Integration of machine learning and 3D plant biophysical models for acceleration of agricultural system design, management, and crop improvement

Brian N Bailey @ UC Davis

Abstract:

Helios is a flexible, high-performance plant modeling framework that explicitly represents the 3D geometry and interactions between plants and their mircoenvironment, and is implemented as an open-source C++ API. The core engine of Helios manages geometry and data associated with 3D models, and acts as the model coupler. Model and utility routines are implemented as plug-ins to the core engine, which include, e.g., models of radiation transfer, energy balance (for computing temperature and water use), photosynthesis, stomatal conductance, soil water transport, in addition to utilities for processing aerial and terrestrial LiDAR data, and procedurally constructing randomized 3D plant geometries. Many of these plug-ins utilize graphics processing units (GPUs) to perform computations in parallel to maximize the modeled range of scales and level of physical realism.


This presentation will highlight a number of ongoing applications of Helios relevant to agricultural production and breeding, including:

  • Generation of auto-annotated simulated sensor data (e.g., RGB-D, multispectral, thermal, LiDAR) for efficient training of machine learning models for physiologically-based phenotyping

  • 3D computer-aided design and management of efficient and sustainable agricultural systems

  • An irrigation system CAD tool integrating irrigation hydraulics, soil hydrology, and plant demand

  • Computer-aided mechanical harvester design with explicit 3D representation of harvester-plant-fruit interactions

  • Novel algorithms and implementations for processing LiDAR data into useful 3D model inputs and traits


Bio:

Dr. Brian Bailey brings an interdisciplinary research background that spans the fields of engineering, computer science, and plant biology. He received his PhD in Mechanical Engineering in 2015, before working at the USDA-ARS in Corvallis, OR as a Research Engineer. Since joining the Department of Plant Sciences at the University of California, Davis in 2016, his research program has focused on merging his interests in biophysics and plant physiology in order to develop next-generation 3D plant models for computer-aided design, management, and breeding of efficient agricultural systems. Applications of these modeling tools have focused on canopy design, irrigation design and management, disease management, and integration with machine learning models for high-throughput physiologically-based phenotyping.


Summary:

  • Motivation: CAD for agricultural crops

  • Design parameters (e.g. for vineyards):

    • Location

    • Cultivar/roostock

    • Training (trellis, head height, pruning)

    • Row spacing/orientation

    • Irrigation system

    • Micrometeorology

    • Regulations

  • Crop modeling is quite popular

    • Process-based crop models: APSIM, DSSAT

      • ODEs that capture the rates of development

      • Don’t include the biological drivers of development

      • ODEs created empirically from observed trends, require lots of data across various locations, seasons, varieties, management practices

      • Not spatially explicit

      • Poor models of perennial crops

  • Helios

    • Detailed 3D model of the plant

    • Detailed geometry resolved down to sub-leaf/branch scale

    • Can be used to model a wide range of natural, agricultural, agro-photovoltaic systems

    • Includes many plugins: Visualizer, solar radiation, photosynthesis, procedural plant model generator

    • Working on plugins: soil water transport, irrigation hydraulic design, carbohydrate transport

  • Observation: It is important to capture the illumination across each leaf (varies based on other leafs and sun angle)

    • Using leaf-averaged illumination doesn’t produce accurate results

    • Can use LIDAR surveys to parameterize sub-leaf model

    • Illumination onto leafs inferred via backward ray tracing (efficiency samples illumination onto all types of leaves, including scattering)

  • Outputs of HELIOS are validated using LIDAR data

    • HELIOS can predict the exact way each plant will look

    • Developed an automated leaf angle and area measurement model

  • Applications:

    • Pest propagation, infestation

    • Evaluation/design of different trellising & shade cloth strategies

    • Computer-aided design of harvesters, especially for bruisable fruits

    • Project GEMINI (collaboration with Mineral)

      • Genotype x Environment x Management interactions

      • Efforts:

        • 3D Biophysical Crop Modeling

        • Pre-breeding and Genomics

        • AI-Enabled Phenotyping

      • Crops: Sorghum, Cowpea, Common Bean (focus is sub-Saharan Africa)

    • Using the Mineral rover

      • Multi-band video: RGB, 735hnm 850hm, thermal infrared

      • Since HELIOS can produce video, can use real video to tune the model’s parameters

      • Not using LIDAR, so giving up 3D structure information and LIDAR can penetrate through the canopy somewhat

  • Integration with AgML: Open-source Agriculture ML infra

    • Access to datasets, benchmarks, pre-trained models