Error on my matrix

tw=imread('twins.tif');
t=rgb2gray(tw);
t_sp=imnoise(t,'salt & pepper');
imnoise(t,'salt & pepper',0.2);
t_ga=imnoise(t,'gaussian');
t_spk=imnoise(t,'speckle');
s=size(t);
[x,y]=meshgrid(1:s(1),1:s(2));
p=sin(x/3+y/5)+1;
t_pn=(im2double(t)+p/2)/2;

the error message is

Matrix dimensions must agree.

Error in a (line 10)
t_pn=(im2double(t)+p/2)/2;

Answer 1

[madhan ravi]

t_pn = (im2double(t) + p.' / 2) / 2;