ERROR: Could not build wheels for opencv-python which use PEP 517 and cannot be installed directly

Question

I was trying to install OpenCV4 in a docker on jetson nano. It has jetpack 4.4 s os. The docker was successfully created and Tensorflow is running but while installing OpenCV using pip it is showing CMake error.

root@5abf405fb92d:~# pip3 install opencv-python
Collecting opencv-python
  Downloading opencv-python-4.4.0.42.tar.gz (88.9 MB)
     |████████████████████████████████| 88.9 MB 2.5 kB/s 
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Requirement already satisfied: numpy>=1.13.3 in /usr/local/lib/python3.6/dist-packages (from opencv-python) (1.18.4)
Building wheels for collected packages: opencv-python
  Building wheel for opencv-python (PEP 517) ... error
  ERROR: Command errored out with exit status 1:
   command: /usr/bin/python3 /usr/local/lib/python3.6/dist-packages/pip/_vendor/pep517/_in_process.py build_wheel /tmp/tmpqpzwrofy
       cwd: /tmp/pip-install-93nxibky/opencv-python
  Complete output (9 lines):
    File "/tmp/pip-build-env-o_hualnr/overlay/lib/python3.6/site-packages/skbuild/setuptools_wrap.py", line 560, in setup
      cmkr = cmaker.CMaker(cmake_executable)
    File "/tmp/pip-build-env-o_hualnr/overlay/lib/python3.6/site-packages/skbuild/cmaker.py", line 95, in __init__
      self.cmake_version = get_cmake_version(self.cmake_executable)
    File "/tmp/pip-build-env-o_hualnr/overlay/lib/python3.6/site-packages/skbuild/cmaker.py", line 82, in get_cmake_version
      "Problem with the CMake installation, aborting build. CMake executable is %s" % cmake_executable)
  Traceback (most recent call last):
  
  Problem with the CMake installation, aborting build. CMake executable is cmake
  ----------------------------------------
  ERROR: Failed building wheel for opencv-python
Failed to build opencv-python
ERROR: Could not build wheels for opencv-python which use PEP 517 and cannot be installed directly

Answer 1

I had the same problem and i did this,

pip install --upgrade pip setuptools wheel

then install opencv again,

pip install opencv-python

this worked for me

Answer 2

Yes .. Finally found a work around. Follow this https://github.com/mdegans/nano_build_opencv and build from source and finally gets installed.

PS: It may take a bit long for building, for me it took 10 Hrs :P.

Happy Image-Processing..