CAREER: Blind-Label and Label-Free Acoustic Far-Field Subwavelength Imaging

This Faculty Early Career Development (CAREER) grant will enable new imaging methodologies that combine both hardware and software innovations to significantly improve the resolution and the practicality of acoustic imaging. In biomedical diagnosis, the imaging systems sought in this research will improve medical ultrasound imaging quality and expand examination applications.

Locations in human and animal bodies, such as deep brain tissues, kidney stones with sub-millimeter sizes, and lesions on the blood vessel walls, which are difficult to access using the existing ultrasound technologies, will be accessible via the newly developed imaging systems. In underwater sensing, this research will provide enhanced sensing capabilities for underwater imaging/communication, underwater robots/vehicles, underwater infrastructure maintenance, fishery, marine biology, and underwater natural resource exploration.

In non-destructive inspection, this research will enhance soil and rock imaging quality in agriculture and the mining industry, and support quality control in the manufacturing industry. The educational objective of this project is to promote and broaden participation in interdisciplinary acoustics research and STEM education at all levels. This objective will be accomplished through developing an education workshop for high school interdisciplinary acoustics education, creating a pipeline that combines undergraduate courses with lab-based projects for undergraduate students, especially those from underrepresented groups, and demonstrating interdisciplinary acoustics research to general public through interactive exhibitions and public demonstrations.

This project will provide new solutions to the long-existing tradeoff between resolution and penetration depth in far-field acoustic imaging. Most of the existing subwavelength imaging approaches that address this trade-off require exogenous “labels”, such as metamaterials and contrast agents, to be deposited close to the objects. Those labels need to be either static or precisely tracked during imaging.

Therefore, current label depositions are extremely restrictive in practical applications. This project will provide blind-label and label-free solutions to overcome the restrictions. Blind-label approaches will be developed for situations where the external label deposition is viable, e.g., imaging in shallow water and imaging of areas in and around blood vessels.

Label-free approaches will be developed for situations where the external label deposition is difficult and impractical, such as deep underwater sonar imaging, non-destructive structure inspection, and biomedical imaging of deep tissue regions. Both blind-label and label-free approaches will follow a hardware and software co-design framework that consists of the two parts as follows: 1) spatial mixing: a physical imaging process based on blind labels, which are randomly deposited acoustic scatterers, or label-free environmental inhomogeneities, and 2) computational reconstruction: computational signal processing and imaging reconstruction using algorithms co-optimized with the spatial wave mixing process.

Beyond concept and methodology developments, in-lab imaging systems emulating application-specific environmental and hardware/software conditions will be developed to validate the proposed blind-label and label-free approaches in the areas of biomedical ultrasonography, underwater sonar imaging, and structure non-destructive testing.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.