fig6
![Beat-to-beat continuous blood pressure estimation with optimal feature set of PPG and ECG signals using deep recurrent neural networks](https://image.oaes.cc/2d9a6bd6-f7b9-482e-a79f-72fce41efe76/vp7030.fig.6.jpg)
Figure 6. The proposed deep RNN architecture. Each circle represents a LSTM cell. Each red dashed box is a Bi-LSTM layer, which consists of forward (green) and backward (blue) LSTM. The blue dashed box represents the LSTM layer with residual connections.