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Multispectral imaging
question:multispectral-imaging

The Public Lab near infrared imaging project is an open source community effort to modify consumer cameras to capture near infrared imagery for a range of purposes, including plant health. All open or accessible near infrared imaging hardware and software efforts are welcome here! **Join in by:** * Reading about goals and asking great questions * Converting a camera using one of our starter kits * Trying (and critiquing) our community-made how-to guides * Posting your own how-to guides and mods * Building on others’ work; hack and remix the kits to refine and expand them * (proposed?) Submit your improvements for inclusion in an upcoming starter kit release or add-on * (proposed?) Serve on a Research Review Group for a 3 month period ## Activities This is a list of community-generated guides for specific applications using your near-infrared imaging setup (either a camera you converted yourself with a filter pack, a ready-made near-infrared camera, or double camera setup). Some may be more reproduced -- or reproducible -- than others. Try them out to build your skills, and help improve them by leaving comments. Together, we can repeat and refine the activities into experiments. [activities:multispectral-imaging] Add your guide here Request a guide _Guides should include a materials list and a step-by-step construction guide with photo documentation. See an example._ **** ## Hardware Mods Have you added to your starter kit, improved it, or redesigned it? Show others how to take it to the next level by posting a build guide here: [upgrades:multispectral-imaging] Add your hardware modification here Request a hardware modification _Upgrades should include a parts list and a step-by-step construction guide with photo documentation. See an example._ **** ## Builds There’s a lot going on in open source near-infrared imaging -- if you’ve developed another open source design you’d like to show others how to construct, post it here! * Rasberry Pi NoIR * X * XX **** ## Choosing a tool / Starter Kits The question to start with is whether you can capture all the channels you need for your research question with a single converted camera or whether you should use a dual camera rig with one converted camera and one unconverted. That choice plays out in terms of what filter (blue or red) to use for converting your camera. Public Lab’s Kits initiative offers several starter kits, one with the basic components and instructions for converting your own digital camera to capture near-infrared imagery and a second option -- a readymade lightweight near-infrared camera. The point of the kits is to lower the barrier to capturing your own near-infrared imagery. * **The Infragram filter pack** is our least expensive way to get started with near-infrared imaging, but it does require an afternoon and some technical work to perform the camera conversion yourself. ... etc etc etc **[Visit the Infragram DIY filter pack]()** * **The Infragram point and shoot** is a Mobius camera that we worked with a factory to modify. ... etc etc etc **[Visit the Infragram Point&Shoot page](/wiki/infragram-point-shoot)** **** ## Processing near-infrared imagery Once you take a multispectral photograph with a modified camera, you must post-process it, compositing the infrared and visible data to generate a new image which (if it works) displays healthy, photosynthetically active areas as bright regions. In-depth articles on the technique by Chris Fastie can be found here: * https://publiclab.org/wiki/ndvi * https://publiclab.org/wiki/ndvi-plots-ir-kit **** ## Software How to process your images: we're working on an easy process to generate composite, infrared + visible images that will reveal new details of plant health and photosynthesis. There are several approaches: * The **easiest way** is to process your images online at the free, open source [Infragram.org](http://infragram.org) * [Ned Horning's](/profile/nedhorning) [PhotoMonitoring plugin](/wiki/photo-monitoring-plugin) * Manual processing * [in Photoshop](/notes/warren/10-25-2011/video-tutorial-creating-infrared-composites-aerial-wetlands-imagery) * [or GIMP](/notes/warren/10-27-2011/video-tutorial-creating-false-color-ndvi-aerial-wetlands-imagery) * Command-line processing of single images and rendering of movies using a Python script: Source code is [here](https://github.com/Pioneer-Valley-Open-Science/infrapix) and here: [here](https://github.com/publiclab/infrapix) * For those who use the webcam and have a Python interpreter, there are some image processing codes available at [Python Webcam Codes](/wiki/python-webcam-codes) * Using MapKnitter.org (deprecated) **** ## Comparison to standard tools Infrared imagery for agricultural and ecological assessment is usually captured from satellites and planes, and the information is used mainly by large farms, vineyards, and academic research projects. For example, see this illustrated [PDF, page 210](http://www.beckshybrids.com/Portals/0/SiteContent/Literature/PFR%20Book%202010%20optimized%20small.pdf) from a commercial imagery provider who has been studying the usefulness of infrared imagery and has quotes from farmers who make use of it. There are public sources of infrared photography for the US available through the Department of Agriculture -- [NAIP](http://datagateway.nrcs.usda.gov/) and [Vegscape](http://nassgeodata.gmu.edu/VegScape/) -- but this imagery is not collected when, as often, or at useable scale for individuals who are managing small plots. **** ## Frequently Asked Questions Ask a question about multispectral-imaging Get notified of new questions and help out [notes:question:multispectral-imaging] ...


Author Comment Last activity Moderation
sam14 "Great, thanks Liz! " | Read more » about 2 years ago
ltata5613 "Hello, same with me. I hope someone else can answer this. endralia " | Read more » about 2 years ago
liz "Hi @Sam14, Image Sequencer has experimental support for processing gifs: https://github.com/publiclab/image-sequencer#experimental-gif-processing-s..." | Read more » about 2 years ago
warren "Hi! It could be interesting to try measuring the berries themselves as well; check out the spectrometer work by this group for a reference! #webval..." | Read more » about 2 years ago
cfastie "If photos are taken of plants in two treatments (top and bottom) with the same camera settings (all manual control) under the exact same lighting c..." | Read more » about 2 years ago
M0nk3y "Hi there, i did'nt wanted to re-do a topic that would have been really similar as this one. I hope i will be enough precise to get an answer to my ..." | Read more » about 2 years ago
warren "Yes of course!!! " | Read more » about 2 years ago
yaina "This is this illuminating article for all of us. Extremely incredibly seriously incomprehensible content parts. We essentially gain searching state..." | Read more » over 2 years ago
lev29 "Thank you, Chris! You've given me much to read and think about, but please, don't misconstrue that as meaning you shouldn't add any additional pert..." | Read more » over 2 years ago
cfastie "Using green foliage (or chlorophyll) to set a custom white balance deserves more consideration than I gave it in my last comment. Foliage absorbs r..." | Read more » over 2 years ago
cfastie "The goal of the custom white balance hack is to fool the camera into wildly exaggerating the brightness of the blue channel (when using a red filte..." | Read more » over 2 years ago
lev29 "Thank you so much, Chris! With respect to what to use as a reference to calibrate the White Balance (WB), I have not yet "digested" whether your re..." | Read more » over 2 years ago
cfastie "If your K610 filter is a cutoff filter that passes wavelengths greater than 610nm and blocks shorter wavelengths, then it is similar to many filter..." | Read more » over 2 years ago
lev29 "Thank you, Chris, for helping to clarify my question. In fact, as you suspected, I was misusing the term "bandpass"! Those I signify with a "K" fol..." | Read more » over 2 years ago
cfastie "`>> for simple bandpass filters, I use the letter "K" followed by the approximate cutoff wavelength Are your filters bandpass filters or cut..." | Read more » over 2 years ago
ThomasTaufan "Chris, please look at my image taken from modified camera using red filter bought from Public Lab. Is this the correct results or should I do some ..." | Read more » over 2 years ago
zomb23 "Hi Chris, thank you for the quick and comprehensive response. That sounds really promising. I will look into chlorophyll fluorescence and if/how I ..." | Read more » over 2 years ago
cfastie "I think NDVI will provide some information about the photosynthetic rate of mosses. Moss leaves capable of rapid photosynthesis will probably be ab..." | Read more » over 2 years ago
nickyshen0306 "Thanks for giving me so many solutions!! I will try it. " | Read more » over 2 years ago
lfent "@cfastie I found that I needed the heavy cyan filtration (at the expense of all the exposure variables you mention) to achieve an image approximati..." | Read more » over 2 years ago
cfastie "@lfent, Is there any difference between using two filters and using one filter if both photos are exposed so the photos have the same general brigh..." | Read more » over 2 years ago
lfent "Yes, a cyan filter will block the red light from the red-NIR pixels, may I suggest the Rosco 4390 CalColor 90 Cyan gel filter. I found that I need ..." | Read more » over 2 years ago
nedhorning "Here are a couple ways to do this. One is to use two cameras mounted as close as possible to one another with the shutter release synchronized to b..." | Read more » over 2 years ago
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