【作者】 崔莉；

【导师】 曹军；

【作者基本信息】 东北林业大学 ， 控制理论与控制工程， 2010， 硕士

【摘要】 随着木材科学的发展,通过计算机图像处理技术对木材细胞进行分析已成为当今木材研究的一个重要方向。木材细胞图像中的边缘信息是极为有用的,它是进行细胞图像分割的基础,是反映木材性质重要参数分析的一种快速准确技术环节。本文从传统常用的边缘检测算子的原理入手,对木材细胞图像进行了边缘检测。传统的边缘检测算子大都是基于边缘的灰度不连续性利用梯度局部最大值或二阶导数过零点来检测边缘,容易受噪声干扰；Canny算子计算量大,定位不够精确。基于小波变换的多尺度边缘检测方法弥补了上述不足。根据边缘检测的评价标准,参照最佳边缘滤波器的设计要求,确定用于边缘检测的小波基函数的一般准则,得出“最佳”边缘检测小波,即二次B样条小波。文中说明了二次样条小波边缘检测算子的优越性,并从数学表达式上推导出二次样条小波是基于Canny最优准则的边缘检测算子。接下来,我们用二次样条作为小波函数,根据小波变换的木材细胞图像边缘检测原理,采用基于二次样条小波快速多尺度的边缘检测算法。应用此算法对各种木材细胞显微图像进行多尺度边缘检测,其仿真结果比经典的边缘检测算法有明显的改善,得到较好的边缘检测效果,但也存在不完善之处。最后,本文提出一种基于图像融合的边缘检测算法。首先对源图像进行小波分解,在不同分解层用小波模极大值法对高频子图像进行边缘检测,用数学形态学对低频子图像进行边缘检测,然后采用一定的融合规则将这两个边缘检测图像融合在一起。实验结果表明,这种方法优于单独使用小波模极大值法或数学形态学法,对噪声具有很好的鲁棒性,得到的图像边缘连续、清晰。更多还原

【Abstract】 Along with the developing of wood science, it has become an important direction of wood research to analysis wood cell by Computer Image Processing. The edge information of cell image is very useful, which is the basis of cell image segment and an accurate approach of all important parameters to reflect wood’s property.In this paper, we introduce the application of some typical image edge detection algorithm, and then determine the methods adapting to wood cell image edge detection. Mostly, traditional arithmetic of image edge detection distill edge using gradient maximum or zero-crossing which base on gray discontinuousness on edge. They are affected easily by noise. Canny arithmetic has shortcomings such as big computing and confirming positions inaccur-ately. Image edge detection based on multi-resolution wavelet transform makes up these shortages before.According to the criterion of edge detection and consulting the design-aim of optimal edge-filter, we come out with the best edge detection wavelet, namely Quadratic B-Spline wavelet. We not only illustrate the superiority of quadratic spline wavelet edge detection’s arithmetic, but also prove quadratic spline wavelet are optimum edge detection’s arithmetic based on Canny optimum criterions of edge detection.Then, according to the application of wavelet transform in wood cell image edge detection, we define quadratic spline as wavelet and put forward the principle of quadratic B-Spline wavelet multi-scale quick edge detection algorithm. Application of the algorithm of the microscopic image of wood cells multi-scale edge detection, the results show that they are improver than traditional edge detection algorithm and get good edge detection effect, but also exist imperfections.In the last, an edge detection algorithm based on image fusion is proposed. Firstly, the source image is decomposed by wavelet, using wavelet modulus maxima algorithm extracts edges in high-frequency images on the different levels and using mathematical morphological method extracts edges in low-frequency image, then the two edge images are fused according to some fusion rules. The experimental results show that the approach is superior to wavelet modulus maxima algorithm or mathematical morphological method alone and is good robust to noise and the edge is consecutive and clear.更多还原