Change Color of Segmented object based on Solidity

I have used regionprops to calculate the Convexhull of each shape in the image shown and then drawn the region in red around it. I want to color each blob differently according to the solidity value and then display the colormap on the figure itself on the side. Essentially, the lower the value, the darker I want it to be.

I have thought about implementing it manually through if statements but then how would I display the colormap on the side?

Much appreciated!

HOW IT LOOKS CURRENTLY:

HOW I WANT IT TO LOOK:

stats = regionprops(mask,{...
    'Centroid',...        
    'MajorAxisLength',... 
    'MinorAxisLength',...
    'Orientation', ...
    'Circularity', ...
    'ConvexHull', ...
    'Solidity', ...
    'Eccentricity', ...
    'BoundingBox', 'Area' })

figure , imshow(img)
hold on

for k = 1 : size(stats)
    tempHull = stats(k).ConvexHull;
    tmpSize = size(tempHull);
    x = tempHull(:, 1);
    y = tempHull(:,2);
    tempSolid = round(stats(k).Solidity, 2);
   
    fill(x, y, fillColor);
   
    plot(x, y, 'LineWidth', 1, 'Color', 'r');
    text(stats(k).Centroid(1), stats(k).Centroid(2), num2str(tempSolid), 'FontSize', 12);
    
end
hold off

title("Solidity", 'FontSize', 18);

Answer 1

[DGM]

I don't have a good example image, so I'll just use this:

mask = rgb2gray(imread('sources/blobs.png'))>10;

stats = regionprops(mask,{...
    'Centroid',...        
    'MajorAxisLength',... 
    'MinorAxisLength',...
    'Orientation', ...
    'Circularity', ...
    'ConvexHull', ...
    'Solidity', ...
    'Eccentricity', ...
    'BoundingBox', 'Area' });

% no need to use imshow(); it just complicates colormap handling

hold on
for k = 1 : size(stats)
    tempHull = stats(k).ConvexHull;
    tmpSize = size(tempHull);
    x = tempHull(:, 1);
    y = tempHull(:,2);
    tempSolid = round(stats(k).Solidity, 2);
    % fill color is solidity value
    fill(x, y, stats(k).Solidity);
    
    plot(x, y, 'LineWidth', 1, 'Color', 'r');
    text(stats(k).Centroid(1), stats(k).Centroid(2), num2str(tempSolid), ...
    	'FontSize', 12, 'horizontalalignment','center');
end
hold off

set(gca,'ydir','reverse','xtick',[],'ytick',[])
axis equal
box on
xlim([0 size(mask,2)])
ylim([0 size(mask,1)])
colorbar
colormap(summer)

At that point, all you need to do is generate the desired colormap and apply it using colormap() as shown. You might need to tweak things with caxis().

[Shahil Khan]

Thats really great thank you!