Reconstructing Specimens Using

Abstract— Differential interference contrast (DIC) microscopyis a powerful visualization tool used to study live biological cells.Its use, however, has been limited to qualitative observations. Theinherent nonlinear relationship between the object properties andthe image intensity makes quantitative analysis difficult. Towardquantitatively measuring optical properties of objects from DICimages, we develop a method to reconstruct the specimen’s opticalproperties over a three-dimensional (3-D) volume. The method isa nonlinear optimization which uses hierarchical representationsof the specimen and data. As a necessary tool, we have developedand validated a computational model for the DIC image formationprocess. We test our algorithm by reconstructing the optical prop-erties of known specimens.Index Terms— Differential interference contrast microscopy,hierarchical reconstruction, iterative parameter estimation,nonlinear optimization. I. I NTRODUCTION T HE NOMARSKI differential interference contrast (DIC)microscope is the preferred method for visualizing livebiological specimens. The DIC microscope is an interferometer,and therefore, the refractive structure of the specimen is madevisible. In biological research, live, transparent cells can be im-aged with this microscope modality. Three-dimensional (3-D)structure can be visualized by optically-sectioning