Highly accurate geometric calibration for infrared cameras using inexpensive calibration targets

Geometric camera calibration is affected by two sources of error: the lack of accuracy of the calibration target and the uncertainty in locating the control points in the images. Both issues are especially difficult to solve with infrared cameras because they require features that can be distinguished in terms of infrared radiation. In this work we propose a novel design for calibration targets for infrared cameras, easy to build, yet extremely accurate and also inexpensive. This work presents a far more cost efficient solution than previous works: calibration targets are printed on aluminum composite material with a continuous industrial flatbed printer used for advertising boards. This is an easy process that can be used to build calibration targets quickly and with the required size for each particular application. Two calibration targets with different calibration patterns are built and tested, including a thorough analysis of the emissivity and the consequences for the required calibration procedure. Extensive tests are performed to compare the calibration targets, the calibration indoors and outdoors, and the measurement accuracy. Results show excellent performance, with an average measurement error of less than 70 μm, below 0.09% of the real measurement value.