How to find the width of plotted graph at selected Y-axis level?

I want to measure the width of each signal at the y-axis's 20(TE reflection efficiency). Could you please help me with that code?

[Rik]

Your curves look like they have a relatively poor sampling. I would suggest using one of the interpolation functions. What did you try yourself?

[Dinuka Ravimal]

Thank you

Answer 1

[Star Strider]

Try this:

lambda = linspace(0.4, 0.6);                                            % Wavelength Vector
s = sinc(((0.47:0.02:0.55).' - lambda)*1E+2)*30;                        % Signal Matrix (Row Vectors)

for k = 1:size(s,1)
    [maxv,idx] = max(s(k,:));                                           % Index Of Peak
    idxv1 = idx+[-2 0];
    lmda(k,1) = interp1(s(k,idxv1), lambda(idxv1), 21, 'pchip');        % Interpolate Rising Edge
    idxv2 = idx+[0 2];
    lmda(k,2) = interp1(s(k,idxv2), lambda(idxv2), 21, 'pchip');        % Interpolate Falling Edge
    wdth(k) = lmda(k,2) - lmda(k,1);                                    % Calculate Width
end

figure
hold on
for k = 1:size(s,1)
    hp = plot(lambda, s(k,:));
    plot(lmda(k,:), [1 1]*21, '+', 'Color',hp.Color)                    % Plot ‘+’ In Same Color As Signal
end
hold off
grid

Make appropriate changes to get my code to work with your signals. It may require some ‘tweaking’, however it should produce reasonable results.

[Dinuka Ravimal]

Thank you so much, through your code I got results.

[Star Strider]

As always, my pleasure!