As MacNN reported yesterday, the USPTO recently granted patent 7,566,858 to Apple. This patent helps remote control systems “distinguish predetermined light sources from stray light sources” and relates specifically to the Apple TV.

Like the vast majority of home entertainment device remotes, the controller bundled with the Apple TV uses infrared signals. These are low cost and relatively easy to implement, but they have some issues. One is that infrared signals cannot penetrate opaque objects, and so require “line of sight.” Another is that there are other everyday sources of infrared radiation, so the “noise level” can be high, limiting effective range. Perhaps the most common source of infrared radiation is sunlight, so you may have noticed that your TV remote works better at night than when the sun is pouring in at noonday.

For simple commands (power on/off, changing the volume, etc), this noise is not much of a problem. But for more complicated applications — those sending more information in each signal — noise from sunlight or reflections from other remote controls can cause a problem, and Apple now has a patent on a method to remedy the situation.

What kinds of applications might these be? Glad you asked. The Nintendo Wii actually uses two kinds of technology in its remote controls. It uses Bluetooth — a radio frequency signal — to send information about button presses and accelerometer data, but it also uses good old infrared for motion tracking, as this (very cool) video from Johnny Chung Lee at Carnegie Mellon shows:

Is this another spoke in the wheel of Apple’s possible plans to turn the Apple TV into a stealth gaming device, perhaps with iPhone or iPod touch controllers?