My goal here is to convert an off the shelf Canon digital camera into a NIR camera to be used to create plant health imagery.
There are multiple excellent resources available for those looking to do this including PublicLab.org, which is the source of the filter and a repository for a wealth of information on the topic, youtube (http://youtu.be/XFOHWaL7XsM), and Instructable (http://www.instructables.com/id/Turn-a-Canon-camera-into-a-Plant-He...).
**SAFETY** DO NOT TOUCH THE CAPACITOR LOCATED AT THE TOP OF THE CAMERA. This can be hazardous and care must be taken to not touch this with your fingers or a screwdriver when the case has been opened.
The infrared filter in front of the camera’s sensor must be removed. This requires opening up the camera and after the filter removal, reassembling the components. Special care must be taken to not touch the sensor, or lose any of the screws in the housing.
After reassembling the camera and inserting batteries, it would not power on so I opened the case back up. Everything appeared correct, but I suspected the ribbon connector from the LCD to the main board having an improper seat. I removed and reinserted the ribbon, and this proved to correct the powering issue.
Photos from the conversion:
The PublicLab.org Infragram DIY Plant Analysis Filter Kit with Blue and Red Filters.
Camera before starting the conversion.
Camera with batteries and SD card removed. Duct tape makes an excellent place to keep small screws.
Back case removed.
LCD “flipped over” to reveal back of sensor.
The sensor must be lifted up to gain access to the filter. Once the filter is removed, the red or blue filter can be placed in its place, after being cut to size. I do not have photos of this step, as it is somewhat difficult to keep everything aligned while doing this. If I had an extra set of hands, I would have taken a photo.
Here I have reattached the sensor, and am about to reattach the blue button assembly before putting the back case on.
Camera completely reassembled. At this point, it is important to check power and focus.
Infragram.org is a free tool that allows users to upload raw images from a NIR camera, and produce NDVI (and other) images using the NIR and VIS channels. Below is a sample from my very first attempt at creating an NDVI image.
NIR Photo of houseplants.
NDVI Image made using Infragram (not correct scaling – my first try!)
Infragram is offered for free from PublicLab.org and has multiple NDVI conversion options, depending on the type of filter that is used. The Infragram tool is web-based, and has an intuitive, graphical interface for converting NIR images to NDVI.
New “DIY” Infragram kits include both a blue filter and a red filter. Much of the work that has been done by those in the Public Lab community has shown that the Red filter works better when converting to NDVI, for most cameras. In the previous post, I used the red filter to replace the stock filter in the Canon A 495.
Below are the technical sheets for each of the filters that have been shown to work well for creating NDVI imagery with a converted digital camera.
Here are some Near Infrared (NIR) and Infragram converted Normalized Differential Vegetation Index (NDVI) images of plants from the Omaha Henry Doorly Zoo. My recent trip presented some great opportunities to photograph plants in various states of health with the Canon A 495 with a Red Filter installed in front of the camera’s sensor.
A nice description of how to use a previous version of Infragram can be found here: http://publiclab.org/notes/warren/08-17-2013/infragrammar-compositi...
This is still very useful for anyone who is using an “Infrablue” filter, but the newer version has some nice preset capabilities that allow users to select the color of their filter before starting with an image.