Passive calibration board for alignment of VIS-NIR, SWIR and LWIR images

Abstract

This paper presents a new non-electrically powered calibration rig designed for geometric calibration and spatial alignment of cameras operating in the VIS-NIR, SWIR and LWIR wavebands. Quantitative tests and experiments have been performed to identify materials, paint, varnish and configuration offering optimal properties in all wavebands. The performances obtained with this new rig were evaluated in terms of image contrast and corner detection ability. We demonstrate that the design is suitable to be used not only indoor, but also in outdoor environment with varying illumination (night, sunny and overcast day) and weather conditions (wind, cold temperature).

Robust low resolution thermal stereo camera calibration

“…The resolution of their visible and thermal images was respectively 640 × 480 and 160 × 128. St Laurent et al [12] try to find the best calibration pattern in order to calibrate stereo thermal infrared cameras. They present a passive calibration grid that is able to produce optimal image contrast in order to get a robust calibration.…”

“…First, we discarded passive calibration grids even if they are easier to handle but the external thermal condition influences the quality of the image [12]. Given that we wanted to collect many images, the grid can get cool more and less quickly changing the measured information in the images over time.…”

Automatic Calibration and Co-Registration for a Stereo Camera System and a Thermal Imaging Sensor Using a Chessboard

“…Reflective targets using different emissivity surfaces are also possible, but require different temperatures for the target itself and an illumination source (Shibata et al (2017) and Aguilera et al (2018)). An extensive evaluation of best suitable material and coating for such a passive board can be found in St-Laurent et al (2017). However in both cases, visually perceptive contrast between the elements used for the target composition is needed for simultaneous acquisition of VIS/RGB images.…”

Optimal Material Search for Infrared Markers under Non-Heating and Heating Conditions

“…For these applications, infrared markers play an essential role in device calibration and evaluation. In multi-modal imaging, both infrared and visible cameras capture the observation target, and the markers are mainly used to calibrate the spatial positions of the two cameras [ 5 , 6 ]. For infrastructure inspection, a thermography camera can capture invisible structural deformations, such as floating and peeling.…”