Blurry morning pics

[wrybread]

I'm using a Dahua Z12 camera and get good sharp pics when there's a lot of light, but my early morning pics are blurry. I'm using a fixed focus and zoom, and have a Python script running once a minute to set the focus and zoom so autofocus shouldn't be an issue.

Here's a plate read at 6am today (just after sunrise):

http://sinkingsensation.com/stuff/low_light2.jpg

Here's a plate read just now (5 hours after sunrise):

http://sinkingsensation.com/stuff/good_light.jpg

Both have the exact same zoom and focus. I'm wondering if it's my exposure settings? Or some other setting? Attached are my settings, all others are default.

 

[biggen]

You could probably turn your 3D NR down but I don't think that is the problem.

Can you post your other cam video settings as well like shutter speed etc... Ah nevermind I see it says "Auto". That is probably the issue. Need to set it for a range in the daytime like 0 - 2ms.

 

[wittaj]

Dawn and Dusk are usually the tough spots. With that said, it appears you are running an auto shutter - those will be too slow during those times. Looking at that, maybe try 1/1,000 - the vehicles might be slow enough to catch at that. Most here run 1/2000. Try knocking NR down a little too.

What shutter speed do you run at night?

 

[wrybread]

Thank you! I run 1/2000 at night, screenshot attached.

I just set my Day shutter to 1/2000 as well. It looks good currently (mid day), I'll see how it looks in the morning. No one goes faster than 10 mph thru that are camera's view.

What value do you recommend for NR?

Edited to add: attached are my new Day settings.

 

[wittaj]

Setting the shutter speed should help for those early morning and evening when auto will not cut it.

My NR is 30. But each spot is so site dependent.

 

[biggen]

Mine are set for around 20ish during the day and 30ish at night. Really its only night that is a problem with "grain" which the NR tries to reduce. Lighting is good enough during the day NR really isn't needed.

That shutter is fixed you just set so you may have issues with overexposure during the day. You may have to use the range during the day as I explained above.

 

[wrybread]

@biggen: thanks, I didn't notice your post the first time. I just set the shutter to a range, see attached.

How's that look to you?

 

[biggen]

Thats the same screenshot as above.

Click the shutter dropdown and go to the bottom. You can customize the range there.

 

[wrybread]

Whoops! Attaching the correct one.

 

[biggen]

Turn your 3D NR down to 25ish and let that run tonight and tomorrow and see how it looks. That should work better though!

 

[wrybread]

Awesome, done. Will post about how it does tomorrow morning.

 

[wrybread]

Thank you so much, pics look great today. Nice crisp plate reads.

 

[wrybread]

I wonder if anyone has any suggestions for my night settings? I'm getting most reads, but every now and then I miss one. And the pics are always a bit blurry:

http://sinkingsensation.com/stuff/night.jpg

And my settings:

http://sinkingsensation.com/stuff/night_settings.jpg

I'm wondering if I should be using a range for shutter speed at night? And if I should lessen my NR?

 

[biggen]

Those settings don’t look bad. A lot of folks here suggest not using a range at night and using a fixed shutter like you are doing. I agree as well. I used to use a range at night but found fixed works better.

How are you switching to night mode? You have to make sure you are switching early enough to give the camera with that fast shutter enough light to focus with. Also, do you have any backlighting enabled?

You could turn the 3D NR down to 30.

 

[wrybread]

I'm not using auto focus, I'm using a fixed focus. Are you getting good results with auto focus at night?

I'm not using windows so I couldn't use the existing utility, so I made a little python script that sets the zoom and focus levels once a minute. And I'm using the camera's scheduler to switch between day and note profiles, so my script also sets my local sunrise and sunset times. Basically does the same thing (I think) as the windows service.

 

[biggen]

I use auto focus. I have a bash script that changes the cameras to night mode 45 minutes before sunset. That gives enough ambient light to focus with. I then have another script that changes them back to day mode 45 minutes after sunrise. Again, the makes sure there is enough light for focusing.

Changing the zoom and focus every minute may be an issue. I'm not sure there is enough light to focus at night with a fast 1/2000 shutter speed anyway.

 

[wrybread]

I dont think so since I'm not changing the focus, just setting it (in other words when there's no change it has no effect). And I get exactly the same pics when I disable my cron job (except that it won't maintain manual focus after changing profiles).

I'm not sure there is enough light to focus at night with a fast 1/2000 shutter speed anyway.

That's why I do manual focus. So silly that this camera has no way internal way to maintain fixed focus when using profile scheduling.

I may try to add some lights to get better plate reads. But my conditions are relatively ideal:

• there's already some ambient light
• decent camera angle
• vehicles going at most 10 mph

But I'm still not getting super crisp reads. And looking at the camera's saved footage I can see I'm missing lots of plates at night.

 

[wittaj]

Turn on BLC in backlight

Turn down NR to 30.

Turn gain down to 30 too or use the other setting that is shutter priority at 1/2000 and that should fix it - did for mine.

 

[wittaj]

@wrybread - You do not need more light - you are close enough. Try my adjustments above - I think changing it to shutter priority 1/2000 will fix it.

Other threads have exhausted the inadequacy of the focus issue and profile, which was why someone here created a utility that fixes that problem, or people set it up to go to night mode 45min before sunset so that it has something to focus on.

I am getting plates at 35mph at 140 feet away in total darkness. The IR is fine on this camera - what is that setting - make it max IR as well.

 

[biggen]

Have you tried just leaving it to auto focus, and having your profile change over earlier with more ambient light so it can focus properly then? May be worth a shot to test with.