Table 1 A selection of vegetation indices

Normalised difference vegetation index (NDVI)

(RNIR − RRED)/(RNIR + RRED)

RRED ~ 680, RNIR ~ 800

[50]

Range: − 1 to 1

Common range: 0.2–0.8

Broadband

Red edge NDVI

(R750 − R705)/(R750 + R705)

[50]

Range: − 1 to 1

Typical healthy range: 0.2 to 0.9

Narrowband (hyperspectral data)

Simple ratio index (SRI)

RNIR/RRED

RRED ~ 680, RNIR ~ 800

[20]

Range: 0 to > 30

Typical healthy range: ~ 2–8

Broadband

Photochemical reflectance index (PRI)

(R531 − R570)/(R531 + R570)

[50]

[51]

Range: − 1 to 1

Typical healthy range: − 0.2 to 0.2

Vegetation health prior to senescence

Plant senescence reflectance index (PSRI)

(Red–Green)/NIR

[50]

Range: − 1 to 1

Typical healthy range: − 0.1 to 0.2

>PSRI ~ canopy stress, onset of senescence, fruit ripening

Normalised phaeophytinization index (NPQI)

(R415 − R435)/(R415 + R435)

[52]

Chlorophyll degradation

0.56–1.41

Unacidified and acidified solutions [53]

Structure Independent Pigment Index (SIPI)

(R800 − R445)/(R800 + R680)

[50]

[51]

[54]

Range: 0–2

Typical healthy range: 0.8–1.8

Good with canopy variety

Leaf rust disease severity index (LRDSI)

6.9 × (R605/R455) − 1.2

[23]

Accuracy of 89% in study may vary with other data.