Creating 2D sinusoid image with spatial frequency

Hello, I am confused as to how I should create the following type of image in MATLAB.

"Consider ? x ? grey level images that are raised 2D sinusoids of some spatial frequency ? cycles per ? pixels where ?=256.

?(?,?)= 1/2(1+sin (2?/? ? ?))."

We have to convolve the above image using gaussian filtering.

Answer 1

[KSSV]

k = 3. ; 
N = 256 ; 
x = 1:N ; 
y = 1:N ; 
[X,Y] = meshgrid(x,y) ; 
I = 1/2*(1+sin(2*pi/N*k*X)) ;