Camera not picking up vehicles coming up driveway at night

[Jake1979]

Camera works great during the day, at night it won't pick up the car coming in. It does pick up people at night. I've tried turning IR on and off. It's off currently. I've had min contrast in the middle, still will not pick it up. Any suggestions?Other thing is it won't pick up the plates and I'm sure part of it is the bright headlights.

Dahua SD49425XB-HNR

 

[wittaj]

You have to decide what you want - overview or plates. Won't get both from one camera at night.

You need a much faster shutter and zoomed in more to get plates. The faster the shutter, the darker the image.

At night, we have to run a very fast shutter speed (1/2,000) and in B/W with IR and the image will be black. All you will see are head/tail lights and the plate. Some people can get away with color if they have enough street lights, but most of us cannot. Here is a representative sample of plates I get at night of vehicles:

See the LPR subforum for more details.

And a PTZ is harder to get plates because you cannot manually set a focus like you can with a fixed lens varifocal. You would have to set it up to get plates before it gets dark and turn it into a fixed camera all night or else the moment it moves it will hunt for a focus all night.

To get it to trigger in BI you need to set the min contrast to the smallest number.

 

[bigredfish]

^^^^^
This

Thats a horrible picture. Once you decide if you want it to do LPR or be an auto-tracking PTZ, you need to spend some time dialing it in. Its useless at night currently

For starters, turn IR back on to AUTO and under Backlight turn on HLC to about 70

 

[Jake1979]

Thank you both, I'll play with those settings. Assuming it's possible to make night mode to have a faster shutter speed. I may end up putting a turret in place of the PTZ and put the PTZ somewhere else. New house- trying to figure out where I want the coverage.

 

[wittaj]

Yes you can set the shutter speed in the 49425 to manual and 1/1000 or 1/2000, but like I said, plates with PTZs can be tricky.

 

[bigredfish]

I would use something else for LPR

Try exp of 1/120 manual or 0-8.33 ms. IR on Auto or Manual 100%. You may not have enough light
Then start backing it off to 0-9, 0-10 etc until you get a decent image with as little blur as possible.

The HLC will help tame the bright headlights

 

[Jake1979]

I'm not trying to specifically do LPR, I just want to make them out in the video. I'll play with it but I think I'm going to swap the cameras around.

 

[wittaj]

Again, the only way you will be able to read plates is with a faster shutter. The faster the shutter, the darker the image, which means you won't see people or cars at night.

The plate is too reflective with infrared for the slower shutter speeds to be able to make out the video and people, so the plate will be washed out white. It is only with the faster shutter speeds that allow the plate to manually read, even if not moving.

 

[bigredfish]

You will need 2 cameras to do both things.

 

[looney2ns]

Thread 'New to LPR? Considerations Before You Begin'

Nov 12, 2020

Thought I would throw together a post on my experiences so far with LPR in an effort to help others that are considering running down that rabbit hole. There are some practical considerations you should know about LPR. I am approaching this from the position of using Blue Iris and Plate Recognizer Snapshot as that is what I have done so far. If you are using an NVR or some other plate OCR, then some of the discussion may not apply to you.


Plate Recognizer (PR) is very easy to set up in Blue Iris (BI). It uses the Alert image from the trigger alert in BI. BI sends that Alert image to PR...

• samplenhold
• Replies: 160
• Forum: LPR

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