Stereoscopic visualization of laparoscope image using depth information from 3D model

Laparoscopic surgery is indispensable from the current surgical procedures. It uses an endoscope system of camera and light source, and surgical instruments which pass through the small incisions on the abdomen of the patients undergoing laparoscopic surgery. Conventional laparoscope (endoscope) systems produce 2D colored video images which do not provide surgeons an actual depth perception of the scene. In this work, the problem was formulated as synthesizing a stereo image of the monocular (conventional) laparoscope image by incorporating into them the depth information from a 3D CT model. Various algorithms of the computer vision including the algorithms for the feature detection, matching and tracking in the video frames, and for the reconstruction of 3D shape from shading in the 2D laparoscope image were combined for making the system. The current method was applied to the laparoscope video at the rate of up to 5 frames per second to visualize its stereo video. A correlation was investigated between the depth maps calculated with our method with those from the shape from shading algorithm. The correlation coefficients between the depth maps were within the range of 0.70-0.95 (P<0.05). A t-test was used for the statistical analysis.