[Chicago] OpenALPR - Transformations

[Jordan Bettis]

I've not used OpenALPR but mathematically what you need is projective
geometry.

Presumably you should be able to obtain reference shape like that of the
license plate itself.

It will be a quadrilateral that won't be a rectangle unless your line of
sight is perpendicular to the plate's plane. Your job is determine the
geometric transformations you need to turn it into a rectangle. Then,
apply the same transformations to the contents of the image.

Here's an example of transforming an irregular quadrilateral into a
rectangle using scikit-image:

http://stackoverflow.com/questions/33283088/transform-irregular-quadrilateral-to-rectangle-in-python-matplotlib#33288851

On 11/03/2016 02:52 PM, Chris Vinzons wrote:
> Hi,
> 
> I'm using OpenALPR to read still license plates, but the thing is that
> my sometimes that it doesn't read it correctly. I think this is because
> of the license plate is tilted. Is there a way to untilt it or is there
> some kind of training data I could do in python?
> 
> 
> Thanks
> 
> Chris V
> 
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