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Proceedings Paper

Evaluation Of Bi-Plane Radiographs By Epipolar Ray Correlation
Author(s): B. Drerup; W. Frobin; G. Haussler
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Paper Abstract

A problem in evaluating bi-plane radiographs is the determination of corresponding points. If the angle of convergence is small, this can be done by stereoscopic vision. In the case, when this angle is large and no stereoscopic vision is possible, epipolar rays may be used for supporting the image evaluation. The proposition of epipolar ray correlation is: corresponding image points lie on con-jugate epipolar rays emerging from centers in each of the two image planes. The conjugate rays intersect in the intersection line of the two image planes. For the construction of the epipolar rays different methods can be used: 1) - Mechanically, the epipolar rays can be represented by two threads, one for each radiograph. The correspondence of the threads, also when moved over the images, is established by a simple gear system. An apparatus based on this concept is shown. With this apparatus evaluations of radiographs can be done point by point. 2) - Electronically, the epipolar lines can be plotted by a computer on transparent paper, so that by contacting the radiographs with the drawn lines, again a point by point evaluation is possible. 3) - The epipolar rays can be generated and superimposed to the radiographs by means of the display-stereocomparator described in the paper of E. Hierholzer. As a stereoscopic vision is not possible in most cases of bi-plane radiographs, this device has to be used monocularly.

Paper Details

Date Published: 29 July 1980
PDF: 8 pages
Proc. SPIE 0166, NATO Symposium on Applications of Human Biostereometrics, (29 July 1980); doi: 10.1117/12.956946
Show Author Affiliations
B. Drerup, Orthopadische Universitatsklinik (R.F.A.)
W. Frobin, Orthopadische Universitatsklinik (R. F . A.)
G. Haussler, Orthopadische Universitatsklinik (R.F.A.)


Published in SPIE Proceedings Vol. 0166:
NATO Symposium on Applications of Human Biostereometrics
A. M. Coblentz; Robin E. Herron, Editor(s)

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