How can I remove white background from this Image?

I am working on a project where I need to remove the back from similar images in order to stack randomly them over a 100um x 100um matrix.

Thank you!

[Image Analyst]

What does "remove" mean to you? Set to black? Crop?

What does "stack" mean to you? Copy and paste?

[Riddhiben Joshi]

Hi Thank you for responding, by remove i mean to crop the white background portion and only have blue part.

And by stack i meanto say place next to each other in a 2D such that i can control distance between them. I have 7 different images which i wish to stack randomly.

I hope this helps!

Answer 1

[yanqi liu]

sir, may be remove the background, and make some add function, such as

clc;
clear all;
close all;
im = imread('https://ww2.mathworks.cn/matlabcentral/answers/uploaded_files/741089/20um.jpeg');
im2 = rgb2hsv(im);
bw = im2bw(im2(:,:,2), 0.5);
bw = imfill(bw, 'holes');
im = im .* uint8(cat(3,bw,bw,bw));
% add some images
im = imadd(im, im);
figure; imshow(im);

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[Riddhiben Joshi]

Hi thank you for responding, I tried to use the above code code but I keep getting this error.

Error using rgb2hsv>parseInputs (line 95)

MAP must be a Mx3 array.

Error in rgb2hsv (line 36)

[r, g, b, isColorMap, isEmptyInput, isThreeChannel] = parseInputs(varargin{:});

[Riddhiben Joshi]

Thank you, it worked for me.

Answer 2

[Image Analyst]

Try this:

% Demo by Image Analyst.
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clearvars;
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 16;
fprintf('Beginning to run %s.m ...\n', mfilename);
%-----------------------------------------------------------------------------------------------------------------------------------
% Read in image.  This is a horrible image.  NEVER use JPG format for image analysis.  Use PNG, TIFF, or BMP instead.
folder = [];
baseFileName = '20um.jpeg';
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
rgbImage = imread(fullFileName);
[rows, columns, numberOfColorChannels] = size(rgbImage)
% Display the image.
subplot(2, 2, 1);
imshow(rgbImage, []);
axis('on', 'image');
hp = impixelinfo(); % Set up status line to see values when you mouse over the image.
caption = sprintf('Original RGB Image : "%s"\n%d rows by %d columns', baseFileName, rows, columns);
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
hp = impixelinfo(); % Set up status line to see values when you mouse over the image.
% Set up figure properties:
% Enlarge figure to full screen.
hFig1 = gcf;
hFig1.Units = 'Normalized';
hFig1.WindowState = 'maximized';
% 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.
hFig1.Name = 'Demo by Image Analyst';
% Get a binary image.
grayImage = rgb2gray(rgbImage);
binaryImage = ~imbinarize(grayImage, 'global');
% Remove frame around the outside.
binaryImage = imclearborder(binaryImage);
% Fill holes
binaryImage = imfill(binaryImage, 'holes');
subplot(2, 2, 2);
imshow(binaryImage);
% Get the bounding box.
props = regionprops(binaryImage, 'BoundingBox');
% Crop the images.
croppedImage = imcrop(rgbImage, props.BoundingBox);
binaryImage = imcrop(binaryImage, props.BoundingBox);
% Mask the image using bsxfun() function to multiply the mask by each channel individually.  Works for gray scale as well as RGB Color images.
croppedImage = bsxfun(@times, croppedImage, cast(binaryImage, 'like', croppedImage));
% Display the image.
subplot(2, 2, 3);
imshow(croppedImage, []);
axis('on', 'image');
hp = impixelinfo(); % Set up status line to see values when you mouse over the image.
title('Cropped Image', 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
msgbox('Done!');

[Riddhiben Joshi]

Thank you!