Automatically blur numbers and letters using ruby or imagemagick?

Question

I have an application where users upload images of cars. I want to build a script that will scan these images for number plates and automatically blur them, partially or fully.

How would I achieve this? I am using Ruby on Rails and ImageMagick for my app. Is there a script that will allow me to recognise numbers and letters, or maybe the shape of a number plate?

http://stackoverflow.com/questions/981378/how-to-recognize-vehicle-license-number-plate-anpr-from-an-image — dangerousdave, Oct 30 '11 at 11:11
You can use 1k backends with photoshop somewhere on outsourse :) — fl00r, Oct 30 '11 at 11:48

score 2 · Accepted Answer · answered Oct 30 '11 at 11:10

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Image recognition is very complex, and resource intensive. Perhaps you could use some sort of OCR (optical character recognition) software to look for the number plate characters. Run this software on a separate machine, and have it trawl through uploaded images, and perform selective blurs using imagemagick, before marking the image as being safe to publish.

answered Oct 30 '11 at 11:10

dangerousdave

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yes, a setup in which another tool runs over the images in order to blur them would probably be the way to go. Alternatively I can just let the images be uploaded and be visible on the site for a limited time only, if the image parser reaches the image and blurs out the numbers after a few minutes I can live with that. – Mosselman Oct 30 '11 at 19:16
Thanks for your answer, I will end up doing what you describe to a certain extent. The essence is here. – Mosselman Apr 06 '12 at 18:13

score 1 · Answer 2 · answered Oct 30 '11 at 19:14

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You could look into this: http://www.rubyinside.com/camellia-image-processing-from-ruby-20.html

It seems that it does exactly what I need. I could let camellia recognise the location of the licence plate number and then blur that section out.

Does anyone have any comments about using camellia with rails?

answered Oct 30 '11 at 19:14

Mosselman

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Camellia ended up being very bugged and non-functional for my use. I think the library has been given up. Instead there are some other systems that I will look at. – Mosselman Apr 06 '12 at 18:12

Automatically blur numbers and letters using ruby or imagemagick?

2 Answers2