MATLAB: How to find the infelction points from the data

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Hello all can any one help me how to find the inflection point from the data I have. I am new to matlab and tried various methods to find but cannot help for my data.
Can anyone help me to find the inflection point. The data which I have provided is the medical data of patient with pulse waves. I want to find the inflection point at the point where the reflection is ocuuring. Please help me to find the point in each curve.
Thankyou

Best Answer

If you want to find the dicrotic notch in each arterial pulse wave, try this: 
D = load('data_1.mat');
y = D.column1;                                                      % Data
x = linspace(0, numel(y), numel(y));                                % Create ‘x’ Vector
ix1 = islocalmin(y, 'MinProminence',1.1, 'MinSeparation',100);
ix2 = islocalmin(y, 'MinProminence',5);
ix = ix1 & ~ix2;
figure
plot(x, y)
hold on
plot(x(ix), y(ix), '+r')
hold off
grid
It gets most of them, however since your signal is a bit noisy, it is difficult to get all of them. Other functions, such as findpeaks, might be able to do better. I did not try findpeaks here.
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