Importance of Image Enhancement and CDF for Fault Assessment of Photovoltaic Module Using IR Thermal Image

• Published in: Applied Sciences
• Main Authors: Bubryur Kim, Ronnie O. Serfa Juan, Dong-Eun Lee, Zengshun Chen
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Subjects: convolutional neural network (CNN); cumulative distribution function (CDF); fault diagnosis; image processing; infrared thermography; photovoltaic module
• Online Access: https://www.mdpi.com/2076-3417/11/18/8388

Infrared thermography is the science of measuring the infrared energy emitted by an object, translating it to apparent temperature variance, and displaying the result as an infrared image. Significantly, acquiring thermal images delivers distinctive levels of temperature differences in solar panels that correspond to their health status, which is beneficial for the early detection of defects. The proposed algorithm aims to analyze the thermal solar panel images. The acquired thermal solar panel images were segmented into solar cell sizes to provide more detailed information by region or cell area instead of the entire solar panel. This paper uses both the image histogram information and its corresponding cumulative distribution function (CDF), useful for image analysis. The acquired thermal solar panel images are enhanced using grayscale, histogram equalization, and adaptive histogram equalization to represent a domain that is easier to analyze. The experimental results reveal that the extraction results of thermal images provide better histogram and CDF features. Furthermore, the proposed scheme includes the convolutional neural network (CNN) for classifying the enhanced images, which shows that a 97% accuracy of classification was achieved. The proposed scheme could promote different thermal image applications—for example, non-physical visual recognition and fault detection analysis.