`skimage.graph._graph:pixel_graph`

source: /dev/scikit-image/src/skimage/graph/_graph.py :34

Signature

   def     pixel_graph (    image    ,  * ,     mask    =  None   ,    edge_function    =  None   ,    connectivity    =  1   ,    spacing    =  None   ,    sparse_type    =  matrix     )

Summary

Create an adjacency graph of pixels in an image.

Extended Summary

Pixels where the mask is True are nodes in the returned graph, and they are connected by edges to their neighbors according to the connectivity parameter. By default, the value of an edge when a mask is given, or when the image is itself the mask, is the Euclidean distance between the pixels.

However, if an int- or float-valued image is given with no mask, the value of the edges is the absolute difference in intensity between adjacent pixels, weighted by the Euclidean distance.

Parameters

image : array: The input image. If the image is of type bool, it will be used as the mask as well.
mask : array of bool: Which pixels to use. If None, the graph for the whole image is used.
edge_function : callable: A function taking an array of pixel values, and an array of neighbor pixel values, and an array of distances, and returning a value for the edge. If no function is given, the value of an edge is just the distance.
connectivity : int: The square connectivity of the pixel neighborhood: the number of orthogonal steps allowed to consider a pixel a neighbor. See scipy.ndimage.generate_binary_structure for details.
spacing : tuple of float: The spacing between pixels along each axis.
sparse_type : {"matrix", "array"}, optional: The return type of graph, either scipy.sparse.csr_array or scipy.sparse.csr_matrix (default).

Returns

graph : scipy.sparse.csr_matrix or scipy.sparse.csr_array: A sparse adjacency matrix in which entry (i, j) is 1 if nodes i and j are neighbors, 0 otherwise. Depending on sparse_type, this can be returned as a scipy.sparse.csr_array.
nodes : array of int: The nodes of the graph. These correspond to the raveled indices of the nonzero pixels in the mask.

Aliases

skimage.graph.pixel_graph