Development of novel endoscope with NIR camera using real-time video composite method

Recently, a near-infrared (NIR) Fluorescence Biomedical Imaging (FBI) attracts increasing attention from many researchers. The light wavelength region in 1000 nm to 1700 nm has been known to be a “biological window” where the both tails of scattering and infrared absorption decrease to form a valley in optical loss spectra of biological objects. The inside of biological objects which cannot be usually seen in a normal endoscopy can be seen by using NIR, because of NIR light can penetrate in biological objects, and the further development of medical equipment is expected by using NIR. We are developing towards the realization of a NIR laparoscope which composes of a NIR camera and a visible light camera. The visible light camera can observe the surface in biological objects, and the NIR camera can observe the inside of biological objects. The NIR laparoscope has a potential of the helpful in the early detection of tumor. In our current system, the images captured by a NIR laparoscope and a normal laparoscope are shown on the separate screens simultaneously. The operator need to more experience to use the system. It was difficult to figure out the clinical usefulness of the NIR laparoscope with a visible light camera. We proposed the image composite method using a projection transform and a distance correction. The proposed method, compared to existing methods, is simple and fast. The proposed composite method of the two video images from a NIR camera and a visible light camera can facilitate the diagnosis and the surgery. The proposed system can reduce not only operator’s burden but also patient one’s. We are applying the proposed method to a laparoscope and conducting the evaluation experiment of the proposed method.