Show Coordinates and/or Color of the found Boundaries

Hello,

i´ve some problems solving my Issues with my program. First of all, the program should find the edges of some blocks. For that i used "bwboundaries". Now my blocks are marked. Now i have to, somehow, get the coordinates and the color (RGB-Code or exact color)of each block, but i´ve no idea how that should work. I attach you a picture of my current status and my code in matlab. Thanks in advance!

Code:

I = imread('test.jpg');
G = rgb2gray(I);
subplot(2, 1, 2);
imshow(I);
title('Originalbild');

set(gcf, 'Position', get(0,'Screensize'));

C = edge(G,'canny');
subplot(2, 2, 2);
imshow(C);
title('CannyEdge');

subplot(2, 2, 1);
imshow(G);
hold on;
title('Kanten markiert');

Raender = bwboundaries(C);
for k =1:length(Raender);
    R = Raender{k};
    plot(R(:,2),R(:,1),'g','LineWidth',3);
end
hold off

Answer 1

[Vidya Viswanathan]

The function "bwboundaries" traces the exterior boundaries of objects, as well as boundaries of holes inside these objects. It returns a P x 1 cell array, where P represents the number of objects or holes. Each cell in the cell array contains a Q x 2 matrix where Q represents the number of boundary pixel for the corresponding region. Each row in the matrix contains the row and column coordinates of the boundary pixel. I believe this addresses your first question.

In regard to your query on obtaining the color of the boundary pixel, you can use the original image matrix I and the coordinates of the boundary pixels. If 'r' represents the row coordinate and 'c' represents the column coordinate, the pixel intensity at location (r,c) can be found using I(r,c,:) (if I is not a 2D matrix). In case I is a grayscale or binary image, the pixel intensity is directly computed using I(r,c).