hi,in my image has 2 shapes ;triangular and circular(in binary). how can I eliminate the circular shape so that it just detect triangular shape.many thanks!
MATLAB: Detect certain shapes in binary
detect certain shape
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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');
OK, here, try this, adjusting thresholding parameters as needed.
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;% Check that user has the specified Toolbox installed and licensed.
hasLicenseForToolbox = license('test', 'image_toolbox'); % license('test','Statistics_toolbox'), license('test','Signal_toolbox')
if ~hasLicenseForToolbox % User does not have the toolbox installed, or if it is, there is no available license for it.
% For example, there is a pool of 10 licenses and all 10 have been checked out by other people already.
ver % List what toolboxes the user has licenses available for.
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 gray scale demo image.
folder = pwd; % Determine where demo folder is (works with all versions).
baseFileName = 'image.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; endendrgbImage = imread(fullFileName);% Display the image.
subplot(2, 2, 1);imshow(rgbImage, []);title('Original Image', 'FontSize', fontSize, 'Interpreter', 'None');axis on;hp = impixelinfo();% 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(rgbImage);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(rgbImage);
% 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 = rgbImage(:, :, 1); % Take red channel.
else grayImage = rgbImage; % It's already gray scale.
end% Display the image.subplot(2, 2, 1);imshow(grayImage, []);title('Gray Scale Image', 'FontSize', fontSize, 'Interpreter', 'None');axis on;%------------------------------------------------------------------------------
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);% 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') % Get binary image.
binaryImage = grayImage > 10;% Get rid of white frame.
binaryImage = imclearborder(binaryImage);% Display the image.subplot(2, 2, 1);imshow(binaryImage, []);title('Binary Image', 'FontSize', fontSize, 'Interpreter', 'None');axis on;% Fill holes
binaryImage = imfill(binaryImage, 'holes');% Display the image.subplot(2, 2, 2);imshow(binaryImage, []);title('Binary Image', 'FontSize', fontSize, 'Interpreter', 'None');axis on;% Let's measure things to see what we're starting with.
props = regionprops(binaryImage, 'Solidity', 'Area', 'perimeter');allAreas = [props.Area]allSolidities = [props.Solidity]allCircularities = 4 * pi * allAreas ./ [props.Perimeter] .^ 2% Display the histograms.
subplot(2, 2, 3);histogram(allSolidities);grid on;title('Histogram of Solidities', 'FontSize', fontSize, 'Interpreter', 'None');subplot(2, 2, 4);histogram(allCircularities);grid on;title('Histogram of circularities', 'FontSize', fontSize, 'Interpreter', 'None');% Take the 24 smoothest blobs.
% Get rid of blobs less solid than 0.85%.
binaryImage2 = bwpropfilt(binaryImage, 'Solidity', [.85, inf]);figure;% Display the image.subplot(2, 1, 1);imshow(binaryImage2, []);title('Binary Image2 - high solidity', 'FontSize', fontSize, 'Interpreter', 'None');axis on;% Get rid of blobs with low circularity.
highCircularityIndexes = find(allCircularities > 0.6);labeledImage = bwlabel(binaryImage);binaryImage3 = ismember(labeledImage, highCircularityIndexes);% Display the image.subplot(2, 1, 2);imshow(binaryImage3, []);title('Binary Image3 - high circularity', 'FontSize', fontSize, 'Interpreter', 'None');axis on;
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