Matlab：将RGB图像粘贴到更大的图像中

Question

I am trying to read an image and paste it into a bigger image in which I will, later, paste other images (same heights and widths). I have to say that I'm not experienced in Matlab so any suggestions are welcome.

Right now I'm creating a bigger matrix of zeroes and pasting the elements (RGB) of the image into it. But it is not being displayed as I would want, it shows a mostly-white image:

Bigger is the name of the bigger image

[im1 map1] = imread('/12937.png');
[height width rgbsize]=size(im1)
bigger=zeros(height+200,width+200,3);
figure('name','original');imshow(im1) %displays my image correctly
bigger(1:height,1:width,:)=im1(:,:,:); 
figure('name','after');imshow(bigger); %displays a mostly white image with dark right and bottom borders (the extra size)

Answer 1

Some of the image functions are sensitive to the data types. imread gives you a matrix of type uint8, whereas by default, zeros gives you matrices of type double. imshow (or image or imagesc ) can operate with all double data, but they expect it $\\in [0,1]$ rather than $\\in [0,255]$.

Try this:

[im1 map1] = imread('/12937.png');
[height width rgbsize]=size(im1)

% note: initialise the data type as well as the size
bigger=zeros(height+200,width+200,3, 'uint8');

figure('name','original');imshow(im1) 
bigger(1:height,1:width,:)=im1(:,:,:); 
figure('name','after');imshow(bigger); 

You can check what type im1 is with the command whos , or looking in the workspace part of the GUI. If it isn't uint8, then adjust the zeros command accordingly.