More descriptive explanation of the gradient map showing varied levels of IR reflection relative to plant health and photosynthesis levels:
With a large amount of interest in the sUAS community focused on the uses in the agriculture industry, we have begun development on a lightweight, imaging set for acquiring NIR and RGB (visible spectrum) data sets. the "Horizon 1080 p HD camera" from Foxtech seems to be a good candidate. Our goal will be to modify one camera by removing the low pass or infrared blocking filter from behind the lens set and replacing with an "ultrablue" filter. The other camera we will leave as is. This camera system has been designed specifically for use with small remotely piloted aircraft and will produce images similar in quality to the GoPro camera. This design also features the ability of triggering the shutter via an extra channel on the remote or directly from the APM's (autopilot) trigger output. This will allow us to remove the servo from the system thereby decreasing the overall weight and increasing reliability through simplifying the electrical-mechanical interface.
After removing the infrared blocking filter from the back of the lens a small peice of #74 "Ultra-blue" filter was cut to fit into the back of the lens holder. This filter has been developed by Public Labs to work best with CMOS sensors when capturing NIR images for vegetation analysis
Below is a series of four images showing a standard RGB photograph, followed by a NIR (near infrared image) composite into a grey scale NDVI (normalized difference vegetation index). This shows the reflected infrared light that a healthy plant will reflect during photosynthesis. The final image is known as a false heat map and is designed to enhance a grey scale NDVI to show more clearly areas where the plant health is compromised due to pests, disease, lack of water or proper fertilizer.
Over this past weekend we were able to join Nerds for Nature at the Bioblitz at Lake Merritt in Oakland CA. While there we ran the first of a series of experiments using HUGO to land at predefined way points in the lake to receive and log sensor data from an array attached to the outside of the aircraft. For the proof of concept flights this weekend we recorded temperature and pH readings that were stored on a sD card located inside the shell. Check out our article in Scientific American
Here you can see the sensor array we have designed for water quality testing. At the front of the array is a temperature probe and behind that will be housed different sensors including pH, salinity, and dissolved oxygen. Moving forward we hope to be able to develop and refine the data we are collecting as well as begin to create accurate maps and ongoing "monitoring stations" based on GPS coordinates.
Here you can see the mission plan created to indicate the sampling locations. Using this method it is possible to have virtual monitoring stations accurate to within a couple meters each time sample readings are taken. These would probably be at inlets and outlets of a body of water and possibly at the location of on shore sources of pollution/runoff.
The first tests were quite successful with the flight plan executing as expected and all sensor data being recorded as planned. One note visible on the readings in the graph below indicate the temperature probe had yet to normalize before moving to the next location. We will make adjustments to the "delay" used to solve for this.
The RoboBoat Competition consists of student teams racing their autonomous surface vehicles (ASVs) through an aquatic obstacle course. This includes littoral area navigation, channel following, and autonomous docking. The competition provides an opportunity for students to develop skills in system engineering by accomplishing realistic missions with autonomous vehicles in the maritime environment.