A snake-based approach to accurate determination of both contact points and contact angles
A snake-based approach to accurate determination of both contact points and contact angles
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DOI：
10.1016/j.colsurfa.2006.03.008
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发表时间：
2006-09-01
影响因子：
5.2
通讯作者：
Hoffmann, P.
中科院分区：
文献类型：
--
作者：
Stalder, A. F.;Kulik, G.;Hoffmann, P.
提出了一种基于B样条曲线（活动轮廓）的高精度接触角测量方法。在这种方法中，我们避免作出物理假设，定义为一个通用的B样条曲线的下降的轮廓。当有用时，我们通过镜像对称来扩展该曲线，以便我们可以利用液滴在基板上的反射来检测接触点的位置。为了保持广泛的适用性，我们避免离散化液滴的轮廓，并且我们选择优化高级图像能量项来驱动曲线的演变。这个术语有方向梯度和基于区域的组件;此外，另一个术语-内部能量-负责蛇的弹性和约束样条的参数化。在保持接触点精度的同时，我们通过约束控制点的非均匀重新划分来限制计算复杂度。蛇的弹性特性将接触角的局部性质与液滴的全局轮廓联系起来。对液滴轮廓的全面了解使我们能够利用液滴在基板上的反射来自动精确地检测接触点线（垂直位置和倾斜）。我们在液滴的图像上应用三次样条插值;然后，演化过程参与这个连续域以避免由像素化和离散化引入的不准确性。Stalder，DropSnake，生物医学成像组，EPFL，[在线]访问2005年。http://bigwww.epfl.ch/demo/dropanalysis].由于我们的高质量图像插值模型，我们的实验具有良好的准确性，同时由于我们先进的图像能量术语，它们显示出对各种图像的适用性。(c)2006 Elsevier B. V.保留所有权利。
We present a new method based on B-spline snakes (active contours) for measuring high-accuracy contact angles. In this approach, we avoid making physical assumptions by defining the contour of the drop as a versatile B-spline curve. When useful, we extend this curve by mirror symmetry so that we can take advantage of the reflection of the drop onto the substrate to detect the position of the contact points. To keep a wide range of applicability, we refrain from discretizing the contour of the drop, and we choose to optimize an advanced image-energy term to drive the evolution of the curve. This term has directional gradient and region-based components; additionally, another term-an internal energy-is responsible for the snake elasticity and constrains the parameterization of the spline. While preserving precision at the contact points, we limit the computational complexity by constraining a non-uniform repartition of the control points. The elasticity property of the snake links the local nature of the contact angle to the global contour of the drop. A global knowledge of the drop contour allows us to use the reflection of the drop on the substrate to automatically and precisely detect a line of contact points (vertical position and tilt). We apply cubic-spline interpolation over the image of the drop; then, the evolution procedure takes part in this continuous domain to avoid the inaccuracies introduced by pixelization and discretization.We have programmed our method as a Java software and we make it freely available [A.F. Stalder, DropSnake, Biomedical Imaging Group, EPFL, [ON LINE] visited 2005. http://bigwww.epfl.ch/demo/dropanalysis]. Our experiments result in good accuracy thanks to our high-quality image-interpolation model, while they show applicability to a variety of images thanks to our advanced image-energy term. (c) 2006 Elsevier B.V. All rights reserved.