Determination of SATI Instrument Filter Parameters by Processing Interference Images

TL;DR

This paper introduces an image processing method to accurately determine interference filter parameters of a spectrometer using radial sections and least squares fitting, improving precision and aligning closer to laboratory measurements.

Contribution

The novel approach combines radial section analysis with least squares fitting to enhance the accuracy of filter parameter determination from spectrogram images.

Findings

Method achieves higher than one pixel precision in parameter estimation.

Filter parameters obtained are closer to laboratory measurements.

Nocturnal course of parameters aligns well with known data.

Abstract

This paper presents a method for determination of interference filter parameters such as the effective refraction index and the maximal transmittance wavelength on the basis of image processing of a spectrogram produced by Spectrometer Airglow Temperature Imager instrument by means of data processing. The method employs the radial sections for determination of points from the crests and valleys in the spectrograms. These points are involved in the least square method for determination of the centres and radii of the crests and valleys. The use of the image radial sections allows to determine the maximal number of crests and valleys in the spectrogram. The application of the least square fitting leads to determination of the image centers and radii of the crests and valleys with precision higher than one pixel. The nocturnal course of the filter parameters produced by this method is presented and compared with that of the known ones. The values of the filter parameters thus obtained are closer to the laboratory measured ones.