Imaging through complex media is a well-known challenge, as scattering distorts a signal and invalidates imaging equations. For coherent imaging, the input field can be reconstructed using phase conjugation or knowledge of the complex transmission matrix. However, for incoherent light, wave interference methods are limited to small viewing angles. On the other hand, time-resolved methods do not rely on signal or object phase correlations, making them suitable for reconstructing wide-angle, larger-scale objects. Previously, a time-resolved technique was demonstrated for uniformly reflecting objects. Here, we generalize the technique to reconstruct the spatially varying reflectance of shapes hidden by angle-dependent diffuse layers. The technique is a noninvasive method of imaging three-dimensional objects without relying on coherence. For a given diffuser, ultrafast measurements are used in a convex optimization program to reconstruct a wide-angle, three-dimensional reflectance function. The method has potential use for biological imaging and material characterization.
© 2014 Optical Society of America
Original Manuscript: February 7, 2014
Manuscript Accepted: March 1, 2014
Published: April 8, 2014
Vol. 9, Iss. 7 Virtual Journal for Biomedical Optics
Nikhil Naik, Christopher Barsi, Andreas Velten, and Ramesh Raskar, "Estimating wide-angle, spatially varying reflectance using time-resolved inversion of backscattered light," J. Opt. Soc. Am. A 31, 957-963 (2014)