Endoscopic illumination and imaging systems for enabling observation of both the forward and rearward directions in a lumen using only a single imaging device. According to one implementation, the system utilizes the effects of a partially reflective mirror to respectively transmit and reflect light from the different portions of the lumen or cavity, and uses separate groups of illumination sources to illuminate one or the other section of the lumen, such that the illuminated section is preferentially imaged by virtue of its increased light level. In a second implementation, electrically switched mirrors are used, having properties switched between a transmissive and a partially reflective state, such that the mirror can be switched between imaging the regions forward of the camera when in a transmissive state, and imaging the regions rearward of the camera when in a reflective state. A mechanically swiveled mirror is described for the same purpose.
