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The PlayStation Move: Motion Detection Gets A Sony-Sanctioned, Academic- And Enthusiast-Developer Groove

Microsoft, with Kinect for the Xbox 360, doesn't have an 'exclusive' on motion-based game console control. Nintendo’s Wii game console released in late 2006 was the trendsetter in this regard, although the company's approach isn't vision-based (at least in the visible light spectrum, that is). The first-generation Wii Remote combines two key circuit subsystems to accomplish its motion sensing magic. A three-axis accelerometer detects spatial position changes over time, while an image sensor detects infrared emissions from the Sensor Bar, usually located above the television, to discern each player’s position in front of the display. A Bluetooth-based wireless protocol relays the data from the Wii Remote back to the game console.

Nintendo subsequently released the MotionPlus accessory, which contained a two-axis tuning fork gyroscope and, when mated to the Wii Remote and used with MotionPlus-cognizant games, enabled more precise real-time location and motion detection. MotionPlus functionality has subsequently been integrated into the Wii Remote Plus controller. And even more recently (last September, to be exact), Sony began selling the Move peripheral for its PlayStation 3 console. Like the Wii Remote, PlayStation Move communicates with the console over Bluetooth. And Move implements a conceptually similar functional subset of the Wii Remote (and Plus) controller, as Wikipedia notes:

A pair of inertial sensors inside the controller, a three-axis linear accelerometer and a three-axis angular rate sensor, are used to track rotation as well as overall motion. An internal magnetometer is also used for calibrating the controller’s orientation against the Earth’s magnetic field to help correct against cumulative error (drift) by the inertial sensors.

However, whereas the Wii Remote embeds an image sensor that captures infrared photons originating at the TV-located Sensor Bar, PlayStation Move in a sense works in reverse, with the location-tracking light source embedded within the motion controller and the image sensor at the console-located PlayStation Eye camera (augmented or supplanted, in some games such as EA Sports Active 2, by Bluetooth-broadcasting transmitters strapped to various locations on players' bodies). Wikipedia again:

The PlayStation Move motion controller features an orb at the head, which can glow in any of a full range of colors using RGB light-emitting diodes (LEDs). Based on the colors in the user environment captured by the PlayStation Eye webcam, the system dynamically selects an orb color that can be distinguished from the rest of the scene. The colored light serves as an active marker, the position of which can be tracked along the image plane by the PlayStation Eye. The uniform spherical shape and known size of the light also allows the system to simply determine the controller’s distance from the PlayStation Eye through the light’s image size, thus enabling the controller’s position to be tracked in three dimensions with high precision and accuracy. The sphere-based distance calculation allows the controller to operate with minimal processing latency, as opposed to other camera-based control techniques on the PlayStation 3.

So what's the 'news' angle on this technology overview? In early February, likely in part due to a desire to 'get ahead' of rumors (which became true later that same month) of Microsoft's Kinect SDK aspirations, Sony 'leaked' that it was planning to bring PlayStation Move support to the PC. And one month later, the company unveiled, another planned attempt to expand PlayStation Move usage., a server application that runs on a PS3 (which subsequently transfers Move data to a LAN-tethered PC), enables 'the masses' (versus, previously, only licensed developers) to create motion-augmented programs.

Sony originally planned on releasing some time later that spring, but in the company's defense, Sony was subsequently and substantially waylaid by console and service hacks. Waylaid...but ultimately not denied. went live on the PlayStation Store yesterday. Quoting from the corporate blog post which announced the news:

Later today, will be available as a complimentary download for members of Academia including Academic researchers, faculty, staff, and students. Interested participants can apply for the Academia Program here. For all other users, will be available later today on the PlayStation Store for $99.99.

For more information, check out the portal home page, along with the community page and this demonstration video.