Plotting intensity vs (x,y) in matlab.

Hi, I am new to matlab and trying to plot a #D plot of the intensity of a grayscale image vs (x,y) coordinates of a pixel. I wrote the following code, but it doesn't seem to work:

>> f=imread('peppers.png');

>> f=rgb2gray(f);

>> [x,y]=meshgrid(1:1:384,1:1:512);

>> mesh(x,y,f(x,y))

The error reported is:

??? Maximum variable size allowed by the program is exceeded.

Please tell me what is wrong with my code. Also tell me a way to plot the intensity.

Answer 1

[Star Strider]

You do not need the meshgrid call.

This works:

f=imread('peppers.png');
f=rgb2gray(f);

figure(1)
mesh(f)
grid on

[Apurv Gupta]

@Star Strider, can we do it using the mesh grid call?

[Star Strider]

You can, but it doesn’t change the plot:

f=imread('peppers.png');
f=rgb2gray(f);
[x,y]=meshgrid(1:1:512, 1:1:384);

figure(1)
mesh(x, y, f)
grid on

I believe your using f(x,y) in your mesh call threw the error, since ‘x’ and ‘y’ are matrices, not vectors.

You don’t need that anyway, because ‘f’ is an array, not a function, and for arrays (in this instance) subscripts are not required.