help tuning night LPR ?

[Andrew F]

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How far are you zoomed in for that? Any idea of the distance to the plate?

 

[Peter Vandenbergh]

Camera is beside the street and not far zoomed in, but it start to read plates from about 35meter. I dont use extra IR.
It took me a long time to get it right, once I changed the exposure setting to 1/2000 and the gain 0-10 the capture is almost 100% accurate.
This felt strange at first because the image is pitch-black when no cars are passing by.
now I have up to 15 correct readings from a car driving 50Km/h in one second. Every reading is a picture taken... so I have about 100.000 (one hundred thousant) pictures a week.

I also use a script to reconfigure the camarasettings based on the current light conditions, like less zoom and BW during thunderstorms and more zoom if the wheater is sunny.

I included a daytime picture on a very cloudy day (picture is bright, but reallity is pretty dark (damm this cam is good)) the car is at 30 meter and the flowerpot is needed to reduce the high load of detections and to give the camera something to focus on. In daytime exposure is also 1/2000

 

[Andrew F]

I also use a script to reconfigure the camarasettings based on the current light conditions, like less zoom and BW during thunderstorms and more zoom if the wheater is sunny.

Can you elaborate on that script? I'm using the Dahua Sunrise Sunset service to switch between day/night profiles. I'm curious how you're responding to lighting conditions on the fly like that.

 

[Andrew F]

Update for those playing along at home: we moved the camera closer to the road, and we have success! My wife deserves the credit for tuning this bad boy and getting it in focus.

Now I just have to figure out a "birdhouse" enclosure or something similar so the cameras aren't terrible tacky.

 

[bigredfish]

Good job @Andrew F wife!

 

[Peter Vandenbergh]

elaborating.. as requested
this is a (simplified) node red flow to change the BW/Collor setting based on brightness of the moment

the left node reads the value of a light sensor, the second node (switch) sends values higher then 300lux to the Color request and lower values to BW
The 'deadband' is there to only let changed values pass. When a message is send to one of the 'WWW.request' then this node send the request to the camera
The rest of the nodes is purely for debugging
settings off the request node below:

In the dahua API reference you find all possible commands to control the camera.
And the sensor can oaso be a timer or sunrise/sunset calculation or even the online wheater reports .
for example, on a low traffic street you could send the command to zoom out completele for 10 seconds to get a overview of the area after detection of a plate. or play a dog barking sound when an unknown plate is seen during the night.

almost everything imaginable is possible

Peter

 

[Andrew F]

this is a (simplified) node red flow to change the BW/Collor setting based on brightness of the moment

That's SWEET work!! Thanks for sharing!

Are you using a separate piece of hardware to sense to the current lighting conditions? Or are you tapping into the Dahua camera's lighting sensors?

 

[Peter Vandenbergh]

In the example I use the average value of 4 KNX sensors around my house, these sensors comunicate to 'openhab' and 'openhab' is connected to the node-red server
KNX L - Sensors Outdoor (Weather) - KNX Bus System - Products/Shop - Elsner Elektronik

but... it was way to expensive (wat was I thinking...) alot cheaper would be if you build a sensor with a ESP8266 module or a Wemos configured with MQTT and a light sensor, price would be below 10$