Endoscopic double-pulse electronic-speckle-pattern interferometer for technical and medical intracavity inspection

An endoscope electronic-speckle-pattern interferometer (ESPI) camera system is presented that can be applied to examinations of technical objects as well as for in vitro and in vivo minimal invasive medical diagnostics. Integration of optical fibers for the guidance of a cw-laser beam and an endoscopic imaging system yield a compact ESPI system that opens up new possibilities for highly sensitive interferometric intracavity inspection under handheld conditions. A CCD camera in combination with a fast frame-grabber system allows dynamic image subtractions at a frequency rate of as much as 25 Hz with high fringe contrast. Results from investigations of technical objects and biological objects in vitro and in vivo are obtained. In endoscopic minimal invasive therapy this method could substitute for the missing operator's tactile contact with the treated tissue by replacing it with visual information (endoscopic taction).