Sky Class Based Prediction of Cloud Movements in Afyonkarahisar Region Conditions

Abstract

The intermittent and variable nature of solar energy makes its efficient use very difficult. The biggest factor in this intermittency and variability is cloud movements. In the study, the performance of a flow-based algorithm for tracking and predicting the movements of clouds was investigated under the conditions of the Afyonkarahisar region. For this purpose, a digital camera was installed in Afyon Kocatepe University Engineering Faculty and sky images were recorded at regular intervals. Cloud and sky classifications were made on the images obtained. In order to follow the clouds, the most suitable corner points for tracking were determined using the Shi-Tomasi algorithm. The corner points found were followed on sequential images using the Lucas-Kanade optical flow algorithm and the motion direction and speed information of the clouds were obtained with the help of linear regression. Finally, using the relevant motion direction and velocity information, cloud motions with a resolution of 20 seconds for a time horizon of 340 seconds are estimated. For the data set used in the study, estimates were made with an error performance of 5.88%. The method has shown that it has a high potential in cloud motion prediction.

Keywords

• Cloud Motion Tracking
• Cloud Motion Prediction
• Shi-Tomasi Algorithm
• Lucas-Kanade Optical Flow
• Solar Energy

Afyonkarahisar bölgesi şartlarında bulut hareketlerinin gökyüzü sınıfları tabanlı tahmini

Öz

Güneş enerjisinin kesikli ve değişken yapıda olması verimli kullanımını oldukça zorlaştırmaktadır. Bu kesiklilik ve değişkenliğin oluşmasındaki en büyük etmen bulut hareketleridir. Gerçekleştirilen çalışmada, bulutların takibi ve hareketlerinin tahmini için akış tabanlı bir algoritmanın performansı Afyonkarahisar bölgesi şartlarında araştırılmıştır. Bu amaç doğrultusunda Afyon Kocatepe Üniversitesi Mühendislik Fakültesine bir dijital kamera yerleştirilmiş ve belirli aralıklarla gökyüzü görüntüleri kaydedilmiştir. Elde edilen görüntüler üzerinde bulut ve gökyüzü sınıflandırmaları gerçekleştirilmiştir. Bulutların takibinin gerçekleştirilebilmesi için takibe en uygun köşe noktaları Shi-Tomasi algoritması kullanılarak belirlenmiştir. Bulunan köşe noktaları Lucas-Kanade optik akış algoritması kullanılarak sıralı görüntüler üzerinde takip edilmiş ve doğrusal regresyon yardımıyla bulutların hareket yön ve hız bilgilerine ulaşılmıştır. Son olarak, ilgili hareket yön ve hız bilgilerinin kullanılmasıyla 340 saniye zaman ufku için 20 saniye çözünürlüğünde bulut hareketleri tahmin edilmiştir. Çalışmada kullanılan veri seti için %5.88’lik hata performansı ile tahminler gerçekleştirilmiştir. Yöntem, bulut hareketi tahmininde yüksek potansiyele sahip olduğunu göstermiştir.

Anahtar Kelimeler

• Bulut Hareketi Takibi
• Bulut Hareketi Tahmini
• Shi-Tomasi Algoritması
• Lucas-Kanade Optik Akış
• Güneş Enerjisi

Kaynakça

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