Thesis (PDF) - Signal & Image Processing Lab

Algorithm 4 RAG image representation
The gray-level image can be represented as a graph, where each node stands for the
image flat zones and the edges connect all the neighboring nodes. The algorithm,
that we have developed for graph building, involves the following stages:
1: Initialize current label to zero. Mark all pixels as not processed. Start arbitrary
from the image border. Insert all the pixels of the image border into fifo1 .
2: if fifo1 is not empty then
3: Get pixel current p1 from fifo1 .
4: if this pixel was not processed yet then
5: Increment emcurrent label, give this new current label to the current pixel
current p1 and insert this pixel into the fifo2 . Go to 12.
6: else
7: Go to 2.
8: end if
9: else
10: End algorithm.
11: end if
12: if fifo2 is not empty then
13: Get pixel current p2 from fifo2 .
14: else
15: Go to 2.
16: end if
17: for every neighbor of the current pixel current p2 do
18: if it was not processed yet then
19: if it belongs to the same flat zone as current p2 then
20: Insert it into fifo2 .
21: else
22: Insert it into fifo1 .
23: end if
24: else
25: if it belongs to another flat zone then
26: Then connect this flat zone in the graph to the current flat zone.
27: Go to 12.
28: end if
29: end if
30: end for
115