The aim of this study is to investigate whether eye temperature is different among MDD patients than among healthy individuals. Previous studies suggest that altered corneal temperature may be a feature of schizophrenia, but the association between major depressive disorder (MDD) and corneal temperature has yet to be assessed. George, Shefin Sam Viswanathan, Rekha Puzhavakkathumadom Fitzgerald, Paul B. Using thermographic cameras to investigate eye temperature and clinical severity in depression As it must be expected, also accuracy appears higher in the visible camera, and the geometric comparison between thermographic cameras shows slightly better Verification results show repeatability better than 1 mm for all cases, being better than 0.5 mm for the visible one. The calibration system based on burning lamps shows its capability to perform the internal orientation of the thermal cameras. Two thermographic cameras from Flir and Nec manufacturers, and one visible camera from Jai are calibrated, verified and compared using calibration grids and the standard artefact. Reflectivity was the chosen material propriety due to the thermographic and visual cameras ability to detect it. Two sets of targets with different reflectivity are fixed to the spheres and cubes to make data processing and photogrammetric restitution possible. Metrology traceability for the artefact is obtained from a coordinate measuring machine.
The artefact designed for the geometric verification consists of five delrin spheres and seven cubes of different sizes. A grid based on burning lamps is used for the geometric calibration of thermographic cameras. These results allow the incorporation of this information into the quality control processes of the companies. This work presents a calibration procedure that allows the photogrammetric restitution and a portable artefact to verify the geometric accuracy, repeatability and drift of thermographic cameras. Moreover, the geometric information is important for many fields as architecture, civil engineering and industry. Black bodies are used for these purposes. Infrared cameras acquire temperature and geometric information, although calibration and verification procedures are only usual for thermal data. Quality assessment in the measurements performed with the thermal cameras should be achieved through metrology calibration and verification. Infrared thermography is a technique with an increasing degree of development and applications. Calibration and verification of thermographic cameras for geometric measurements
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