Twisted Cubic: Degeneracy Degree and Relationship with General Degeneracy

Fundamental matrix, drawing geometric relationship between two images, plays an important role in 3-dimensional computer vision. Degenerate configurations of space points and two camera optical centers affect stability of computation for fundamental matrix. In order to robustly estimate fundamental matrix, it is necessary to study these degenerate configurations. We analyze all possible degenerate configurations caused by twisted cubic and give the corresponding degenerate rank for each case. Relationships with general degeneracies, the previous ruled quadric degeneracy and the homography degeneracy, are also reported in theory, where some interesting results are obtained such as a complete homography relation between two views. Based on the result of the paper, by applying RANSAC for degenerate data, we could obtain more robust estimations for fundamental matrix.