Public Lab Wiki documentation


This is a revision from May 17, 2013 21:10. View all revisions
9 | 123 | | #7558

"The Infra-whatnow?"

The Infragram is a simple, affordable infrared camera platform -- developed collaboratively, by the Public Lab community -- for measuring plant health and geeking out on gardening. It's for home gardeners, hikers, makers, farmers, amateur scientists, teachers, artists, and anyone curious about the secret lives of plants!


It was originally developed to assess damage to wetlands in the wake of the BP oil spill; but it's also a simple, easy-to-modify, open-source hardware and software tool that anyone who's curious about plant physiology and health can use.

What is it good for?

  • Take pictures to examine plant health in backyard gardens, farms, parks, and nearby wetlands
  • Monitor your household plants
  • Teach students about plant growth and photosynthesis
  • Create exciting science fair projects
  • Generate verifiable, open environmental data
  • Check progress of environmental restoration projects
  • Document unhealthy areas of your local ecology


Vineyards, large farms, and NASA all use near-infrared photography for assessment, usually by mounting expensive sensors on airplanes and satellites. Infragram brings this technology to average citizens, enabling them to monitor their environment through quantifiable, citizen-generated data.


Just as photography was instrumental to the rise of credible print journalism, DIY data collection technologies like Infragram democratize and improve reporting about environmental impacts.

Remote infrared imaging

The study of Earth's environment from space got its start in 1972 when the first Landsat satellite was launched. The multispectral scanner it carried, like the scanners on all subsequent Landsat satellites, recorded images with both visible and near infrared light. Remote sensing scientists quickly learned that by combining visible and infrared data, they could reveal critical information about the health of vegetation. For example, the normalized difference vegetation index (NDVI) highlights the difference between the red and infrared wavelengths that are reflected from vegetation. Because red light is used by plants for photosynthesis but infrared light is not, NDVI allows scientists to estimate the amount of healthy foliage in every satellite image. Thousands of scientists, including landscape ecologists, global change biologists, and habitat specialists have relied on these valuable satellite-based NDVI images for decades.

Up-close infrared imaging

The goal of the Infragram project is to bring the power of NDVI and other infrared vegetation images back to earth where everyone can now take close-up images of plants or landscapes and instantly learn about their health and vigor.

There are public sources of infrared photography for the US available through the Department of Agriculture -- NAIP and Vegscape -- but this imagery is not collected when, as often, or at useable scale for individuals who are managing small plots. By creating a low-cost camera and working with farmers and environmental activists, we hope to explore grassroots uses for this kind of technology. What could farmers or activists do with leaf-scale, plant-scale, lot-scale, and field-scale data on plant health if the equipment costs as little as $10 or $35?


Screenshot from 2011-09-10-colorado-boulder-foothills-community-park-NRG.

See how clearly plants are identifiable from bare earth or pavement.

The unique colors in this photo will be explained below, keep reading!

Why does it work? (quick science)

Though we cannot perceive it with our eyes, everything around us (including plants) reflects and absorbs wavelengths of light in red, green, blue and beyond into infrared, ultraviolet, and more. Our colorful world is created by varying amounts of particular wavelengths being absorbed and reflected. This also means that everything has a recognizable "spectral signature". Whoa. Let's focus on plants:

Why do plants reflect a lot of infrared?

Plants use visible light (mainly blue and red light) as 'food' -- but not so much green light, which is why they reflect more green light away, and thus look green to our eyes. They also happen to reflect a lot of near infrared light (which is just beyond red light, but not visible to the human eye). This is because they chemically cannot convert infrared into usable food, and so they just bounce all of it away to stay cool. The illustrations show what colors of light plants absorb versus reflect away. By using this unique property of plants, plus our ability to take near-infrared photos we can create composite images which highlight where plants are and how much they are photosynthesizing.

To composite these four bands of information (infrared, red, green, blue) into the three bands that our eyes can see (red, green, and blue), we have to get creative. We drop the information that is normally contained in the red band, and use it to draw near-infrared:


By using this method of re-writing what information is contained in the red-green-bllue images that our eyes can see, we can make images that depict how actively plants are photosynthesizing:


Figure above: Normal color photo (top) and normalized difference vegetation index (NDVI) image. NDVI image was derived from two color channels in a single photo taken with a camera modified with a special infrared filter. Note that tree trunks, brown grass, and rocks have very low NDVI values because they are not photosynthetic. Healthy plants typically have NDVI values between 0.1 and 0.9.


How do we do it? (prototypes, links)

The Public Lab community has been hacking cheap digital cameras for years. There are many different versions now, and we're offering our favorites as rewards for Kickstarter backers. For all these models, this campaign is our opportunity to go in together and make a bulk order so that we all get the biggest bang for our buck.

  • You can get started with infrared imaging for as little as $10. The DIY Filter Pack contains a square of DIY "superblue" filter, a white balance card, and instructions to convert your camera/webcam into an infrared plant camera.

  • For $35, you can try the Infragram Webcam: a small, cheap, barebones webcam for taking composite photos which can be converted and viewed online. Perfect for using from your laptop or a Raspberry Pi.

  • The Infragram Point & Shoot is the camera we designed for ourselves: at $95, it is a simple but experimental camera for taking infrared/visible photos which can be processed online. The minimum featureset will be low -- 2 megapixel, small and no LCD -- but will improve if we get a lot of backers.

The images below depict other prototypes that were created by our community over the years. If you are interested in the story of how this project got started, check out our early prototypes and experiments on this page: