A novel approach to depolarization analysis in PS-OCT: complex inner product versus DOPU

Polarization-Sensitive Optical Coherence Tomography (PS-OCT) is an extension of OCT that provides image contrast based on the polarization state of backscattered light. PS-OCT is a promising tool for non-invasive imaging due to its capability to offer depth-resolved polarization-sensitive contrasts. Among these contrasts, the Degree of Polarization Uniformity (DOPU) is a commonly used metric to represent variations in the polarization state. Depolarization refers to the random change in the polarization state of incident light at spatially adjacent sample locations. However, acquiring DOPU contrasts faces challenges that can impact image resolution. DOPU contrast depends on several factors, such as the incident polarization state, the size and shape of the averaging kernel. In this paper, we demonstrate a novel application of the Complex Inner Product (CIP) of two orthogonal linearly polarized virtual inputs as an alternative way to represent depolarization. CIP is analyzed on different OCT images, and the results show a strong correlation between CIP and DOPU. We compare these two parameters and investigate the advantages and drawbacks of the CIP parameter compared to DOPU.