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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
by joshvm 7y ago
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 extraction would save a huge amount of bandwidth.
- siftrics 7y agoHey, 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 recognition is just as accurate as Google Cloud Vision —- it can handle human handwriting and even cursive, in most cases. If you’re interested in trying it out: https://siftrics.com/ https://siftrics.com/
- amenod 7y agoOff topic: great video, love it how you explain what it is about. Good luck!
- xFlynnRider 7y agoProbably yeah, but the potential of the cloud was much more appealing to me. Detecting the license plates is really cheap computationally speaking, but not on the RPi. The most expensive part computationally was identifying the words (letters) - that's because detecting the text within the bounding boxes obtained from YOLOv3 is based on a VGG-16 model. Running that multiple times in a single frame (for multiple license plates) is expensive. Surprisingly, the bandwidth was the least of my concerns. I was very surprised to see I didn't need much at all. For YOLOv3@ 416p and @30FPS I need about ~3Mbps. I wouldn't consider that much. Now, this is a demo of what a production system could theoretically look like. I know it could be much better optimized.
- joshvm 7y agoSure, it's a good exercise in infrastructure. 3Mbps doesn't sound much, but that's constant bandwidth. I have a 15 minute commute, which would make each journey about 400MB of data. That adds up quite fast especially on a mobile contract.
- 01100011 7y agoI'd think a Jetson Nano would be more than enough as well. No need to invoke the cloud.