LPR: Blurry Images During Day Time

rfj

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I have an IPC-HFW5241E-Z12E specifically for reading license plates. I can read most license plates easily during night time. However, during day time they seem more blurry and in some cases unreadable. See attachment which shows the top left quarter of what the camera records. I am using some settings I found on the forum. Attached are my settings. Both use a shutter of 1/10000 which seems high but actually works pretty ok at least for the night images. Gain range for day is 0-50 and for night 40-60 so noise should be less of a problem for the daytime images. So why do my daytime images come out (a lot) more blurry than my night images?
 

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wittaj

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You get plates at 1/10,000 shutter at night?

Most of us use 1/2,000 or 1/1,000 for night.

In many instances the focus between visible and infrared light is different. Have you stopped a car in that field of view during the day and do a manual focus to get it sharp and then lock it in?

My one LPR camera is about 40 points different in focus numbers between day and night and the other one they are the same. It all comes down to each individual field of view.

Here is a great older post that goes into detail how the focus for daytime and nighttime can be different because of IR. For some they are the same, but for a lot of people, it is different:

Infrared focus shift - explanation

You could drop to 1/4,000 shutter during the day.

You gotta knock the DAY NR down as well - try like 25 or 30.

Could probably knock DAY gain down to 35 or so as well.

What are you other parameters during the day (brightness, gamma, etc.) as they can directly impact the focus.

 
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Flintstone61

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We have heard of people focus changing in the switch over from day to night on this camera. I find that if your dedicated to LPR( I have this cam) Leaving it on Night settings stops that from happening. So don't run a Night/Day schedule and it wont Focus hunt
 

rfj

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I was indeed running it at 1/10,000s at night. At least to me the license plates look pretty good. See Night1.png. The left plate is from a parked car and the right one is from a moving car. In any case, as recommended I made some adjustments for the exposure settings. See attachment NightExposure1.png and DayExposure1.png.

I also played with the focus or a parked car. The focus adjustment goes from 0 to 1800. I had it set at 1500 (see Focus1500.png). The finest adjustment I could do is +/-20 but that made a huge difference. 1520 (see Focus1520.png) can still be read fine but at 1480 (see Focus1480.png) it's impossible to read the plates. I am surprised about the huge difference. Considering this is possible to make finer adjustments than +/-20? Also, it seems the zoom/focus cannot be adjusted separately for day and night (see Focus1.png). Or am I missing something? If the focus can shift with IR then I would expect that the focus can be adjusted for different settings.

Attached are also the picture (Brightness, contrast, ...sharpness, gamma, etc) settings. See DayPicture1.png and DayPicture2.png. For the day setting I have to dial the sharpness all the way down as otherwise I get terrible noise. See Sharpness67Gamma71.png. This is with sharpness set at 67 but even at 50 or 30 the 'noise' is still really bad.

@Flintstone61 If you don't have day and night mode then how do you get the license plates without being blown out from the high reflection?

Edit: I added Video1.png and FocusZoom1.png as asked by @samplenhold
 

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wittaj

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The Speed setting on the zoom/focus page is the fine tuning. Change it to 1 instead of 20 and you can dial in a crisp focus.

You cannot focus on that parked car as the f-stop gets larger the more zoom and that means a tighter circle of focus. It will be in focus for that parked car but then as a car drives by closer the moving car plate will be out of focus. Like literally folks that have a more perpendicular shot that straight down like you will have blurry on either side of the street but clear focus in the center where the street is.

Yes you can set a focus for day and night profile. Set it to manual for each profile and then set the focus for day and night.
 
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rfj

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Regarding focus, I will try to set it to the point where it's most likely for me to see the license plate of a moving car going either direction. I guess my point regarding the big difference between +/-20 (out of 1800) is that the depth of field seem rather narrow. I will try to play with it more but at least for the night images I never really thought that in one part of the image the license plates are blurry and in other areas sharp.

Changing the speed indeed allows me to make finer adjustments. Thank you!

As for focus for day and night I don't really understand how to do this. The setting under Conditions->Focus & Zoom are set to manual both for Night and Day. See attachment FocusZoom1.png. So I would expect that under the tab Zoom and Focus I have a dropdown for Profile. However, there isn't any such profile. See ZoomAndFocus1.png. I tried to go to the tab Conditions, select the profile there, switch to the tab Zoom and Focus, adjust the focus, go back to Conditions and click on Save. However, when I then change the profile on the tab Conditions the focus also changed for the other profile.
 

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wittaj

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That is correct - leave that at Manual and then whatever profile is live will be whatever focus you set it to. Then change to the other profile and make it live and then adjust the focus and then it will switch between the profiles.
 

rfj

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That is correct - leave that at Manual and then whatever profile is live will be whatever focus you set it to. Then change to the other profile and make it live and then adjust the focus and then it will switch between the profiles.
That is what doesn't work for me. I must be doing something wrong. Here are my steps:

1a) Go to Profile Management, select Full Time (which I already have) and set "Always Enable" = Day. Click Save.
1b) Go to Zoom and Focus. Adjust the focus. I just put it way out of focus so I can easily distinguish between day and night (just testing).
1c) Go to Conditions and click on Save. I assume that means it will now save what I just set under Zoom and Focus in 1b) for the profile I set in 1a)

2a) Go to Profile Management, select Full Time (which I already have) and set "Always Enable" = Night. Click Save.
2b) Go to Zoom and Focus. Adjust the focus (is quite different than in 1b)
2c) Go to Conditions and click on Save. I assume that means it will now save what I just set under Zoom and Focus in 2b) for the profile I set in 2a)

3a) Go to Profile Management, select Full Time (which I already have) and set "Always Enable" = Day. Click Save.
3b) Got to Zoom and Focus. I now expect to see the settings I made in 1b). However, I see the settings I made in 2b). So whatever I set in Zoom and Focus seems to be independent of the profiel.
 

wittaj

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Are you using Internet Explorer?

You may need to use one of these features to force the focus. This was created before the manual feature was added, but many of us still use it for LPR and our other cameras.

 

rfj

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I am using Chrome. For switching profiles I initially used DahuaSunriseSunset but then switched to BI (described in the same forum post you linked to). However, isn't that independent of my issue in setting a different focal point for the day and night profile? DahuaSunriseSunset and BI are just triggering the switching of the profile between day and night. The actual profile data for day and night is stored on the camera. And that is where my problem is. It seems I cannot set the focus per profile but just globally for all camera profiles.
 

wittaj

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Try using Explorer as these cameras tend to be browser specific.

The DahuaSunriseSunset utility can set the focus as well for varifocal cameras.

You could do it in BI as well by knowing the API for the focus.


 

rfj

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I now tried Edge (which is basically Chrome) and the old Internet Explorer. For both I did what I listed in post #9 with the same result, i.e. it doesn't store the focus per profile but only globally. I start wondering if it has to do with my FW or SW as when looking for the latest FW for my camera everybody seems to refer to earlier version (V2.810 or earlier while I am on V2.820). Mine seems newer but maybe something was messed up or my FW is newer but the web version is older than others.

Device Type IPC-HFW5241E-Z12E
System Version V2.820.15HM000.0.R, Build Date: 2020-11-14
WEB Version V3.2.1.980255
ONVIF Version 20.06(V2.9.0.970440)
 

IReallyLikePizza2

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Can you add more zoom? Also what happens if you up the bit rate

Same camera and I get crystal clear shots

1673324313668.png
 
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You cannot focus on that parked car as the f-stop gets larger the more zoom and that means a tighter circle of focus. It will be in focus for that parked car but then as a car drives by closer the moving car plate will be out of focus.
That is possible, but I do not have that issue. My cams are in focus from 40 to 110 feet and the other is 65 to 110 feet.

8.JPG

How far away is your target? What is your zoom setting? My zoom and focus are at 1020 and 1450 for my LPR-E cam and 880 and 1610 for my LPR-W cam.

You look like you could zoom in more as you have wasted space at the bottom of your view, driveway. I am guilty of this also, but have not had an issue to make me change it.
 

rfj

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@IReallyLikePizza2 that's some seriously clean image. I must be doing something wrong. I took the measuring tape out and from the camera to about the center of the frame it is around 60'. The camera is about 1.5' above ground and not at a very steep angle to the road. As for the other questions:

  • Distance to target about 60 feet
  • Zoom set at 1000 with max 1200 --> 5mm + (60mm-5mm)/(1200/1000) = 51mm
  • Focus set at 1510 with max 1800. 1510/1800=0.84 and 1000/1200=0.83. Not sure if zoom and focus ratio need to be approx. the same or if this is just coincidence.
  • Video settings: 8192Kb/s, 15fps, I-frame 15, CBR, H.264, smart codec off
  • Day picture: Sharpness = 5 (otherwise it gets very noisy), Brightness = contrast = saturation = gamma = 50.
  • Day exposure: mode = manual, shutter = 1/4000, gain 0-35, iris = exposure comp = 50, advanced 2D and 3D = 27
  • Backlight Off, WB = Auto
  • Focus mode = manual

Note that based on the input today I made some changes so I need to post new pictures tomorrow what I get during daytime. What puzzles me the most is why I need to set the sharpness so low (5) to avoid really bad artifacts. Even with those low settings I still don't anywhere close to what @IReallyLikePizza2 showed.

Also note that my BI settings for Image format are pretty strange (856x480, 30fps, etc) and seem to change themselves. However, it is my understanding I can ignore all those when I have direct to disc enabled which I have on all my cameras.
 

Alaska Country

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These are some setting both day and night for a Dahua 7442 LPR camera of what works at my location. Your lighting, camera model, camera to vehicle distance, settings, height above ground, etc may be totally different.

day.jpg night.jpg
 

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IReallyLikePizza2

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I'm at 120 feet!

Here are all my settings, bit rate is much, much higher than you. Also I couldn't get good shots with 15fps, I had to go to 25 to get clean pictures

1673359910195.png

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1673360471012.png

1673360479558.png

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1673360512349.png
 
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