MartyG-RealSense
commented
3 years ago Hi @sergorl When using the High Accuracy preset, accuracy is prioritized over the amount of detail ('fill rate') in the scene. You may get a more detailed scene whilst still achieving accuracy if you use the Medium Density preset that balances between accuracy and fill-rate.
If you have a dark grey carpet as the RGB elements of the images would seem to suggest, you may not get much depth detail from the floor. This is because general physics dictates that dark grey and black colors absorb light, and this makes such surfaces hard for the camera to read depth from unless strong illumination is cast on the surface. The darker the shade of the surface is, the harder it is for the camera to analyze it for depth detail.
In the absence of a strong light source on the floor suface, casting the infrared dot pattern projection onto the floor may help to provide the camera with a texture source to analyze for depth detail.
If fluorescent ceiling lights (lights that have a heated gas inside them instead of a conventional bulb) are in the scene then this may generate noise on the image, because fluorescent lights can flicker at a rate that is hard to see with the human eye. If the lights are fluorescent, setting a camera FPS value close to the operating frequency of the lights may help to reduce the impact. For some lights the appropriate frequency may be 60 FPS and for others it may be 30 FPS. Having said that, I am not convinced that the ceiling lights are a significant factor in your particular scene.
There is the possibility though that your tiled ceiling is creating a repetitive pattern of similar horizontal / vertical arrangements that confuses the camera. This may also cause the kind of floaty 'ghost noise' areas that do not represent the location of actual objects that are appearing in your images. Resources that provide information about this phenomenon and ways to combat it can be found in the link below.
https://github.com/IntelRealSense/librealsense/issues/7792#issuecomment-729017927
Though surfaces can becomore more wavy on a point cloud as the camera becomes further from the observed surface, the extremely distorted waviness you are experiencing may be another form of ghost noise.
sergorl
I use high accuracy preset in "RealSense Viewer". I got point cloud from D455 camera and see all objects (with heights 0.1, 0.2, 0.3 m ) are on distance more than 3 meters are very distorted (especially by height), also I have floor fluctuation with deviation amplitude 0.1 m and looks like point cloud "breathes" - I watch many fluctuations on floor, walls, and objects.
What's the nature of such fluctuations? I want to understand the physics. How can I fix it?