Researchers measure plant chlorophyll using leaf images
Scientists in the US have developed their very own pair of rose-tinted spectacles by adapting Google Glass to measure the chlorophyll concentration of leaves.
Aydogan Ozcan and his research group at the University of California are passionate about creating new technologies through innovative, photonic methods and are well acquainted with the possibilities of wearable technology in scientific research. Chlorophyll concentration is a handy metric for monitoring plant health and the system devised by Ozcan’s team combines Google Glass with a custom made leaf holder and bespoke software to determine just that.
By placing the leaf into the handheld 3D-printed leaf holder and illuminating it with red then white LEDs, the system exploits chlorophyll’s low light absorption in the green part of the visible spectrum. Google Glass images the leaf through software that is initiated by the voice command ‘Okay Glass, image a leaf’, which is sent to a remote server to process the results. In less than 10 seconds, an estimated chlorophyll content result is then sent back to the Glass for viewing. ‘Performing the experiments on the UCLA campus was a funny experience,’ explains Ozcan, ‘wearing the Google Glass attracted everyone’s attention’.
Currently the gold standard for measuring chlorophyll concentration involves chemical extraction, which is destructive, complex and time-consuming. Portable chlorophyll metres do exist as a non-destructive alternative. The most reliable meter available is the SPAD-502, which analyses the light absorption of a leaf in the range 650–940nm. However, this method requires multiple measurements for a single leaf as each one is made over a small area (6mm2) to estimate an overall estimate for the chlorophyll level.
Ozcan’s Google Glass-based solution offers a number of advantages over other systems on the market. It can record measurements over a circular area of 5cm2 and holds up to 12GB of data, which corresponds to several thousand tests, and owing to the Google Glass cloud-connection these are transferred to a database available on the web. The major advantage of Google Glass is that it can also provide GPS information of the measurements – Ozcan believes this will be beneficial for tracking results and later comparisons.
Biomedical engineer Tony Huang, of Pennsylvania State University, US, is impressed with the speed and accuracy of the new Glass commenting that it ‘has great potential in agriculture and environmental applications’.
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