Fig. 2.

Cross-correlation examples. (a) Cross-correlation of two vectors $\overrightarrow{v_{\text{A}}}$ and $\overrightarrow{v_{\text{B}}}$ is maximized with the delay 1. The directed edge is valid and remains in the graph, because the estimated delay is non-negative. (b) Cross-correlation of two vectors $\overrightarrow{v_{\text{A}}}$ and $\overrightarrow{v_{\text{B}}}$ is maximized with the delay −2 or −3 which indicates the optimal direction of the edge is opposite. The edge is invalid and removed from the graph