Shape from shading and optical flow used for 3-dimensional reconstruction of endoscope image.
CONCLUSIONS
The shape from shading and optical flow are implemented to three-dimensional (3D) reconstruction.


OBJECTIVE
Solve the problem of 3D reconstruction in endoscope imaging.


METHODS
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.


RESULTS
The stability of surface reconstruction is improved when the photometric calibration is used before shape from shading.
a Department of Otolaryngology Head and Neck Surgery , Chinese PLA General Hospital , Beijing , PR China.
Lei
L
Lei
a Department of Otolaryngology Head and Neck Surgery , Chinese PLA General Hospital , Beijing , PR China.
Jianhui
J
Li
b School of Optoelectronics , Beijing Institute of Technology , Beijing , PR China.
Meiqing
M
Liu
b School of Optoelectronics , Beijing Institute of Technology , Beijing , PR China.
Xiaoming
X
Hu
b School of Optoelectronics , Beijing Institute of Technology , Beijing , PR China.
Ya
Y
Zhou
a Department of Otolaryngology Head and Neck Surgery , Chinese PLA General Hospital , Beijing , PR China.
Shiming
S
Yang
D000465:Algorithms; D004724:Endoscopy; D021621:Imaging, Three-Dimensional / Q000379:methods*
3D reconstruction; optical flow; photometric calibration; shape from shading