MATLAB: I have 12 objects and only 10 objects have a yellow dot inside it .How to extract the ids of the objects with only the yellow dot

Image Processing Toolboximage segmentation

The yellow dot is not at the centeroid of the object. I have created a yellow mask for each of the objects, but i am struggling to create a for loop to extract the ids of the objects with only the yellow dot inside of it

Best Answer

Segment the objects. Then segment the yellow dots. Then label the objects and use that labeled image to get a list of blobs that have the dot, and call unique. Then call ismember() to get the mask with only the yellow dots

% Fill yellow holes in the objects.
objectMask(yellowHoleMask) = true;
% Fill the objects in case the yellow was in a "lake" in the blob and didn't actually touch the blob itself.
objectMask = imfill(objectMask, 'holes');
% Label each blob.
[labeledObjects, numBlobs] = bwlabel(objectMask);
% Find labels with yellow dots in them
indexesWithYellow = unique(labeledObjects(yellowHoleMask))
% Extract only those blobs that have a yellow dot in them
objectsWithYellowInside = ismember(labeledObjects, indexesWithYellow); % Creates a binary image

If you want the original blobs without the yellow spot being filled in them (so they'll have a hole in them) then you'll need a slight modification, as this code will give filled blobs where the yellow and containing blob are all one blob. If that's the case, then supply your two binary images.

Related Solutions

MATLAB: Red object detection picking up yellow color.

You extracted ONLY the red channel. Then you looked for red colors. But there are other colors which have the red channel maxxed out, yet are not red. Color is THREE dimensional. If you ignore the other two channels, expect to fail at your task. Your methodology would have found the [1 1 0] color too, calling it "red".

If your goal is to find ONLY colors which are explicitly and exactly [1 0 0], then use tools that can do so.

MATLAB: Recognize black dot

Well now that you posted an image, and I see you have black spots not only on the dice but also on the red background, I need to modify my answer to have you threshold on the blue or green channel:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures.
clear;  % Erase all existing variables.
workspace;  % Make sure the workspace panel is showing.
fontSize = 20;
folder = 'C:\Documents and Settings\user\My Documents\Temporary stuff';
% Read in a color demo image.
baseFileName = 'IMG_0584.JPG';
fullFileName = fullfile(folder, baseFileName);
% 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;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorBands should be = 3.
[rows columns numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 2, 1);
imshow(rgbImage, []);
title('Original color Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'Position', get(0,'Screensize')); 
% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
spots = blueChannel < 128;
subplot(2, 2, 2);
imshow(spots, []);
title('Thresholded Blue Channel', 'FontSize', fontSize);
spots = imclearborder(spots);
subplot(2, 2, 3);
imshow(spots, []);
title('Border Cleared', 'FontSize', fontSize);
% Fill holes
spots = imfill(spots, 'holes');
subplot(2, 2, 4);
imshow(spots, []);
title('Final Spots Image', 'FontSize', fontSize);
% Count them
[labeledImage numberOfSpots] = bwlabel(spots);
message = sprintf('Done!\nThe number of spots (total on both dice) is %d', numberOfSpots);
msgbox(message);

Best Answer

Related Solutions

MATLAB: Red object detection picking up yellow color.

MATLAB: Recognize black dot

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