3D Reconstruction of Small SolarSystem Bodies using Rendered and Compressed Images

Sammanfattning: Synthetic image generation and reconstruction of Small Solar System Bodies and theinfluence of compression is becoming an important study topic because of the adventof small spacecraft in deep space missions. Most of these missions are fly-by scenarios,for example in the Comet Interceptor mission. Due to limited data budgets of smallsatellite missions, maximising scientific return requires investigating effects of lossycompression. A preliminary simulation pipeline had been developed that uses physicsbasedrendering in combination with procedural terrain generation to overcomelimitations of currently used methods for image rendering like the Hapke model. Therendered Small Solar System Body images are combined with a star background andphotometrically calibrated to represent realistic imagery. Subsequently, a Structurefrom-Motion pipeline reconstructs three-dimensional models from the rendered images.In this work, the preliminary simulation pipeline was developed further into the SpaceImaging Simulator for Proximity Operations software package and a compressionpackage was added. The compression package was used to investigate effects of lossycompression on reconstructed models and the possible amount of data reductionof lossy compression to lossless compression. Several scenarios with varying fly-bydistances ranging from 50 km to 400 km and body sizes of 1 km and 10 km weresimulated and compressed with lossless and several quality levels of lossy compressionusing PNG and JPEG 2000 respectively. It was found that low compression ratiosintroduce artefacts resembling random noise while high compression ratios removesurface features. The random noise artefacts introduced by low compression ratiosfrequently increased the number of vertices and faces of the reconstructed threedimensionalmodel.