Covert surf 3D image to 2D matrix

Hello,

I have a code like this:

[x,y] = meshgrid(1:15,1:15);
tri = delaunay(x,y);
z = peaks(15);
trisurf(tri,x,y,z)
view(2)

and it gives me a 2D projection on XY plane of a 3D surface like this:

I have two questions:

1. How can I convert this projection to a new 2D image?
2. I want to extract the Z values of the same figure to form a 2D matrix with arbitrary size, such as a 3*3 matrix. Is there any way to do this?

Thanks!

Answer 1

[Vedant Shah]

Hi @Haomin Wang,

To save an image into a new 2D projection, the “saveas” function can be used. Additionally, to extract z-values from the figure into a matrix of any arbitrary size, the “interp2” function can be employed by interpolating the x and y values and calculating the corresponding z-values. For more information about these functions, please refer to the documentation using the following commands in MATLAB command line:

web(fullfile(docroot, "/matlab/ref/saveas.html")) 
web(fullfile(docroot, "/matlab/ref/interp2.html")) 

To save the image as a new 2D image, the following line can be added to your existing code:

saveas(gcf, 'projection.png') 

To save the z-values as an arbitrary 3x3 matrix, you can refer to the following code:

% Define new grid size 
new_size = 3; 

% Create new grid 
[xq, yq] = meshgrid(linspace(1, 15, new_size), linspace(1, 15, new_size)); 

% Interpolate Z values 
z_new = interp2(x, y, z, xq, yq); 

% Display the new matrix 
disp(z_new); 

Using this approach, we can obtain the z-values in a 3x3 matrix format as a result.