There is a problem with the face depth map

[FUWhy]

I tried to generate some depth maps, but the results were strange, the depth maps seemed to be the same across different faces. My anconda environment is as follows： Ubuntu20.04 ,docker based python 3.6.13 tensorflow-gpu 1.15.0 dlib 19.24.99 opencv-python 4.7.0.72 I tested it directly using demo.py，The results are as follows： test 1: test 2: test 3: I tried to solve the problem, but without success. I don't know what the problem is，I hope you can get some help. Thank you.