## 4 Conclusions  
In this study we compared the parameters derived from the MMT and MMPD methods thoroughly by measuring two types of tissue samples: seven kinds of thin tissue slices and five kinds of bulk tissue samples, with a transmission Mueller matrix microscope and backscattering Mueller matrix measurement setup. After grouping the parameters with the same polarization properties, namely diattenuation, linear retardance, linear birefringence fast axis orientation and depolarization, we performed both correlation and statistical analysis. Our preliminary experimental results showed that: (1) for obtaining the diattenuation property of complex tissues, we can calculate it through the modified MMT parameter \(t_{121314}\), with a fast speed and a high correlation with the MMPD parameter \(D\); (2) for revealing the linear retardance value related to the density of birefringent structures like layered fibers of thin tissues, the modified MMT parameter \(t_{gr}\) can reach a high linear correlation with the MMPD parameter \(\delta\). While for the bulk tissue samples, it is more reasonable to use the MMPD parameter \(\delta\) to extract the linear retardance value accurately; (3) for characterizing the orientation distribution of the birefringent structures, the modified MMT parameter \(\phi_{gr}\) and MMPD parameter \(\theta_{e}\) can both reach similar accurate results for thin and thick tissues; (4) the modified MMT parameter \(1-b_{m}\) shows a high degree of consistency with the MMPD parameter \(\Delta\) for the bulk tissue samples with strong depolarization, so it can be used to quickly evaluate the tissue depolarization property. In summary, based on the analysis and discussion regarding the applicability of the MMPD and MMT parameters, this study gave suggestions for the appropriate selection of parameters in Mueller matrix imaging for different types of tissue samples, which can be useful for biomedical and clinical polarimetry. Conceptualization, B.C. and Y.L. ; Data curation, B.C. and Y.L. ; Formal analysis, B.C. ; investigation, B.C., H.Z. and L.D. ; Funding acquisition, H.H. ; Methodology, B.C. and Y.L. ; Project administration, H.H. ; Software, B.C., H.Z. and L.D. ; Supervision, H.H. and H.M. ([PERSON]); Writing--original draft, B.C. ; Writing--review and editing, H.H., H.M. ([PERSON]) and H.M. ([PERSON]). All authors have read and agreed to the published version of the manuscript. National Natural Science Foundation of China (NSFC) (No. 61527826), Shenzhen Fundamental Research and Discipline Layout Project (No. JCYJ20170412170814624), and Overseas Research Cooperation Project of Tsinghua Shenzhen International Graduate School (No. HW2018005). The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of the Shenzhen International Graduate School, Tsinghua University (protocol code 2021-29, date of approval 16 March 2021, and protocol code 2021-40, date of approval 31 May 2021). Informed Consent StatementInformed consent was obtained from all subjects involved in the study. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Type**} & \multirow{2}{*}{**Tissues**} & \multicolumn{4}{c}{**Depolarization**} \\ \cline{3-6}  & & \(R^{2}\) & & \(p\) & \\ \cline{3-6}  & & \(\Delta\)—\(1-b\) & \(\Delta\)—\(1-b_{m}\) & \(\Delta\)—\(1-b\) & \(\Delta\)—\(1-b_{m}\) \\ \hline \multirow{4}{*}{Backward} & breast & 0.96 & 0.99 & \textgreater{}0.05 & \textgreater{}0.05 \\  & rat-skin & 0.98 & 0.99 & \textgreater{}0.05 & \textgreater{}0.05 \\  & porcine-intestine & 0.98 & 0.99 & \textgreater{}0.05 & \textgreater{}0.05 \\  & porcine-stomach & 0.98 & 0.99 & \textgreater{}0.05 & \textgreater{}0.05 \\  & porcine-liver & 0.97 & 0.99 & \textless{}0.01 & \textgreater{}0.05 \\  & Total & 0.98 & 0.99 & \textgreater{}0.05 & \textgreater{}0.05 \\ \hline \hline \end{tabular}
\end{table}