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Direct Recovery of Shape From Multiple Views: A Parallax Based Approach
, 1994
"... Given two arbitrary views of a scene under central projection, if the motion of points on a parametric surface is compensated, the residual parallax displacement field on the reference image is an epipolar field. If the surface aligned is a plane, the parallax magnitude at an image point is directly ..."
Abstract

Cited by 76 (13 self)
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Given two arbitrary views of a scene under central projection, if the motion of points on a parametric surface is compensated, the residual parallax displacement field on the reference image is an epipolar field. If the surface aligned is a plane, the parallax magnitude at an image point is directly proportional to the height of the point from the plane and inversely proportional to its depth from the camera. We exploit the above theorem to infer 3D height information from oblique aerial 2D images. We use direct methods to register the aerial images, develop methods to infer heightinformation under the following three conditions: (i) focal length and image center are both known, (ii) only the focal length is known, and (iii) both are unknown. 1 Introduction Traditional methods in motion analysis have expressed the image motion of rigid bodies as a sum of two image displacement fields: a rotation field and a epipolar (translation) field. In this paper, wedevelop an alternative approac...
Shape Recovery From Multiple Views: A Parallax Based Approach
, 1994
"... Given two arbitrary views of a scene under central projection, if the motion of points on a parametric surface is compensated, the residual parallax displacement field on the reference image is an epipolar field. The parallax magnitude at a point, after suitable scaling, is an affine invariant# if t ..."
Abstract

Cited by 55 (5 self)
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Given two arbitrary views of a scene under central projection, if the motion of points on a parametric surface is compensated, the residual parallax displacement field on the reference image is an epipolar field. The parallax magnitude at a point, after suitable scaling, is an affine invariant# if the surface aligned is a plane, it is directly proportional to the height of the point from the plane and inversely proportional to its depth from the camera. We exploit the above result to infer 3D height information from oblique aerial 2D images. We use direct methods to register the aerial images, develop methods to infer height information under the following three conditions: (i) focal length and image center are both known, (ii) only the focal length is known, and (iii) both are unknown. Weusetheinvariance property of the scaled parallax magnitudes to combine multiple frame information to obtain accurate heights, and to extrapolate new views from a given set of views (i.e., in photogram...
Rectification for Any Epipolar Geometry
, 2001
"... This paper proposes a new approach to rectification, a process whereby a stereo pair of images is resampled so as to make imposing the two view geometric constraint simple. This is normally performed by applying a single linear transformation per image, a method which has the drawback that some cam ..."
Abstract
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This paper proposes a new approach to rectification, a process whereby a stereo pair of images is resampled so as to make imposing the two view geometric constraint simple. This is normally performed by applying a single linear transformation per image, a method which has the drawback that some camera motions produce rectified images which are heavily distorted or unbounded. More recent attempts have used nonlinear transformations to allow any camera motion, but as a consequence distort images so that matching features no longer look the same in both images. This work provides a hybrid linear/nonlinear method that greatly reduces this problem, and simplifies the technique. The technique also provides further improvements by selecting the rectifying transformation so as to minimise perspective effects between the images.