Blender is a Free Software for 3D modeling and rendering. The software also contains an extensive suite of image adjustments and composition. Aim of research is to explore methodology of generating psuedo color imagery using Blender image compositor system.

1. Analyzing NDVI Imagery Using Blender
Hideki Saito
September 8, 2014
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2. Contents
1 About This Research 2
1.1 Companion Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Motivation 2
3 Process 3
4 Outcome 3
5 Further Improvements 4
6 Yet Another Improvements 5
7 Version Similar to Infragram.org Output 8
7.1 Some Examples From My Yard (and Surroundings) . . . . . . . . . . . . . . . . . . . . . . . . 10
8 Conclusion 12
8.1 Next Step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Abstract
Blender is a Free Software for 3D modeling and rendering. The software also contains an extensive
suite of image adjustments and composition. The aim of research is to explore the methodology of
generating pseudo-color imagery using the Blender image compositor system.
1 About This Research
1.1 Companion Files
Data files for this research is available at the following Public Lab research note page:
http://publiclab.org/notes/unsignedint/08-27-2014/analyzing-ndvi-imaginary-using-blender
1.2 License
This research is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License.
2 Motivation
Using Blender[2] software, I have attempted to create node settings that allow researchers easy and efficient
way to generate a composite image for NDVI imageries.
The advantage of this setting includes:
1. The software is free, and runs on various platforms
2. It’s easy to adjust individual components, such as color maps, as well as channel adjustments.
3. Image files can be packed into single “blend” file. Research can send others one file containing the
complete set up of the original researcher. (“Lab in a file”)
4. Processing movie files or set of image sequences (such as time lapse) is no harder than processing a
still image.
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3. 3 Process
First, for this example, I have used an image that came with a Infragram point-and-shoot camera. (Mobius
Actioncam)
This file was named example-before-processing.jpg. I wanted to plug this into Blender process, therefore
I have imported this image into Blender, using a input node.
The process pass is as follows. (Please see the attached .BLEND file for details.)
1. Image input is separated to RGBA, breaking B component, connecting the rest to RGBA combiner.
2. I have applied color map, I have tried with Ned’s protanopia-friendly lut[4] as a color map for this
example. I have also included a color ramp using one of the examples in the New NDVI colormap[1]
3. Finally coloring is mixed, 50/50, coming from “GB” component of the image, as well as “B” component
mapped to the color ramp – balance for this component can be adjusted to fit your need, too.
4 Outcome
I have obtained the following result using this process.
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4. 5 Further Improvements
I have further investigated better separation of the needed component, by subtracting R component (visible
light) from B, to filter out visible light portion of the image, which provided the sample below.
This could be mapped to the color scale:
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5. Better separation also allows me to composite the result better to the visible light, which may be appro-priate
for identifying possible vegitation activities.
6 Yet Another Improvements
I have combined NDVI processing into group node – which (hopefully) doing the NDVI processing correctly
based on the formula of NDV I = (IRR)
(IR+R) .
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8. 7 Version Similar to Infragram.org Output
Infragram.org[3] provides web based conversion, the setting could be further adjusted to provide the output
similar.
This can provide three types of output, similar to Basic, Colorized, and combined (basically Colorized
format overlain by visible light – no Stretch and Fastie colormap, yet)
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10. 7.1 Some Examples From My Yard (and Surroundings)
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12. 8 Conclusion
Blender has a potential to efficiently process image NDVI images for various applications. I would like to
experiment with it further to improve the process further.
8.1 Next Step
I am still new to NDVI, having just received the camera a day ago. My future attempts, including trying
the process using additional images as well as trying better color ramps and adjustments.
Comments, suggestions and improvements are highly appreciated!
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13. References
[1] cfastie. Public lab: New ndvi colormap. http://publiclab.org/notes/cfastie/08-26-2014/
new-ndvi-colormap. Accessed: 2014-09-08.
[2] Blender Foundation. blender.org - home of the blender project - free and open 3d creation software.
http://www.blender.org. Accessed: 2014-09-08.
[3] Public Lab. Infragram: online infrared image analysis. http://www.infragram.org/. Accessed: 2014-
09-08.
[4] Public Lab. Public lab: ndvi-gradients. http://publiclab.org/wiki/ndvi-gradients. Accessed:
2014-09-08.
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