Stitching three channels of an image

i need to stitch the three components red blue and green of an rgb image P to form a gray image PS. At first i separate the three channels as Rp, Gp, and Bp using the code " Rp = image(:,:,1);". Now how can i stitch those three?

Answer 1

[Rik]

In Matlab (and some other languages) this is referred to as concatenation, for which you can use the function cat.

Rp=image(:,:,1);
Gp=image(:,:,2);
Bp=image(:,:,3);
%code that changes Rp, Gp and Bp
%
image2=cat(3,Rp,Gp,Bp);

alternatively:

Rp=image(:,:,1);
Gp=image(:,:,2);
Bp=image(:,:,3);
%code that changes Rp, Gp and Bp
%
image2=image;%create a copy
image2(:,:,1)=Rp;
image2(:,:,2)=Gp;
image2(:,:,3)=Bp;