A Kinect® tracker is the technology contained within a peripheral device that is used in conjunction with the Xbox 360®. The internal components of the Kinect® detect and monitor human movement and incorporate these movements into an animated character depicted in compatible games. Individuals participate in game play by movement only but may use props if desired. The device is also capable of facial recognition and allows limited voice commands.
Designed by the Microsoft Corporation, the Kinect® tracker was initially assigned the code name Natal Project. Within 60 days of the Xbox® accessory's public introduction, eight million units were sold. The device consists of a thin rectangular box that connects horizontally to a pivoting base. The unit attaches to the Xbox® via an audio/visual cable. Positioning the Kinect® requires the box to be 2 to six 6 off the floor and placed either above or below the Xbox® unit.
A projector in the Kinect® tracker emits an infrared laser grid into the room. The Kinect® motion sensors, or complimentary metal oxide semiconductor (CMOS) sensors, receive data with any interruption of the grid field. Programmed to recognize human shapes, the sensors translate this information into three dimensional grey scale patterns. The software correlates the images with a human skeleton and creates dozens of lines connecting every joint in the body.
The software contains a library of data that includes hundreds of skeletal movements. When a person performs a position change in front of the Kinect®: tracker, the software interprets the movement as skeletal line changes and immediately recognizes the body position by referencing the database. Data reception and interpretation occur in less than the blink of an eye as the device receives 200 frames per second. The software then transfers these position changes to the game, and animated characters mimic player movement.
Through the Kinect® tracker, players control on/off, menu selections and game play with hand movements. The internal camera and sensors also enable facial recognition, allowing players to log into the Xbox® once the program has recorded a person's face. Four microphones in the device monitor room noise and enable verbal commands that allow the user to open and close the compact disc tray, play a game, play music or video, and return to the menu.
A motor in the Kinect® base tilts the device up or down 27 degrees in either direction and also has a 57 degree horizontal view range. A player typically stands 3.9 to 11 feet (1.2 to 3.5 m) away from the device for adequate detection. The more players involved in a game simultaneously, the more space required between the device and the players. Device instructions suggest individuals use the Kinect® in a well lit room for optimal tracking. Reportedly, the device does not track well when players wear dark colored clothing as the infrared beams are absorbed rather than reflected.