StructVIO : Visual-inertial Odometry with Structural Regularity of Man-made Environments

We propose a novel visual-inertial odometry approach that adopts structural regularity in man-made environments. Instead of using Manhattan world assumption, we use Atlanta world model to describe such regularity. An Atlanta world is a world that contains multiple local Manhattan worlds with different heading directions. Each local Manhattan world is detected on-the-fly, and their headings are gradually refined by the state estimator when new observations are coming. With fully exploration of structural lines that aligned with each local Manhattan worlds, our visual-inertial odometry method become more accurate and robust, as well as much more flexible to different kinds of complex man-made environments. Through extensive benchmark tests and real-world tests, the results show that the proposed approach outperforms existing visual-inertial systems in large-scale man-made environmentsComment: 15 pages,15 figure

Persistent Upflows and Downflows at Active Region boundaries Observed by SUTRI and AIA

Upflows and downflows at active region (AR) boundaries have been frequently observed with spectroscopic observations at extreme ultraviolet (EUV) passbands. In this paper, we report the coexistence of upflows and downflows at the AR boundaries with imaging observations from the Solar Upper Transition Region Imager (SUTRI) and the Atmospheric Imaging Assembly (AIA). With their observations from 2022 September 21 to 2022 September 30, we find 17 persistent opposite flows occurring along the AR coronal loops. The upflows are prominent in the AIA 193 \AA images with a velocity of 50-200 km/s, while the downflows are best seen in the SUTRI 465 \AA and AIA 131 \AA images with a slower velocity of tens of kilometers per second (characteristic temperatures (log T(K)) for 193 \AA, 465 \AA and 131 \AA are 6.2, 5.7, 5.6, respectively). We also analyze the center-to-limb variation of the velocities for both upflows and downflows. The simultaneous observations of downflows and upflows can be explained by the chromosphere-corona mass-cycling process, in which the localized chromospheric plasma is impulsively heated to coronal temperature forming a upflow and then these upflows experience radiative cooling producing a downflow with the previously heated plasma returning to the lower atmosphere. In particular, the persistent downflows seen by SUTRI provide strong evidence of the cooling process in the mass cycle. For upflows associated with open loops, part of the plasma is able to escape outward and into the heliosphere as solar wind