PV Array EL Imaging with Dynamic Flight Speed and Frame Alignment
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Solution Overview
Problem
Existing methods for on-site electroluminescence (EL) inspection of photovoltaic (PV) arrays are time-consuming, labor-intensive, and prone to errors due to the need to dismount PV modules and the limitations of capturing images from a tripod.
Innovation Solution
A method and system for processing EL images of a PV array, involving extracting frames from EL images, determining a reference frame with the highest image quality, aligning the frames to the reference frame, and processing the aligned frames to produce enhanced images with higher resolution and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PV modules are dismounted for EL measurement in a controlled darkroom environment, then measurement reliability is improved, but productivity deteriorates due to time-consuming handling and large scale inspection infeasibility
Solution Approach 1:
The patent replaces the mechanical system of physically dismounting PV modules with an optical imaging system. An aerial vehicle equipped with EL imaging equipment captures images of PV modules in their installed positions, eliminating the need for mechanical handling while maintaining measurement capability through optical detection of electroluminescence signals.
Solution Approach 2:
The patent introduces an aerial vehicle as an intermediary between the PV array and the imaging system. This intermediary platform carries the EL imaging equipment to capture images from above, providing a controlled imaging environment without requiring module dismounting or ground-based tripod setup.
2Productivity
If EL images are captured using a tripod-mounted camera during the day with lock-in current control, then productivity is improved by avoiding module dismounting, but measurement precision deteriorates due to perspective and intensity distortions
Solution Approach 1:
The patent changes the viewing geometry from ground-level asymmetric perspective to top-down symmetric perspective. The aerial vehicle positions the camera directly above the PV array, creating a nadir view that eliminates perspective distortion and provides uniform imaging conditions across the entire array.
Solution Approach 2:
The patent changes the imaging parameters by moving from daytime visible light imaging to nighttime electroluminescence imaging. This parameter change allows capture of emitted near-infrared light from the PV modules themselves, providing intrinsic quality information without external light sources that cause intensity variations.
3Productivity
If EL images are captured at night using a tripod-mounted camera, then productivity is improved by avoiding module dismounting, but measurement reliability deteriorates due to labor-intensive operation and image quality limitations
Solution Approach 1:
The patent transitions from a static tripod-mounted system to a dynamic aerial vehicle platform. The aerial vehicle can actively position itself over different sections of the PV array, adjust altitude, and optimize imaging parameters dynamically, improving both coverage efficiency and image quality consistency.
Solution Approach 2:
The patent implements automated image processing algorithms that automatically align, stitch, and analyze EL images captured by the aerial vehicle. This self-service processing eliminates manual labor-intensive operations while maintaining high measurement reliability through consistent computational methods.
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
The method enables the production of enhanced EL images with higher resolution and lower noise, allowing for more efficient identification of defective PV modules and improved monitoring of PV array performance without the need for module dismounting.
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
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 210 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.