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Fig. 7 | Plant Methods

Fig. 7

From: Development of an accurate low cost NDVI imaging system for assessing plant health

Fig. 7

Analysis to verify calibration by testing an array of wavelengths from spectrometry-derived NDVI calculations, to identify which wavelengths produce NDVI values that most closely correspond to the NDVI values that were actually obtained from Raspberry Pi imagery. Measuring the percentage (%) difference between the two NDVI values. A NDVI with the wavelength for visible red ranging from 600 up to 700 nm, with NIR wavelength fixed at 750 nm. B NDVI wavelength for NIR ranging from 700 up to 800 nm, with visible red fixed at 620 nm. From this data, the wavelengths which produced an NDVI value that best matched the values as measured by the Raspberry Pi system, correspond to the wavelengths that the Raspberry Pi images were calibrated to; 620 nm for red and 750 nm for NIR, indicated by the red bars. Error ± S.D (n = 150)

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