Minimum Temperature Difference Perceived for Undersampled Medical Thermal Imager

Authors

DOI:

https://doi.org/10.20535/1810-0546.2017.5.100137

Keywords:

Minimum temperature difference perceived, Nyquist frequency, Average modulation at optimum phase

Abstract

Background. Currently, thermal imagers with matrix radiation detectors (MRD) are widely used in medicine. A common feature of these thermal imagers is the ability to sample the signal in two directions: horizontal and vertical. Such thermal imagers are undersampled. That is why the question of evaluating the effectiveness of such thermal imagers is very relevant now.

Objective. The aim of the paper is to provide a physico-mathematical model of a thermal imager to calculate the minimum temperature difference perceived (MTDP).

Methods. It is proposed to determine MTDP based on the physico-mathematical model of the thermal imager for determining the minimum resolution temperature difference.

Results. The developed physico-mathematical model of a thermal imager with MRD allows calculating MTDP that enables determining the spatial resolution of a thermal imager outside the Nyquist frequency. It is proposed to consider the Average Modulation at Optimum Phase (AMOP) as the line scale average contrasts, which allow obtaining an equation for calculating the MTDP function.

Conclusions. The proposed physico-mathematical model provides an opportunity to determine the spatial resolution of the thermal imager outside the Nyquist frequency, which is an important factor in the effect on the thermal imaging quality.

References

V.G. Kolobrodov and M.I. Lyholit, Design of Thermal and Television Observing Systems. Kyiv, Ukraine: NTUU KPI, 2007 (in Ukrainian).

Experimental Assessment Parameters and Procedures for Characterisation of Advanced Thermal Imagers. France: Research and Technology Organization, 2003.

K. Chrzanowski, Testing Thermal Imagers. Warsaw, Poland: MilitaryUniversity of Technology, 2010.

Standard Test Method for Minimum Resolvable Temperature Difference for Thermal Imaging Systems, ASTM standard E 1213-2002.

W. Wittenstein, Minimum Temperature Difference Perceived – A New Approach to Assess Undersampled Thermal Imagers. SPIE Optical Engineering Press, 1998, pp. 773–781.

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Published

2017-10-31

Issue

No. 5 (2017): Engineering

Section

Art

License

Copyright (c) 2017 Igor Sikorsky Kyiv Polytechnic Institute

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