How to change color in overlapping image ?

clc;  % Clear command window.
clear;  % Delete all variables.
close all;  % Close all figure windows except those created by imtool.
workspace;  % Make sure the workspace panel is showing.
fontSize = 20;
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.
  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;
  end
end
%===============================================================================
% Read in a first gray scale demo image.
folder = pwd;
baseFileName = 'frame0017.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;
  end
end
grayImage1 = 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(grayImage1);
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.
  grayImage1 = rgb2gray(grayImage1);
  % 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(grayImage1, []);
title('Gray Image 1', 'FontSize', fontSize, 'Interpreter', 'None');
% 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')
% Threshold the image.
binaryImage1 = grayImage1 < 128;
% Display the image.
subplot(2, 3, 4);
imshow(binaryImage1, []);
title('Binary Image 1', 'FontSize', fontSize, 'Interpreter', 'None');
%===============================================================================
% Read in a second gray scale demo image.
folder = pwd;
baseFileName = 'frame0031.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;
  end
end
grayImage2 = 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(grayImage2);
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.
  grayImage2 = rgb2gray(grayImage2);
  % 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, 2);
imshow(grayImage2, []);
title('Gray Image 2', 'FontSize', fontSize, 'Interpreter', 'None');
% Threshold the image.
binaryImage2 = grayImage2 < 128;
% Display the image.
subplot(2, 3, 5);
imshow(binaryImage2, []);
title('Binary Image 2', 'FontSize', fontSize, 'Interpreter', 'None');
% Find out where they match
matching = binaryImage1 & binaryImage2;
% Make black image
blackImage = zeros(size(binaryImage1), 'uint8');
% Put binaryImage1 into red channel and binaryImage2 into blue channel
rgbImage = cat(3, uint8(binaryImage1), blackImage, uint8(binaryImage2));
% Make uint8 RGB
rgbImage = uint8(255 * rgbImage);
% Make black background white.
blackMask = ~binaryImage1 & ~binaryImage2;
blackMask = uint8(255 *cat(3, blackMask, blackMask, blackMask)); % Make color.
% Mask the image using bsxfun() function
rgbImage = blackMask + rgbImage;
% Display the image.
subplot(2, 3, 6);
imshow(rgbImage, []);
title('Final Color Image', 'FontSize', fontSize, 'Interpreter', 'None');

Image Analyst 2017-7-26

在 MATLAB Online 中打开

You're welcome - thanks for Accepting. Actually you don't need this line

matching = binaryImage1 & binaryImage2;

I ended up not using it.

Bruno 2017-7-26

Okay,

Great Code

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Answer 2

Saif 2023-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/350230-how-to-change-color-in-overlapping-image#answer_1198915

how we change background color into logo colour and logo into backgorund color white and green

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DGM 2023-3-23

Please open a new question for this by clicking Ask at the top of the page. When you do, make sure to provide example images for context and explain specifically which parts of which image(s) should be a particular color.

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Answer 3

DGM 2023-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/350230-how-to-change-color-in-overlapping-image#answer_1199190

在 MATLAB Online 中打开

Imfuse() does support channel specification. That may suffice in some cases.

% read the files

frame1 = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/83841/frame0017.png');

frame2 = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/83840/frame0031.png');

% one line

outpict = imfuse(frame1,frame2,'colorchannels',[1 0 2]);

imshow(outpict)

Of course, these images are negative (black-on-white), so it's confusing. The object colors are actually swapped because the black regions are colored by the background of the opposite image. It would be a lot simpler to just invert the source images.

% invert sources for less confusion

frame1 = imcomplement(frame1);

frame2 = imcomplement(frame2);

outpict = imfuse(frame1,frame2,'colorchannels',[1 0 2]);

imshow(outpict)

Note that this does not require any information to be lost in binarization, and it still allows the use of other features of imfuse().

Now let's say you wanted the background to stay white. For this simple diagram, the object polarity seems almost arbitrary, but let's consider a different set of sources.

frame1 = imread('cameraman.tif');

frame2 = fliplr(frame1);

frame1 = imcomplement(frame1);

frame2 = imcomplement(frame2);

outpict = imfuse(frame1,frame2,'colorchannels',[1 0 2]);

imshow(outpict)

In this case, we have images where the primary object content is obviously supposed to be dark-on-light. It's also plausible that we wouldn't want to binarize the sources.

This is an extra complication that really can't be solved with imfuse() directly. One might think that the current output could simply be inverted, but that would require specifying that the image colors are yellow and cyan -- and we can't specify two secondary colors. Not only does imfuse() not allow it, we'd be losing a lot of color mixing if we did.

One way to deal with the problem is by doing a lightness inversion on the output. If you have the tools, this adds only one line.

frame1 = imread('cameraman.tif');

frame2 = fliplr(frame1);

frame1 = imcomplement(frame1);

frame2 = imcomplement(frame2);

outpict = imfuse(frame1,frame2,'colorchannels',[1 0 2]);

% invert L

outpict = imtweak(outpict,'hsl',[0 1 -1]);

imshow(outpict)

Now the primary object in frame1 appears red and in the appropriate polarity. The same can be applied to the original images:

frame1 = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/83841/frame0017.png');

frame2 = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/83840/frame0031.png');

frame1 = imcomplement(frame1);

frame2 = imcomplement(frame2);

outpict = imfuse(frame1,frame2,'colorchannels',[1 0 2]);

% invert L

outpict = imtweak(outpict,'hsl',[0 1 -1]);

imshow(outpict)

Note that this transformation works in HSL, but not in HSV. Base MATLAB/IPT do not have HSL conversion tools, so I'm using imtweak() from MIMT to do the adjustment.

Personally, I'd rather avoid the confusion and stay with light-on-dark polarity, as it makes it easier to visually understand the contributions from each image. It's my opinion that having the images in the original polarity is unimportant when treating imfuse() simply as a visual comparison tool.

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DGM 2023-3-23

在 MATLAB Online 中打开

I mentioned that we'd lose some color mixing if we tried to do the blending using two secondary-color images. Here's an example of what would happen. First, let's consider the case with a continuous image.

frame1 = imread('cameraman.tif');

frame2 = fliplr(frame1);

% invert sources

frame1 = imcomplement(frame1);

frame2 = imcomplement(frame2);

% reduce each image to grayscale (same thing imfuse() does)

frame1 = im2gray(frame1);

frame2 = im2gray(frame2);

% assemble two secondary-color images

blank = zeros(size(frame1));

frame1 = cat(3,blank,frame1,frame1); % cyan

frame2 = cat(3,frame2,frame2,blank); % yellow

% combine them by addition, invert

outpict = imcomplement(frame1 + frame2);

imshow(outpict)

That doesn't look so bad. In fact, in some cases, this might be preferable. Let's see what happens when we try this with our high-contrast black-on-white images.

frame1 = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/83841/frame0017.png');

frame2 = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/83840/frame0031.png');

% invert sources

frame1 = imcomplement(frame1);

frame2 = imcomplement(frame2);

% reduce each image to grayscale (same thing imfuse() does)

frame1 = im2gray(frame1);

frame2 = im2gray(frame2);

% assemble two secondary-color images

blank = zeros(size(frame1));

frame1 = cat(3,blank,frame1,frame1); % cyan

frame2 = cat(3,frame2,frame2,blank); % yellow

% combine them by addition, invert

outpict = imcomplement(frame1 + frame2);

imshow(outpict)

We lose color mixing in the overlap regions, since the combination of two secondary colors truncates to white.

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How to change color in overlapping image ?

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How to change color in overlapping image ?

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