Comparative study of Mueller matrix transformation and polar decomposition for optical characterization of turbid media

Mueller matrix polarimetry (MMP) is a fast and non-invasive optical technique for characterization of turbid media such as biological tissues, where the experimental Mueller matrix M contains the complete information of polarization properties of the sample. The individual optical properties in M are present in a complex interwoven way and need to be extracted; Mueller matrix polar decomposition (MMPD) and Mueller matrix transformation (MMT) are two widely used methods for this purpose. Here, we compared these two methods (i.e., MMPD and MMT) and assessed the possible correlation between their corresponding parameters in a comprehensive sample cohort containing different types of tissues and associated pathologies (n = 47), tissue phantoms (n = 21) and standard optical components (e.g., air, polarizer, quarter wave plate, etc.) (n = 09). Specifically, we calculated two sets of optical variables (Delta(T), b) and (delta, t) representing depolarization and retardance for the MMPD and MMT methods, respectively. Qualitative correlation via graphical tools (i.e., violin, parallel coordinate, scatter, Bland and Altman plots) in tandem with correlation coefficients was investigated. The parameters of both methods are indicative of the structural features of the turbid samples; however, the MMT parameters (b, t) give higher values than the MMPD parameters (Delta(T), delta) with moderate statistical correlation. This study assessed the link between the two methods and would provide a useful reference for such comparative analyses.y