3-D optic disk reconstruction from low-resolution stereo images based on combined registrations and sub-pixel matching

Three dimensional (3-D) visualization of optic disk surface is very useful for clinical application. It allows clinicians to measure the disk parameters more accurately and thus make the diagnosis easier. This work describes an automated 3-D optic disk reconstruction method from a pair of stereo images for which efficient steps including sparse-image registration, and dense-depth recovery are used. A combination of two registration methods is used to detect the sub-pixel correspondences. The proposed method takes the advantages of both the correlation method which is robust to noise and the feature based method on its accuracy. Only sparse match points are computed to speed up the processing and the sub-pixel matching is used to overcome the problem of low resolution in the image. This is followed by the cubic interpolation to obtain the dense depths. The result is then smoothed and displayed as the final 3-D shape.