Find the interval of an envelope corresponding to a specific peak after peak detection

I have done the peak detection to find the highest peak in the image below. How do I find the interval of the envelope corresponding to that peak?

Answer 1

[KSSV]

Let (x,y) be your data.

[val,idx] = max(y) ; 
x_max = x(idx) ; 
y_max = y ; 

Read about max

[madhan ravi]

"I have done the peak detection to find the highest peak in the image below."

[KSSV]

"How do I find the interval of the envelope corresponding to that peak"

[madhan ravi]

max() doesn't find the interval(range) it just gives the maximum value as well as the index of the max value.

[KSSV]

If index is know....if he wants some range...he can do [idx-n idx+n] .

[madhan ravi]

finding n is the tricky part

[KSSV]

I am not here to help them completely.....just giviing a clue would suffice....if the user wants he may ask further questions..If I know I will answer else some other person who knows will answer.

[D_coder]

yea finding n is the tricky part. I already mentioned i did the peak detection. Its not about finding the max its about finding the interval

[KSSV]

Attach your data....it can be done...

[D_coder]

There you go

[KSSV]

load('peak_data.mat') ;
y = MDL_1_env_norm ;
x = 1:length(y) ;
%
threshold = 0.01 ;
x1 = x ;
y1 = y ;

y1(y>threshold) = NaN ;
x1(isnan(y1)) = 0 ;

% Seeprate nans seperately 
ii = zeros(size(x1));
jj = x1 > 0;
ii(strfind([0,jj(:)'],[0 1])) = 1;
idx = cumsum(ii).*jj;
out = accumarray( idx(jj)',x1(jj)',[],@(x){x'});

idx0 = out{1}(end) ; 
idx1 = out{2}(1) ;
idx2 = out{2}(end) ; 
idx3 = out{3}(1) ;

idx = [idx0 idx1 idx1 idx2 idx3] ;

plot(x,y,'r') ;
hold on
plot(x(idx),y(idx),'*b') ;