The AFM image scan size is 20 by 20 m and contains 512 x 512 data points. The height information is displayed by the color contrast. The actual height data is contained in an excel file called PTFE Surface Topography Data - AFM.xls. This file contains the Z-height of a surface at an equally spaced distance in the X and Y direction. Each row represents the scan length of 20 m in the X direction and there are 512 data points. Similarly, each column represents the scan length of 20 m in the Y direction and there are 512 data points.

Using the above information what does the following Matlab code need to change to function?

% Read in the excel file containing the surface topography data

data = readmatrix('PTFE Surface Topography Data - AFM.xlsx');

% Extract the x and y coordinates and z values from the data

x = data(:,1);

y = data(:,2);

z = data(:,3);

% Plot a 2D image of the measured surface

figure(1)

imagesc(x, y, z)

colorbar

xlabel('x')

ylabel('y')

title('2D Image of Measured Surface')

% Plot a 3D image of the surface

figure(2)

surf(x, y, z)

colorbar

xlabel('x')

ylabel('y')

zlabel('z')

title('3D Image of Measured Surface')

% Calculate surface topography parameters

mean_z = mean(z);

z_range = range(z);

Ra = sum(abs(z-mean(z)))/length(z);

Rq = sqrt(sum((z-mean(z)).^2)/length(z));

skewness_z = skewness(z);

kurtosis_z = kurtosis(z);

Rp = max(z);

Rv = min(z);

% Calculate Bearing Area Ratio (BAR)

threshold = Rv + 200e-9;

binary_z = z > threshold;

total_area = length(z)*(x(2)-x(1))*(y(2)-y(1));

masked_area = sum(binary_z(:))*(x(2)-x(1))*(y(2)-y(1));

BAR = masked_area/total_area;

% Show a 2D image of the masked surface

figure(3)

imshow(binary_z)

title('Binarized Image of the Masked Surface')