I work on one-dimensional (1-D) time series classification using 1D-CNN. But the length of the time series data is variant, e.g., from 80 to 120. So it's hard to specify the size of input layer of CNN model.
A simple method is to pad (or truncate) the input to the same length, e.g., 100.
The second possible method I tried is using FFT/IFFT to resample the time series to the same length (100).
Interpolation ?
I am not sure if my methods are good options or not. Thanks in advance if someone can provide some widely acceptable and reasonable methods to handle this problem.