<span style="mso-bookmark: _Hlk193396203;"><span style="mso-fareast-font-family: DengXian; mso-fareast-theme-font: minor-fareast;">Study on the Design of Quantitative Metrics for Focus Measure Operators<span style="mso-bookmark: _Hlk193396203;"><span style="mso-fareast-font-family: DengXian; mso-fareast-theme-font: minor-fareast;">

Given the variety of focus measure operators, selecting an appropriate one based on scene requirements is critical. Based on the evaluation of the focusing curve morphology and considering the accuracy and robustness of metrics, four metrics were designed: the steep region width (Ws), the steep to gentle ratio (Rsg), the curvature of peak point (Cp), and the relative root mean square error (RRMSE). Several typical focus measure operators were chosen for experimental evaluation. The results demonstrate that the proposed metrics effectively characterize the performance and features of various operators. These metrics serve as a valuable reference for selecting appropriate operators and provide a theoretical foundation for designing new ones.