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Different approaches......

by RQ-05 | July 11, 2015 21:15 | 50 views | 6 comments | #12051 | 50 views | 6 comments | #12051 11 Jul 21:15

Apparently, I am lost in the world of NDVI images. I need to figure out how to find the LUTs for images created in the sandbox.

The two images attached are my efforts.

The grey image seems to show only plant mass, while the colorized shows extra reflectance of bare soil.

I am interested in mapping using a small UAS with a modified MOBIUS with the PL red filter. Any guidance would be very much appreciated. Thank you in advance. ColorNDVI.jpg


6 Comments

It will probably be possible to give you some guidance if you attach a couple of the photos straight from the camera.
Chris

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Chris, Here is the original of the two that are already processed. Is it possible to only use the PL Sandbox to get usable images, or do I need another program? The help is much appreciated! RQ-05

IMAG0001.JPG

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Hi RQ-05, Using Infragrammar in the Infragram sandbox is a good way to experiment. I usually use Ned Horning's Fiji plugin to produce NDVI images. It allows a couple of things that are hard to do at infragram.org. To make the image below, I stretched the histogram of the NIR (blue) channel and applied the included color table.
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RQ-05NDVI.jpg
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The NDVI values are in the right ballpark, but could be a little higher. If your photo from the camera is a little more turquoise, the NDVI values could be closer to where they should be.

Chris

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Wow.....really great stuff! So, I need to get the Mobius settings adjusted to a more tourquis appearence. Would that be in the white balance or an increase in the blue channel settings? I am also going to download ImageJ program many people talk about. Thanks very much for your help so far. RQ-05

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Altering the white balance settings could have made made that photo more turquoise. Some experimentation is called for. Changing the exposure (so the photo is brighter or darker) can also alter the NDVI results. So that is another experiment to try.

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I will start with the experimentation on the exposure. Thanks. I will keep you posted. RQ-05

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