The Sentera Single Sensor on a DJI Phantom 4. Sentera / Facebook
Flying in the wind is tricky at the best of times. Add to that capturing accurate agricultural crop imagery and data, and you’ve got a problem on your hands. If you’re an agronomist, ag consultant or primary producer, and owner of a DJI Phantom series drone, you’ve now got a viable solution courtesy of Sentera. The Minneapolis-based drone solution company has now introduced an upgrade to the specialised Sentera Single sensor, which was developed to monitor crop health using near-infrared spectorscopy (NIR), normalized difference vegetation index (NDVI) and normalized difference red edge (NDRE) data collection.
Available across the board for the DJI Phantom 4 Pro, Advanced, and Standard drone platforms, this little gimbal is designed to smooth the ride for the Single Sensor, compensating for drone pitch and roll in high wind conditions. Capturing imagery closer to a straight-down (nadir) position, the Micro Gimbal is intended to help ag professionals gather more consistent NDVI and NDRE data.
Sentera’s Micro Gimbal Upgrade compensates for drone pitch and roll, allowing for more uniform NDVI or NDRE data capture. PRNewsfoto / Sentera
With spring in the air, Sentera has timed the release carefully. “Sentera’s Micro Gimbal for the NDVI and NDRE Single sensors couldn’t come at a better time for our Northern Hemisphere customers,” explains Kris Poulson, vice president of agriculture for Sentera. “Especially relevant for ag professionals in wind-prone regions, this advancement removes yet another data-collection variable and allows producers to focus on data insights and application decisions.”
Collecting data in windy or high speed conditions can be difficult due to the “pitch and roll” effect endured by the drone in the air. Sentera’s sensors already compensate for the camera’s position relative to the ground as well as the angle of the sun, but deviations can still present a problem under adverse conditions. These discrepancies can bias the vegetative index data, an issue that Sentera now seeks to correct with the introduction of the Micro Gimbal.
Comparison of 2 NDVI outputs of the same field flown 2 months apart from a Sentera sensor. Source: Dronemate Agriculture / Youtube
“Our most sophisticated sensors compensate for the angle of the sun and the camera relative to the ground, known as the bidirectional reflectance distribution function, or BRDF,” elaborates Ryan Nelson, Sentera’s chief mechanical engineer. “The micro-gimbal product eliminates part of the variability that arises from BRDF for our smallest and most affordable imagers. Once the imager is stabilized with the micro gimbal, the remaining effects, like those due to the position of the sun in the sky, can be largely eliminated in software.”
“Angle of incidence has some effect on vegetative index measurements. Without compensation, growers could see small variations even flying the same field under different wind direction or velocities. Micro Gimbal users will see more uniformity in their data,” added Nelson.
The upgrade will allow Sentera’s agricultural customers to produce high quality data with relatively lower costs. The micro gimbal can be installed by the customer, and does not change in anyway the functionality or performance to either Sentera’s NDVI or NDRE Single Sensor cameras, nor the native DJI Phantom RGB camera.
Users of DJI Phantom 4 owner in the agricultural can contact Sentera to determine whether their specific applications will require a gimbaled or fixed-mount Single Sensor to address BRDF compensation.