Size measurement in endoscopic images by low coherence interferometry.

We present a novel optical sensor that is able to measure the real dimensions and areas of anatomical objects in endoscopic images by taking advantage of the knowledge of the real distance from the endoscope tip to the anatomical wall under examination. At present the major obstacle to quantitative endoscopy is the inability of calibrating the acquired images because of the magnification system. In order to solve this problem in a satisfactory way we have studied and realized a new system combining an imaging system, applied to a clinical endoscope, with an absolute distance sensor based on fiber optic low coherence interferometry (FOLCI). Up to now the sensor has been tested on pig trachea, simulating the real humidity and temperature (37 °C) conditions. The sensor show high sensitivity, providing correct measurements of the size of biological samples even in the case of very low reflected power (down to 2-3 nW). [ABSTRACT FROM AUTHOR]