光电工程, 2011, 38 (4): 87, 网络出版: 2011-04-28
采用双树轮廓波及压缩传感的多聚焦图像融合
Multi-focus Image Fusion Using Dual-tree Contourlet and Compressed Sensing
多聚焦图像 图像融合 双树轮廓波 压缩传感 两步迭代收缩算法 multi-focus image image fusion dual-tree Contourlet compressed sensing two-step iterative shrinkage/threshold algorithm
摘要
为了拓展压缩传感(CS)的应用潜力,提出一种结合双树轮廓波(DT-Contourlet)及CS 的多聚焦图像融合方法。该方法首先采用DT-Contourlet 对源图像进行分解,提取图像的多尺度信息及方向信息,克服传统轮廓波变换不具平移不变性的缺点。接着,在DT-Contourlet 域,将分解系数看成包含稠密和稀疏两部分;对稠密成份,根据散焦的表现形式,采用邻域梯度作为清晰度指标,用选择法实现融合处理;对稀疏成份,则在CS 框架下,通过少数线性测量的融合,依据L1 范数最小化,采用两步迭代收缩的重构算法,得到融合结果。实验表明,该方法重构时收敛速度比正交匹配追踪法快,且融合结果无论在视觉质量及定量指标上都明显优于传统方法。
Abstract
In order to expand the capability of Compressed Sensing (CS), a fusion method for multi-focus image using Dual-tree Contourlet (DT-Contourlet) and CS is proposed. First, the source images are decomposed using DT-Contourlet for extracting multiscale and direction information while overcoming the limitation of traditional contourlet which is lack of shift invariance. Then, in DT-Contourlet domain, the decomposition coefficients are treated as containing two components, i.e., dense and sparse components. The dense components are fused using selection method by introducing neighborhood gradient as clarity index to indicate the characteristics of defocus. The sparse components are fused under the framework of CS via fussing a few linear measurements by solving the problem of L1 norm minimization which is based on a two-step iterative shrinkage/threshold reconstruction algorithm. The experiments demonstrate that the convergence rate of reconstruction is faster than that of orthogonal matching pursuit. Meanwhile, the proposed method provides more satisfactory fusion results in terms of visual quality and quantitative criterion.
金炜, 符冉迪, 叶明, 励金祥. 采用双树轮廓波及压缩传感的多聚焦图像融合[J]. 光电工程, 2011, 38(4): 87. JIN Wei, FU Ran-di, YE Ming, LI Jin-xiang. Multi-focus Image Fusion Using Dual-tree Contourlet and Compressed Sensing[J]. Opto-Electronic Engineering, 2011, 38(4): 87.