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CRI 1&2 indicies Fields

Attempting to input some leaf pigment indicies as noted below into the index calculator for Fields and Mapper. Really struggling with getting these to work with the index generator and would be very appreciative of anyone in the community that could provide some insight into this. For reference, these indexes are being applied to some vineyard scan data collected using Micasense RE sensor.

Carotenoid Reflectance Index 1 (CRI1):
The CRI1 is a reflectance measurement that is sensitive to carotenoid pigments in plant foliage. Estimation of leaf carotenoid content from reflectance is much more difficult than estimation of chlorophyll because of the overlap between chlorophyll and carotenoid absorption peaks and because of the higher concentration of chlorophyll than carotenoid in most leaves. At 510nm, the reciprocal reflectance of carotenoid is maximal, but this value is also influenced by chlorophyll. To remove the effect of chlorophyll, the reciprocal reflectance at 550nm is used, which is influenced more purely by chlorophyll alone. Higher CRI1 values mean greater carotenoid concentration relative to chlorophyll.
CRI1 = (1/510nm) - (1/550nm)
The values of this index range from 0 to more than 15. The common range for green vegetation is between values of 1 to 12.

Carotenoid Reflectance Index 2 (CRI2):
The CRI2 is a reflectance measurement that is sensitive to carotenoid pigments in plant foliage. The CRI2 is a modification of CRI1. The reciprocal reflectance at 700nm is used to remove the effect of chlorophyll on the reciprocal reflectance at 510nm. It provides better results in areas of high carotenoid concentration. Higher CRI2 values mean greater concentration of carotenoid relative to chlorophyll.
CRI2 = (1/510nm) - (1/700nm)
The values of this index range from 0 to more than 15. The common range for green vegetation is between values of 1 to 11.

Anthocyanin Reflectance Index 1 (ARI1):
The ARI1 is a reflectance measurement that is sensitive to anthocyanin in plant foliage. The reciprocal reflectance of anthocyanin is highest around 550nm; however, the reciprocal reflectance value at 550nm is also influenced by chlorophyll. The reciprocal reflectance at 700nm is used as a measure of chlorophyll content to remove the chlorophyll contribution from reflectance around 550nm. Increases in ARI1 indicate changes in foliage via new growth or death.
ARI1 = (1/550nm) - (1/700nm)
The values of this index range from 0 to more than 0.2. The common range for green vegetation is between values of 0.001 to 0.1.

Anthocyanin Reflectance Index 2 (ARI2):
The ARI2 is a reflectance measurement that is sensitive to anthocyanins in plant foliage. Increases in ARI2 indicate canopy changes in foliage via new growth or death. The ARI2 is a modification of the ARI1 which detects higher concentrations of anthocyanins in vegetation.
ARI2 = 800nm [(1/550nm) - (1/700nm)]
The values of this index range from 0 to 0.2. The common range for green vegetation is 0.001 to 0.1.

Hi Jhogan,

These indices are narrow-band indices and require a hyperspectral camera or a multispectral camera custom made with these wavelengths. If you see https://support.micasense.com/hc/en-us/articles/214878778-What-is-the-center-wavelength-and-bandwidth-of-each-filter-on-the-RedEdge-camera-, for the rededge camera, the green band has center wavelength 560 nm and rededge 717 nm. If you use these formuals above for the micasense bands, you will not be able to get CR1or the other indices, you can just get an approximation of AR1. For AR1, the formaula will be AR1=(1/green)-(1/rededge). AR2 can also be generated if you use the NIR band though the center wavelength is 840 nm and it would be too much approximation. Here are the narrowband indices: https://www.harrisgeospatial.com/docs/NarrowbandGreenness.html and here are the broadband ones: https://www.harrisgeospatial.com/docs/broadbandgreenness.html. This page explains well the difference between narroawband and broadbands.

Momtanu,

Thank you so much. You have been fantastic with answering my newbie questions! It is very much appreciated.

Regards,

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