how to embed a watermark in a color image

i=imread('golf.jpg'); imshow(i); j=rgb2gray(i); imshow(j); n=imread('copy.jpg'); l=imresize(n,0.5); m=rgb2gray(l); imshow(m); [r,c]=size(j); startrow=1; startcol=1; j(startrow:startrow+size(m,1)-1,startcol:startcol+size(m,2)-1) = m; imshow(j); i used this code for watermarking a grayscale image and i can embed the watermark anywhere by replacing the values but it doesnot work for color images how can i watermark a color image?

Answer 1

[Image Analyst]

You can do that same thing in every color channel.

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
% Now put in watermark, then recombine  
newRGBImage = cat(3,watermarkedRed, watermarkedGreen, watermarkedBlue);

[SUBROTO KUNDU]

Hi, Image Analyst

How tcan I embed a watermark in a color image using binomial transform and cholesky decomposition?

What would be the possible matlab code?

[Image Analyst]

I have no idea - I'd have to research it just like you'll have to do. Start your research here: http://www.visionbib.com/bibliography/contents.html

Why do you think you need to do that particular operation? What's your use case?

[SUBROTO KUNDU]

Hi Image Analyst,

I have tried several times to write the code. But it does not give the correct output. Please help me.

https://www.mathworks.com/matlabcentral/answers/473297-reversible-watermarking-based-on-binomial-transform-and-cholesky-decomposition

[Image Analyst]

But you didn't answer my two questions. And I'd have to research it just like you would, but since it's your project, not mine, and it will probably take more than about 5 minutes, I can't afford to donate that much time to you. Sorry. I'm sure you'd do just as good a job of delving into the intricate details as I could.

Answer 2

[cui,xingxing]

see here: https://ww2.mathworks.cn/matlabcentral/answers/1451879-how-does-matlab-add-transparent-fonts-to-pictures#answer_786044