Stealth Plates?

djernie

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I thought someone had figured a way to defeat the license plate reading cameras. But after going over video from earlier in the day i found out it was a new vehicle and it did not have front plates. I only figured it out when the vehicle passed by earlier in the day i was able to get a reading of the rear plates.

 

weigle2

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Question - Do you still see the plate number on a car that has the smoked plastic cover (also can add polariztion meaning you can only see the number head on), on an LPR camera that is at any angle to the street.
 

djernie

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Question - Do you still see the plate number on a car that has the smoked plastic cover (also can add polariztion meaning you can only see the number head on), on an LPR camera that is at any angle to the street.
I can see every plate that passes my Dahua SD49225T-HN that i am using right now for LPR. I will be adding another camera for LPR duties in the future. I have seen you tube test, that show none of the attempts to hide the plate works.
 

bigredfish

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I don’t get 100% at night. Theres too many old mangled and dirty plates, let alone methods to conceal to get 100% at night with IR. 80-90 maybe

Daytime in color 99% is doable
 

stevtanc

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I can see every plate that passes my Dahua SD49225T-HN that i am using right now for LPR. I will be adding another camera for LPR duties in the future. I have seen you tube test, that show none of the attempts to hide the plate works.
I just got a new one and trying to set it up to capture plates. Can you share your settings for EmpireTech SD49225T-HN?
 

djernie

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I just got a new one and trying to set it up to capture plates. Can you share your settings for EmpireTech SD49225T-HN?
It is best to try and focus to this position during the day as it is hard for the camera to focus at night. Check out this thread for great information.
 

djernie

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You have to zoom real close to the front of the car, and you will not use this camera for anything else other than LPR duty. Mine is doing this temporarily until i purchase the dedicated LPR For this duty. But this PTZ works great for now.
 

CCTVCam

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Question - Do you still see the plate number on a car that has the smoked plastic cover (also can add polariztion meaning you can only see the number head on), on an LPR camera that is at any angle to the street.
That's going to depend on the plate system used. Many of the stealth plates don't restrict viewing angles because it would be obvious to authorities and instead rely on highly reflective surfaces to try to blind a speed camera with a reflection of it's own flash. With modern video editing tools, it seems they rarely work and are still spotted by the fact they're too reflective of headlights. As CCTV doesn't use flash, these are highly unlikely to be an issue. If however someone was to risk fitting a privacy screen such as that fitted to pc screens in some workplaces, then no camera is going to pick up the plate because no light is transmitted to the side. Anyone who's worked in an office will know a few degrees off centre and you can't read the screen. That said, any criminal is simply going to put false plates on if they really want to conceal their true identity. A privacy screen will stand out like a sore thumb to law enforcement. A false plate goes un-noticed unless you give law enforcement a reason to want to stop you and read the plate. A plate that appears non existent when they look across the street is a definite pull.
 

guykuo

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You have to zoom real close to the front of the car....

On 2MP cameras, I get best license plate imaging when width of the car covers 1/5 or more of the frame. Farther than that, things get less usable. Here are three frames of same vehicle stacked together. You can see how readability changes as the apparent car size grows. Nearest image is about 50 feet out from camera. This is also with a Dahua SD49225T-HN. Only major difference in settings from yours is my camera switches to manual focus mode during the night. A PHP script runs pre-sunset and post dark to brighten scene, position for night LPR, autofocus, lock into manual focus mode, and drop back down to LPR exposure settings.

license zoom framing.jpg
 

guykuo

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night settings.jpg

Also here are my PHP scripts for setting day vs night LPR capture on a Dahua SD49225T-HN

===============================================================
#Set Dahua SD49225T-HN LPR NIGHT mode

import requests
from requests.auth import HTTPDigestAuth
import time

#autofocus mode
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInFocus[0][1].Mode=2'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#long exposure to temporarily get enough light for focusing
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInExposure[0][1].Value1=1&VideoInExposure[0][1].Value2=100'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#ptz preset 1 has stored position for best night LPR framing
url = 'http://<ip>/cgi-bin/ptz.cgi?action=start&channel=0&code=GotoPreset&arg1=0&arg2=1&arg3=0'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
#wait several seconds
time.sleep(5)

#manual focus mode
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInFocus[0][1].Mode=4'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#short exposure for LPR capture
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInExposure[0][1].Value1=1&VideoInExposure[0][1].Value2=1'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

===============================================================

#Set Dahua SD49225T-HN LPR DAY mode

import requests
from requests.auth import HTTPDigestAuth
import time

#day profile. Day Profile must also include autofocus as its focus setting.
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInMode[0].Config[0]=0'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#ptz preset 2 is framed for daytime LPR. Daytime can view a bit wider than night time.
url = 'http://<ip>/cgi-bin/ptz.cgi?action=start&channel=0&code=GotoPreset&arg1=0&arg2=2&arg3=0'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)
 
Last edited:

djernie

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View attachment 54239

Also here are my PHP scripts for setting day vs night LPR capture on a Dahua SD49225T-HN

===============================================================
#Set Dahua SD49225T-HN LPR NIGHT mode

import requests
from requests.auth import HTTPDigestAuth
import time

#autofocus mode
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInFocus[0][1].Mode=2'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#long exposure to temporarily get enough light for focusing
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInExposure[0][1].Value1=1&VideoInExposure[0][1].Value2=100'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#ptz preset 1 has stored position for best night LPR framing
url = 'http://<ip>/cgi-bin/ptz.cgi?action=start&channel=0&code=GotoPreset&arg1=0&arg2=1&arg3=0'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
#wait several seconds
time.sleep(5)

#manual focus mode
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInFocus[0][1].Mode=4'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#short exposure for LPR capture
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInExposure[0][1].Value1=1&VideoInExposure[0][1].Value2=1'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

===============================================================

#Set Dahua SD49225T-HN LPR DAY mode

import requests
from requests.auth import HTTPDigestAuth
import time

#day profile. Day Profile must also include autofocus as its focus setting.
url = 'http://<ip>/cgi-bin/configManager.cgi?action=setConfig&VideoInMode[0].Config[0]=0'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)

#ptz preset 2 is framed for daytime LPR. Daytime can view a bit wider than night time.
url = 'http://<ip>/cgi-bin/ptz.cgi?action=start&channel=0&code=GotoPreset&arg1=0&arg2=2&arg3=0'
requests.get(url, auth=HTTPDigestAuth('<username>', '<password>'))
time.sleep(1)
I don't use any scripts, i just let the camera do it's own thing. My distance is only about 35 feet. PTZ1.20200119_213011779_1.jpgPTZ1.20200120_082648938_1.jpgPTZ1.20200119_182104304_1.jpg
 
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