Application of neutral-density filters to nonuniformity correction

Area of Science:

• Infrared imaging technology
• Optical engineering
• Sensor calibration

Background:

• Two-point nonuniformity correction (NUC) is crucial for infrared imagers but typically requires two flux references, which can be challenging to acquire.
• Existing NUC methods face limitations in practical applications due to the difficulty in obtaining stable, distinct flux references.

Purpose of the Study:

• To introduce a novel, simplified two-point NUC method for cooled infrared focal plane arrays.
• To address the limitations of conventional NUC by enabling correction with a single reference source.

Main Methods:

• Development of a neutral-density filter-based system integrated with an additional concave mirror.
• Implementation of NUC using a single reference at ambient temperature, eliminating the need for multiple flux levels.
• Experimental validation of the proposed NUC method's performance and practicality.

Main Results:

• The proposed method achieves excellent performance, comparable to conventional two-point NUC techniques.
• Experimental results confirm the effectiveness and reliability of the single-reference NUC approach.
• The new method demonstrates significant advantages in terms of cost-effectiveness and operational convenience.

Conclusions:

• The neutral-density filter-based solution provides an effective and simplified approach to two-point NUC for infrared focal plane arrays.
• This innovative method enhances the practicality and accessibility of NUC in diverse scientific and commercial infrared imaging applications.
• The proposed NUC technique offers a more economical and user-friendly alternative to traditional methods, broadening the scope of infrared imager utilization.