Can't detect multiple QR codes in an image

Hi all!
I’m trying to detect multiple QR codes in a single image.

I’m using VL.OpenCV, and QRCodeDetector but it seems like it’s only capable of detecting one QR code at the time, as it only outputs a String, not a Spread.

I looked inside the QRCodeDetector, and saw that it’s using DetectAndDecode() method. From OpenCV documentation, there is another method called DetectAndDecodeMulti(). But this one doesn’t seem to be part of VL.OpenCV yet.

I could find DetectMulti() and DecodeMulti() in VL.OpenCV but I didn’t managed to use them: I constantly get the error points.size().width > 0 with DecodeMulti().

Did someone already find a way to detect multiple QR codes in a image with QRCodeDetector, or other method?


The DetectMulti node has a Result output which you have to use as a condition when calling the DecodeMulti node. ie. only call the latter if the former was successful.

Aaah, I see!
Yeah, now it outputs multiple results.
I have to understand those EpsilonX and EpsilonY values for now as it doesn’t make much sense to me.

For information :

This has been added in VL.OpenCV as of version 2.2.0


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