PhenoBee

 

Recently, proximal hyperspectral imaging (HIS) sensors such as LeafSpec, a handheld hyperspectral imager invented at Purdue ABE Plant Sensor Lab, was developed to improve imaging quality in plant phenotyping. However, the operation of LeafSpec was still limited by its low throughput and intensive labor cost. Few automation solutions were available to use LeafSpec in autonomous phenotyping, especially for dicot plants which are the most common. PhenoBee was developed to address the issue by providing an autonomous solution to infield proximal hyperspectral imaging. PhenoBee is a drone-based robot that integrates a self-developed drone and a robotic arm system. The drone platform can carry the robotic arm and LeafSpec on long-range flights. For each data collection, PhenoBee lands on a specified GPS location and the robotic arm approaches a leaf candidate with a LeafSpec. After imaging, PhenoBee takes off and flies to the next location. The cycle time for each data collection is about 1 min.

 

In 2020, A robotic system was developed to operate LeafSpec to collect leaf-level hyperspectral images for in vivo soybean phenotyping. A machine vision algorithm was developed for a 3D camera to detect the top mature (fully developed) trifoliate and estimate the poses of the leaflets. A control and path planning algorithm was developed for an articulated robotic manipulator to grasp the target leaflets. The system was tested in a greenhouse in 2020 and showed detection and scanning accuracy of more than 85%.

 

In 2022, the system was further developed for infield plant phenotyping. As infield proximal imaging would be challenging for dense and large fields, a self-developed drone was built as a platform for carrying the robotic system in the field. The flight controller was tuned to lift a payload of 30 kg and has been tested in 30 mph wind. The drone's positioning was controlled by an RTK system which provided landing accuracy of up to 1.3 cm. A customized landing gear provided high clearance for the robotic arm to operate on top of plants. PhenoBee has been tested in Purdue's research farm for collecting more than 150 data points in the summer of 2022. During development, PhenoBee intentionally left extra payload capacity for extra sensors and integrations. More phenotyping projects are under planning with PhenoBee Involved.