B3 Non-refereed conference proceedings
Noise reduction in asteroid imaging using a miniaturized spectral imager (2021)

Wolfmayr, M., Pölönen, I., Lind, L., Kašpárek, T., Penttilä, A., & Kohout, T. (2021). Noise reduction in asteroid imaging using a miniaturized spectral imager. In S. R. Babu, A. Hélière, & T. Kimura (Eds.), Sensors, Systems, and Next-Generation Satellites XXV (Article 118580P). SPIE. Proceedings of SPIE : the International Society for Optical Engineering, 11858. https://doi.org/10.1117/12.2600201

JYU authors or editors

Publication details

All authors or editors: Wolfmayr, Monika; Pölönen, Ilkka; Lind, Leevi; Kašpárek, Tomáš; Penttilä, Antti; Kohout, Tomáš

Parent publication: Sensors, Systems, and Next-Generation Satellites XXV

Parent publication editors: Babu, Sachidananda R.; Hélière, Arnaud; Kimura, Toshiyoshi

Place and date of conference: Online, 13.-24.9.2021

Journal or series: Proceedings of SPIE : the International Society for Optical Engineering

ISSN: 0277-786X

eISSN: 1996-756X

Publication year: 2021

Number in series: 11858

Article number: 118580P

Publisher: SPIE

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1117/12.2600201

Publication open access: Not open

Publication channel open access: 

Abstract

In October 2024, European Space Agency’s Hera mission will be launched, targeting the binary asteroid Didymos. Hera will host the Juventas and Milani CubeSats, the first CubeSats to orbit close to a small celestial body performing scientific and technological operations. The primary scientific payload of the Milani CubeSat is the SWIR, NIR, and VIS imaging spectrometer ASPECT. The Milani mission objectives include mapping the global composition and the characterization of the binary asteroid surface. Onboard data processing and evaluation steps will be applied due to the limited data budget for the downlink to Earth and to perform the technological demonstration of a novel semi-autonomous hyperspectral imaging mission. Before downloading, the image data is evaluated in terms of sharpness and coverage and processed by compression. The challenges and their proposed solutions for the data processing part of the mission are investigated through studies. Since most noise contributors are unknown until Milani is activated, different noises are studied based on previous missions and derived from hyperspectral images taken in a laboratory environment mimicking the real-life situation. The hyperspectral camera technology in the laboratory is similar to the one used in the ASPECT imager payload. Both ASPECT and the imagers utilized in our measurements are based on employing a Fabry-Pérot interferometer as an adjustable transmission filter. The imagers are also designed and built by the same party, the Technical Research Centre of Finland (VTT). Best performing denoising techniques for each noise type are discussed on the one hand for the entire datacubes and on the other hand for the spatial domain only since the mission includes images taken only at specific wavebands. The advantage of applying denoising for the whole datacube comes from the internal dependencies between the wavebands, allowing efficient processing. A trade-off study for several noise reduction algorithms is presented. The goal is to implement efficient image processing algorithms with low computational complexity, securing the successful execution of the mission.

Keywords: hyperspectral imaging; asteroids; satellites (technical object); signal processing; noise (radio technology); space technology

Free keywords: Asteroid imaging; Binary asteroid Didymos (Didymos-Dimorphos); European Space Agency's Hera mission; Fabry-Pérot interferometer; Milani CubeSat; Noise reduction in hyperspectral imaging; Onboard data processing; Signal-to-noise ratio improvement

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Ministry reporting: Yes

Reporting Year: 2021