Try this code:
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
imtool close all; % Close all imtool figures.
clear; % Erase all existing variables.
workspace; % Make sure the workspace panel is showing.
fontSize = 20;
% Open an image.
% Browse for the image file.
[baseFileName, folder] = uigetfile('*.*', 'Specify an image file');
fullImageFileName = fullfile(folder, baseFileName);
if folder == 0
return;
end
% Read in image into an array.
[rgbImage, storedColorMap] = imread(fullImageFileName);
[rows, columns, numberOfColorBands] = size(rgbImage)
% If it's monochrome (indexed), convert it to color.
% Check to see if it's an 8-bit image needed later for scaling).
if strcmpi(class(rgbImage), 'uint8')
% Flag for 256 gray levels.
eightBit = true;
else
eightBit = false;
end
if numberOfColorBands == 1
if isempty(storedColorMap)
% Just a simple gray level image, not indexed with a stored color map.
% Create a 3D true color image where we copy the monochrome image into all 3 (R, G, & B) color planes.
rgbImage = cat(3, rgbImage, rgbImage, rgbImage);
else
% It's an indexed image.
rgbImage = ind2rgb(rgbImage, storedColorMap);
% ind2rgb() will convert it to double and normalize it to the range 0-1.
% Convert back to uint8 in the range 0-255, if needed.
if eightBit
rgbImage = uint8(255 * rgbImage);
end
end
end
% Display the original image.
subplot(2, 2, 1);
imshow(rgbImage);
set(gcf, 'Position', get(0,'Screensize')); % Enlarge figure to full screen.
set(gcf,'name','Image Analysis Demo','numbertitle','off')
drawnow; % Make it display immediately.
if numberOfColorBands > 1
title('Original Color Image', 'FontSize', fontSize);
grayImage = rgbImage(:,:,1);
else
caption = sprintf('Original Indexed Image\n(converted to true color with its stored colormap)');
title(caption, 'FontSize', fontSize);
grayImage = rgbImage;
end
% Display it.
subplot(2, 2, 2);
imshow(grayImage, []);
title('Grayscale Image', 'FontSize', fontSize);
% Binarize the image.
binaryImage = grayImage < 100;
% Display it.
subplot(2, 2, 3);
imshow(binaryImage, []);
title('Binary Image', 'FontSize', fontSize);
% Remove small objects.
binaryImage = bwareaopen(binaryImage, 300);
% Display it.
subplot(2, 2, 4);
imshow(binaryImage, []);
title('Cleaned Binary Image', 'FontSize', fontSize);
[labeledImage numberOfObjcts] = bwlabel(binaryImage);
blobMeasurements = regionprops(labeledImage,'Perimeter','Area', 'Centroid');
% for square ((a>17) && (a<20))
% for circle ((a>13) && (a<17))
% for triangle ((a>20) && (a<30))
circularities = [blobMeasurements.Perimeter].^2 ./ (4 * pi * [blobMeasurements.Area])
hold on;
% Say what they are
for blobNumber = 1 : numberOfObjcts
if circularities(blobNumber) < 1.19
message = sprintf('The circularity of object #%d is %.3f, so the object is a circle',...
blobNumber, circularities(blobNumber));
theLabel = 'Circle';
elseif circularities(blobNumber) < 1.53
message = sprintf('The circularity of object #%d is %.3f, so the object is a Rectangle',...
blobNumber, circularities(blobNumber));
theLabel = 'Rectangle';
else
message = sprintf('The circularity of object #%d is %.3f, so the object is a triangle',...
blobNumber, circularities(blobNumber));
theLabel = 'Triangle';
end
text(blobMeasurements(blobNumber).Centroid(1), blobMeasurements(blobNumber).Centroid(2),...
theLabel, 'Color', 'r');
uiwait(msgbox(message));
end
