False result why applying interp1 function!

Hi to all,

I have data taken at non-regular intervals, and I'd like to interpolate the data to have values every 100ms.

if 
17:43:08.437 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.477 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.497 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.516 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.537 > ATT_HandleValueNotification: status=0 h=45 n=3 09 C7 17
17:43:08.577 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
end

My code is :

if s=data(:,3)+data(:,4)/1000; % convert to seconds+fractions
t = datenum(2014,07,18,data(:,1),data(:,2),s)*86400;
t = t - t(1);
sample = interp1(t,res(:,1:3), 0:0.01:t(end)); % i fixed a time to 100ms to obtain estimated data in this time 

 // end

Thanks in advance

end

[Azzi Abdelmalek]

This is not clear, what are your data? cell array? sting?

[Star Strider]

This seems to be a duplicate of: http://www.mathworks.com/matlabcentral/answers/142334-interp1gives-me-error-results

[inti]

Thanks for your reply.

My data is cell array , My table res is like this:(3 columns) contains 380 rows

 if 
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,140625000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
  end

The problem here that when i appliy interp1 function , it gives me a table with 4230 rows!!!

[the cyclist]

@inti,

By far the best thing you can do to help us solve your problem is to give us a small piece of functioning MATLAB code (including the part that defines the data) that illustrates the problem. Otherwise, we spend far too much time guessing.

[inti]

Thanks for your reply.

I have irregular time series data: (time (h:m:s:ms), X-acceleration, Y-acceleration, Z-acceleration)in hexadecimal

Portion of my log file

if 17:43:08.437 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.477 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.497 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.516 > ATT_HandleValueNotification: status=0 h=45 n=3 07 C7 17
17:43:08.537 > ATT_HandleValueNotification: status=0 h=45 n=3 09 C7 17
end

The first column is for a Time and the three last columns are for acceleration's data (x,y,z).

My goal here is to interpolate irregular Time series to regular time series and i like to obtain acceleration's data every 0.01 seconds.

After converting acceleration's data from hexadecimal to acceleration's g , i obtain this table

if 0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,140625000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000

end

And this a portion of a table sample after applying interp1 function :

if 
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000
0,110866306584362  -0,890625000000000  0,359375000000000
0,125746056832695  -0,890625000000000  0,359375000000000
0,140624576267240  -0,890625000000000  0,359375000000000
0,132812426778048  -0,890625000000000  0,359375000000000
0,125000277288855  -0,890625000000000  0,359375000000000
0,117188127799663  -0,890625000000000  0,359375000000000
0,109375978310470  -0,890625000000000  0,359375000000000
0,109375000000000  -0,890625000000000  0,359375000000000

end
i think that i have a duplicate values