NDVI and NRG

NDVI stands for "Normalized Difference Vegetation Index". NRG stands for "Near-infrared / Red / Green". NDVI and NRG are both ways to visualize the amounts of infrared and other wavelengths of light reflected from vegetation. Because both these methods compare ratios of blue and red light absorbed versus green and IR light reflected, they can be used to evaluate the health of vegetation. It's a snapshot of how much photosynthesis is happening. This is helpful in assessing vegetative health or stress. (Read more here: https://www.agronomy.org/publications/jeq/articles/36/3/832)

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Notes on ndvi by cfastie

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Dual NDVI Ultra Probe Unit

by cfastie about 1 year ago | 8 | 629 | 4

*Above: The Dual NDVI Ultra Probe Unit is powered by a Nano Logger (enhanced by an array of beryl...

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Graze anatomy

by cfastie about 2 years ago | 8 | 1,546 | 4

[](//i...

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Calibration cogitation

by cfastie about 2 years ago | 11 | 1,283 | 5

Normalized difference vegetation index (NDVI) has been computed from satellite and airborne data ...

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Pole NDVI of deer grazing

by cfastie about 2 years ago | 3 | 1,897 | 6

This month Nature published an article with the following assertions: There is three time...

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Single vs. dual cameras

by cfastie over 2 years ago | 1 | 3,222 | 3

*Above: Ned Horning taking an aerial photo of the scene for testing filters and calibration targe...

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Testing MIDOPT filters

by cfastie over 2 years ago | 8 | 2,266 | 3

*Above: A folder full of photos of the same scene taken with different filters and different whit...

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Dual bandpass filters

by cfastie over 2 years ago | 2 | 3,761 | 2

*Above: I don't really understand how interference filters work, and I'm pretty sure the person w...

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Crown Point Fort infrared

by cfastie about 3 years ago | 2 | 2,780 | 6

Below is a half spherical panorama taken over the 1759 British Fort at Crown Point, New York with...

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Orange is the new red

by cfastie over 3 years ago | 11 | 5,374 | 6

A couple of weeks ago Joe Sommer from Penn State [asked about using an orange filter instead of a...

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Event38 NDVI over Cocodrie

by cfastie over 3 years ago | 3 | 3,720 | 1

The camera [flown by Charles Malveaux during the Barnrainsing](http://publiclab.org/notes/cfastie...

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The KAPtober Collection

by cfastie almost 4 years ago | 1 | 4,284 | 5

This weekend I hosted some family in Vermont and we combined leaf peeping with kite photography. ...

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NIR and water

by cfastie almost 4 years ago | 1 | 6,066 | 6

Above: Pure NIR photo of white water lily (Nymphaea odorata). . The interaction of infrar...

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LEAFFEST aerials

by cfastie almost 4 years ago | 1 | 3,129 | 3

*Image above: Teddy and the Iris with the radio remote transmitter (bottom center), and his lapto...

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The LEAFFEST Line

by cfastie almost 4 years ago | 2 | 4,437 | 0

LEAFFEST is only a week away, an...

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New NDVI colormap

by cfastie almost 4 years ago | 26 | 14,135 | 8

NDVI is an index (a unit-free number) related to how much photosynthetic activity is occurring. A...

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Titan 2 IR flight

by cfastie almost 4 years ago | 2 | 3,777 | 3

I took a new Titan 2 IR rig for a test flight yesterday. I flew the Fled kite over a clearing whe...

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Titan 2 IR

by cfastie about 4 years ago | 5 | 5,435 | 5

Once again I have been remiss in field testing the aerial camera rigs that I have been designing ...

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Super Redstone

by cfastie about 4 years ago | 3 | 3,429 | 3

I took a new super-red Infragram camera for a test flight yesterday over a field that was scarred...

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The Titan 2 Rig

by cfastie about 4 years ago | 1 | 4,116 | 0

The Infragram camera makes capturing aerial photos for in...

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Mobius NDVI

by cfastie about 4 years ago | 29 | 8,528 | 3

*Above: It should be pretty easy for a DIY NDVI image to differentiate between things in this sce...

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Mobius white balance

by cfastie about 4 years ago | 2 | 7,709 | 3

Above: Wratten 25A Infragram of Hedwigia ciliata* taken with a [modified Mobius ActionCam](http...

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NIR and white balance

by cfastie about 4 years ago | 1 | 4,767 | 1

*Above: An LED which emits only near infrared light around 850 nm photographed under normal room ...

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Mobius IR conversion

by cfastie over 4 years ago | 21 | 16,192 | 2

*Above: The Mobius ActionCam opens with two screws. One more set screw and you can expose the IR ...

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Mobius Filter-O-Matic

by cfastie over 4 years ago | 4 | 8,171 | 1

To figure out how to get the best plant health images with a Mobius ActionCam, I will remove the ...

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