Shape from shading and optical flow used for 3-dimensional reconstruction of endoscope image.

CONCLUSION The shape from shading and optical flow are implemented to three-dimensional (3D) reconstruction. OBJECTIVE Solve the problem of 3D reconstruction in endoscope imaging. METHOD One of the fundamental approaches in the domain of computer vision is shape from shading. This algorithm was proposed to obtain the shape of an object from a single intensity image. Because of the severe conditions are required in shape from shading to reconstruct 3D surface. The photometric calibration is proposed from the view of image processing. The calibration is important for illumination-based visualization techniques such as SFS (shape-from-shading). However, the surface reconstruction from SFS is the relative variation in the grey gradient field. So the change from relative variation to absolute variation is necessary when the actual size of surroundings has to be known. Then the optical flow is introduced to solve this change in the paper. The optical tracker is also used in this system to capture the pose of endoscopy. RESULT The stability of surface reconstruction is improved when the photometric calibration is used before shape from shading.