MacRumors has discovered a patent application filed by Apple that highlights use of finger gesture over camera on iPhone to control features like voicemail playback, pause and rewind, while holding the phone near your ear. Apple also describes use of accelerometer to detect finger tapping for controlling iPhone functions. In the patent application Apple explains:

In one embodiment, to access his voice mailbox, a user may tap the phone to cause playback of message to pause, tap the phone again to resume playback, swipe his finger over the camera lens in one direction to fast forward playback, and swipe his finger over the camera lens in another direction to rewind playback. These actions allow the user to control functions of voicemail review without removing the device from over his ear.

In another embodiment, functions for controlling call features utilize similar user actions or motions. Features such as merging multiple calls, putting a call on hold, and switching between or among multiple simultaneous calls may be controlled by single or double (or any number of) taps of the device, as detected by an accelerometer of the device. These taps may be preprogrammed by a manufacturer, or selected and programmed by a user.

In the patent application Apple also describes use of finger swipe over camera for navigation in a document or application. The patent application shows interesting use of camera and accelerometer on an iPhone, but will these functionality ever ship on an actual product is everyone’s guess.