c++ – Is a shadow with parallax effect expected from libfreenect and Xbox 360?

I’m using libfreenect v0.7.5 (latest) on the recent raspberry pi OS (trixie, Debian 13.1) on a Raspberry Pi 5/16GB.

I see the following symptom with my own code using the Python wrappers and the distributed CPP examples in the freenect repository.

All depth sensor depth maps have a “shadow” blacked out in the depth map that is parallel to shapes in the depth map. The shadow’s offset from the actual shape decreases as the shapes distance from the sensor increases. The shadow disappears at around 4 feet from the sensor.

The attached image is a picture of the freenect demo ‘freenect-cppview’ built as part of the library install:

All demos show the same effect.

I’ve disabled the RGB camera, even covering it with tape to make sure it was not the source of this.

In my own code, I’ve tried the different depth map formats “_MM” and “_REGISTERED” which made no difference.

To reproduce:

clone the repo at github.com/OpenKinect/libfreenect
Follow build instructions with default options
Connect an Xbox 360 sensor to a USB 3.0 port
Run bin/freenect-cppview