I am interested in getting an ipad mini for my inlaws so I read up on apple website. It like usual BS about how well the mini is designed with thin edge and incredible software to distinguish between a thumb resting on the thin edge, and real interaction of a thumb with the screen. The ipad 2 I have has pretty smooth intactions with fingers so I don't think doing a running average is the solution. It will lose the responsiveness. Note, the thin edge is too slim to support a thumb. You inevitably touch the screen when holding it in portrait orintation. So tomorrow it comes into the stores.
They may have done it in hardware, with 4 separate touch sensors on each boarder. If you are holding the device with your thumb over the boarder and the edge of the display, your thumb won't count. But how do we confirm with some exploitation?
My thought is that the glass contains carbon that makes it conductive then, the touch sensors are in zones. Two or more sensors take readings to establish x,y coordinates. I would guess each sensor takes a reading one at a time so as to not effect the other sensors electrically.