Friday, 12 August 2011

Leaf Drying and Range Calibration

Before SALCA is taken back to Halo Photonics, we need to complete a couple of experiments in order to make better use of the data sets we have already collected and to see if future plans are viable. Consequently,I have completed a leaf drying test and also a close-range calibration experiment.
Leaf used in experiment

Sand paper, Spectralon panel and mounted leaf

The leaf experiment was carried out using a fresh, whole leaf, which was fitted into a pre-weighed mount and placed next to 2 panels of known reflectances. The three targets were then scanned repeatedly over the course of 3 days with the mounted leaf being weighed after each scan. The purpose of this experiment is to see if the ratio of the two wavelengths changes during the drying process (as theory indicates), which would then be a useful indicator of moisture levels within canopies.
Leaf drying experiment

The close-range experiment is important because we have found a fluctuation in intensities at ranges of 0.25 m - 7 m. This experiment was conducted using 2 panels of known reflectance. One panel was kept static and another was placed at different distances from SALCA before being scanned. 16 scan positions were measured up to 7m, which should provide useful information for characterising the fluctuation in order to correct any values within this range.
Range Calibration: Left hand panel is stationary. Right hand panel moves in between scans.

Oliver Gunawan
12th August 2011

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