Matlab interpolation for 3 axis data

[Menton85]

Hi,
I'm doing a project in medicine, I've used MATLAB to create 3d graphs using a vector with 5 fixed values as X, a vector with 7 fixed values as Y. As Z I have 5*7 measured values.

I need to interpolate my graph to "smoothen" the lines in the graph, but I am totaly lost, I have no idea how to do this. Could someone show me a practical example of needed MATLAB code for this I would be very thankful.

 

[MRFMengineer]

This might get you started, it interpolates and smooths the data by 4X. It only works on a square matrices at the moment.

clear all; close all;
mat = rand(7);
[X,Y] = meshgrid(1:7,1:7);
[XI,YI] = meshgrid(1:.25:7); %This increases sampling by 4X)
colormap(hsv)
surf(mat)
shading interp
Zsmooth = interp2(X,Y,mat,XI,YI, 'spline');
figure2 = figure;
figure2 = surf(XI,YI,Zsmooth);
shading interp

 

[oswaler]

Interpolation in MATLAB can be achieved using the "interp1" function. This function allows you to interpolate data for a given set of points. In your case, you can use the "interp1" function to interpolate your 3-axis data.

First, you will need to define your X, Y, and Z vectors as follows:

X = [x1, x2, x3, x4, x5]; % 5 fixed values for X axis
Y = [y1, y2, y3, y4, y5, y6, y7]; % 7 fixed values for Y axis
Z = [z11, z12, z13, z14, z15, z16, z17,
z21, z22, z23, z24, z25, z26, z27,
z31, z32, z33, z34, z35, z36, z37,
z41, z42, z43, z44, z45, z46, z47,
z51, z52, z53, z54, z55, z56, z57]; % 5*7 measured values for Z axis

Next, you can use the "interp1" function to interpolate your data. The syntax for this function is as follows:

Vq = interp1(X,V,Xq) % where Vq is the interpolated values and Xq is the query points

In your case, X will be your fixed X values, V will be your Z values, and Xq will be a set of query points for which you want to interpolate the Z values. You can define Xq as follows:

[Xq,Yq] = meshgrid(1:0.1:5,1:0.1:7); % defines a grid of query points with a step size of 0.1

Finally, you can use the "interp1" function to interpolate your Z values for the query points as follows:

Zq = interp1(X,Z,Xq); % interpolates Z values for the query points

You can then plot your interpolated data using the "surf" or "mesh" functions in MATLAB. Here's an example code for plotting the interpolated data:

surf(Xq,Yq,Zq); % plots the interpolated data as a surface plot
xlabel('X axis'); % labels for the axes
ylabel('Y axis');