B-1

Procedure for the determination of the average MRTD_av

　

The average MRTD (MRTD_av) Is determined as follows:

1) Draw a graphic of spatial frequency (vertical axis) against temperature difference (horizontal axis) using values obtained from +he MRTD-graph, The resulting graph shows the "spatial resolution function" (SRF).

　

NOTE: The SRF is the inverse function of the MRTD (See also Fig.1 and fig. 2).

　

fig. 1 MRTD-curves

fig. 2 SRF-curves.

　

2) Determine at a given temperature difference ΔT the SRF_h and the SRF_v.

3) Calculate an average SRF_av (ΔT) according to equation (1):

　

　

4) Repeat step 2 and 3 for a number of values of temperature difference ΔT.

5) Draw a curve, using the average SRF-values found at step 3 and 4.

6) Reverse the process of step 1. Draw the MRTD-curve with spatial frequency along the horizontal axis and temperature difference along the vertical axis. For the average MRTD_av-curve use the calculated average SRF_av -values.

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