How to change a matrix within a function

I want to pass a matrix into a function and to change the matrix within the function. For example, in my case I want to set some elements of the matrix:

function setRedComponent(Image,val)
    Image(:,:,1)=val;
end

Image is a 3D matrix representing an RGB image.

I know I can return the image, but I prefer to use the function as follows:

I=zeros(64,64,3);
setRedComponent(I,255);

and not

I=zeros(64,64,3);
I = setRedComponent(I,255);

Answer 1

[Walter Roberson]

function setRedComponent(Image,val)
    Image(:,:,1)=val;
    inname = inputname(1);
    if ~isempty(inname)
      assignin('caller', inname, Image);
    end
end

This style of coding is not recommended at all!