How to annotate border around original RGB image

So I have a RGB image with two tags, I have binarized the image, removed the noise so it is just the two tags remaining. I have used rangefilt to then extract the border of each tag.

I now want to place the borders of the tag back on the original RGB image, with the border lines having 2 different colours for each tag. I am unsure how to do this, I have tried to use bwboundaries but this is unable to give me the outcome I desire with just the different colour borders alone on top of the original image.

The code:

clear all;

close all;

clc;

RGB = imread('tagPhoto.bmp');

%Yellow Tag

yellowChannel1Min = 0.000;

yellowChannel1Max = 255.000;

yellowChannel2Min = 71.000;

yellowChannel2Max = 255.000;

yellowChannel3Min = 0.000;

yellowChannel3Max = 40.000;

yellowSliderBW = (RGB(:,:,1) >= yellowChannel1Min ) & (RGB(:,:,1) <= yellowChannel1Max) & ...

(RGB(:,:,2) >= yellowChannel2Min ) & (RGB(:,:,2) <= yellowChannel2Max) & ...

(RGB(:,:,3) >= yellowChannel3Min ) & (RGB(:,:,3) <= yellowChannel3Max);

yellowBW = yellowSliderBW;

yellowMorph = imclose(yellowBW, ones(25));

%Red Border

redChannel1Min = 71.000;

redChannel1Max = 255.000;

redChannel2Min = 0.000;

redChannel2Max = 41.000;

redChannel3Min = 0.000;

redChannel3Max = 54.000;

redSliderBW = (RGB(:,:,1) >= redChannel1Min ) & (RGB(:,:,1) <= redChannel1Max) & ...

(RGB(:,:,2) >= redChannel2Min ) & (RGB(:,:,2) <= redChannel2Max) & ...

(RGB(:,:,3) >= redChannel3Min ) & (RGB(:,:,3) <= redChannel3Max);

redBW = redSliderBW;

redSE = strel("rectangle",[5 4]);

redOpen = imopen(redBW, redSE);

redMorph = imclose(redOpen, ones(25));

unionBW = redMorph | yellowMorph;

border = rangefilt(unionBW);

Input Image:

Binarised Image & Removed Noise:

Image with just borders (want to put over Input Image with different colours):

[Shaista K]

hi good day can you please tell me how to find the centroid and region props readin on both these tags?

[DGM]

% this is the mask that would be generated in the given code
% i'm just going to load a copy instead of pasting the entire thing again
unionBW = imread('union.png');

S = regionprops(unionBW,'area','centroid') % S is a struct of properties for all objects

S = 2×1 struct array with fields:
    Area
    Centroid

vertcat(S.Area) % for example, show the areas 

ans = 2×1

2795 2947

vertcat(S.Centroid) % for example, show the centroids 

ans = 2×2

89.2483 255.9213 498.7177 258.3529

Answer 1

[DGM]

This is actually a good case for imoverlay(). The one thing imoverlay() does is render a binary mask as a colored overlay on an image.

RGB = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1179438/image.bmp');

%Yellow Tag
yellowChannel1Min = 0.000;
yellowChannel1Max = 255.000;
yellowChannel2Min = 71.000;
yellowChannel2Max = 255.000;
yellowChannel3Min = 0.000;
yellowChannel3Max = 40.000;
yellowSliderBW = (RGB(:,:,1) >= yellowChannel1Min ) & (RGB(:,:,1) <= yellowChannel1Max) & ...
    (RGB(:,:,2) >= yellowChannel2Min ) & (RGB(:,:,2) <= yellowChannel2Max) & ...
    (RGB(:,:,3) >= yellowChannel3Min ) & (RGB(:,:,3) <= yellowChannel3Max);
yellowBW = yellowSliderBW;

%Red Border
redChannel1Min = 71.000;
redChannel1Max = 255.000;
redChannel2Min = 0.000;
redChannel2Max = 41.000;
redChannel3Min = 0.000;
redChannel3Max = 54.000;
redSliderBW = (RGB(:,:,1) >= redChannel1Min ) & (RGB(:,:,1) <= redChannel1Max) & ...
    (RGB(:,:,2) >= redChannel2Min ) & (RGB(:,:,2) <= redChannel2Max) & ...
    (RGB(:,:,3) >= redChannel3Min ) & (RGB(:,:,3) <= redChannel3Max);
redBW = redSliderBW;

yellowMorph = imclose(yellowBW, ones(25));
redSE = strel("rectangle",[5 4]);
redOpen = imopen(redBW, redSE);
redMorph = imclose(redOpen, ones(25));
unionBW = redMorph | yellowMorph;
border = rangefilt(unionBW);

outpict = imoverlay(RGB,border,'g'); % pick any color

imshow(outpict)

If you want each border object to be a different color (i.e. a color from a colormap), you can use labeloverlay() instead.

L = bwlabel(border);
outpict = labeloverlay(RGB,L,'colormap',hsv(6));

imshow(outpict)

[Ted]

Amazing, thanks.

This is exactly what I was looking for.

[Shaista K]

I'm looking for this as well but im not sure how to individually set a particular color around each tag, as well as to make them thicker and easliy distingushable without having to zoom up to properly see the outline. would you be able to help with that?

[DGM]

Just considering the last part of the above code:

% ...

% create a colormap for all the objects
% this can be literally constructed, or you can use
% colormap tools like jet(), parula(), etc
mycolormap = [0.5 0 1; 1 0 0.5];

% if you want the border to be thicker, you could dilate it
fatborder = imdilate(border,strel('disk',5)); % set size

L = bwlabel(fatborder);
outpict = labeloverlay(RGB,L,'colormap',mycolormap);
imshow(outpict)

The ordering of the colors corresponds to the ordering of the labels in L. Tools like bwlabel(), regionprops(), bwconncomp() order the blobs as they scan the image columnwise from left to right. In this example, blob 1 is the red tag and blob 2 is the yellow tag.

[Shaista K]

thank you so much!