how do i assign a color to the same type of shape (2024)

clearvars % clean up

close all

clc

fontsize = 8; % used for figure labels

textbgc = 'y';

RGB = imread('test_shapes.jpg'); %read the loaded image

sharp=imsharpen(RGB); %sharpen the read image

grayscale=rgb2gray(sharp); %convert from rgb image to grayscale format

h = fspecial('gaussian',40,1); %create a smoothing filter

filtered = imfilter(grayscale,h); %filtering

Edgecanny = edge(filtered,'canny'); %edge detection

X = imfill(Edgecanny,'holes'); %fill in with holes

% get rid of all the tiny blobs created by doing edge detection on a JPG

Bw = bwareaopen(X,1500);

% get the label image

[L numblobs] = bwlabel(Bw);

% define shape class names

shapeclasses = {'Circle','Square','Triangle','Rectangle','Pentagon', ...

'Hexagon','Ellipse','Octagon','Diamond','Unknown'};

% preallocate

blobcentroids = zeros(numblobs,2); % the [x y] centroid location for each blob

blobclasses = zeros(numblobs,1); % the class number for each blob

blobaream = zeros(numblobs,1); % the unrounded area for each blob (in sq m)

for n=1:numblobs

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% SHAPE FACTORS

thisblobonly = L==n; % do it once instead of 14 times

[row, col] = find(thisblobonly);

% Find Bounding Box

sx = min(col)-0.5; %starting position for column

sy = min(row)-0.5; %starting position for row

breadth = max(col)-min(col)+1; %gives breadth of the box

length = max(row)-min(row)+1; %gives length of the box

BBox = [sx sy breadth length]; %Bounding Box value for the range of n

% Find area ratio

blobarea = bwarea(thisblobonly); %calculates the area of each binary component

blobaream(n) = round(blobarea) * 0.001; %converting from mm to m

bboxarea = (length*breadth); %calculates the area of each bounding box

extent = blobarea/bboxarea; %calculates the ratio of area's

fprintf('Extent: %.4f\n',extent)

% Find Perimeter

thisboundary = bwboundaries(thisblobonly); %Find the boundary of the labeled components boundary pixels

c = cell2mat(thisboundary(1)); %converts the cell to a matrix

Perimeter = 0; %declaring a start at zero for sum

for i = 1:size(c,1)-1 %creates a loop that extracts perimeter of each binary component

Perimeter = Perimeter+sqrt((c(i,1)-c(i+1,1)).^2+(c(i,2)-c(i+1,2)).^2);

end

fprintf('Perimeter: %.3f\n',Perimeter); %display perimeter

% Find Roundness

Roundness = (4*blobarea*pi)/Perimeter.^2; %defines how close the binary component is to a circle

fprintf('Roundness: %.3f\n',Roundness); %display roundness factor

% Find aspect ratio instead of distance between first three vertices

aspectratio = min(BBox(3:4))/max(BBox(3:4)); % normalized

fprintf('Aspect: %.3f\n',aspectratio);

% Find Centroid

X = mean(col); %calculates average of columns

Y = mean(row); %calculates average of rows

blobcentroids(n,:) = [X Y]; %matrix of centroid dimensions

fprintf('Centroid: [%d %d]\n',round(blobcentroids(n,:))); %display centroid

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% SHAPE CLASSIFICATION

if extent>=0.782 && extent<=0.800 && Roundness>=0.909

blobclasses(n) = 1; % CIRCLE

elseif aspectratio>=0.9 && extent>=0.97

blobclasses(n) = 2; % SQUARE

elseif extent>=0.526 && extent<=0.550 && Roundness>=0.541 && Roundness<=0.559

blobclasses(n) = 3; % TRIANGLE

elseif aspectratio<0.9 && extent>=0.97

blobclasses(n) = 4; % RECTANGLE

elseif extent>=0.694 && extent<=0.714

blobclasses(n) = 5; % PENTAGON

elseif extent>=0.758 && extent<=0.769

blobclasses(n) = 6; % HEXAGON

elseif extent>=0.782 && extent<=0.800 && Roundness<0.909

blobclasses(n) = 7; % ELLIPSE

elseif extent>=0.833 && extent<=0.909

blobclasses(n) = 8; % OCTAGON

elseif extent>=0.526 && extent<=0.535 && Roundness>=0.714 && Roundness<=0.769

blobclasses(n) = 9; % DIAMOND

else

blobclasses(n) = 10; % NOT CLASSIFIED SHAPE

end

% dump another message into the console

fprintf('Blob %d is a %s\n\n',n,lower(shapeclasses{blobclasses(n)}));

end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% create a bunch of subplots

% doing the junk with blind axes position manipulation is a nightmare

% it's entirely dependent on the relationship between the aspect ratio of the figure window

% and the aspect ratio of the images.

% there's no reason to expect that the titles will even be visible.

% the modern suggestion would be to use tiledlayout, but that wasn't an option in 2014.

% FEX subplot_tight() would have probably been sufficient at the time

subplot_tight(2,2,1)

imshow(RGB)

title('Original Image');

subplot_tight(2,2,3)

% idk why the original plotted the input image twice

% i'm just going to plot the binarized image

% since that's why this whole mess wouldn't work in the first place

imshow(Bw)

title('Binarized Image');

subplot_tight(2,2,2)

imshow(Bw)

title('Classified Shapes');

for k = 1:numblobs

ht = text(blobcentroids(k,1),blobcentroids(k,2),shapeclasses{blobclasses(k)});

set(ht,'horizontalalignment','center','fontsize',fontsize,'backgroundcolor',textbgc)

end

subplot_tight(2,2,4)

imshow(Bw)

title('Area in m^2');

for k = 1:numblobs

ht = text(blobcentroids(k,1),blobcentroids(k,2),sprintf('%.3f',blobaream(k)));

set(ht,'horizontalalignment','center','fontsize',fontsize,'backgroundcolor',textbgc)

end

%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% create an image with blobs colored by class

% this could also have been done in the main loop

labeledbyclass = zeros(size(Bw),'uint16'); % integer-class

for k = 1:numblobs

thisblobonly = L==k;

labeledbyclass(thisblobonly) = blobclasses(k);

end

% labeloverlay() was not available in 2014

% treat the new label image as an indexed image

% indexed image mapping depends on the numeric class

% for float inputs, mapping starts at 1

% for integer-class inputs, mapping starts at 0

CT = brewermap(numblobs,'paired'); % create the color table

CT = [0 0 0; CT]; % include a black row for the background

coloredbyclass = ind2rgb(labeledbyclass,CT);

figure

imshow(coloredbyclass)