Mathematical Models for Computer Graphics

In the simplest case, we can decompose a signal into two parts: a low frequency part, which is some sort of average of the original signal, and a high frequency part, which is what remains after the low frequency part is subtracted from the original signal. If we are interested in the low frequency part and hence discard the high frequency part, what remains is a smoother representation of the original signal with its low frequency components intact. Alternatively, if we are most interested in the high frequency part, we may be able to discard the low frequency part instead.