Abstract: Feedback is provided when an optical navigation device acquires an image that is not suitable for navigation purposes. An image sensor embedded within the optical navigation device acquires an image of a surface. An image monitor determines the navigability of the captured image and generates a signal indicative of the image's navigability. A comparator compares the signal to a threshold navigability level. When the image navigability is determined to be below the threshold and thus non-navigable, the comparator asserts a feedback signal. The feedback signal may trigger a variety of feedback mechanisms to alert the user that the surface is non-navigable. Possible feedback mechanisms include a warning message on a display screen, an illuminated light on the optical navigation device, or an audible sound.