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sklearn.feature_extraction.image.img_to_graph(img, mask=None, return_as=<class 'scipy.sparse.coo.coo_matrix'>, dtype=None)[source]

Graph of the pixel-to-pixel gradient connections

Edges are weighted with the gradient values.

Read more in the User Guide.


img : ndarray, 2D or 3D

2D or 3D image

mask : ndarray of booleans, optional

An optional mask of the image, to consider only part of the pixels.

return_as : np.ndarray or a sparse matrix class, optional

The class to use to build the returned adjacency matrix.

dtype : None or dtype, optional

The data of the returned sparse matrix. By default it is the dtype of img


For sklearn versions 0.14.1 and prior, return_as=np.ndarray was handled by returning a dense np.matrix instance. Going forward, np.ndarray returns an np.ndarray, as expected.

For compatibility, user code relying on this method should wrap its calls in np.asarray to avoid type issues.