How did the parameter "StructureSensitivity" of fibermetric affect the result?

I know the document had wrote "The structure sensitivity is a threshold for differentiating the tubular structure from the background". However I don't know the definition of the "background" means. So when I adjust the parameter, the result changes not as I expected. Is it meas the original pixel value or ...?

And I also want to make sure that "tubular structure" is the value that fibermetric calculate right?

If someone can answer my question, thanks a lot !

Answer 1

[Manish]

Hi RD,

I understand that you want to know:

• The essence of the 'StructureSensitivity' parameter in the 'fibermetric' function.  
• The meaning of the term 'background' and ‘tubular structure’ as described in the 'fibermetric' documentation.

As mentioned in the documentation of ‘fibermetric’:

• Tubular structures in an image resemble tubes or elongated shapes, fibers in material science images.
• The "background" typically refers to the parts of the image that are not of primary interest.
• In the context of ‘fibermetric’, background is considered to be the areas in the image that do not exhibit the tubular or line-like structures that the function is designed to enhance or detect.
• Adjusting the "StructureSensitivity" , significantly alters the pixel-level data in the image.

Here is the sample code snippet that demonstrates how varying the 'StructureSensitivity' parameter affects pixel differences:

function plotSensitivityVsDifference()
    I = imread('threads.png'); 
    I_gray = im2double(I); 
    sensitivityValues = 1:5;
    totalDifferences = zeros(size(sensitivityValues));
    for i = 1:length(sensitivityValues)
        J = fibermetric(I_gray, 'StructureSensitivity', sensitivityValues(i));
        diffImage = abs(I_gray - J);
        totalDifferences(i) = sum(diffImage(:));
    end
    % Plot
    plot(sensitivityValues, totalDifferences, '-o', 'LineWidth', 2, 'MarkerSize', 8);
    xlabel('StructureSensitivity');
    ylabel('Total Pixel Difference');
    title('Effect of StructureSensitivity on Pixel Difference');
    grid on;
end
plotSensitivityVsDifference();

For better understanding of ‘fibermetric’ function, refer the documentation below:

• https://www.mathworks.com/help/releases/R2020a/images/ref/fibermetric.html

Hope this helps!