Image Processing Toolboximage segmentationmaskingwatershed
gradmag2 = imimposemin(gradmag, bgm | fgm4);L = watershed(gradmag2);I4 = I;I4(imdilate(L == 0, ones(3, 3)) | bgm | fgm4) = 255;figure, imshow(I4), title('Markers and object boundaries superimposed on original image (I4)');bw = imread('bw.png');if ndims(bw) > 1 bw = bw(:,:,1);end% Threshold
bw = bw > 128;subplot(1, 2, 1);imshow(bw, []);% Fill holes
bw = imfill(bw, 'holes');% Get areas
props = regionprops(bw, 'Area');sortedAreas = sort([props.Area], 'descend')% Looks like we need to throw away any blobs less than 1000 pixels or so
bw = bwareaopen(bw, 1000);subplot(1, 2, 2);imshow(bw);% Count the blobs
[labeledImage, numBlobs] = bwlabel(bw);fprintf('Found %d shapes.\n', numBlobs);clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;format compact;fontSize = 20;%===============================================================================
% Get the name of the image the user wants to use.
baseFileName = 'coins.png'; % Assign the one on the button that they clicked on.
% Get the full filename, with path prepended.
folder = fileparts(which('cameraman.tif')); % Determine where demo folder is (works with all versions).
fullFileName = fullfile(folder, baseFileName);%===============================================================================% Read in a standard MATLAB gray scale demo image.
grayImage = imread(fullFileName);% Get the dimensions of the image.
% numberOfColorBands should be = 1.
[rows, columns, numberOfColorChannels] = size(grayImage);if numberOfColorChannels > 1 % It's not really gray scale like we expected - it's color.
% Convert it to gray scale by taking only the green channel.
grayImage = grayImage(:, :, 2); % Take green channel.
end% Display the image.
subplot(3, 3, 1);imshow(grayImage, []);caption = sprintf('Original Grayscale Image, %s', baseFileName);title(caption, 'FontSize', fontSize, 'Interpreter', 'None');% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off') % Display the histogram so we can see what gray level we need to threshold it at.
subplot(3, 3, 2);histogram(grayImage);title(caption, 'FontSize', fontSize, 'Interpreter', 'None');% Threshold it.
binaryImage = grayImage > 80;% Fill the blobs
binaryImage = imfill(binaryImage, 'holes');% Get rid of blobs smaller than 50 pixels:
binaryImage = bwareaopen(binaryImage, 150);subplot(3, 3, 3);imshow(binaryImage, []);axis on;caption = sprintf('Binary Image');title(caption, 'FontSize', fontSize, 'Interpreter', 'None');% Label the image
[labeledImage, numBlobs] = bwlabel(binaryImage);props = regionprops(labeledImage, 'Area');allAreas = [props.Area]smallBlobIndexes = find(allAreas < 2000)bigBlobIndexes = find(allAreas >= 2000)% Extract the small blobs
smallBlobsImage = ismember(labeledImage, smallBlobIndexes);% Show the small blobs.
subplot(3, 3, 4);imshow(smallBlobsImage, []);title('Small blobs', 'FontSize', fontSize); axis image; % Make sure image is not artificially stretched because of screen's aspect ratio.
hold on;% Extract the big blobs
bigBlobsImage = ismember(labeledImage, bigBlobIndexes);% Show the big blobs.
subplot(3, 3, 5);imshow(bigBlobsImage, []);title('Big blobs', 'FontSize', fontSize); axis image; % Make sure image is not artificially stretched because of screen's aspect ratio.hold on;% Grow the small blobs
radius = 5;se = strel('disk', radius, 0);smallBlobsImage = imdilate(smallBlobsImage, se);% Show the small blobs.subplot(3, 3, 7);imshow(smallBlobsImage, []);title('Small blobs Dilated', 'FontSize', fontSize); axis image; % Make sure image is not artificially stretched because of screen's aspect ratio.hold on;% Shrink the big blobs
se = strel('disk', radius, 0);bigBlobsImage = imerode(bigBlobsImage, se);% Show the small blobs.subplot(3, 3, 8);imshow(bigBlobsImage, []);title('Big blobs eroded', 'FontSize', fontSize); axis image; % Make sure image is not artificially stretched because of screen's aspect ratio.hold on;% Combine them to form the final binary image
finalImage = smallBlobsImage | bigBlobsImage;% Show the small blobs.subplot(3, 3, [6,9]);imshow(finalImage, []);title('Final image', 'FontSize', fontSize); axis image; % Make sure image is not artificially stretched because of screen's aspect ratio.hold on;
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