Question surf() fuction

I am generationg a revolution solid of a gaussian fuction and when I use the surf() fuction I get the graphic that I need, but I have to get this figure in a matrix NxN with each element of this matrix be a gray value (it will be my height) but I don´t know how do it!

Can you help me?

This is my code:

 r = x(1:1024); %0:0.1:30; x(513:1024)

Unrecognized function or variable 'x'.

z = gaussmf(r,[13.32 0]);%exp(-r.^2/(2*(13.32).^2));
theta = 0:pi/20:2*pi;
xx = bsxfun(@times,r',cos(theta));
yy = bsxfun(@times,r',sin(theta));
zz = repmat(z',1,length(theta));
figure()
surf(xx,yy,zz)
axis equal

Answer 1

[AR]

Hi @Esteban Suárez,

As per my understanding, you want to convert the 3D surface plot into a 2D NxN matrix where each element represents a grayscale value corresponding to the height of the surface.

To do this conversion, you can follow the below steps:

1. Set the resolution for the output Matrix - size N

N = 1024; % Define the resolution of the output matrix 

2. Use “meshgrid” to create a grid (xq,yq) which will represent the NxN matrix.

[xq, yq] = meshgrid(linspace(min(xx(:)), max(xx(:)), N), linspace(min(yy(:)), max(yy(:)), N)); 

3. Use “griddata” to interpolate zz onto 2D grid (xq,yq).

zq = griddata(xx, yy, zz, xq, yq); 

4. Normalize the heights to fit into the grayscale image.

zq_normalized = uint8(255 * mat2gray(zq)); 

5. Display the 2D matrix as a grayscale image.

figure(); 
imshow(zq_normalized, []); 
title('Grayscale Matrix of Revolution Solid'); 

You can refer the below MathWorks Documentations for more information:

• meshgrid: https://www.mathworks.com/help/matlab/ref/meshgrid.html
• griddata: https://www.mathworks.com/help/matlab/ref/griddata.html