ScryGlass is a card scanning utility for Android that uses the phone's camera to recognize, inventory, and price cards for Magic: The Gathering. It uses "whole card" image recognition, and does not need to have a precisely aligned image of the card's artwork or title. Simply place the card on a clear surface where the entire border of the card can be seen (you may need to back your phone up a bit) and the card will be recognized.

If there is glare, or if the scanner can't see a clear border ALL the way around the card, then scanning will not work very well. Scanning through sleeves generally works well so long as there isn't glare.