Infrared Camera Geometric Calibration: A Review and a Precise Thermal Radiation Checkerboard Target

Area of Science:

• Optics and Photonics
• Computer Vision
• Metrology

Background:

• Infrared (IR) camera geometric calibration is often overlooked due to low thermal image resolution and complex target requirements.
• Existing IR calibration targets are often intricate and less accessible for general users.
• The pinhole model is a standard for optical camera calibration, but its application in IR requires specialized targets.

Purpose of the Study:

• To review existing IR camera geometric calibration targets and their performance.
• To develop a practical and accurate checkerboard target for IR camera geometric calibration.
• To provide a user-friendly solution with minimal reprojection errors for less experienced users.

Main Methods:

• A comprehensive literature review of IR camera calibration targets was conducted.
• Two planar checkerboard targets were fabricated using laser engraving and UV printing on stainless steel (SS304).
• The performance of the fabricated targets was evaluated based on reprojection errors (MRE and RMSE).

Main Results:

• The UV-printed checkerboard target on polished stainless steel achieved a mean reprojection error (MRE) of 0.057 pixels.
• The root mean square error (RMSE) of reprojection was found to be 0.063 pixels, with a standard deviation below 0.003 pixels.
• The UV-printed target demonstrated higher accuracy than other checkerboard designs and comparable results to leading circular targets.

Conclusions:

• High emissivity contrast and precise intersection points are crucial for accurate IR checkerboard targets.
• The UV-printed checkerboard target offers an optimal balance of accuracy and practicality for IR camera calibration.
• This developed target provides a valuable tool for improving the geometric accuracy of thermal imaging systems.