A Non-linearity Correction Method for Calibration of Optical Sensor at Low Level Light

Abstract

This paper describes a methodology developed for calibrating optical detector for light engineering, especially for devices used at low level light, including auroral imager, star sensor, astronomical camera and similar optical instruments. In order to know the physical meaning of optical sensor output, calibration is the first and most important process in a complete analysis of observed data. It is found that optical sensors, like CCDs, are not perfectly linear systems as they were assumed. After bias frame subtraction, the number of ADU counts is not exactly proportional to the number of incident photons. A key component of this paper is non-linearity correction. One of current applications using this method is auroral imager which is used for measuring aurora, high-altitude clouds, and other atmospheric optical objects light intensity, which is the first step to complete an optical object tomography simulation.

Auroral meridian scanning photometer calibration using Jupiter

“…Utility of stellar calibration for all-sky imagers has been demonstrated (Wang, 2011;Wang et al, 2012;Grubbs et al, 2016) and these methods would be even more effective with a brighter source. Given the complexities of absolute calibration, it might be helpful if observations were presented in some standard format, e.g., data numbers normalized to source magnitude D 0 as defined in Eq.…”

“…Practical application may be restricted by instrumental limitations and complications including man-made interfer There is a long history of using astronomical sources to determine the alignment of auroral instruments (Stormer, 1915;Fuller, 1931;Chapman, 1934;Kinsey, 1963). Absolute calibration using stellar spectra appears to be a more recent development (Gladstone et al, 2000;Whiter et al, 2010;Dahlgren et al, 2011;Wang, 2011;Wang et al, 2012;Grubbs et al, 2016). Detailed discussions of these topics are not always provided in the primary scientific literature, but must often be extracted from conference proceedings, technical reports, and theses.…”

Auroral meridian scanning photometer calibration using Jupiter

“…The merits of Jupiter as a calibration source also apply to other types of auroral instruments. Utility of stellar calibration for all-sky imagers has been demonstrated (Wang, 2011;Wang et al, 2012;Grubbs et al, 2016) and these methods would be even more effective with a brighter source. Given the complexities of absolute calibration, it might be helpful if observations were presented in some standard format, e.g., data numbers normalized to source magnitude D 0 as defined in Eq.…”

“…There is a long history of using astronomical sources to determine the alignment of auroral instruments (Stormer, 1915;Fuller, 1931;Chapman, 1934;Kinsey, 1963). Absolute calibration using stellar spectra appears to be a more recent development (Gladstone et al, 2000;Whiter et al, 2010;Dahlgren et al, 2011;Wang, 2011;Wang et al, 2012;Grubbs et al, 2016). Detailed discussions of these topics are not always provided in the primary scientific literature, but must often be extracted from conference proceedings, technical reports, and theses.…”

Stellar spectral flux calibration of auroral H‐beta photometer signal and background channels

“…Stellar calibration of auroral instruments has been successfully used for studies of electron aurora [Gladstone et al, 2000;Dahlgren, 2010;Wang, 2011;Wang et al, 2012;Wedlund et al, 2013;Grubbs et al, 2016;Jackel et al, 2016]. For this study we demonstrate an application of astronomical sources for the calibration of a sensitive meridian scanning photometer (MSP) designed for observations of the proton aurora at 486 nm.…”