Evaluation of an algorithm for the assessment of the MTF using an edge method

Area of Science:

• Optics and Imaging Science
• Signal Processing
• Metrology

Background:

• The modulation transfer function (MTF) is a critical metric for evaluating imaging system performance.
• Existing algorithms for MTF calculation from angled edge images have inherent transfer functions that can affect accuracy.
• Quantifying these algorithmic transfer functions is essential for reliable MTF assessment.

Purpose of the Study:

• To derive and incorporate the profile registration transfer function, accounting for edge angle errors, into a comprehensive MTF calculation algorithm.
• To fully characterize the overall transfer function of the MTF calculation algorithm.
• To develop and provide a user-friendly software tool for MTF analysis.

Main Methods:

• Derivation of the profile registration transfer function considering edge angle determination errors.
• Integration of the derived transfer function with previously reported algorithm component transfer functions.
• Analysis of the impact of edge angle errors on MTF accuracy at the system cutoff frequency.
• Development of a Windows-based software program for MTF calculation and analysis.

Main Results:

• Small errors in edge angle determination lead to disproportionately large errors in the calculated MTF.
• Misalignment errors amplify with an increasing number of registered profiles.
• A 0.07-degree error in edge angle determination (1% error) resulted in a 36% MTF error at the system cutoff frequency for 50 profiles.
• The developed software tool integrates the MTF calculation algorithm and transfer function analysis.

Conclusions:

• Precise determination of the edge angle is crucial for accurate MTF calculation.
• The developed transfer function analysis highlights the sensitivity of MTF results to algorithmic parameters.
• The provided software offers a valuable tool for researchers and engineers to accurately assess imaging system MTF.