A rear-viewing endoscope includes a rigid section having first and second ends, and a cavity situated between the first and second ends. The rigid section has a longitudinal length and defining a longitudinal axis (LAR).The endoscope further includes a flexible section having proximal and distal ends, where the proximal end is coupled to the second end of the rigid section and an imaging unit having first and second ends and a cavity situated between the first and second ends, the second end of the imaging unit coupled to the distal end of the flexible section, the endoscope further comprising a limiting aperture portion between the first and second lens groups, wherein the CMBF pair is formed upon a surface of the limiting aperture.The CMBF filter collimated image rays passing therethrough so as to output filtered image rays. A camera or detector receives the filtered image rays and forms corresponding video information for stereoscopic imaging.
