An endoscopic probe includes a rotatable core for guiding first light from a first light source to a sample； a non-rotatable sheath arranged concentrically around the rotatable core； and a plurality of fibers surrounding the distal end of the non-rotatable sheath. The rotatable core includes a plurality of patterns built-in at the distal end thereof. Some of the fibers are used to detect the first light scattered by the sample, some fibers are used to irradiate the patterns with second light, and some fibers are used to collect the second light reflected from the patterns. The fibers are aligned with plurality of patterns to collect the reflected second light as the rotatable core rotates, and the rotation position of the rotatable core is determined by correlating intensity variation the reflected light with time collection. NURD of a SEE image is compensated based on the position information.
