"""
===========
RAG Merging
===========

This example constructs a Region Adjacency Graph (RAG) and progressively merges
regions which are similar in color. Merging two adjacent regions produces
a new regions with all the pixels from the merged regions. Regions are merged
till no two adjacent regions are similar enough.

"""

from skimage import graph, data, io, segmentation, color


img = data.coffee()
labels = segmentation.slic(img, compactness=30, n_segments=400)
g = graph.rag_mean_color(img, labels)
labels2 = graph.merge_hierarchical(g, labels, 40)
g2 = graph.rag_mean_color(img, labels2)

out = color.label2rgb(labels2, img, kind='avg')
out = segmentation.mark_boundaries(out, labels2, (0, 0, 0))
io.imshow(out)
io.show()