Described herein is a novel 3-D optical imaging system based on active stereo vision and motion tracking for to tracking the motion of patient and for registering the time-sequenced images of suspicious lesions recorded during endoscopic or colposcopic examinations. The system quantifies the acetic acid induced optical signals associated with early cancer development. The system includes at least one illuminating light source for generating light illuminating a portion of an object, at least one structured light source for projecting a structured light pattern on the portion of the object, at least one camera for imaging the portion of the object and the structured light pattern, and means for generating a quantitative measurement of an acetic acid-induced change of the portion of the object.
