CIF - Small: High Resolution Computational Imaging with Motion in Spatially Varying Fields

Purdue University, West Lafayette IN

Investigators

Abstract

Basic questions about optical information in the presence of scatter, and more specifically, related to object motion in spatially varying electromagnetic fields, is being addressed. Light provides key information through spectroscopy, paramount in human health applications, and allows for high-resolution imaging. However, random optical scatter due to tissue, for example, can obfuscate an object of interest. Such random scatter produces speckle, the granular nature of light seen when a laser pointer scatters from a rough surface. A new computational imaging method is being developed to image hidden objects based on motion in such structured fields. With control over laser illumination and precise motion, far-subwavelength feature information can be obtained. This understanding is being developed into a high resolution computational imaging approach, critical in a variety of applications. One aspect of this project involves the use of optical speckle correlations over object position or as a function of time for imaging through or within a heavily scattering medium at potentially wavelength scale resolution. The goal of this project is to take the initial presentation of this concept to a practical computational imaging modality. Measured laser speckle images with example scattering media, representative of several centimeters of tissue, are being used with various levels of understanding about the moving objects. The other direction is to develop a computational method to determine if a small object is present by precisely scanning a sample in a spatially varying field established by two or more laser beams. A key application is to determine whether a defect exists in a semiconductor material system. More generally, opportunities for far-subwavelength optical imaging based on motion in structured illumination is being pursued.