Optical coherence tomography from viewpoint of information efficiency

Abstract

Optical coherence tomography (OCT) is a novel method for producing three-dimensional images of weakly scattered objects, in particular, biological tissue. OCT is based on interferometry with broadband (low-coherence) light. There are two principal approaches to the realizations of OCT: time-domain OCT (TDOCT), based on scanning low-coherence interferometry; and frequency-domain OCT (FDOCT), based on spectral interferometry. The important factors characterizing OCT are the measurement speed and the quality of the images obtained. The aim of the present work is to unite these contradictory factors in terms describing the information efficiency of OCT. By analogy with Shannon's capacity of communication channels, the information capacity of measurement process is proposed. This term identifies the greatest possible amount of information produced in a unit time during the measurement process. Information capacities are determined for TDOCT and FDOCT. It is shown that the information capacity of FDOCT can be greater than that of TDOCT by a factor equal to the number of resolvable elements in a single in-depth scan of the sample investigated. Parameters characterizing the speed and image quality of TDOCT and FDOCT are also introduced and compared.