Near-Infrared Camera

_The Infragram Kickstarter video, a great introduction to the project._ ###Introduction Vineyards, large farms, and NASA all use **near-infrared photography** for assessing plant health, usually by mounting expensive sensors on airplanes and satellites. At Public Lab, **we've developed a Do-It-Yourself way to take these kinds of photos**, enabling us to monitor our environment through quantifiable data. Our technique uses a modified digital camera to capture near-infrared and blue light in the same image, but in different color channels. We then [post-process the image](#How+to+process+your+images:) (using []( to attempt to infer how much it is photosynthesizing. This allows us to better understand and quantify how much of the available light plants are metabolizing into sugar via photosynthesis. > You can do this yourself (as with all Public Lab tools) but there is also an [Infragram DIY Filter Pack]( available in the Public Lab Store. We [ran a Kickstarter]( for a version of this camera we call the **Infragram**. [Read more about it here »](/wiki/infragram) Here's the video from the Kickstarter, which offers a nice visual explanation of the technique: ###What is it good for? Multispectral or infrared/visible photography has seen a variety of applications in the decades [since it was developed](#Background:+satellite+infrared+imaging). We have focused on the following uses: - 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 (for instance, algal blooms) Notable uses include [this photograph of an unidentified plume of material in the Gowanus Canal](/notes/liz/8-3-2011/infrared-balloon-image-reveals-gowanus-plume) (and [writeup by TechPresident]( and a variety of projects at a small farm in New Hampshire [at the annual iFarm event](/tag/ifarm). The [Louisiana Universities Marine Consortium]( has also [collaborated with Public Lab contributors to measure wetlands loss](/notes/shannon/5-29-2011/plots-and-lumcon-collaboration) following the Deepwater Horizon oil disaster. **Here's an example** of what one of our "Infragram" cameras sees (left) and the post-processing analysis which shows photosynthetic activity, or plant health (right). This picture was taken from a commercial airplane flight: [![infragram](]( ###How does it work? **Camera modification:** We've worked on several different techniques, from [dual camera systems](/wiki/dual-camera-kit-guide) to the current, single-camera technique. This involves removing the infrared-blocking filter from [almost any digital camera](/tag/infragram-conversion), and adding a [specific blue filter](/wiki/infragram#Filters). ![swap.png]( This filters out the red light, and **measures infrared light in its place** using a piece of carefully chosen "NGB" or "infrablue" filter. Read more about [the development of this technique here]( You can also learn more about how digital camera image sensors detect colors [at this great tutorial by Bigshot]( **Post-processing:** Once you take a multispectral photograph with a modified camera, you must [post-process it](#How+to+process+your+images:), compositing the infrared and visible data to generate a new image which (if it works) displays healthy, photosynthetically active areas as bright regions. An in-depth article on the technique by Chris Fastie (albeit using red instead of blue for visible light) [can be found here](/wiki/ndvi-plots-ir-camera-kit). **History of the project:** While we used to use a two-camera system, [research by Chris Fastie](/notes/cfastie/04-20-2013/superblue) and [other Public Lab contributors](/tag/near-infrared-camera) have led to the use of a **single camera which can image in both infrared and visible light simultaneously**. The Infrablue filter is just a piece of carefully chosen theater gel which was examined using [a DIY spectrometer](/wiki/spectrometer). You can use this filter to turn most webcams or cheap point-and-shoots into an infrared/visible camera. ###Background: satellite 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. 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. ![ndvi-vis-comparison.jpg](/system/images/photos/000/001/289/medium/ndvi-vis-comparison.jpg) Caption: 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. Images by Chris Fastie. Visit the [gallery of high-res images by Chris Fastie]( **** ## Frequently Asked Questions Ask a question about infrared imaging [notes:question:infragram] **** ## How to process your images (this section is moved to and updated at 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 []( * [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) * Using (deprecated) * Command-line processing of single images and rendering of movies using a Python script. Source code is [here]( **Note:** Older versions of this page have been kept at the following wiki page:

Author Comment Last activity Moderation
cfastie "There is no information at the Public Lab store about what filter is used except that it is a red filter. I suspect the filter is a Rosco `#19 filt..." | Read more » over 6 years ago
RexToother "Sorry, I thought that was going to be posted directly to the product page. Here is the link to it:" | Read more » over 6 years ago
warren "Hi, just curious which lens you're referring to? Thanks! " | Read more » over 6 years ago
nedhorning "How about testing it on subsets of satellite imagery? You can pick the 3 bands and the band order you want for the testing and can compare that to ..." | Read more » about 7 years ago
ccpandhare "Thanks for the amazing explanation and reference, @warren! I'll be grateful for your help @nedhorning and @warren :) " | Read more » about 7 years ago
warren "Hi, Ned - i'm not asking about calibration at this point, just for a way to empirically test (in the sense of automated testing -- https://en.wikip..." | Read more » about 7 years ago
ccpandhare "Thanks for that @warren! " | Read more » about 7 years ago
nedhorning "Hi Jeff - I think I might be able to help with this but I'm not sure what you are looking for. NDVI is simply an algorithm applied to two bands so ..." | Read more » about 7 years ago
warren "Hey @ccpandhare - just a heads up on this! " | Read more » about 7 years ago
Monoxyde " " | Read more » almost 9 years ago
Monoxyde " Goodmorning everyone. This is a first test of NDVI dimensional mapping from aerial vehicles (UAVs ) . I took only a small portion of the map , ..." | Read more » almost 9 years ago
Monoxyde "Hello Jorge, in my humble opinion, the problem in this approach is in the difficulty to multispectral data to produce and then white balance settin..." | Read more » almost 9 years ago
JorgeV "Hello @cfastie and @monoxyde, I just realize you guys answered me. I really appreciate that you took the time to do it. I did understand how to us..." | Read more » almost 9 years ago
Monoxyde "Hello to all this is a shot made ​​in full shade , in a day of strong sun and with a lot of contrast . " | Read more » almost 9 years ago
Monoxyde "Jorge Hello Jorge , First of all, Thank you and sorry for the delay in responding ! Unfortunately with the Mobius I only did a few tests . I decid..." | Read more » almost 9 years ago
cfastie "JorgeV, The process is very sensitive to both the color balance and exposure of each photo. If the grass in your photos was a little less bright a..." | Read more » almost 9 years ago
JorgeV "Hello @monoxyde, First of all, let me tell you, those pictures are great. You can actually see the difference between vegetation, soil & sky, ..." | Read more » almost 9 years ago
CHUMBA "Hello @monoxyde good pictures there, I can see very well that in the shadow areas no NDVI its shown, good !!!! " | Read more » almost 9 years ago
Monoxyde "Good morning , no comment to My NDVI images ? " | Read more » almost 9 years ago
Monoxyde "Good morning, in these days , I modified a Canon PowerShot Elph 130IS . IR filter removed and replaced with Wattern #25 Red . I used the settings f..." | Read more » almost 9 years ago
Monoxyde "Hi Chris. Ok , I had read about the best results of the red filter , compared to blue . What worries me most is the difference in value Area betwee..." | Read more » almost 9 years ago
cfastie "The standard lens on the Mobius might be too wide to allow good analytical photos. But other lenses are available:" | Read more » almost 9 years ago
Monoxyde "Thanks again Chris , actually the question as phrased , was not very specific . I noticed that my Mobius against wide-angle lens , for aerial appli..." | Read more » almost 9 years ago
cfastie "I think the NDVI_VGRYM.lut color scheme is a good one to start with. What ever you use, include a key to the colors with every NDVI image you share..." | Read more » almost 9 years ago