change color "bwperim"

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Rahma Yeni
Rahma Yeni on 16 Apr 2012
Commented: Markus Kokot on 29 Dec 2020
Hello... I got this code form Help MATLAB, in "Detecting a Cell Using Image Segmentation"
BWoutline = bwperim(BWfinal);
Segout = I;
Segout(BWoutline) = 255;
The edge color of that picture is white.. Is possible change the color to another color..?? Thank you.. ^^

Accepted Answer

Walter Roberson
Walter Roberson on 16 Apr 2012
You are working with gray-scale images at present. In order to change the edge color you would have to convert the gray-scale to color.
For example,
SegoutR = I;
SegoutG = I;
SegoutB = I;
%now set yellow, [255 255 0]
SegoutR(BWoutline) = 255;
SegoutG(BWoutline) = 255;
SegoutB(BWoutline) = 0;
SegoutRGB = cat(3, SegoutR, SegoutG, SegoutB);
  4 Comments
Rahma Yeni
Rahma Yeni on 17 Apr 2012
Thank you Image Analyst.. ^^
Markus Kokot
Markus Kokot on 29 Dec 2020
for me it does not work - which picuture name would than be in the end to show in this example ?
and is "I" the imread picture from your beginning which is not in greyscale?

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More Answers (1)

Spandan Tiwari
Spandan Tiwari on 16 Apr 2012
You can change the color by filling the perimeter pixels with a color value instead of a scalar 255. One possible way to do this is as follows:
% First make a RGB image for display:
Segout = repmat(I, [1 1 3]);
% Find indices of the boundary pixels
outline_idx = find(BWoutline);
% Find the indices to fill in the RGB image
Segout_idx = [outline_idx; numel(BWoutline)+outline_idx; ... 2*numel(BWoutline)+outline_idx];
% Select the color (RGB triplet) for the boundary. I choose red.
colorValue = [255; 0; 0]; % For green [0 255 0]
% Prepare a color vector to fill in the RGB image
outline_fill_values = kron(colorValue,ones(size(outline_idx)));
% Fill the RGB image with the color value
Segout(Segout_idx) = outline_fill_values;
% Display the RGB image
figure, imshow(Segout), title('outlined original image');

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