In order to make plausible estimation of a flash effects on electro-optical and IR devices, the information such as the radiance and the size of a flash are essential. In this paper, the spectral IR radiance measurements of flash lights are carried out and the extraction method and usage of equivalent radius of flash are proposed.
The spectral IR radiance measurement is carried out with the measurement system, of which each channel consists of optical band-pass filter and IR detector to divide the wavelength of two interested wavebands of MWIR and LWIR to detect the wavelength-divided IR radiation, respectively. The measurements of spectral radiance of flash show that flash A is the strongest among three and followed by those of source C and B. With the measured IR radiance over MWIR and LWIR ranges on each source, the radiative temperature of the sources is extracted by fitting the measured radiance data to blackbody radiance. The best fitted radiative temperatures, which are the equivalent black-body temperature, of the three flash sources are 3300K, 1120K and 1640K for the source A, B and C, respectively.
In order to analysis the effect on the observation devices by flash, the equivalent radius and its extraction method from the observed image of a flash are proposed. It is shown from the measured equivalent radius that flash A is the strongest among three and followed by those of source C and B such as spectral radiance. In addition, it was observed secondary peak of flash A and B at 100∼200ms. but secondary peak is not observed in the explosive flash C. For the combustive flash A and B, the secondary peak is occurred by the second burning of remaining powder contents. However, this second peak can not be observed in the explosive flash, since the duration time of explosion is very short, so only the burning of the remaining powder can be observed.
As a result, the spectral radiance and effective equivalent radius of a flash are very important factors in estimating the flash effects. Furthermore, the analysis of this study is expected to provide the basis of the future M&S of flash effects.