Kinect for Windows 1.6, 1.7, 1.8
Infrared (IR) light is electromagnetic radiation with longer wavelengths than those of visible light. As a result, infrared light is used in industrial, scientific, and medical applications to illuminate and track objects without visible light.
The depth sensor generates invisible IR light to determine an object's depth (distance) from the sensor. The primary use for the IR stream is to improve external camera calibration using a test pattern observed from both the RGB and IR camera to more accurately determine how to map coordinates from one camera space to another. You can also use IR data to capture an IR image in darkness as long as you provide your own IR source.
The infrared stream is not really a separate data stream, but a particular configuration of the color camera stream.
Infrared data is available in the following format.
|Infrared||16 bits, using the top 10 bits from a PixelFormats.Gray16 format (with the 6 least significant bits always set to 0). To work with infrared data, specify NUI_IMAGE_TYPE_COLOR_INFRARED for C++ and InfraredResolution640x480Fps30 for managed code when you open an infrared data stream.|
There is only one color image stream available per sensor. The infrared image stream is provided by the color image stream, therefore, it is impossible to have a color image stream and an infrared image stream open at the same time on the same sensor.
As there is only one color image stream available per sensor, attempting to open a second color image stream on a given sensor does NOT open a second stream but resets the existing color image stream to the parameters specified in the second open call.