Get "-inf" values from camera sensors. What causes the "-inf" value in the image tensor?

Hi team,
When I got depth image tensors from camera sensors, I got an “-inf” value of one pixel. However, there is no unmeasurable situation exists. The white dot in the top right corner of the image below is the pixel of “-inf”.


The camera is attached with gripper.
What causes the “-inf” value in the image tensor?

And the image below is my environment.