delivery driver) would likely move closer to the camera as they approach.

 

[wittaj]

At 40 feet you will want the Z4E and that only comes in a bullet.

Yes Andy ships to the UK - you can also order direct from him via DM.

 

[Ri22o]

T54IR-ZE at 12mm and 40ft.


B54IR-Z4E at 32mm and 50ft.

 

[EagleEye7]

So looks like the T54IR-ZE @ 12mm is not quite going to cut it for 40ft - I will see about sourcing a B54IR-Z4E and update this thread accordingly.

 

[steve1225]

One more thing:
Your pictures shows that You don't have there enough lighting to run cams in color at night..

So you will do them probably on IR..

5442 bullet have very strong and uniform IR. it have double set of wide and narrow IR emitters and you can configure proportion between them to have ideal uniform IR lighting..

5442 turret don't have this (due small chassis).. and have very bad hot spotting where middle of frame is over exposed and outside areas are dark...

So You should look at bullets for this installation, even on places where zoom level will be lower (and basic varifocal will fit)..