1. A spatial-domain low-coherence quantitative phase microscopy apparatus, comprising: an imaging system that collimates a white light from a light source; a component that tunes a wavelength of the white light to a spectral resolution shared by multiple imaging contrasts; a device that projects the tuned light onto a sample, wherein the sample scatters at least a portion of the tuned light back; a camera that records the scattered portion of the tuned light and generates a depth-resolved three-dimensional image based, at least in part, on a measurement of the scattered portion; and an image registration module that is configured to co-registers the depth-resolved three-dimensional image with a bright field image of a stained version of the sample using coordinate transformation information generated from an unstained transmission phase image of the sample and a stained transmission phase image of the stained version of the sample.