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See the original posting at FLIGHTRIOT

It seems that it is now possible and relatively easy to modify a digital camera to capture wavelengths necessary for producing Vegetation Indexes such as Normalized Differential Vegetation Index (NDVI). Recently, I tested some of the work being done by folks at publiclab.org along with others and some amazing results are coming to fruition. I’ve been communicating with Chris Fastie and Ned Horning over the past month or two regarding methods for generating NDVI and other Vegetation Indexes (VI) from a single digital camera.

If you look at the Infragram project on kick starter or on publiclab you can read about their current project, which is intended to result in a low cost single camera  solution for NDVI and other VI production. I simply jumped the gun and made my own modified camera. The main reason I proceeded this way is that I rely on Canon cameras for UAV mapping because of the CHDK option. The camera I used here (Canon A490) cost around $40 used plus a couple hours of modifying and testing it. The results are preliminary as of now but I’m very impressed and I see great potential here.

The images below are the results of my first tests using the new methods with one modified Canon A490. I simply implemented the work that Chris, Ned, and others atpublic lab have accomplished and shared. Chris’s posts are very informative and he was kind enough to send me filter material to test (Rosco #2007), which was used in the images below. Ned has also been very helpful and a real game changer in terms of open source image post processing. Both have been instrumental in being able to get this far with UAV agriculture mapping efforts.

Okay, so here is what you need to DIY.

Below are the resources needed to modify a point and shoot camera and use open source software to generate NDVI from captured images:

•  You’ll need a digital camera with the IR filter removed such as this one (publiclab tutorial)
• Some Rosco Storaro # 2007 VS which will either be placed internally where the camera’s IR filter used to be or used on the outside of the lens with tape. There are advantages to each method. Currently I have the film mounted internally and this is the method used to take the photos below. I also set a custom white balance using the Rosco material.
• The Fiji version of ImageJ
• Ned Horning’s Photo Monitoring Plugin , the Photo Monitoring Plugin Guide, and the Readme file. Just download all the files  including each of the Look Up Table (LUT) files in the luts folder and follow the installation instructions in the documentation.

Ned’s plugin is a piece of cake to use and surprisingly fast!

I’m grateful for all the hard work that went in to making this possible.

Below is a series of images taken using the Canon A490 with the stock IR filter removed and replaced with Rosco #2007 filter.The images were post processed using Ned’s Photo Monitoring Plugin in the Fiji version of ImageJ. Left to right the images are as follows: unaltered from camera, NDVI floating value- Range of -1 to 1, Ned’s LUT color NDVI range 0 to 1, Ned’s LUT color NDVI range -1 to 1.  Click on any of the images below to view a larger version.

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