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I built a DIY license plate reader with a Raspberry Pi and machine learning

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Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#32
I really do appreciate the effort and the quality of the writeup, but this approach is a very inefficient and round-about way of going about things.

You can do real-time number plate recognition on a Pi3/4 with a Coral TPU or Movidius 2. Both of which costs ~US80. It's probably got a lot to do with hammers and nails. Not everything needs to be 'web-centric' or 'cloud based'

Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#33
post #12

The obvious question is why not use a local accelerator? Either the Neural Compute Stick or the Google Coral both have more than enough grunt to run real-time object detection models. Both will run on USB2 power. I don't know the overhead of good OCR, but license plates are a very standard format so perhaps you could train a second detector to extract the letters? Even if you do OCR in the cloud, local bounding box e…

Hey, founder of a relevant startup here. Just wanna chime in on OCR + bounding boxes performance. We offer text recognition with bounding boxes as a service. Our average processing duration, between reading bytes off the wire and writing the JSON response, is just under 3 seconds on average. Obviously that throws it out the window for frame-by-frame applications, but I think it’s still worth mentioning. The recogniti…

Off topic: great video, love it how you explain what it is about. Good luck!

Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#35
post #4

Earlier quoted context omitted.

I may have missed something, but I believe the T4s are running in the cloud, so it wouldn't have any effect on the car's power consumption.

To clarify, I mean indirectly the power consumption. I guess this will become an important point of discussion soon-ish, as we get more and more electric cars and ML stuff in them. My view is, if your car uses electrons, and some of those are for compute, and you just offload the compute to the cloud, you haven't actually reduced the total electricity consumption. Similarly here, the total "footprint" of the car is i…

Whether the car uses electrons or fossil fuels is pretty irrelevant, right?

Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#36
post #11

So now medium is straight up not letting people read an article unless they're logged in ... Disgusting.

Disgusting, indeed. But as long as these links are accepted here, nothing won't change. Take this in the meantime: https://outline.com/qsv7ab

Would be great if we could have built-in Outline support on HN, or some kind of bot commenting a link automatically when someone posts a story with a paywall. Just throwing an idea out there. :)

Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#37
post #24
post #17

Earlier quoted context omitted.

There is also a limit on articles you can read before they throw up a paywall. No clue why anybody would use this as their blogging platform.

I thought that was opt-in by the author?

No, they've changed that. They probably received funding and are now desperate to earn that money back. There should be a site like Medium that wasn't tainted by Vulture Capitalists.

Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#38

"Machine Learning" is the wrong tool for the job here. Tesseract OCR can do this, using only the Raspberry Pi, at a "good enough" framerate for any real driving situation.

Tesseract only does well if the input is clean, aligned, two tone image, already cut down -- but LPR images you get from a moving camera are anything but.

Machine learning is a fine tool for this job. The specific machine learning setup is an overkill, though.

Re: I built a DIY license plate reader with a Raspberry Pi and machine learning

#40
post #11

So now medium is straight up not letting people read an article unless they're logged in ... Disgusting.

The article works fine for me, and I do not have an account for that. (I don't like the formatting, but it is readable.) (I don't even see any mention of login.)
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