I played along with the samples of the OpenCV lib. and now I want to start coding on my own. However with the huge possibilities of the library I am lost here.

The "setup":
Assume a table with playing cards on it. The cards will be arranged in 2 rows, the number of cards per row is not fix, but has a certain number as a max. The size and shape of the cards are all the same, but the pictures on it are different (however, not too complex).
The code should be able to detect each card(picture) and the row of the card.

The problem:
Whats the best solution to that? Haar ? ... etc. I simply don´t know whats the fastest approach is here according to run-time.
Bonus question: If I want to do that stuff on a mobile device is there another faster way ?

best regards