UAV Electroluminescence Imaging for High-Resolution PV Defect Detection
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Solution Overview
Problem
Existing methods for inspecting solar panels in large-scale solar farms are time-consuming, labor-intensive, and prone to introducing defects during module handling, and existing imaging technologies struggle to accurately detect faults in solar panels.
Innovation Solution
A method and system using an unmanned aerial vehicle (UAV) equipped with an optical subsystem and onboard processing capabilities to capture and process electroluminescence (EL) images of PV arrays, including functions like POINT, FIND, ALIGN, SCAN, AUTO, FREEZE, and MAP, to enhance image quality and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PV modules are dismounted for EL measurement in a controlled darkroom environment, then measurement accuracy is improved, but inspection time and labor requirements increase significantly
Solution Approach 1:
The patent introduces a darkroom tent as a portable controlled environment that can be set up on-site near the PV array. This intermediary structure provides the necessary dark conditions for accurate EL measurements without requiring modules to be dismounted and transported to a fixed laboratory, thus maintaining measurement accuracy while enabling faster in-situ inspection.
Solution Approach 2:
The patent replaces the traditional mechanical approach of dismounting and transporting modules with an optical/electrical system. By using a portable darkroom tent with controlled lighting conditions and an EL imaging system, the measurement process is transformed from a mechanical handling operation to an in-situ optical measurement, eliminating the need for physical module removal while maintaining measurement quality.
2Reliability
If PV modules are dismounted for inspection, then measurement control is improved, but the risk of introducing defects during handling increases
Solution Approach 1:
The patent replaces mechanical handling operations with an in-situ optical measurement system. By setting up a portable darkroom tent at the installation site and using EL imaging to capture module performance data in place, the system eliminates the need to physically remove, transport, and reinstall modules, thereby preventing handling-induced defects while maintaining controlled measurement conditions.
Solution Approach 2:
The inspection system is designed to perform measurements in the field without requiring module removal. The portable darkroom tent and EL imaging equipment enable the modules to be inspected in their installed position, allowing the system to serve itself by capturing data directly from the operational configuration without external intervention that could cause damage.
3Ease of operation
If EL imaging is performed at night with a tripod-mounted camera, then module dismounting is avoided, but image quality suffers from perspective and intensity distortions
Solution Approach 1:
The patent employs an adjustable and reconfigurable darkroom tent structure that can be dynamically positioned and configured to optimize imaging conditions. The tent includes adjustable lighting systems and positioning mechanisms that allow real-time optimization of the imaging geometry, eliminating fixed perspective distortions associated with tripod-mounted cameras while maintaining operational simplicity.
Solution Approach 2:
The system changes the lighting parameters and geometric configuration by introducing a controlled darkroom environment with adjustable illumination. By modifying the lighting conditions and camera positioning within the portable darkroom, the system optimizes image quality parameters such as intensity uniformity and perspective accuracy, overcoming the limitations of fixed tripod-based nighttime imaging.
4Measurement precision
If a mobile trailer with darkroom is used for EL inspection, then controlled measurement environment is achieved, but large scale inspection becomes time consuming and impractical
Solution Approach 1:
The patent divides the large mobile trailer darkroom into a series of smaller, modular portable darkroom tents. Each tent is independently deployable and can be positioned close to specific PV array sections. This segmentation reduces the complexity and portability burden while maintaining controlled measurement environments, enabling scalable inspection across large solar farms without requiring a single large trailer.
Solution Approach 2:
The patent transitions from a horizontal, ground-based mobile trailer to a vertical, air-supported tent structure. This dimensional change allows the darkroom environment to be elevated and positioned directly over or adjacent to the PV array, reducing the need for large ground-based trailers and improving accessibility and portability while maintaining controlled measurement conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and accurate detection of defects in solar panels without dismounting them, reducing time and labor, and providing high-resolution images for analysis.
Implementation Method 1
For EL measurements, PV modules of the solar panels are connected to a power supply and put under forward bias. The emitted near-infrared light is captured with a camera that is sensitive in the near-infrared waveband.
Data Source
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AI summary
A method (400) of capturing and processing electroluminescence (EL) images (1910) of a PV array (40) is disclosed herein. In a described embodiment, the method 400 includes controlling the aerial vehicle (20) to fly along a flight path to capture EL images (1910) of corresponding PV array subsections (512b) of the PV array (40), deriving respective image quality parameters from at least some of the captured EL images, dynamically adjusting a flight speed of the aerial vehicle along the flight path, based on the respective image quality parameters for capturing the EL images (1910) of the PV array subsections (512b), extracting a plurality of frames (1500) of the PV array subsection (512b) from the EL images (1910); determining a reference frame having a highest image quality of the PV array subsection (512b) from among the extracted frames (2100); performing image alignment of the extracted frames (2100) to the reference frame to generate image aligned frames (2130), and processing the image aligned frames (2130) to produce an enhanced image (2140) of the PV array subsection (512b) having a higher resolution than the reference frame. A system, image processing device, and aerial vehicle for the method thereof are also disclosed.