Skeletal Tracking
Kinect for Windows 1.5, 1.6, 1.7, 1.8
- Overview
- Field of View
- Skeletal Tracking Precision and Multiple Kinect Sensors
Overview
Skeletal Tracking allows Kinect to recognize people and follow their actions.
Using the infrared (IR) camera, Kinect can recognize up to six users in the field of view of the sensor. Of these, up to two users can be tracked in detail. An application can locate the joints of the tracked users in space and track their movements over time.
Figure 1. Kinect can recognize six people and track two
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Skeletal Tracking is optimized to recognize users standing or sitting, and facing the Kinect; sideways poses provide some challenges regarding the part of the user that is not visible to the sensor.
To be recognized, users simply need to be in front of the sensor, making sure the sensor can see their head and upper body; no specific pose or calibration action needs to be taken for a user to be tracked.
Figure 2. Skeleton tracking is designed to recognize users facing the sensor
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Field of View
Kinect field of view of the users is determined by the settings of the IR camera, which are set with the DepthRange Enumeration.
In default range mode, Kinect can see people standing between 0.8 meters (2.6 feet) and 4.0 meters (13.1 feet) away; users will have to be able to use their arms at that distance, suggesting a practical range of 1.2 to 3.5 meters. For more details, see the k4w_hig_main.
Figure 3. Kinect horizontal Field of View in default range
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Figure 4. Kinect vertical Field of View in default range
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In near range mode, Kinect can see people standing between 0.4 meters (1.3 feet) and 3.0 meters (9.8 feet); it has a practical range of 0.8 to 2.5 meters. For more details, see Tracking Skeletons in Near Depth Range.
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Skeletal Tracking Precision and Multiple Kinect Sensors
The infrared emitter of a Kinect sensor projects a pattern of infrared light. This pattern of light is used to calculate the depth of the people in the field of view allowing the recognition of different people and different body parts. If you use more than one Kinect sensor to illuminate the target area, you may notice a reduction in the accuracy and precision of skeletal tracking due to interference with the infrared light sources. To reduce the possibility of interference, it is recommended that no more than one Kinect sensor (or infrared light source) points to a field of view where skeletal tracking is being done.
In This Section
Skeletal Joint Smoothing White Paper
Describes the filtering techniques and best practices for using skeleton joint data for Kinect-enabled titles. Also helps developers choose an appropriate filtering technique and fine-tune the filter parameters to match the specific needs of a Kinect-enabled application.