WAHRSIS: A low-cost high-resolution whole sky imager with near-infrared capabilities

Dev, Soumyabrata; Savoy, Florian M.; Lee, Yee Hui

doi:10.1117/12.2052982

Cited by 54 publications

(69 citation statements)

References 12 publications

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“…In the future, we intend to provide a detailed statistical analysis of the performance of the proposed forecasting technique by using weather records of larger time period. We also intend to use other meteorological sensors [7] and ground-based cameras [8] to further improve the forecasting accuracy.…”

Section: Discussionmentioning

confidence: 99%

Predicting Solar Irradiance in Singapore

Fathima

Nedumpozhimana

Lee

et al. 2019

2019 Photonics &Amp; Electromagnetics Research Symposium - Fall (PIERS - Fall)

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Solar irradiance is the primary input for all solar energy generation systems. The amount of available solar radiation over time under the local weather conditions helps to decide the optimal location, technology and size of a solar energy project. We study the behaviour of incident solar irradiance on the earth's surface using weather sensors. In this paper, we propose a time-series based technique to forecast the solar irradiance values for shorter lead times of upto 15 minutes. Our experiments are conducted in the tropical region viz. Singapore, which receives a large amount of solar irradiance throughout the year. We benchmark our method with two common forecasting techniques, namely persistence model and average model, and we obtain good prediction performance. We report a root mean square of 147 W/m 2 for a lead time of 15 minutes.

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Section: Discussionmentioning

confidence: 99%

Predicting Solar Irradiance in Singapore

Fathima

Nedumpozhimana

Lee

et al. 2019

2019 Photonics &Amp; Electromagnetics Research Symposium - Fall (PIERS - Fall)

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“…In our research group, we have designed and built custom low-cost high-resolution sky imagers, which we call WAHRSIS, i.e. Wide Angle High Resolution Sky Imaging System (Dev et al, 2014). A WAHRSIS imager essentially consists of a high-resolution digital single-lens reflex (DSLR) camera with a fish-eye lens and an on-board micro-computer.…”

Section: Data Collectionmentioning

confidence: 99%

“…The entire device is contained inside a weather-proof box with a transparent dome for the camera. Over the years, we have built several versions of WAHRSIS (Dev et al, 2014(Dev et al, , 2015. They are now deployed at several locations around our university campus, capturing images of the sky at regular intervals.…”

Section: Data Collectionmentioning

confidence: 99%

Estimating solar irradiance using sky imagers

2019

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Ground-based whole sky cameras are extensively used for localized monitoring of clouds nowadays. They capture hemispherical images of the sky at regular intervals using a fisheye lens. In this paper, we propose a framework for estimating solar irradiance from pictures taken by those imagers. Unlike pyranometers, such sky images contain information about cloud coverage and can be used to derive cloud movement. An accurate estimation of solar irradiance using solely those images is thus a first step towards short-term forecasting of solar energy generation based on cloud movement. We derive and validate our model using pyranometers co-located with our whole sky imagers. We achieve a better performance in estimating solar irradiance and in particular its short-term variations as compared to other related methods using ground-based observations. IntroductionClouds have a significant impact on solar energy generation. They intermittently block the sun and significantly reduce the solar irradiance reaching solar panels. A short-term forecast of solar irradiance is needed for grid operators to mitigate the effects of a drop in power generation. With rapid developments in photogrammetric techniques, ground-based sky cameras are now widely used (Dev et al., 2016e). These cameras, known as Whole Sky Imagers (WSIs) are upward looking devices that capture images of the sky at regular intervals of time. These images are subsequently used for automatic cloud coverage computation, cloud tracking, and cloud base height estimation. In our research group, we use these imagers to study the effects of clouds on satellite communication links (Dev et al., 2018b;Yuan et al., 2016;Dev et al., 2017e).Localized and short-term forecasting of cloud movements is an on-going research topic (Shakya et al., 2017;Jiang et al., 2017;Feng et al., 2018). Optical flow techniques can be used to forecast images using anterior frames (Dev et al., 2016d).Similarly, cloud motion vectors are exploited for solar power prediction from satellite images (Jang et al., 2016). Our proposed method for estimating solar irradiance is thus a first step towards solar irradiance forecasting, as the input data used to estimate the irradiance is the same as the one used to forecast the sky condition.The accurate estimation and prediction of solar energy generation is a challenging task, as clouds greatly impact the total irradiance received on the earth's surface. In the event of clouds covering the sun for a short time, there is a sharp decline of the 1 arXiv:1910.04981v1 [eess.IV]

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“…These ten images were randomly selected from SWINSEG (Singapore Whole sky Nighttime Imaging SEGmentation database) [14] dataset. The images were captured using a ground-based whole sky imager, called Wide Angle High Resolution Sky Imaging System (WAHRSIS) [15]. This ground-based camera captures the images of the atmosphere at regular time intervals, with an interval of five minutes.…”

Section: Visual Quality Assessmentmentioning

confidence: 99%

Subjective Quality Assessment of Ground-based Camera Images

Lévêque

Dev

Hossari

et al. 2019

2019 Photonics &Amp; Electromagnetics Research Symposium - Fall (PIERS - Fall)

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Image quality assessment is critical to control and maintain the perceived quality of visual content. Both subjective and objective evaluations can be utilised, however, subjective image quality assessment is currently considered the most reliable approach. Databases containing distorted images and mean opinion scores are needed in the field of atmospheric research with a view to improve the current state-of-the-art methodologies. In this paper, we focus on using ground-based sky camera images to understand the atmospheric events. We present a new image quality assessment dataset containing original and distorted nighttime images of sky/cloud from SWINSEG database. Subjective quality assessment was carried out in controlled conditions, as recommended by the ITU. Statistical analyses of the subjective scores showed the impact of noise type and distortion level on the perceived quality.

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WAHRSIS: A low-cost high-resolution whole sky imager with near-infrared capabilities

Cited by 54 publications

References 12 publications

Predicting Solar Irradiance in Singapore

Predicting Solar Irradiance in Singapore

Estimating solar irradiance using sky imagers

Subjective Quality Assessment of Ground-based Camera Images

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