A Smart Spectral Polarimetric Imager for Autonomous Plant Health Monitoring

For future long-duration space exploration missions, NASA expressed the need for plant systems that may provide a nutrient dense supplement to crew diet and possibly other life support functions, such as CO2 removal, O2 production, water recovery, and waste recycling. Current and future infrastructure for plant growth include chambers with controlled environments. To ensure optimal growing conditions in these chambers, the plants will require precise monitoring of health throughout the plant life cycle. These monitoring systems will need to operate autonomously with little crew involvement. Current plant monitoring instruments include multispectral and hyperspectral sensing that require post-process algorithms to detect physiological phenomena. In Phase I, Space Lab Technologies (Space Lab) and the Space Plants Lab at the University of Florida (UF) investigated an improved approach for monitoring space plant health using a smart spectral polarimetric (SSP) imager to monitor morphological features and stresses. The Phase II work builds upon the prototypes and analyses completed in Phase I, which includes a deliverable of an engineering demonstration unit (EDU) to NASA Kennedy Space Center. The EDU is compact and intended for use in the ground-based plant growth chamber equivalents of the Advance Plant Habitat (APH) or VEGGIE. Space Lab and UF propose the following innovations: Fully Characterized Spectral Polarization Flux for Plant Canopy Reflectance – The reflected light from the canopy will be processed to provide a full characterization of polarization information for the spectrum of interest. Stray stimuli may be removed, and plant morphology and stress response is monitored. Phase I demonstrated that polarimetric NDVI improves over traditional NDVI with earlier stress detection times, increased sensitivity, and higher dynamic range. Compact Digital Signal Processing for Autonomous Monitoring – The flight system will include an on-board FPGA device capable of real-time image processing. This allows for autonomous monitoring of plant morphological features and detection of plant stresses. The Phase II Objectives include: To examine common spectral polarimetric reflectance image features with respect to plant health. To determine image processing algorithms for autonomous plant health assessments. To develop an integrated engineering demonstration unit (EDU) that interfaces to planned flight systems (e.g., mechanical, power, and data for planned plant chambers). To verify the EDU in a ground-based plant growth chamber in a space relevant environment. Deliverables: Final Report SSP Imager EDU EDU Graphical User Interface User's Guide for Operation of the EDU
Benefits: Plant Health Monitoring in Space Habitats Space Crops Food Safety Spacecraft Structural Stress or Fracture Detection Remote Sensing of Earth Planetary Science Agriculture - Crop Health Controlled Environment Agriculture Food Processing and Safety Mechanical Stress and Fracture Detection Industrial Process Monitoring Laboratory Polarized Spectrometer for Research