Hello, I am new to NDVI but am trying to figure out what the difference is between an NGB and NRG...
Public Lab is an open community which collaboratively develops accessible, open source, Do-It-Yourself technologies for investigating local environmental health and justice issues.
All topics »
If you cannot use the ReCaptcha to verify you are not a bot, use this alternative verification.
As an open source community, we believe in open licensing of content so that other members of the community can leverage your work legally -- with attribution, of course. By joining the Public Lab site, you agree to release the content you post here under a Creative Commons Attribution Sharealike license, and the hardware designs you post under the CERN Open Hardware License 1.1 (full text). This has the added benefit that others must share their improvements in turn with you.
sign up to join the Public Lab community
Forgot your password? Reset it here
by abrenner |
April 22, 2017 19:11 |
Hello, I am new to NDVI but am trying to figure out what the difference is between an NGB and NRG filter. Which may be the better option, and why?
Are you interested in the difference between a blue filter and a red filter? A blue filter could be referred to as NGB (red is blocked and NIR replaces red in RGB). A red filter could be referred to as RGN (blue is blocked and NIR replaces blue in RGB). Ned has a note about why a red filter can be better for vegetation analysis: https://publiclab.org/notes/nedhorning/11-01-2013/why-a-red-filter-should-work-well-for-ndvi. Also, blue filters don't seem to work very well with small CMOS sensors which most webcams and small cameras have.
Is this a question? Click here to post it to the Questions page.
Reply to this comment...
Log in to comment
There can be a lot of NIR contamination in the red channel when using RGN filters, especially in bright tropical sun at midday. To get higher NDVI contrast, I usually subtract the blue NIR channel from the red visual channel in Fiji/ImageJ before running the NDVI calculation.
This is on a cheap action camera, maybe compact and DSLR cameras have cleaner sensors.
Wapmon is a wap portal where users can get access to trending videos on the internet. This is a platform that has millions of videos up for users to download.