Not really sure what is a hole and a void. Are the holes the Octagons wit a gray level of 255? If so just threshold for those to get a hole mask then fill appropriate parts. Full demo:
% Demo by Image Analyst
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 = 22;
markerSize = 40;
%--------------------------------------------------------------------------------------------------------
% READ IN IMAGE
folder = [];
baseFileName = '#90_nelx_100_nely_150_vf_0.31_maxit_150_penal_6_rmin_4_comp_254_time_24.png';
fullFileName = fullfile(folder, baseFileName);
% Check if file exists.
if ~exist(fullFileName, 'file')
% The file doesn't exist -- didn't find it there in that folder.
% Check the entire search path (other folders) for the file by stripping off the folder.
fullFileNameOnSearchPath = baseFileName; % No path this time.
if ~exist(fullFileNameOnSearchPath, 'file')
% Still didn't find it. Alert user.
errorMessage = sprintf('Error: %s does not exist in the search path folders.', fullFileName);
uiwait(warndlg(errorMessage));
return;
end
end
grayImage = imread(fullFileName);
% Get the dimensions of the image.
% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.
[rows, columns, numberOfColorChannels] = size(grayImage)
%--------------------------------------------------------------------------------------------------------
% Display the image.
subplot(2, 2, 1);
imshow(grayImage);
impixelinfo;
axis('on', 'image');
title('Original Gray Scale Image', 'FontSize', fontSize, 'Interpreter', 'None');
if numberOfColorChannels > 1
% It's not really gray scale like we expected - it's color.
fprintf('It is not really gray scale like we expected - it is color\n');
% Extract the blue channel.
grayImage = grayImage(:, :, 3);
end
% Update the dimensions of the image.
% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.
[rows, columns, numberOfColorChannels] = size(grayImage)
% Maximize window.
g = gcf;
g.WindowState = 'maximized';
drawnow;
%--------------------------------------------------------------------------------------------------------
% Threshold the image to get the bright blobs.
% https://www.mathworks.com/matlabcentral/fileexchange/29372-thresholding-an-image?s_tid=srchtitle
lowThreshold = 255;
highThreshold = 255;
% [lowThreshold, highThreshold, lastThresholdedBand] = threshold(lowThreshold, highThreshold, grayImage)
holeMask = grayImage >= lowThreshold & grayImage <= highThreshold;
% Get rid of part touching the edge of the image.
holeMask = imclearborder(holeMask);
% Fill holes.
holeMask = imfill(holeMask, 'holes');
subplot(2, 2, 2);
imshow(holeMask)
title('Binary Mask Image', 'FontSize', fontSize, 'Interpreter', 'None');
%--------------------------------------------------------------------------------------------------------
% Get the black part
blackMask = ~bwareafilt(grayImage == 255, 1);
% Erode it a bit
se = strel('disk', 20, 0);
blackMask = imerode(blackMask, se);
% Fill holes.
blackMask = imfill(blackMask, 'holes');
subplot(2, 2, 3);
imshow(blackMask)
title('Black Part Mask', 'FontSize', fontSize, 'Interpreter', 'None');
% Make that part in the original image black.
grayImage2 = grayImage; % Initialize.
grayImage2(blackMask) = 0;
% Now write the white part into the image
grayImage2(holeMask) = 255;
subplot(2, 2, 4);
imshow(grayImage2)
title('Part With Holes Only', 'FontSize', fontSize, 'Interpreter', 'None');
