Detecting and analysing geomorphological structures in images of comet 67P/Churyumov-Gerasimenko using Fourier transform

TL;DR

This paper introduces a Fourier transform-based method for automatic detection and analysis of quasi-periodic geological structures in comet images, revealing insights into the comet's formation and surface processes.

Contribution

The paper presents a novel Fourier transform-based technique for pixel-precise detection of lineament structures in comet images, applicable to various geological features.

Findings

Layering structures are ubiquitous with consistent orientations and spacings of 9-20 m.

Furrows are unevenly distributed and aligned with local gravity, indicating down-slope movement.

The method is broadly applicable to geological texture and structure analysis.

Abstract

We present a method for automatised detection and analysis of quasi-periodic lineament structures from images at pixel-precision. The method exploits properties of the images' frequency domain found by using the Fourier transform. We developed this method with the goal of detecting lineament structures in an image of the Hathor cliff of comet 67P/Churyumov-Gerasimenko, which are caused by layerings and furrows in the nucleus material. Using our method, we determined the orientation and wavelength-range of these structures. The detected layering edges have similar orientations, spatial separations of 9-20 m, and are ubiquitous throughout the image. We suggest that the layerings are a global feature of the comet nucleus that provide information about formation and evolution of comet 67P. The furrows are non-uniformly distributed throughout the image. Their orientation is broadly parallel to the direction of the local gravity vector at the Hathor cliff, with spacings similar to that of the layering structures. The furrows are interpreted as signatures of local down-slope movement of cliff material. We demonstrate that the developed method is broadly applicable to the detection and analysis of various kinds of quasi-periodic structures like geological layering, folding and faulting, and texture analysis in general. In order to facilitate the application of our method, this paper is accompanied by a demo program written in Matlab.