Patent ID: 8461532

Claim:
A method of imaging subsurface features of an object, the method comprising: illuminating the object with a first illumination beam directed towards an imaging location on a surface of the object at a first angle relative to a normal of the surface; illuminating the object with a second illumination beam directed towards the imaging location at the first angle relative to the normal of the surface, wherein the second illumination beam is rotated about the normal by a second angle relative to the first illumination beam, wherein the first and second illumination beams comprise illumination in an imaging wavelength range, wherein the object comprises subsurface features, and wherein the object comprises material positioned between the surface and the subsurface features, the material having an index of refraction that is greater than an index of refraction of a surrounding medium that at least partially surrounds the object; capturing reflected illumination from the surface of the object with an imaging device comprising an objective lens having an acceptance angle, wherein the first angle is greater than the acceptance angle.