Example showing how we obtained the parameters of a streamer blob. Panel (a) shows a running-difference image of LASCO/C2, where the dark blue line marks the propagating path of a streamer blob. Panel (b) is a time-distance diagram obtained along the dark blue line marked in panel (a) based on the running-difference images. The propagation of the blob is shown as the dark feature and the bright one above, marked by red triangles. Based on the trajectory of the blob shown in panel (b), a fitting curve was obtained using the quadratic fitting method, as shown in panel (c).