Detecting maximum with threshold

%example threshold detection code
function [MAXES] = identifyMaximums(Avg) 
X = Avg;
threshold = 30;
[Xon, Xoff] = detectThreshold(X,threshold);
nSteps = length(Xon);
firstOff = 1;
while Xoff(firstOff) > Xon(1)
    firstOff = firstOff+1;
end
lastOn = nSteps;
while Xon(lastOn) > Xoff(end)
    lastOn = lastOn-1;
end
%Adjust ons and offs
Xon_align = Xon(1:lastOn);
Xoff_align = Xoff(firstOff:end);
%Count number of steps after aligning
nStepsFinal = length(Xon_align);
%Initialize matrix of maximums
MAXES = NaN(nStepsFinal,1);
for i = 1:nStepsFinal
    MAXES(i) = max(X(Xon_align(i):Xoff_align(i)));
end
    function [Ons,Offs] = detectThreshold(signal,threshold)
        overThreshold = signal>threshold;
        onOffs = diff(overThreshold);
        
        Offs = find(onOffs==-1)+1;
        Ons  = find(onOffs==1);
    end
end

Error:

Index exceeds the number of array elements. Index must

not exceed 0.

Error in identifyMaximums (line 14)

while Xoff(firstOff) > Xon(1)

Error in load_data_10_15 (line 119)

[MAXES] = mean(identifyMaximums(Avg));

Data (Avg) that is being processed:attached image

Hello I hope all is well. I am currently working on a side project where I am trying to match data from a sensor to a force plate. At the moment I am trying to linearize the data. To do so, I must collect the peak values. For some reason I am getting this error and I am not sure why. If you have the time, please look over my work and provide some guidence.

Thank you!

Answer 1

[Steven Lord]

You may want to take a look at the islocalmax function.

[Hanna Armstrong]

Hi Steven, So I did the localmax function and plotteded it and this is what I am getting, do you have any reccomendations in regards to filtering out the bottom values?

Answer 2

[Matt J]

If you have the time, please look over my work and provide some guidence.

In detectThreshold(), you need to add control logic to handle the case where find() returns empty [].

Offs = find(onOffs==-1)+1;
Ons  = find(onOffs==1);

[Hanna Armstrong]

Hi Matt, thank you for responding!

If you can, may you please elaborate on what you mean by adding control logic? At the moment I don't understand how I am supposed to change it.

Thanks.

[Matt J]

I left it to you because only you knowwhat's supposed to happen when no peaks are detected.