Previously I had been using platerecognizer.com for License plate recognition. Couple days back they sent a note saying I was at 95% of quota, followed by another saying I was at 100%. Quota is 2500 images, suggesting 250 images a day. That seems a lot. I did some things about this:

  • Firstly, I debugged why so many images. I turned on logging of the plate images and a web server to show me the images. It turned out that many were cars driving by. I added filtering for cars on the road to frigate, and the number of detections dropped.

  • Secondly, I added some Prometheus metrics to frigate_plate_recognizer.

  • Thirdly, I set up and started using Code Project AI for License plate recognition. The main problem with this was actually testing it with curl. Command I ended up with is

curl  -F upload=@Downloads/videoframe_1987228.png -X POST http://codeproject-ai.tail464ff.ts.net:32168/v1/vision/alpr

So far performance is OK.