finding the duration of a sequence of data

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sarmad m on 6 Jul 2017
Commented: sarmad m on 7 Jul 2017
I need to find the duration of a sequence of data values that represents head yaw movements .
where the positive values are head looking to right and negative values are head looking to left .
the below signal has different duration of looking right and left. How can I find these duration ?
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Answers (2)

Andy on 6 Jul 2017
positive = (data>0); % Identifies when the head is to the right.
pos_count = sum(positive); % gives you the number of measurements.
If you have the logging frequency it is easy to calculate time.
The similar code can be used for determining left movement. Instead of using data>0 use another number to give a bit of tolerance on what constitutes looking ahead.
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sarmad m on 6 Jul 2017
Thanks ,but how the duration of each sequence can be found as shown in the image ?

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Andrei Bobrov on 6 Jul 2017
d = csvread('case2.csv');
d1 = d(d ~= 0);
t = d1 > 0;
tt = diff([1;t(:)]) ~= 0;
out = accumarray(cumsum(tt),d1);
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Andrei Bobrov on 6 Jul 2017
another variant
t = d ~= 0;
d1 = d(t);
t1 = d1 > 0;
tt = [true;diff(t1)~=0];
ii = cumsum(tt);
out = accumarray(ii,1).*sign(d1(tt));
sarmad m on 7 Jul 2017
the plot below shows a signal and (out) plot . out values are :
-25 122 -130 25 -7 138 -17 37 -53 58 -46 so do they represent the duration of each sequence ?

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