Journal Article

The Martian Boulder Automatic Recognition System, MBARS

Ewing, R. C., Levy, J., Karunatillake, S., Fassett, C. I., Hood, Don R., Sholes, S. F.

2022

Overview

Boulder‐sized clasts are common on the surface of Mars, and many are sufficiently large to be resolved by the high resolution imaging science experiment (HiRISE) camera aboard the Mars reconnaissance orbiter. The size, number, and location of boulders on the surface and their spatial distribution can reveal the processes that have operated on the surface, including boulder erosion, burial, impact excavation, and other mechanisms of boulder transport and generation. However, quantitative analysis of statistically significant boulder populations, which could inform these processes, entails prohibitively laborious manual segmentation, granulometry, and morphometry measurements over large areas. Here, we develop, describe, and validate an automated tool to locate and measure boulders on the Martian surface: the Martian Boulder Automatic Recognition System (MBARS). Our open‐source Python‐based toolkit automatically measures boulder diameter and height in HiRISE images enabling rapid and accurate assessments of boulder populations. We compare our algorithm with existing boulder‐counting methods, manual analyses, and objects of known size to verify accuracy and precision. Additionally, we test how MBARS quantitatively characterizes boulders around an impact crater in the Martian northern lowlands. We compare this to previous work on rock excavation during impact cratering using manually counted boulders around lunar craters. Plain Language Summary Large boulders (>1 m diameter) are widely distributed on the Martian surface. They are easily observed from orbit, making them visible with high‐resolution imaging. Mapping the location, number, and size of boulders is helpful for understanding which geological processes bring boulders to the surface, move them around, and fragment them into smaller rocks and soil. Here, we describe and validate the Martian Boulder Automatic Recognition System (MBARS), a set of tools that automatically locates and measures boulders in high‐resolution images of the Martian surface. We compare results generated by MBARS with results from other automated boulder‐measuring tools as well as with results from manual boulder measurements to ensure accuracy. We also use MBARS to map boulders around an impact crater on Mars and compare the boulder distribution to a similar‐sized crater on the Moon. Key Points The Martian Boulder Automatic Recognition System (MBARS) is a new tool to detect and measure boulders on the Martian surface MBARS is comparably or more accurate than prior published algorithms that measure boulders MBARS readily reproduces manually measured results

• Publisher: John Wiley & Sons, Inc,American Geophysical Union (AGU)
• Subject: Algorithms / Automation / Calibration / Cameras / impact phenomena and cratering / instruments and techniques / Mars / Measurement techniques / Methods / remote sensing / Rock excavation / Spatial distribution / Statistical analysis / surface materials and properties / Topography