A Thermoacoustic Imaging System for Non-Invasive and Non-Destructive Root Phenotyping
Note: Please view the desktop site in order to see images.
Population growth, resource depletion, and climate change pose an increasing threat to global food security, demanding substantial improvements in crop yield and production efficiency. Plant phenotyping—the quantitative assessment of a plant’s anatomical, physiological, biochemical, and developmental traits—has emerged as a key tool to address these challenges. By providing a data-driven approach to identify cultivars with superior yield, drought and disease resistance, and improved nutrient content, phenotyping accelerates progress in crop breeding and precision agriculture. Remote-sensing technologies leveraging satellite and drone platforms equipped with spectral, optical, and thermal sensors are now widely used for high-throughput, field-based phenotyping of above-ground traits. However, there remains a critical lack of tools for high-throughput, non-destructive, and field-deployable phenotyping of below-ground traits. Bridging this measurement gap could enable the development of root-focused cultivars with optimized root architectures—potentially catalyzing a second Green Revolution to meet global food demands.
The opaque and heterogeneous nature of soil makes below-ground sensing significantly more challenging than above-ground observation. Existing root phenotyping techniques are typically either high-resolution but limited to controlled laboratory settings, or field-based approaches that are invasive, labor-intensive, and often destructive. This limitation has motivated ongoing efforts to develop non-invasive, high-throughput field systems capable of dynamic root trait measurement.
To address these challenges, we propose a non-contact thermoacoustic (NCTA) sensing system that enables high-throughput, autonomous, and non-destructive below-ground imaging. The approach exploits the thermoacoustic (TA) effect, where microwave illumination induces localized heating that generates acoustic or ultrasonic (US) waves at interfaces with dielectric contrast. TA waves originate from root–soil interfaces and are detected in air using highly sensitive ultrasonic transducers. This multi-modal architecture decouples excitation and detection mechanisms, offering multiple degrees of freedom for system design and enabling simultaneous sensing of diverse below-ground traits.
Conceptual view of proposed non-contact thermoacoustic below-ground sensing system along with the multi-modal design and sensing knobs.
Publications
[1] A. Singhvi, A. Fitzpatrick, J. D. Scharwies, J. R. Dinneny, and A. Arbabian, "A Thermoacoustic Imaging System for Non-Invasive and Non-Destructive Root Phenotyping," IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 69, no. 5, May 2022, pp 2493-2497.
[2] A. Fitzpatrick*, A. Singhvi*, and A. Arbabian, “Dynamic Tuning of Sensitivity and Bandwidth of High-Q Transducers via Nested Phase Modulations,” 2022 IEEE International Symposium on Circuits and Systems (ISCAS), May 27- June 1, 2022.
[3] A. Singhvi*, M. L. Wang*, A. Fitzpatrick* and A. Arbabian, "Multi-Task Learning for Simultaneous Speed-of-Sound Mapping and Image Reconstruction Using Non-Contact Thermoacoustics," 2021 IEEE International Ultrasonics Symposium (IUS), Virtual Symposium, Sept 11-16, 2021.