Photon Systems Instruments PlantPen NDVI 310, Руководство пользователя и инструкция пользователя

Страница: 14 / 36

© PSI (Photon Systems Instruments), spol. s r. o.
14
•
Press SET to confirm.
•
PlantPen measure PRI
•
Value of PRI appears on display after measuring.
•
During the measurement all data are stored into the device memory.
7.2 NDVI MEASUREMENT
7.2.1 CALIBRATION
Calibration assures you that your measurements are accurate within the specification limits that led you to select the
instrument in the first place. It is better to calibrate your device before every set of samples. For Calibration of PlantPen
use white reflectance standard.
The calibration of the white reflectance standard is an indispensable part of a correct
calculation of NDVI.
Prior NDVI measurement perform the calibration as follows:
•
For calibration use white reflectance standard (It is part of leaf clip)
•
Turn ON device – hold SET button for 1 sec.
•
Close the leaf clip (white standard is on bottom part of the leaf clip)
•
Go to Calibration (“ Insert white sample ” appears on display)
•
Press SET button to confirm the calibration and wait until the calibration step is completed.
•
Calibration is automatically stored into the device memory.
•
The device is now ready to measure other samples.
7.2.2 MEASUREMENT
The PlantPen model NDVI 310 measures Normalized Difference Vegetation Index , which is an important indicator of
chlorophyll content in plants. The pigment in plant leaves, chlorophyll, strongly absorbs visible light (from 0.4 to 0.7 µm)
for use in photosynthesis. The cell structure of the leaves, on the other hand, strongly reflects near-infrared light (from 0.7
to 1.1 µm). The NDVI 310 device compares reflected light at two distinct wavelengths, 635 and 760 nm.
Please follow these instructions to perform a measurement:
•
Insert a leaf sample into the leaf clip. The leaf clip is important for the sample stabilization.
•
Go to Measurement
•
Press SET to confirm.
•
PlantPen measure NDVI
•
Value of NDVI appears on display after measuring.
•
During the measurement all data are stored into the device memory.
It is necessary to calibrate PlantPen after every switch ON.