image processing
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
imtool close all; % Close all imtool figures if you have the Image Processing Toolbox.
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;format compact;fontSize = 22;% Check that user has the Image Processing Toolbox installed.
hasIPT = license('test', 'image_toolbox');if ~hasIPT % User does not have the toolbox installed.
message = sprintf('Sorry, but you do not seem to have the Image Processing Toolbox.\nDo you want to try to continue anyway?'); reply = questdlg(message, 'Toolbox missing', 'Yes', 'No', 'Yes'); if strcmpi(reply, 'No') % User said No, so exit.
return; endend%===============================================================================
% Read in a demo image.
folder = pwd; %fileparts(which('peppers.png')); % Determine where demo folder is (works with all versions).
baseFileName = 'find_gaps.png';% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);if ~exist(fullFileName, 'file') % Didn't find it there. Check the search path for it.
fullFileName = baseFileName; % No path this time.
if ~exist(fullFileName, 'file') % Still didn't find it. Alert user.
errorMessage = sprintf('Error: %s does not exist.', fullFileName); uiwait(warndlg(errorMessage)); return; endendgrayImage = imread(fullFileName);% Get the dimensions of the image. numberOfColorBands should be = 3.
[rows, columns, numberOfColorBands] = size(grayImage);if numberOfColorBands > 1 fprintf('This image is RGB. I will change it to binary.\n'); grayImage = grayImage(:, :, 2);end% Make it binary
binaryImage = grayImage > 128;clear('grayImage');% Display the original image.
subplot(2, 2, 1);imshow(binaryImage);axis('on', 'image');title('Binary Image', 'FontSize', fontSize);impixelinfo;% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'Outerposition', [0, 0.1, 1, 0.9]);% Do a closing on it
se = true(3);binaryImage2 = imclose(binaryImage, se);% Display it.
subplot(2, 2, 2);imshow(binaryImage2, []);axis('on', 'image');title('Closing', 'FontSize', fontSize);% Now do an xor
binaryImage2 = xor(binaryImage, binaryImage2);% Label each individual blob.
[labeledImage, numRegions] = bwlabel(binaryImage2);% Let's assign each blob a different color to visually show the user the distinct blobs.
coloredLabels = label2rgb (labeledImage, 'hsv', 'k', 'shuffle'); % pseudo random color labels
% Display it.subplot(2, 2, 3);imshow(coloredLabels, []);axis('on', 'image');caption = sprintf('XOR Found %d Lines', numRegions);title(caption, 'FontSize', fontSize);props = regionprops(labeledImage, 'Area', 'Centroid');% Sort in order of decreasing area.
[allAreas, sortOrder] = sort([props.Area], 'Descend');% Sort props the same way.
props = props(sortOrder);% Display the original image.subplot(2, 2, 4);imshow(binaryImage);axis('on', 'image');title('Line Centroids Marked with *', 'FontSize', fontSize);hold on;% Display centroids over each line.
for k = 1 : length(props) x = props(k).Centroid(1); y = props(k).Centroid(2); plot(x, y, 'r*', 'MarkerSize', 15, 'LineWidth', 2); fprintf('Blob #%d is at (%.1f, %.1f) and has length %d.\n', ... k, x, y, allAreas(k));end
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