How to concatenate only two planes of an image.

I have split an RGB image into its 3 different components, now i need a new image that is just the combination of the red and green planes. How do I do this? I used the 'cat' function, and then displayed the image, but it just displays these images next to each other.

Answer 1

[Image Analyst]

Try this

blackImage = zeros(size(redChannel), 'uint8');
rgbImage = cat(3, redChannel, greenChannel, blackImage);
imshow(rgbImage);

[Aditya]

Thank you for helping, I have tried this already but i want the new image to be only in 2 dimensions not 3.

[Image Analyst]

Then to get a 2D image, stitch them together either side by side or top and bottom

tallImage = [redChannel; greenChannel];
wideImage = [redChannel, greenChannel];

Of course the images will be gray scale not color since to be color you need a third dimension.

Answer 2

[Azzi Abdelmalek]

img =  imread('ngc6543a.jpg');
red = img(:,:,1); % Red  
green = img(:,:,2); % Green  
blue = img(:,:,3); % Blue 
[n,m,~]=size(img)
a = zeros(n, m);
out=cat(3,red,green,a)

[Aditya]

Thank you for helping, I have tried this already but i want the new image to be only in 2 dimensions not 3.

[Vivek]

Same problem Aditya I have two images and I want to make a single image from these two but using these commands the output image is in 3d dimension but I want to in 2D dimension.

[Image Analyst]

@Vivek I think you overlooked my answer above.

https://www.mathworks.com/matlabcentral/answers/275336-how-to-concatenate-only-two-planes-of-an-image#comment_352974

It will do that.