Robust calibration method for polarization cameras integrated with chromatic retarders

Area of Science:

• Optics and Photonics
• Image Sensors
• Metrology

Background:

• Polarization cameras offer efficient real-time imaging but face chromatic calibration challenges with wavelength-dependent optics like linear retarders.
• Existing methods struggle to accurately calibrate polarization cameras when retardance varies with wavelength, impacting performance in color sensors.

Purpose of the Study:

• To introduce an analytical calibration method for polarization cameras with chromatic retarders.
• To enable robust and accurate polarization calibration across different spectral channels, accounting for spectral averaging and depolarization effects.

Main Methods:

• Developed an algebraic method to correct for spectral averaging and depolarization effects.
• Validated the method using a commercial color polarization camera (FLIR Blackfly S) and broadband illumination.

Main Results:

• The analytical calibration method effectively addresses chromatic errors in polarization imaging.
• Experimental results show close agreement between obtained effective spectral parameters and theoretical predictions.
• The method is applicable to both monochromatic and color polarization sensors.

Conclusions:

• The proposed analytical calibration method provides a robust solution for polarization cameras with chromatic retarders.
• Accurate polarization calibration is achievable across spectral channels, improving imaging performance.
• This technique enhances the reliability of polarization imaging systems in diverse applications.