MTF Measurement by Slanted-Edge Method Based on Improved Zernike Moments

Area of Science:

• Optical Engineering
• Image Processing
• Photogrammetry and Remote Sensing

Background:

• The modulation transfer function (MTF) is crucial for evaluating optical imaging systems.
• Traditional slanted-edge methods for MTF measurement struggle with noise and blur, leading to inaccurate edge detection.
• Existing methods like ISO 12233, OMNI-sine, Hough transform, and LSD have limitations in accuracy and noise tolerance.

Purpose of the Study:

• To develop a novel MTF measurement method using improved Zernike moments for enhanced accuracy in optical imaging systems.
• To overcome the limitations of traditional edge detection techniques in the presence of noise and blur.
• To improve the reliability and precision of MTF measurements in photogrammetry and remote sensing applications.

Main Methods:

• A novel slanted-edge method based on improved Zernike moments for MTF measurement.
• Utilizing the Otsu algorithm for automatic threshold determination in sub-pixel edge detection.
• Deriving the line spread function (LSF) through edge point projection, ESF sampling, smoothing, fitting, differentiation, and Gaussian fitting.
• Calculating MTF via LSF Fourier transform and modulo normalization.

Main Results:

• The proposed algorithm demonstrates superior edge detection accuracy compared to ISO 12233, OMNI-sine, Hough transform, and LSD methods.
• The method exhibits maximum tolerance to noise and ambiguity in edge detection.
• Simulation and outdoor experiments confirm the algorithm's reliability and improved MTF measurement accuracy.

Conclusions:

• The improved Zernike moments method offers a robust solution for accurate MTF measurement in challenging imaging conditions.
• This technique significantly enhances edge detection precision and noise/blur tolerance.
• The study validates the algorithm's effectiveness, providing a valuable tool for optical system performance evaluation.