BMVC 2004, Kingston, 7th-9th Sept, 2004

Metrology from Vertical Objects
X. Cao and H. Foroosh (University of Central Florida, USA)

In this paper, we describe how 3D Euclidean measurements can be made
in a pair of perspective images, when only minimal geometric information
are available in the image planes. This minimal information consists of one
line on a reference plane and one vanishing point for a direction perpendicular
to the plane. Given these information, we show that the length ratio of two
objects perpendicular to the reference plane can be expressed as a function of
the camera principal point. Assuming that the camera intrinsic parameters remain
invariant between the two views, we recover the principal point and the
camera focal length by minimizing the symmetric transfer error of geometric
distances. Euclidean metric measurements can then be made directly from
the images. To demonstrate the effectiveness of the approach, we present the
processing results for synthetic and natural images, including measurements
along both parallel and non-parallel lines.
(pdf article)