Akihiro SUGIMOTO
Projective Invariant of Lines on Adjacent Planar
Regions in a Single View
Abstract:The importance of projective invariants to many machine vision tasks such as model-based recognition has been recognized. A number of recent studies on projective invariants in a single view concentrate on coplanar objects: coplanar points, coplanar lines, coplanar points and lines, coplanar conics, etc. This paper presents a study on projective invariants of noncoplanar objects, i.e., 3-D objects. A new projective invariant is derived from five lines on two adjacent planar regions in a single view. The condition under which the invariant is nonsingular is also described. In addition, we present some experimental results with real images and find that the values of the invariant over a number of viewpoints remain stable even for noisy images and that a 3-D object has its own proper value of the invariant. Therefore, we no longer need assume coplanar objects. We can directly treat 3-D objects to calculate projective invariants.
Key Words: projective invariant, adjacent planar regions, nonsingularity, 3-D object recognition.