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I've been mulling over trying to build one for our cove/neighborhood. Ring/security cameras are fine but being able to pinpoint a handful of plates to the wee

by atwebb 7y ago

I've been mulling over trying to build one for our cove/neighborhood. Ring/security cameras are fine but being able to pinpoint a handful of plates to the wee hours of the morning would allow theft issues to be handled pretty easily when cross referenced with camera tech. Ex. Right now you get a description like "Older white 4 door" or "White Nissan Sentra" Bounce that against plates from that time and you've got a good match to work off of, especially if the owner matches descriptions from cameras.

scottlamb 7y ago
You don't need automated license plate recognition for that, though. If you find the motion events in the wee hours, and have a sufficiently high-quality video frame [1], you can easily check the type of car and then know the license plate by reading it with the neural network that was preinstalled between your ears rather than a software one. I've been writing my own home surveillance camera network video recorder software, so I've thought about plugging in something like this, but I don't think it's really necessary. The one time I might use it is if there's a car that was likely involved in a burglary, I might scan the previous few weeks to find previous times they were in-frame. Then I might see their scoping the place out, potentially revealing more about themselves. It's too labor-intensive to look through that many motion events by hand. [1] My understanding is this requires some care. You have to select the right kind of camera, place/aim/zoom it carefully, and tune it for license plate recognition, particularly at night. I think the cameras typically come tuned for slow-moving, not-very-reflective-to-IR objects. License plates on a moving car are the opposite, so you want to say decrease the aperture and increase the shutter speed from the default, position it carefully as I said, maybe tweak some other settings, and test it.
Spooky23 7y ago
The danger of doing that systematically is that you have a record to subpoena. So be prepared for the requests from divorce attorneys and police. Better to just have video to make it more difficult.

by atwebb 7y ago

scottlamb 7y ago

You don't need automated license plate recognition for that, though. If you find the motion events in the wee hours, and have a sufficiently high-quality video frame [1], you can easily check the type of car and then know the license plate by reading it with the neural network that was preinstalled between your ears rather than a software one. I've been writing my own home surveillance camera network video recorder software, so I've thought about plugging in something like this, but I don't think it's really necessary. The one time I might use it is if there's a car that was likely involved in a burglary, I might scan the previous few weeks to find previous times they were in-frame. Then I might see their scoping the place out, potentially revealing more about themselves. It's too labor-intensive to look through that many motion events by hand. [1] My understanding is this requires some care. You have to select the right kind of camera, place/aim/zoom it carefully, and tune it for license plate recognition, particularly at night. I think the cameras typically come tuned for slow-moving, not-very-reflective-to-IR objects. License plates on a moving car are the opposite, so you want to say decrease the aperture and increase the shutter speed from the default, position it carefully as I said, maybe tweak some other settings, and test it.

Spooky23 7y ago

The danger of doing that systematically is that you have a record to subpoena. So be prepared for the requests from divorce attorneys and police. Better to just have video to make it more difficult.