Re: [PLOTS] Can anyone help me with a NDVI question?

[Jeffrey Warren]

Hi, Mike - thanks for posting -- i've CC'ed the infrared discussion list as well. 

It looks like a white balance issue - there are good resources on this on the Infragram wiki page here: https://publiclab.org/wiki/infragram

although perhaps we need to tidy that page up (please pitch in!)

In particular your images look like this question posted a while back -- take a look to see if you can follow the same steps!

https://publiclab.org/questions/abdul/10-21-2016/can-anyone-help-me-troubleshoot-my-ndvi-imagery

Hope that helps!

Jeff

On Sat, Sep 9, 2017 at 9:01 PM, 'Mike Rainwater' via The Public Laboratory for Open Technology and Science <publiclaboratory@googlegroups.com> wrote:

I modified my own camera...an original SJ4000. Takes good pictures, I used the Lee Red Fire Filter mentioned in some of the research on infragram. I am having a hard time trying to convince myself it is working properly. Sometimes I get great results with the online processing, other times its confusing. I attached a couple of files to show what I am talking about. The first one is a piece of plywood where I layed out fresh cut green leaves, leaves in between changing colors, and dried brown dead leaves, under that I put a small pile of dirt, pile of mulch and a rock for comparison. It looks like I am able to get separation in the setting I used for that photo, was sort of happy with those results. The second picture is where I am confused. I took a fresh cut green leaf and a dried out brown leaf and held them up at arms lenght side by side and the photo shows them both as being "Healthy" with both reflecting NIR at about the same rate.  Actually the dead one on the left seems to reflect more NIR. Is this because my camera  was too close to the leaves to tell them apart? or is something wrong with my method?

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