mirror of
https://github.com/wassname/scikit-image.git
synced 2026-07-05 10:34:17 +08:00
Vighnesh Birodkar
89 lines
2.4 KiB
Python
89 lines
2.4 KiB
Python
import networkx as nx
|
|
from skimage import util
|
|
from ._build_rag import construct_rag_meancolor_2d
|
|
from ._build_rag import construct_rag_meancolor_3d
|
|
|
|
|
|
class RAG(nx.Graph):
|
|
|
|
"""
|
|
The class for holding the Region Adjacency Graph (RAG).
|
|
|
|
Each region is a contiguous set of pixels in an image, usuall
|
|
sharing some common property.Adjacent regions have an edge
|
|
between their corresponding nodes.
|
|
"""
|
|
|
|
def merge_nodes(self, i, j):
|
|
"""Merges nodes `i` and `j`.
|
|
|
|
The new combined node is adjacent to all the neighbors of `i`
|
|
and `j`. In case of conflicting edges, edge with higher weight
|
|
is chosen.
|
|
|
|
Parameters
|
|
----------
|
|
i : int
|
|
Node to be merged.
|
|
j : int
|
|
Node to be merged.
|
|
|
|
"""
|
|
|
|
if not self.has_edge(i, j):
|
|
raise ValueError('Cant merge non adjacent nodes')
|
|
|
|
for x in self.neighbors(i):
|
|
if x == j:
|
|
continue
|
|
w1 = self.get_edge_data(x, i)['weight']
|
|
w2 = -1
|
|
if self.has_edge(x, j):
|
|
w2 = self.get_edge_data(x, j)['weight']
|
|
|
|
w = max(w1, w2)
|
|
|
|
self.add_edge(x, j, weight=w)
|
|
|
|
self.node[j]['labels'] += self.node[i]['labels']
|
|
self.remove_node(i)
|
|
|
|
|
|
def rag_meancolor(img, labels):
|
|
"""Computes the Region Adjacency Graph of a color image using
|
|
difference in mean color of regions as edge weights.
|
|
|
|
Given an image and its segmentation, this method constructs the
|
|
corresponsing Region Adjacency Graph (RAG).Each node in the RAG
|
|
represents a contiguous pixels with in `img` the same label in
|
|
`arr`
|
|
|
|
Parameters
|
|
----------
|
|
img : (width, height, 3) or (width, height, depth, 3) ndarray
|
|
Input image.
|
|
arr : (width, height) or (width, height, depth) ndarray
|
|
The array with labels.
|
|
|
|
Returns
|
|
-------
|
|
out : RAG
|
|
The region adjacency graph.
|
|
|
|
Examples
|
|
--------
|
|
>>> from skimage import data,graph,segmentation
|
|
>>> img = data.lena()
|
|
>>> labels = segmentation.slic(img)
|
|
>>> rag = graph.rag_meancolor(img, labels)
|
|
|
|
"""
|
|
|
|
img = util.img_as_ubyte(img)
|
|
if img.ndim == 4:
|
|
return construct_rag_meancolor_3d(img, labels)
|
|
elif img.ndim == 3:
|
|
return construct_rag_meancolor_2d(img, labels)
|
|
else:
|
|
raise ValueError("Image dimension not supported")
|