Experimenting with NDVI , fiji + photoscan

Posted by zk876 on February 11, 2015 at 7:37pm

Hello All,

I just started experimenting with NDVI. I bought a IR-PRO.com INFRABLU NDVI LENS for my HERO3 black edition.

This is what I did:

- I went and did a small survey mission at a field and processed the orthomosaic in photoscan.

- I then opened up the ortho in FIJI Image and processed the NDVI.

Using NDVI_VGYRM.lut color map from http://publiclab.org/notes/cfastie/08-26-2014/new-ndvi-colormap

I noticed one thing. If I process the NDVI for a single image that made up the orthomosaic, I am getting mixed colors vs the orthomosaic which is just green mostly.

I have attached both images.

Let me know what you think.

RGB-NDVI.png

single-image-ndvi.jpg

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Replies

Deon van der Merwe February 18, 2015 at 11:42am

The effect you are seeing is likely due to bidirectional reflectance artifacts.
Deon van der Merwe February 18, 2015 at 11:38am

I will be happy to take a crack at processing your images if you'd like, but the Dropbox link does not appear to be working anymore.
- zk876 > Deon van der Merwe February 18, 2015 at 2:54pm
  
  Here is the link.
  
  https://www.dropbox.com/sh/o39n88bvbntjxwc/AADQTKt7l-WHm0jssj5RnHLV...
  
  I suppose i did something wrong.
  
  Dropbox - Error
  
  Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!
criro1999 February 13, 2015 at 3:09pm

Nice work.

What lens exaclty did you buy from http://www.ir-pro.com? Please post the link of lens.

I am in the process to buy an NIR (NDVI lens) from Sunex (link below) for my Hero Back3+. I did remove myself the original lens form my Hero3+ and want to add an NIR lens (also no distorsion). But that model from Sunex can not be enclosed on the waterproof case, are little bit longer.

Is you lens from ir-pro OK on the waterproof case? And is the ir-pro lens you did buy with no fish eyes correction?

http://www.optics-online.com/search_all_products.asp?PartNumber=dsl...
- zk876 > criro1999 February 14, 2015 at 6:45am
  
  Yes, it fits in the waterproof case. I'm using their new hybrid flat lens.
- criro1999 > zk876 February 14, 2015 at 10:34am
  
  Thanks fort your reply.
  
  Those "flat" lens (F5.5mm) from "ir-pro" (last link below) looks as Sunex model (DSL945D).
  
  It feets also inside the waterproof case, but the problem people have with them it's way too zoom that it makes every thing so shaky (even on gimbal). Did you notice this effect on your lens?
  
  For that reason I was looking to use the Sunex DSL355A(F4.2mm), which is less shaky, but it cannot fits inside the waterproof. It is a compromise.
  
  Anyway, thanks for your detail, I am considering on my decision ir-pro lens too, but Sunex looks better as price and quality for me and it looks it is the same lens.
  
  http://www.optics-online.com/search_all_products.asp?PartNumber=DSL...
  
  http://www.optics-online.com/OOL/DSL/DSL945.PDF
  
  http://www.ir-pro.com/mini-camera-lenses/945-10mp-1080p-flat-lens
  
  Search all products
- criro1999 > criro1999 February 14, 2015 at 10:47am
  
  Try to compare the 2 images below. I do not see any differences, see at the light shadow on lens and thread, it looks identical for me. Who did copy who?
- criro1999 > criro1999 March 15, 2015 at 11:27am
  
  see my lens replacememt on GoPro Hero 3+ black with a Sunex lens, non-fish eye effect.
  
  https://vimeo.com/122239436
  
  https://www.youtube.com/watch?v=N2Cg-irR76M
zk876 February 13, 2015 at 4:41am

I got the original images here if anyone is willing to process them to compare from my results?

https://www.dropbox.com/sh/eayj7fokr0dhtgd/AABStkDrUlorCkgSYuD8slZ1...

Dropbox - Error

Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!
- John Hutchison > zk876 February 13, 2015 at 10:50am
  
  I have saved it to my dropbox, but it will be 2 weeks before I am at home and can do it.