## 4 Conclusions  
In summary, we employed the homemade high-fidelity MMIP and effectively differentiated the various lesions of human skin, including normal, BE, and MM, by quantitative and qualitative approaches. For the quantitative classification, eight classifiers using the SVM algorithm were established and evaluated with different retardance-related parameters. The preferred cross-validation accuracy of 98.60% and prediction accuracy of 96.19% can be achieved by the classifier based on vectorial retardance. For the qualitative analysis, a true-color vectorial retardance imaging technique was implemented to help clinicians to read and interpret parameters conveniently but without sacrificing any information about fibers. Compared to the conventional scalar retardance images, this method can significantly enhance the tissue-specific contrast and provide more details, including fiber distribution and orientation. Benefiting from these advantages, many valuable insights into the development of skin disease can be observed directly. We believe that the combined analysis of true-color vectorial retardance imaging technique and SVM can improve the accuracy of the diagnosis of early disease. This will dramatically facilitate the clinical application of polarization imaging.  
Conceptualization, W.W. and G.C.; methodology, W.W. and G.C.; software, W.W. and G.C.; validation, W.W. and G.C.; formal analysis, W.W. and G.C.; investigation, W.W.; resources, W.W.; data curation, W.W.; writing--original draft preparation, W.W. and G.C.; writing--review and editing, W.W.; visualization, W.W.; supervision, G.C. and Y.L.; project administration, Y.L.; funding acquisition, Y.L. All authors have read and agreed to the published version of the manuscript.  
National Natural Science Foundation of China (11627808).  
This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Seventh Center of the General Hospital of the Chinese People's Liberation Army (Ethics Approval No. 2021-52, date of approval 27 July 2021).  
Informed Consent Statement: Informed consent was obtained from all subjects involved in this study.  
Not applicable.  
We would like to acknowledge [PERSON] and [PERSON] at the 7 th Medical Center of the Chinese People's Liberation Army General Hospital for providing us with samples and experimental guidance, which was very important for our study.  
The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Number**} & **Polarimetric Imaging** & **Polarization** & **Polarization** \\  & **Techniques** & **Parameters** & **Staining Methods** \\ \hline \hline
1 & MMIP [33] & Scalar retardance & False-color imaging by \\  & & Azimuth of the slow axis & one parameter \\  & & Diattenuation & True-color imaging by \\
2 & MMIP [34] & Linear retardance & several parameters \\  & & Azimuth of the slow axis & \\
3 & DoFP polarization & Degree of linear & \\  & microscope [41] & polarization & \\
4 & PS-OCT [47] & Stokes parameters & True-color imaging by \\  & & & several parameters \\
5 & Stokes polarimeter [96] & Stokes parameters & True-color imaging by \\  & & & several parameters \\ \hline \hline \end{tabular}
\end{table}
Table 4: The comparison among several represented polarimetric imaging techniques combined with polarization staining methods. Each parameter represents a unique physical quantity.