Electroluminescence imaging of PV devices: camera calibration and image correction

A method for the correction of electroluminescence (EL) images of PV devices is presented. This includes a camera calibration based on focus, dark current, flat field and lens distortion as well as artefact removal, including single-time-effects and erroneous pixels. Image correction allows EL images taken with different systems or perspectives to be normalized and used for quantitative analysis. Results include an image correction of a 4x9 cell module, imaged in different perspective positions. After correction, intensity difference and positional error were found to be less than 1%, respective 2%.