Three Dimensional Refraction Assisted Illuminated Imaging (3D-RAIL)

An illumination source may be directed towards a surface of an object comprising subsurface features, wherein the illumination from the source is directed at a first angle relative to the normal of the surface. The object may have a portion between the subsurface features and the surface, the portion having an index of refraction that is greater than the index of refraction of a surrounding medium that surrounds the object. An imaging device may be placed with an objective lens. The first angle may be larger than an acceptance angle of the objective lens. In some embodiments, multiple illumination beams may be generated by one or more illumination sources. The beams may be rotated relative to one another about the normal of the surface. Also, in some embodiments, multiple images may be taken with the objective of the imaging device at different positions rotated off of the normal. The multiple images may be combined to generate a composite image.