Differentiation-Based Edge Detection Using the Logarithmic Image Processing Model

The logarithmic image processing (LIP) model is a mathematical framework which provides a specific set of algebraic and functional operations for the processing and analysis of intensity images valued in a bounded range. The LIP model has been proved to be physically justified by that it is consistent with the multiplicative transmittance and reflectance image formation models, and with some important laws and characteristics of human brightness perception. This article addresses the edge detection problem using the LIP-model based differentiation. First, the LIP model is introduced, in particular, for the gray tones and gray tone functions, which represent intensity values and intensity images, respectively. Then, an extension of these LIP model notions, respectively called gray tone vectors and gray tone vector functions, is studied. Third, the LIP-model based differential operators are presented, focusing on their distinctive properties for image processing. Emphasis is also placed on highlighting the main characteristics of the LIP-model based differentiation. Next, the LIP-Sobel based edge detection technique is studied and applied to edge detection, showing its robustness in locally small changes in scene illumination conditions and its performance in the presence of noise. Its theoretical and practical advantages over several well-known edge detection techniques, such as the techniques of Sobel, Canny, Johnson and Wallis, are shown through a general discussion and illustrated by simulation results on different real images. Finally, a discussion on the role of the LIP-model based differentiation in the current context of edge detection is presented.     

基于视觉感知的图像放大

为了有效保持图像纹理细节和边界结构,提出了一种基于视觉感知的图像放大算法。构造了一类[C2]连续的双变量有理函数插值模型。根据等值线生成原理,利用等值线方法将图像自适应地划分为边缘区域和平滑区域。基于图像的区域特征,平滑区域采用多项式模型插值,边缘区域采用有理模型插值。根据人眼对比敏感特性,对边缘区域进行参数优化,从而获得高质量插值图像。与其他经典的图像放大方法相比,该方法能有效保持图像的纹理细节和边缘结构,同时获得了较好的客观评价数据。     

基于注意力多源理论的信息感知与处理过程模型

该文采用注意力“多源论”思想,提出了注意力资源分为动态资源和静态资源的构想;建立了基于总体效率最优原则的静态注意力资源的分配模型和动态注意力资源的功能结构模型;并在此基础上,提出了新的基于注意力多源理论的信息感知与处理过程模型,解决了现有同类模型所存在的问题;并针对该模型提出了基于特征匹配测度的信息隶属度模型,构造了基于信息类别隶属度、类别优先权系数及人的倾向性系数的信息重要性指数,实现了模型中基于信息重要性指数的信息选择.     

一种基于小波分析和人眼视觉特性的图像增强方法

在分析视觉系统特性的基础上，提出了一种基于小波分析的图像对比度增强算法。为降低对噪声增强程度，算法对不同尺度上的系数进行不同程度的对比度增强。在此过程中，算法考虑了视觉特性以得到更好的效果。为保证得到足够的对比度增强效果，算法首先对分解得到的尺度系数进行增强；为避免视觉明显的噪声放大，只对处于边缘区域的系数进行对比度拉伸；为了能在各尺度上较为准确地找出边缘区域，算法采用局部阈值技术并利用了各分解尺度上边缘区域的相关性；为降低视觉明显的噪声放大，不同区域的对比度增强程度决定于区域的亮度。算法的实验表明，上述特点使本文算法在充分增强对比度的同时，极大地降低了对噪声的过增强，具有较好的视觉效果。     

偏微分方程(PDEs)模型在图像处理中的若干应用

介绍了偏微分方程(PDEs)模型在图像处理与分析中的应用,基本思想,发展历史和解决问题的基本框架。主要阐述了变分方法和形变模型(曲线演化)在图像恢复和图像分割中的应用。理论和实验结果表明,应用偏微分方程模型进行图像处理是一种有效的工具。最后,分析了这种方法的优点和面临的挑战。