Spectral imaging background spectrum

While many satellites provide images in the visible spectrum, oil cannot be seen in these images unless the spill is very large or rare sea conditions are prevalent that provide a contrast to the oil. Oil has no spectral characteristics that allow it to be enhanced from the background. 

Fig. 8 The SE image of an ammonium sulphate particle A indicates that the beam sensitive particle stays stable at liquid-Nitrogen (LN) temperatures, with some degradation in B after electron beam exposure and further degradation in C after the Raman spectrum was taken. A good spectrum was obtained (i) for the particle prior to electron beam exposure, but the second spectrum (ii) showed band broadening, high background and poor spectral quality.

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