Detecting edges of a card with rounded corners

Question

Hi currently i am working on an OCR reading app where i have successfully able to capture the card image by using AVFoundation framework.

For next step, i need to fi

Answer 1

I know maybe it's too late for this post, but I am posting this in case it might help someone else.

The iOS Core Image framework already has a good tool to detect features such as rectangles (since iOS 5), faces, QR codes and even regions containing text in a still image. If you check out the CIDetector class you'll find what you need. I am using it for an OCR app too, it's super easy and very reliable compared to what you can do with OpenCV (I am not good with OpenCV, but the CIDetector gives much better results with 3-5 lines of code).