'Importing OpenCV - import cv2 or cv3, and why does the directory matter?
I am trying to use OpenCV for Python 3 for the first time. To install, I simply typed "pip3 install opencv-python" into the terminal. When I do this, I see in Finder (I'm on a Mac), that in /usr/local/lib/python3.7/site-packages, I now have a new folder called "cv2". This is strange. Why isn't it cv3, as I used pip3? I do not know.
When I try to import cv2 from python3, it says "No module named 'cv2'". Luckily StackOverflow already has a solution: if I first change directories like: "cd /usr/local/lib/python3.7/site-packages" then I will be able to open cv2. I do not know why this step is necessary for OpenCV. I don't have to do this to "import numpy" for example; "numpy" does not care what directory I start from, and it is listed like just another module like cv2.
Anyways, I change directory to site-packages, start python3, and I import cv2. Now there is a new error. This time cv2 is found, but it says:
"from .cv2 import *
ModuleNotFoundError: No module named 'cv2.cv2'"
For the record, I also have Python 2.7. If I try "cd /usr/local/lib/python2.7/site-packages" and then start Python 2.7, I can import cv2. This is ok, but I want to use OpenCV with Python3.
Let me summarize.
(1) How can I get cv2 or cv3 to import when I start from any directory? Is this ever possible?
(2) How can I get cv3 for python3? cv2 seems to be problematic in python3 because because there is no "cv2.cv2"
Solution 1:[1]
The only thing we need to know here is, that 2 in cv2 is not a version. cv2 uses API of C++ while cv uses C API. Version of it is constantly updating being inside CV2.
Solution 2:[2]
There is no cv3 there's only import cv2 that opencv older or latest that is updated for old python or latest.
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Shreejan Shrestha |
| Solution 2 | Ram |