ANPR tweaks to best get reliable reads?

[codlord]

I just installed a new ANPR camera (iDS-2CD7A26G0/P-IZHSY with H8 firmware on v5.7.80) to replace an older failed model.

Some previous model HikVision ANPR cameras used to log a "NOPLATE" read in the case where they detected a vehicle but could not read a plate. (older ones did not do this at all).

The new model seems to log "UNKNOWN" reads instead. o.k. Not sure why HikVision seem to have changed it but o.k. I can live with that, but I then noticed that the new camera has logged a number of UNKNOWN reads in the first couple of hours after installation despite the number plates being clearly visible in the captured photos.
Focus is good, zoom is good, light is good and vehicles move slowly here. Single lane and the line crossing is all setup.

I can't understand why I am getting these "UNKNOWN" reads.

In config there is a setting I don't fully understand:

Select Mode: "Entrance/Exit" or "City Street" or "Alarm Input"
Can anyone explain what this setting actually does?

The manual is next to useless and just says:
"The license plate information of the detected vehicle will be uploaded when the vehicle passes the detection area and triggers the detection in the entrance/exit."
and
"The license plate information of the detected vehicle will be uploaded when the vehicle passes the detection area and triggers the detection in the city street."

"Entrance/Exit" mode does NOT offer multiple lanes on this camera so I don't understand why the two options and what changes in detection between them...

 

[Kyle]

Hi @codlord

We've seen similar with a customer before, they were getting lots of 'unknown' plate reads on the same model.
They had installed the camera high up, on a pole (using a homemade bracket), looking all the way across a large car park to the detection zone.
After a lot of work with Hikvision, we worked out that the camera would wobble in windy and wet weather, causing the 'unknown' reads as it couldn't capture a sharp enough picture for it to read.
Having lots of cars/people moving in front of the camera made the issue worse.
They were also using the camera for two lanes (one entrance and one exit) - changing it to one lane (as you have) helped a lot too.

Have you installed and configured everything as recommended in the attached guide, and on a secure surface?
When our customer reinstalled their camera following those instructions, it resolved all of the unknown reads.
I'm not sure if the older cameras fared better in challenging positions...

I can't remember exactly how the different modes work (I'll come back if I do), but this video is worth a watch as it walks you through the recommended settings and should be more helpful than the manual:

 

[codlord]

Thanks @Kyle I will have a look/read/play and report back with any findings.

The camera is mounted securely on the face of a building, and no wind today anyway so I am sure it's not vibration/movement of the camera.

 

[Kyle]

No worries - let us know how things go as I can do more digging if need be.
The customer I mention deployed the same camera in 3 other car parks using the same firmware (I can't recall the firmware) without seeing plate read issues.

I've just spotted that there seems to be several newer versions than yours here in the EU portal too - sorry, I didn't think to check this yesterday!

Some are very large files, so I'd recommend updating through them in steps with it being a specialist camera as well...

 

[codlord]

@Kyle I think I have managed to eliminate UNKNOWN reads in daytime. I just zoomed in fully (previously it was mostly zoomed in but not 100%) and also moved the blue crossing line from the middle of the view to a bit lower nearer the camera.

However, it's failing to read most plates at night. Usually I set ANPR exposure to 1/2000 which is higher than the PDF guide but is the only way I found to reliably read plates at night. The downside of this is the image at night is pretty much 100% black apart from vehicle lights/plate.

I can see from this newer camera it's getting way more light in the image than the older models - the captured image I can see a lot of the car, and the surroundings behind and ahead of the vehicle. But the plates are glared out and therefore not being read.

I guess I need to experiment with even higher exposure settings and/or IR settings over the coming nights.