Dark region in camera images

Hi! I am trying the quadruped with vision simulation
https://docs.omniverse.nvidia.com/app_isaacsim/app_isaacsim/ext_omni_isaac_quadruped.html

However, I noticed that on the lower side of the camera images, there are some dark regions. I’m not sure what that is, but it is certainly not surrounding obstacles/terrain color. The video example in the above link also shows similar problem. Any idea about this?

Thanks!

@anahrendra can you provide a screenshot that shows the issue?
The dark region I see is a shadow caused by the lighting and scene geometry