Optical navigation upon grainy surfaces using multiple navigation sensors

Abstract

A mouse for navigating upon grainy surfaces is equipped with at least two optical navigation circuits having different views of the work surface and whose axes may be non-parallel. For each navigation circuit an indication of navigation impairment owing to grain is detected. A suitable algorithm chooses from among the various navigation circuits which one's output to use. The multiple optical navigation circuits can each be separate self-contained mechanisms on separate dies or they can be separate sections of a single integrated circuit. The various metrics used within a navigation circuit for spatial filter selection can be further used by the navigation circuit selection algorithm. Each optical navigation circuit can have its own light source, or they can share a common one. They may also share any imaging optics, although each navigation sensor sees a different image. If the optical navigation sensors have non-parallel axes, their indications of incremental movement are converted to a common framework within the mouse as an adjunct to the navigation selection algorithm.