I have a big amount of light curves (image below) and I am trying to label the points as signal or background (the signal appears usually periodically, several times, for a given light curve). However, the data is not labeled. I tried labeling it by hand and using a bi-directional LSTM succeeds in labeling the data points properly. However, there are thousands of light curves and labeling all of them would take very long. Is there any good unsupervised approach to do this (unsupervised LSTM maybe, but any other method that might work on time series would do just fine)? Thank you!