The effect of complex background infrared radiation on target scattering radiance

The scattering of complex background (the Sun, the Sea and the Sky background) infrared radiation from a target is studied. By coordinate transformation, summation of the visible facets, integration to wavelength, finally angular distribution formula of integral scattering radiance from a lambertian target is achieved. With the Solar spectrum radiance and the sea & the sky background´s spectrum irradiance calculated by Modtran Software, a lambertian cylinder is taken as an example, in wavebands 3~5μm and 8~12μm, angular distribution of horizontal and vertical targets´ integral scattering radiance is simulated numerically. The results show that: in both wavebands scattering radiance of the sea & the sky background radiation from the target plays an important role, especially in waveband 8~12μm scattering radiance of the Sun radiation from the target is far less than that of the sea & the sky background radiation, it could be ignorable; and in waveband 8~12μm scattering radiance of the sea & the sky background radiation than that in waveband 3~5μm; and scattering radiance from the horizontal target is stronger than that from the vertical target, therefore this attitude is more suitable for target detection in waveband 8~12μm.