Other than being a broadband low coherence light, there is no specific requirement on the light source of white light interfero- metry. As the conventional white light source has only one peak that is in the Gaussian distribution in its effective spectrum, its corresponding interference signal always has only one high frequency component, and its fringe contrast function (which is the envelope function of the interference signal) can be reason- ably modeled as a single Gaussian function [15]. So most prior works [5,12–14] have neglected the spectral effects of the light source.