Abstract: An image is created of blood circulation deep (e.g. a plurality of millimeters) below the surface of living tissue to aid in evaluating a patient. A first beam (26) of circularly polarized light is directed forwardly (F) against an outer surface (14) of the tissue. Light that has penetrated to only a shallow depth before moving rearwardly and out of the tissue remains polarized and is blocked by a filter (38). Light that has penetrated to greater depths (12), is scattered more and becomes depolarized, and a portion of it passes through the depolarizing filter (38) and is focused on a photodetector (48) to create an image. Light spots (54) on the image that move, represent spaces between blood platelets (52) that are moving through a capillary, and indicates the velocity of blood through the capillary.

Abstract: A real time image is created of blood circulation deep (e.g. a plurality of millimeters) below the surface of living tissue to aid in evaluating a patient. A first beam (26) of circularly polarized light is directed forwardly (F) against an outer surface (14) of the tissue, the circularly polarized beam penetrating into a deep region (12) of the tissue. Along shallow depths (42), light of the first beam is scattered a minimum amount from tissue and a portion of such light that passes rearwardly and out of the tissue remains polarized. Along greater depths (12), light of the first beam is scattered much more and becomes depolarized, and a portion of that deep light travels rearwardly (R) and back illuminates the overlying tissue. Light emerging from the outer surface of the tissue and traveling rearwardly, which constitutes a second beam (36), is passed through a depolarizing filter (24) that passes primarily only unpolarized light, so light from a shallow depth is largely blocked.