PTZ LPR Help

[jd415]

As some of you know I use a PTZ as a long range (almost 200 ft) LPR. My old PTZ the shots look great however with my new PTZ they look a little pixelated. I've tried adjusting the settings and that didn't help either. If you look carefully at the video when the car comes into the shot the video gets a little dark for a second and goes back to normal. I've included images with my old camera, new camera and also my settings. I hope it's just my settings I set wrong and not a limitation of the new PTZ.

Was hoping someone here can help, tagging a few of you just in case you don't see this post. Thank you!
@wittaj @Parley @bigredfish @lulu5kamz @samplenhold @TonyR

Old camera 4MP 1/2.8"

https://www.amazon.com/gp/product/B07GBFQJCC/

New camera 4MP 1/1.8"

https://www.amazon.com/gp/product/B08GKQSK2W

 

[biggen]

My Z12 does this as well. I think it’s a gain issue. I’ve never found a fix for it other than zooming out.

 

[bigredfish]

Thats normal on some cameras with some settings. The camera is auto adjusting Gain within your specified limits. Its actually beneficial most of the time in that on a bright sunshine day, it can help reduce glare. I run an exposure range during the day and see it.

I think the only way to eliminate it would be to set a fixed range on Gain like 50-50, but that will create other undesirable effects depending on the light and object. Objects it sees as "close up" ie heavily zoomed" that take up a lot of the scene seem to set it off

 

[wittaj]

+ 1 all of above. The bigger sensor lets in more light than your older one, so it probably have a bigger range spread.

We had another post just this week talking about it:

Scene color/saturation changes with motion?

This isn't the end of the world to find a fix for, but just curious why the scene will be a little washed out/dull until any motion is in the FOV and then the saturation/color will change. Settings are basic for Day: typical exposure, low gain, no Backlight, WB set to Outdoor. Z12E-S2 Below is...

ipcamtalk.com

 

[jd415]

I tried adjusting the gain and it didn't help. Is this just the way this camera is? If so I guess I will switch back to the old one but I'm really trying to avoid that.

 

[thlong]

May I ask how do you use this at night for lpr? Do you let it do ptz or fix-position?

 

[jd415]

@thlong at night I also use it as a long range LPR and it works great!

 

[thlong]

@thlong at night I also use it as a long range LPR and it works great!

Do you let it pan around at night?

 

[jd415]

@thlong it's in a fixed position at night

 

[wittaj]

Do you let it pan around at night?

If you let it pan around then it will lose the focus for LPR. Plus the camera is set up with a fast shutter so all you see is the head or tail lights and plate, so even if you did pan, the image would be too dark for anything else.

 

[bigredfish]

So I did some testing today using the 5442-Z4. Seems the newer cameras (possibly all 1/1.8" sensors but certainly the S3) auto adjust both Exposure and Gain by themselves, as expected, if you set a range on either. Not necessarily a bad thing, but if you're using the camera for a purpose such as LPR, probably best to use fixed values for both Exposure and Gain.

It tries to compensate both ways, brightening the image when the scene becomes darker and darkening it (or ignoring it) when the scene is bright.

Normal settings: Exposure 0-2, Gain 0-50
(2 vehicles, wait for it)
View attachment Exp-0-2-Gain-0-50-Home_ch8_20240529123155_20240529123227.mp4
















View attachment Exp-0-2-Gain-0-50-Home_ch8_20240529120128_20240529120134.mp4

 

[bigredfish]

Exposure Range 0-2, Gain Fixed 10-10

View attachment Exp-0-2-GainFixed10-10-Home_ch8_20240530152530_20240530152539.mp4
















View attachment Exp-0-2-GainFixed10-10-Home_ch8_20240530133116_20240530133125.mp4

 

[bigredfish]

And finally, Fixed Exposure AND Fixed Gain

Exp 1/2000 fixed, Gain 10-10 Fixed

View attachment FixedExp-1-2000-Gain10-10-Home_ch8_20240530113634_20240530113647.mp4















\
View attachment FixedExp-1-2000-Gain10-10-Home_ch8_20240530103624_20240530103632.mp4

 

[jd415]

@bigredfish thanks so much, I will give that a try!

 

[jd415]

@bigredfish those videos look amazing! Crystal clear!

I adjusted the gain and the images are still not clear like the old camera. What am I doing wrong?

 

[bigredfish]

Well my tests were with a z4 zoomed in more than you and my targets are quite close- 45-55ft
Cut DNR back to 30-35 , back off brightness to say 46, increase contrast to 55, and back sharpness down to 35-40

The one problem you’re facing you can’t fix is the FStop if your PTZ zoomed in. FStop goes way up (less light allowed in) as you zoom a PTZ.

I think your image looks fine, but part of the pixelization or artifacts you’re seeing is something all of the 4MP 1/1.8 sensors seem to have a problem with. Cutting sharpness back can cure some of it

 

[Alaska Country]

Have attached the settings that I use for the SD5A425XA-HNR PTZ Dahua camera. These work well for my application. However, they will have to be adjusted for your specific lighting conditions.