Development of a cloud cover reader from whole sky images

  • Authors

    • Han-Kyung Yun
    • Sun-Min Whang
    2018-08-29
    https://doi.org/10.14419/ijet.v7i3.33.21023
  • eye observation of cloud, automatic observation system, color space, optical attribute of cloud, optical attribute of cloud.
  • Abstract

    Since the cloud amount in the sky is one of major variables to decide amount of sunshine or solar irradiance. A traditional method is eye-observation and it is widely used up to now. It requires one of observers at observation site for 24 hours due to the hourly observation. Another disadvantage is that there is individual difference and error between observers. Some of leading countries about weather observation have been trying to develop a cloud automatic observation system to replace the eye-observation. As a result, several methods have developed to replace the cloud observers, which have some restriction such as measurement range, accuracy and reliability.  The conventional approach distinguishes between clouds and sky regions by RGB color and the ratio of each color in the image, but our proposed method extracts the cloud region using the optical properties of clouds and sky. The suggested method is applied to a randomly selected one day for 24 hours.  The result shows that the amount of cloud compatible with the results of the existing observations be abele to obtained, and further quantified data can be obtained.

     

  • References

    1. [1] Yun mi Kim, Jhoon Kim, and Hi Gu Cho, Development of objective algorithm for cloudiness using all-sky digital camera, Atmosphere, Korean Meteorological Society, vol. 18(1), (2008),pp. 1–14.

      [2] Seungok Kim, et el, A comparative study of total cloud amount and cloud base height between cloud automatic observation system and visual observations, automatic observations, (2013), Research Report of Meteorological Research Institute, Korea Meteorological Administration.

      [3] Heinle, A., Macke, A., and Srivastav, A., “Automatic cloud classification of whole sky imagesâ€, Atmospheric Measurement Techniques, 3, (2010), pp. 557-567.

      [4] Shields J., Karr M., Johnson R., and Burden A., “Day/night whole sky imagers for 24-h cloud and sky assessment: history and overviewâ€, Applied Optics, 52, (2013), pp.1605-1616.

      [5] Otsu, N., "A Threshold Selection Method from Gray-Level Histograms," IEEE Transactions on Systems, Man, and Cybernetics, Vol. 9, No. 1, (1979), pp. 62-68.

      [6] Ahmed Elsayed Ghitas, “Studying the effect of spectral variations intensity of the incident solar radiation on the Si solar cells performanceâ€, NRIAG Journal of Astronomy and Geophysics, 1, (2012), pp. 165-171.

      [7] Christian A. Gueymard, “The sun’s total and spectral irradiance for solar energy applications and solar radiation modelsâ€, Solar Energy, 76, (2004), pp. 423-453.

  • Downloads

  • How to Cite

    Yun, H.-K., & Whang, S.-M. (2018). Development of a cloud cover reader from whole sky images. International Journal of Engineering & Technology, 7(3.33), 252-256. https://doi.org/10.14419/ijet.v7i3.33.21023

    Received date: 2018-10-05

    Accepted date: 2018-10-05

    Published date: 2018-08-29