S. Liu, R. R. Martin, F. C. Langbein, P. L. Rosin.
Int. J. CAD/CAM, 7(4), 2007.
ISSN 15981800.
Reverse engineering of reliefs aims to turn an existing relief superimposed on an underlying surface into a geometric model which may be applied to a different base surface. Steps in this process include segmenting the relief from the background, and describing it as an offset height field relative to the underlying surface. We have previously considered relief segmentation using a geometric snake. Here, we show how to use this initial segmentation to estimate the background surface lying under the relief, which can be used (i) to refine the segmentation and (ii) to express the relief as an offset field. Our approach fits a B-spline surface patch to the measured background data surrounding the relief, while tension terms ensure this background surface smoothly continues underneath the relief where there are no measured background data points to fit. After making an initial estimate of relief offset height everywhere within the patch, we use a support vector machine to refine the segmentation. Tests demonstrate that this approach can accurately model the background surface where it underlies the relief, providing more accurate segmentation, as well as relief height field estimation. In particular, this approach provides significant improvements for relief concavities with narrow mouths and can segment reliefs with small internal holes.
@ARTICLE{Liu2007b,
author = {Shenglan Liu and Ralph R. Martin and Frank C.
Langbein and Paul L. Rosin},
title = {Background surface estimation for reverse
engineering of reliefs},
journal = {Int. J. CAD/CAM},
year = 2007,
volume = 7,
number = 1,
issn = 15981800,
url = {http://www.langbein.org/research/surfaces/reliefs/liu2007b/},
abstract = {Reverse engineering of reliefs aims to turn an
existing relief superimposed on an underlying
surface into a geometric model which may be applied
to a different base surface. Steps in this process
include segmenting the relief from the background,
and describing it as an offset height field relative
to the underlying surface. We have previously
considered relief segmentation using a geometric
snake. Here, we show how to use this initial
segmentation to estimate the background surface
lying under the relief, which can be used (i) to
refine the segmentation and (ii) to express the
relief as an offset field. Our approach fits a
B-spline surface patch to the measured background
data surrounding the relief, while tension terms
ensure this background surface smoothly continues
underneath the relief where there are no measured
background data points to fit. After making an
initial estimate of relief offset height everywhere
within the patch, we use a support vector machine to
refine the segmentation. Tests demonstrate that this
approach can accurately model the background surface
where it underlies the relief, providing more
accurate segmentation, as well as relief height
field estimation. In particular, this approach
provides significant improvements for relief
concavities with narrow mouths and can segment
reliefs with small internal holes.},
}
Background Surface Estimation for Reverse Engineering of Reliefs,http://www.langbein.org/research/manifolds/reliefs/liu2007b/ by Frank C Langbein [27/October/2008, 21:38].
Copyright © 1995-2012, Frank C Langbein.
Except where otherwise stated, this web site, Ex Tenebris Scientia, by Frank C Langbein is licensed under a Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License.
