MATLAB: How to convert number of pixels from multiple binary images into a single plot numerically

Question

I have binary images and I want to plot the number of black pixels from each images in numerical order of the filenames. Let's say that the numerical order acts as a timestamp for the progression of the total pixels

Thanks in advance

Answer 1

Try this:

clc;    % Clear the command window.
fprintf('Beginning to run %s.m.\n', mfilename);
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
clear global;
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 14;
% Specify the folder where the files live.
myFolder = pwd; % or 'C:\Users\yourUserName\Documents\My Pictures';
% Check to make sure that folder actually exists.  Warn user if it doesn't.
if ~isdir(myFolder)
	errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
	uiwait(warndlg(errorMessage));
	return;
end
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.jpg'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
%------------------------------------------------------------------------------------------

% Can sort this in different ways:
% % Sort list by oldest to newest.
% dateNums = [theFiles.datenum];
% [dateNums, sortOrder] = sort(dateNums, 'ascend');
% theFiles = theFiles(sortOrder);
% Sort in alphanumeric order of the base file names
allFileNames = {theFiles.name};
[allFileNames, sortOrder] = sort(allFileNames);
theFiles = theFiles(sortOrder);
%------------------------------------------------------------------------------------------
% Process all files in a loop.
whitePixelCount = zeros(1, length(theFiles));
for k = 1 : length(theFiles)
	baseFileName = theFiles(k).name;
	fullFileName = fullfile(myFolder, baseFileName);
	fprintf(1, 'Now reading %s\n', fullFileName);
	% Now do whatever you want with this file name,
	% such as reading it in as an image array with imread()
	originalImage = imread(fullFileName);
	subplot(1, 2, 1);
	imshow(originalImage);  % Display image.

	caption = sprintf('Original Image : "%s"\n%d of %d', baseFileName, k, length(theFiles));
	title(caption, 'FontSize', fontSize);
	binaryImage = imbinarize(originalImage(:,:,1));
	subplot(1, 2, 2);
	imshow(binaryImage);  % Display image.
	caption = sprintf('Binary Image : %d of %d', k, length(theFiles));
	title(caption, 'FontSize', fontSize);
	% Count the number of white pixels.
	whitePixelCount(k) = nnz(binaryImage);
	drawnow; % Force display to update immediately.
end
hFig = figure;
bar(whitePixelCount, 1);
xlabel('Image Number', 'FontSize', fontSize);
ylabel('Count of White Pixels', 'FontSize', fontSize);
title('Count of White Pixels in Binarized Images', 'FontSize', fontSize);
grid on;
hFig.WindowState = 'maximized';
fprintf('Done running %s.m.\n', mfilename);