摘要
在传统有理插值函数的基础上构造出一种新的混合插值模型.该混合插值模型是有理函数与分形插值函数的有机整体,可由形状参数和尺度因子唯一确定.由于分形是刻画图像复杂度的有效工具,引入分形维数描述纹理的复杂程度.首先,提出一种基于局部分形维数的自适应阈值选取的方法,将整幅图像划分为纹理区域和非纹理区域.在纹理区域采用有理分形函数插值,在非纹理区域采用有理函数插值.尤其在有理分形插值模型中,提出一种基于分形维数的精确计算尺度因子的方法.最后,通过优化形状参数进一步提高插值图像质量.实验结果表明:提出的基于图像特征的混合插值模型与当前经典算法相比,尤其是在处理纹理图像方面,具有明显优势.
A new interpolation model is proposed based on the bivariate rational interpolation. This model contains rational fractal interpolation and bivariate rational interpolation, which is identified uniquely by the values of iterated function system parameters （scaling factor and shape parameters）. Due to efficient capacity of fractal in description of complex phenomenon, the fractal dimension is employed to texture analysis. Based on the analysis of local fractal dimension （LFD）,a new local adaptive threshold method is proposed. And then images can be divided into texture region and non-texture region. As for texture regions, rational fractal interpolation is used to get high resolution images. Similarly, rational interpolation is used in non-texture region. Considering the parameters in rational fractal interpolation model,we propose a new method for calculating the scaling factor.Further, in order to improve the quality of interpolated image, shape parameters optimization technique is applied. Experimental results show that the presented model achieves very competitive performance with the state-of-the-art interpolation algorithms.
出处
《计算机研究与发展》
EI
CSCD
北大核心
2017年第9期2077-2091,共15页
Journal of Computer Research and Development
基金
国家自然科学基金项目(61373080
61672018
61402261
61373088
61272431
61332015)
山东省高等学校优势学科人才团队培育计划~~
关键词
混合插值
局部分形维数
自适应阈值
参数优化
有理分形
mixing interpolant
local fractal dimension
adaptive threshold
parameters optimizing
rational fractal
