In the preceding preliminary validation (Section 3.1.1), the regularization parameter λ was chosen by minimizing the normalized DRT residual, a strategy feasible because the exact DRT is known for synthetic data. However, this approach is not applicable to experimental data where the true DRT is unknown (Section 3.2). Consequently, we evaluated the effectiveness of the four regularization parameter selection methods detailed in Section 2.2 by comparing the λ values they yielded to the optimal λ determined through minimization of ε γ . The correlation matrix presented in Figure (a) revealed that the regularization parameters derived from the SD and LC methods exhibited the strongest correlation with the optimal values. Furthermore, analysis of the absolute errors and mean squared errors, summarized in Table , underscored that the LC method produced λ values closest to the optimal, followed by the DP method, which were more than one order of magnitude larger. This trend was further substantiated by the violin plots of the normalized DRT residuals (in log scale), as displayed in Figure Method