Patent ID: 7139077
Filing Date: 2006-11-21
Classification: A61B,G01B,G01N

Abstract:
1. An optical mapping apparatus comprising an OCT apparatus, analyzing means, depth adjustment means, and display means; wherein an optical object beam is transferred through an interface optics, transverse scanning means, focusing adjustment means to an object to be scanned and is reflected back therefrom for analysis, wherein said OCT apparatus comprises a source of low coherence or adjustable coherence light, a V OCT interferometer and an H OCT interferometer; wherein light from said source is prepared by a polarizer as a linear state input to the two OCT interferometers; wherein said V and H interferometers share an input splitter having object beam and reference beam output ports; said V interferometer further comprising an output splitter V having an object beam input port and a reference beam input port; said H interferometer further comprising an output splitter H having an object beam input port and a reference beam input port; wherein said output beam splitter of said H interferometer combines an object beam and a reference beam at its respective object beam and reference beam inputs, and has a pair of photodetectors H at its output so as to implement balanced detection via a subtraction electronic amplifier, wherein the output splitter, the two photodetectors and subtraction electronic amplifier form a balance detection unit with maximum sensitivity for the horizontal orientation of polarization of the object beam, and to deliver an output OCTH image; wherein said output beam splitter of said V interferometer combines an object beam and a reference beam at its respective object beam and reference beam inputs, and is terminated on a pair of photodetectors V so as to implement balanced detection via a subtraction electronic amplifier, wherein the output splitter, the two photodetectors and subtraction electronic amplifier form a balance detection unit with maximum sensitivity for the vertical orientation of polarization of the object beam, and to deliver an output OCTV image; wherein said output beam splitter has a substantially 50/50 coupling ratio; wherein said input splitter transfers 1−γ of light input to it from said light source to the respective object beam output port, and the remainder γ of the input light by cross transmission to its respective reference beam output port so as to derive a splitting ratio ε=(1−γ)/γ; wherein said splitting ratio ε is set at a value that optimizes signal-to-noise ratio in said balance detection unit and is dependent on at least the source power P wherein the light from the reference beam output port of said input splitter is directed to a reference polarization beam-splitter via a retarder so as to adjust the polarization state to a linear orientation at 45° from the axes of the reference polarization beam splitter, whose outputs are sent to the reference beam input ports of said output beam splitters in said two interferometers; wherein the polarization state of the light from the object beam output port is prepared in an arbitrary polarization by a variable compensator before being launched into said transverse scanning means; wherein the said object beam originates at the object beam output port of said input splitter to be transferred to the said object, and the light reflected and scattered back from said object is reinjected into the object beam output port of said input splitter and is cross transferred to an object polarization beam-splitter whose different polarization outputs are coupled to said abject beam input ports of said two output splitters in said two interferometers; wherein said input splitter is a bulk beam splitter in the form of a plate, and said output splitters are single mode fiber couplers equipped with fiber ends that are cleaved at an angle at all inputs and outputs thereof; wherein said output splitters have polarization controllers to maximize the signal received at their respective object and reference input ports, and wherein said two output splitters are adapted to process orthogonal linear states of polarization; wherein said transverse scanning means comprises a line scanner and a frame scanner, whereby transverse scanning of an object is effected by an optical image beam that is output from said input beam splitter and is directed over a predetermined target position on said object; wherein said interface optics functions to transfer said optical imaging beam from said transverse scanning means to said object, and functions to transfer an optical output beam which is reflected and scattered back from said object to said input beam splitter through said transverse scanning means; wherein said focusing adjustment means is placed either between said input splitter and said transverse scanning means or between said transverse scanning means and said object to be scanned, so as to focus said optical imaging beam at a specific depth within said object; wherein said depth adjustment means functions to alter the optical path difference synchronously for both said interferometers over a predetermined amount for at least one point in the scanning raster, and the same optical path difference in both OCT interferometers is substantially maintained all the time; and wherein said display means is adapted to generate and display at least two simultaneous images created by said respective pairs of photodetectors wherein a polarization insensitive image OCTI, is generated according to the formula: OCTI=[(OCTV)