iOS/iPhone/iPad: Determine the size of an object lying on a business card

Question

I have a standard business card of known size and I want to open a video stream and snap a hi-res picture of the business card when the appropriate size is reached. For example, if I hover over a business card, the picture is snapped when the scale is correct and I hover over the same card and the picture is snapped again when the scale is correct. If I looked at both images, I want to the business card to be the same size.

A standard business card is 88.9 × 50.8mm or 3.5 × 2" 1.75 ratio.

When the video represents the business card in this scale, I want to immediately snap a hi res photo.

Does anyone have any recommendations on how to do this? What library would be useful for this if there is one?

I guess the way I'd approach it would be to measure the box in the video and when the box meets the measurements above, the picture gets snapped, but I have clue on how I could achieve this.

Answer 1

If I were you, I would start looking for some kind of library related to the computer vision. One well known example is OpenCV. I've never used OpenCVpersonally, but I know for sure that there are a lot of documentation out there. OpenCV link

I hope it helps. Good luck!

Paolo