Optical technique for photovoltaic spatial current response measurements using compressive sensing and random binary projections
journal contribution
posted on 2016-07-21, 13:51authored byMatt Cashmore, George Koutsourakis, Ralph Gottschalg, Simon R.G. Hall
Compressive sensing has been widely used in image compression and signal recovery techniques in recent years; however, it has received limited attention in the field of optical measurement. This paper describes the use of compressive sensing for measurements of photovoltaic (PV) solar cells, using fully random sensing matrices, rather than mapping an orthogonal basis set directly. Existing compressive sensing systems optically image the surface of the object under test, this contrasts with the method described, where illumination patterns defined by precalculated sensing matrices, probe PV devices. We discuss the use of spatially modulated light fields to probe a PV sample to produce a photocurrent map of the optical response. This allows for faster measurements than would be possible using traditional translational laser beam induced current techniques. Results produced to a 90% correlation to raster scanned measurements, which can be achieved with under 25% of the conventionally required number of data points. In addition, both crack and spot type defects are detected at resolutions comparable to electroluminescence techniques, with 50% of the number of measurements required for a conventional scan.
Funding
This work was funded through the European Metrology Research Programme (EMRP) Project
ENG55 PhotoClass. The EMRP is jointly funded by the EMRP participating countries within
EURAMETand the European Union. This work is co-funded by the UK National Measurement
System. This work was supported in part by the Research Councils UK (RCUK) through the
project “Stability and Performance of Photovoltaics (STAPP)” (contract no: EP/H040331/1).
History
School
Mechanical, Electrical and Manufacturing Engineering
Published in
Journal of Photonics for Energy
Volume
6
Issue
2
Citation
CASHMORE, M. ... et al, 2016. Optical technique for photovoltaic spatial current response measurements using compressive sensing and random binary projections. Journal of Photonics for Energy, 6 (2), 025508.
This work is made available according to the conditions of the Creative Commons Attribution 3.0 Unported (CC BY 3.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/3.0/
Acceptance date
2016-06-13
Publication date
2016
Notes
This is an Open Access article published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.