I am using a raspberry pi 3 with raspbian buster and python 3.7.3.
I can install packages fine in my virtual environment using pip3 install. This can be seen when I use the command pip list, all my packages come up correctly:
(cv) pi@raspberrypi:~ $ pip list
Some of these packages are fine, like numpy and pip. However, when I try to import the packages I "pip3 installed" in my virtual environment, it comes up with the ModuleNotFoundError such as with dlib:
>>> import dlib Traceback (most recent call last): File "stdin", line 1, in module ModuleNotFoundError: No module named 'dlib'