Hello, I have a binary image with n white objects (not connected). How can I leave only the object with the biggest amount of scope in the picture I can do it by – bwareaopen, but in this way I have to know approximate size of an object. sorry for my english. thnx
MATLAB: An object with the biggest amount of scope in the Binary image
binary imageimage processingImage Processing Toolboxregionprops
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Do you mean like this:
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;%--------------------------------------------------------------------------------------------------------
% READ IN IMAGE
folder = pwd;baseFileName = 'Q4_4.png';% Get the full filename, with path prepended.
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; endendgrayImage = 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)if numberOfColorChannels > 1 % It's not really gray scale like we expected - it's color.
% Use weighted sum of ALL channels to create a gray scale image.
grayImage = rgb2gray(grayImage); % ALTERNATE METHOD: Convert it to gray scale by taking only the green channel,
% which in a typical snapshot will be the least noisy channel.
% grayImage = grayImage(:, :, 2); % Take green channel.
end% Display the image.
subplot(2, 3, 1);imshow(grayImage);axis('on', 'image');title('Original Grayscale Image', 'FontSize', fontSize, 'Interpreter', 'None');impixelinfo;hFig = gcf;hFig.WindowState = 'maximized'; % May not work in earlier versions of MATLAB.
drawnow;%--------------------------------------------------------------------------------------------------------% Binarize the image.
binaryImage = ~imbinarize(grayImage);% Get rid of particles less than 200 in area.
binaryImage = bwareaopen(binaryImage, 200);% Eliminate partial blobs - those touching the edge of the image.
binaryImage = imclearborder(binaryImage);subplot(2, 3, 2);imshow(binaryImage, []);axis('on', 'image');title('Mask Image', 'FontSize', fontSize, 'Interpreter', 'None');impixelinfo;drawnow;% Find blobs
props = regionprops(binaryImage, 'Centroid', 'Area');xy = vertcat(props.Centroid)allAreas = [props.Area];subplot(2, 3, 3);histogram(allAreas, 10);grid on;title('Histogram of Blob Areas', 'FontSize', fontSize, 'Interpreter', 'None');xlabel('Area', 'FontSize', fontSize, 'Interpreter', 'None');ylabel('Count', 'FontSize', fontSize, 'Interpreter', 'None');% Get blobs smaller than 2500
[labeledImage, numBlobs] = bwlabel(binaryImage);smallIndexes = find(allAreas < 2500);largeIndexes = find(allAreas >= 2500);% Extract the small blobs with ismember()
smallBlobs = ismember(labeledImage, smallIndexes);subplot(2, 3, 4);imshow(smallBlobs);title('Small Blobs', 'FontSize', fontSize, 'Interpreter', 'None');% Extract the large blobs with ismember()
largeBlobs = ismember(labeledImage, largeIndexes);subplot(2, 3, 5);imshow(largeBlobs);title('Large Blobs', 'FontSize', fontSize, 'Interpreter', 'None');
Your image had a white frame/border around it. Use imclearborder() to get rid of that. See corrected code:
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
workspace; % Make sure the workspace panel is showing.
format long g;format compact;fontSize = 20;rgbImage = imread('hole.png');subplot(2,2,1)imshow(rgbImage)title('Original Image', 'FontSize', fontSize);% 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') %binarization
binaryImage = im2bw(rgbImage);% Display this image.
subplot(2,2,2);imshow(binaryImage);title('Original Binary Image', 'FontSize', fontSize);% Important: Get rid of surrounding white border (frame):
binaryImage = imclearborder(binaryImage);% Display this image.subplot(2,2,3);imshow(binaryImage);title('Frame now removed', 'FontSize', fontSize);% Close the holes
filledImage = imfill(binaryImage, 'holes');subplot(2,2,4);imshow(filledImage);title('Image without frame or holes', 'FontSize', fontSize);
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