1. Consider the connected component (cc) labeling algorithm involving single pass of an operator
propagating labels and keeping equivalences.
abc
dp
where p is the pixel under consideration. Explain in the form of a table what happens in the algorithm
for all possible states (There are 16 possible states for the 4 binary variables for the case of p=1). Also
give examples on simple images.
2. Consider the CC labeling algorithm that uses memory after a single pass of the operator described in
question 1. Develop and describe an algorithm that implements this idea, creating unique labels for
each connected component by checking an equivalence table.
3. Write a computer program that applies the second connected component labeling algorithm that was
discussed in class. Recall that this algorithm propagates the unique labels in a single top down scan by
checking the neighbors at positions "a" "b" "c" "d" for each pixel "p" considering the pattern shown
above. It should complete the labeling using an equivalence table.
This program should:
- Use a threshold value "128" to convert the image to a binary image.
- Create unique labels for each foreground pixel positions and store them in a 2D long int array.
- Initialize a data structure to keep and manage an equivalence table.
- Scan the image in a top-down pass and at every pixel position:
* Change the label of pixel "p" using the min label from the labels of "a" "b" "c" "d".
* Update the equivalence table using part 1 and 2.
- When the top-down pass is complete, assign a single label for equivalent labels and:
* Print the number of components on screen.
* Assign discriminating gray values for each CC label and show the result on screen. E.g. if there are
10 distinct labels The first label can be assigned as 25 which is (int)(255/10) and the other labels are 50,
75,100,125...
