code: def test_gaussian_structural_similarity_vs_IPOL():
      """Tests vs. imdiff result from the following IPOL article and code:
      https://www.ipol.im/pub/art/2011/g_lmii/.
  
      Notes
      -----
      To generate mssim_IPOL, we need a local copy of cam_noisy:
  
      >>> from skimage import io
      >>> io.imsave('/tmp/cam_noisy.png', cam_noisy)
  
      Then, we use the following command:
      $ ./imdiff -m mssim <path to camera.png>/camera.png /tmp/cam_noisy.png
  
      Values for current data.camera() calculated by Gregory Lee on Sep, 2020.
      Available at:
      https://github.com/scikit-image/scikit-image/pull/4913#issuecomment-700653165
      """
      mssim_IPOL = 0.357959091663361
      assert cam.dtype == np.uint8
      assert cam_noisy.dtype == np.uint8
      mssim = structural_similarity(
          cam,
          cam_noisy,
          gaussian_weights=True,
          use_sample_covariance=False,
      )
      assert_almost_equal(mssim, mssim_IPOL, decimal=3)
  
file_path: scikit-image/skimage/metrics/tests/test_structural_similarity.py
imports: import numpy
  import pytest
  from numpy.testing import assert_equal, assert_almost_equal
  from skimage import data
  from skimage._shared._warnings import expected_warnings
  from skimage._shared.utils import _supported_float_type
  from skimage.metrics import structural_similarity
label_desc: Use image node_id 8 for calling a global function with example usage: test_gaussian_structural_similarity_vs_IPOL() without return types