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Title: A hybrid approach to estimate the complex motions of clouds in sky images

Tracking the motion of clouds is essential to forecasting the weather and to predicting the short-term solar energy generation. Existing techniques mainly fall into two categories: variational optical flow, and block matching. In this article, we summarize recent advances in estimating cloud motion using ground-based sky imagers and quantitatively evaluate state-of-the-art approaches. Then we propose a hybrid tracking framework to incorporate the strength of both block matching and optical flow models. To validate the accuracy of the proposed approach, we introduce a series of synthetic images to simulate the cloud movement and deformation, and thereafter comprehensively compare our hybrid approach with several representative tracking algorithms over both simulated and real images collected from various sites/imagers. The results show that our hybrid approach outperforms state-of-the-art models by reducing at least 30% motion estimation errors compared with the ground-truth motions in most of simulated image sequences. Furthermore, our hybrid model demonstrates its superior efficiency in several real cloud image datasets by lowering at least 15% Mean Absolute Error (MAE) between predicted images and ground-truth images.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4]
  1. Stony Brook Univ., NY (United States). Dept. of Electrical and Computer Engineering; Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. New Jersey Inst. of Technology, Newark, NJ (United States). Martin Tuchman School of Management
  3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
BNL-113436-2017-JA
Journal ID: ISSN 0038-092X; R&D Project: 07230; YN0100000
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Solar Energy
Additional Journal Information:
Journal Volume: 138; Journal Issue: C; Journal ID: ISSN 0038-092X
Publisher:
Elsevier
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Sky imagery; Cloud motion tracking; Optical flow
OSTI Identifier:
1341691