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An influence of the distance of measured points on results of Savitzky-Golay method of spectral contour differentiation was investigated. Some conclusions based on the differentiation of electronic absorption spectra with vibronic structure were formulated.     

Analysis of linearized version of active contours without gradient

This article details the linearization of the active contours without gradient model first developed by Tony Chan and Luminita Vese. The numerical discretization is presented with a discussion of consistency, stability and convergence, and the model is tested with several images. Results show that the convergence of the linear method is accurate, fast and robust in the presence of noise.     

Motion Geometric Active Contours： Tracking Nonrigid Objects in Clutter Background

MGAC (Motion Geometric Active Contours), a new variational framework of geometric active contours to track multiple nonrigid moving object‘s in the clutter background in image sequences is presented. This framework, incorporating with the motion edge information, consists of motion detection and tracking stages. At the motion detection stage, the motion edge map provides an approximate edge map of the moving objects. Then, a tracking stage, merely using thestatic edge information, is considered to improve the motion detection result. Force field regularization method is used to extend the capture range of the edge attraction force field in both stages.Experiments demonstrate that the proposed framework is valid for tracking multiple nonrigid objects in the clutter background.     

A non-circular iris localization algorithm using image projection function and gray level statistics

Iris recognition technology identifies an individual from its iris texture with great precision. A typical iris recognition system comprises eye image acquisition, iris segmentation, feature extraction, and matching. However, the system precision greatly depends on accurate iris localization in the segmentation module. In this paper, we propose a reliable iris localization algorithm. First, we locate a coarse eye location in an eye image using integral projection function (IPF). Next, we localize the pupillary boundary in a sub image using a reliable technique based on the histogram-bisection, image statistics, eccentricity, and object geometry. After that, we localize the limbic boundary using a robust scheme based on the radial gradients and an error distance transform. Finally, we regularize the actual iris boundaries using active contours. The proposed algorithm is tested on public iris databases: MMU V1.0, CASIA-IrisV1, and the CASIA-IrisV3-Lamp. Experimental results demonstrate superiority of the proposed algorithm over some of the contemporary techniques.     

复杂轮廓激光切割路径优化算法的研究

激光切割的加工路径优化问题实质上是如何缩短激光头在轮廓间移动的空行程距离.复杂轮廓的切割顺序的生成必须考虑轮廓的嵌套问题.本文以轮廓位置关系为约束条件,根据图论原理将加工路径优化问题归结为广义旅行商问题(GTSP).提出了先按照轮廓位置关系构造树形结构,然后以加工起点为基准点按照从内向外的顺序遍历树形结构的优化算法,并给出应用实例.实验统计表明,使用该算法可将激光头空行程距离减少10%以上,明显的提高了激光切割的效率和质量.     

RBF neural network and active circles based algorithm for contours extraction

For the contours extraction from the images, active contour model and self-organizing map based approach are popular nowadays. But they are still confronted with the problems that the optimization of energy function will trap in local minimums and the contour evolutions greatly depend on the initial contour selection. Addressing to these problems, a contours extraction algorithm based on RBF neural network is proposed here. A series of circles with adaptive radius and center is firstly used to search image feature points that are scattered enough. After the feature points are clustered, a group of radial basis functions are constructed. Using the pixels’ intensities and gradients as the input vector, the final object contour can be obtained by the predicting ability of the neural network. The RBF neural network based algorithm is tested on three kinds of images, such as changing topology, complicated background, and blurring or noisy boundary. Simulation results show that the proposed algorithm performs contours extraction greatly.     

一种等值线连通区域填充算法与程序设计

提出了一种等值线连通区域填充算法。该算法是依据追踪后的等值线曲线端点与区域边界的拓扑关系,程序自动建立一种适应于等值线连通区域搜寻的数据结构。在该数据结构信息的关联下,实现了用表达不同意义的颜色填充区域。由于该区域是一个由矢量化线段组成的区域,从而可以实现不同比例、不同方向的变换。为图形输出提供丰富的形式和图形文件保存节约了大量空间。该方法己在ＰＣ机和工作站上实现。     

基于改进蝙蝠算法的甲状腺SPECT-B超图像配准

为了提高甲状腺肿瘤检出的准确率.提出基于改进蝙蝠算法的甲状腺SPECT (single-photo emission computed tomogropby)-B超图像配准方法.针对甲状腺SPECT图像与B超图像灰度差异大,采用2类图像共有的甲状腺及肿瘤轮廓特征进行配准.采用阈值分割法提取SPECT图像中甲状腺及肿瘤轮廓;采用Shearlet变换与基于活动轮廓模型图割算法相结合的方法提取B超图像中甲状腺及肿瘤轮廓;以归一化互信息为相似性测度,以改进的蝙蝠算法为优化算法,优化配准所需的空间变换参数.实验结果表明,提取的B超图像中甲状腺及肿瘤轮廓更准确,改进的蝙蝠算法使配准具有更高的准确性和较好的鲁棒性.     

一种吹吸式排风罩的流场测试及数值模拟

采用计算流体动力学理论建立吹吸式排风罩流场的数学模型。通过数值解法，得出了流场内各点的流函数，从而绘制成等速度线图，实现这种吹吸式排风罩作用范围的预测。阐述了测试该流场所用的热球风速传感器微机采样系统的主要组成部分，标定原理和结果，利用该测试实例风速绘制的等速度线图与理论模拟得等速度线图进行了验证和对照，它们的作用范围是相符的，表明可以用不可压轴对称无旋流动的流函数方程来描述该吹吸流场。     

Affine Invariant Detection: Edge Maps, Anisotropic Diffusion, and Active Contours

In this paper we undertake a systematic investigation of affine invariant object detection and image denoising. Edge detection is first presented from the point of view of the affine invariant scale-space obtained by curvature based motion of the image level-sets. In this case, affine invariant maps are derived as a weighted difference of images at different scales. We then introduce the affine gradient as an affine invariant differential function of lowest possible order with qualitative behavior similar to the Euclidean gradient magnitude. These edge detectors are the basis for the extension of the affine invariant scale-space to a complete affine flow for image denoising and simplification, and to define affine invariant active contours for object detection and edge integration. The active contours are obtained as a gradient flow in a conformally Euclidean space defined by the image on which the object is to be detected. That is, we show that objects can be segmented in an affine invariant manner by computing a path of minimal weighted affine distance, the weight being given by functions of the affine edge detectors. The gradient path is computed via an algorithm which allows to simultaneously detect any number of objects independently of the initial curve topology. Based on the same theory of affine invariant gradient flows we show that the affine geometric heat flow is minimizing, in an affine invariant form, the area enclosed by the curve.