Maskerade for Mac

From bergdesign:

Maskerade is a stand alone application that generates high-accuracy image masks when combined with a special two-shot digital photography technique. With your camera mounted on a tripod, just shoot your object twice with different backgrounds, load them into Maskerade, identify any background lighting gradients, and a high-quality transparency mask is generated for you, with no additional edge detail work required. Extracts perfect sub-pixel masks. Exports as Photoshop file with editable layer mask. Perfect for use with Apple Keynote and Apple Motion.