Detection of clouds on wide-field night sky images

• Thesis title in English: Detection of clouds on wide-field night sky images
• Academic year of topic announcement: 2009/2010
• Thesis type: Bachelor's thesis
• Thesis language: angličtina
• Department: Department of Software and Computer Science Education (32-KSVI)
• Supervisor: RNDr. Josef Pelikán
• Author: hidden - assigned and confirmed by the Study Dept.
• Date of registration: 15.04.2010
• Date of assignment: 15.04.2010

Guidelines

Main goal of this work is to produce reliable cloud detection algorithm for wide-field images, taken by growing network of Bootes night sky camera system. The system uses comercialy available 16 mega pixels detectors to record almost all-sky (180 degrees) image of night sky, continuously through the night. We aren't aware of any available tools to detect clouds on those images.

Student shall research available literature and try to implement and test some algorithms for cloud detections. Algorithm input is digital, gray scale (0-65k range) image of night sky with stars in FITS format. Software developed shall detect where is sky clear and where it is cloudy out. It is expected that the algorithm will either look for the stars (which detection marks clear sky) or for brighter areas, which usually mark clouds (and hence clouded area). The output should be either 2D matrix marking clouded area on the sky or list of clear/clouded areas provided as polygons in altitude-azimuthal system. The algorithms should be integrated into observatory image browser for quick preview of its performance.

Software should be able to run on Linux, with strong preference (due to operational reasons) given to Ubuntu distribution. It has to be well documented, including description of the algorithms. For accessing image data it can use class hierarchy available from the observatory control system (RTS2, see literature).

References

- SeXtractor - http://www.astromatic.net/software/sextractor

- SExtractor: Software for source extraction, Bertin, E. & Arnouts, S. 1996, Astronomy & Astrophysics Supplement 317, 393

- FITS: A Flexible Image Transport System, Wells, D. C., Greisen, E. W., and Harten, R. H., Astronomy & Astrophysics Supplement Series, 44, 363-370, 1981

- RTS2 - http://rts2.org

- RTS2: a powerful robotic observatory manager, Kubánek P. et. al., SPIE 2006, volume 6274

- Meteorite Detection System for Widefield CCDs, Gomboš I., Diploma thesis, MFF UK, 2007