共查询到18条相似文献,搜索用时 78 毫秒
1.
针对导致自适应光学视网膜图像降质退化的原因,提出了一种结合双树复数小波变换(DTCWT)和图像半盲解卷积复原算法的方法。首先,对经过自适应光学实时校正技术得到的视网膜图像进行DT-CWT分解,得到低频和高频部分应的图像。将自适应光学成像系统中残余像差重建的光学传递函数作为图像复原模型的初始估计点扩散函数(PSF),并对低频部分图像进行条件约束的迭代半盲解卷积复原;对高频部分的图像进行去噪处理。最后,将处理后的高频和低频部分图像进行双树复数小波逆变换,获得复原图像。实验和结果表明:由该方法处理的视网膜细胞图像质量得到明显提高,图像客观质量评价参数相对于原始图像提高了5倍多;在视网膜细胞的空间频率范围内(70~90(°)~1),复原图像功率谱平均值提高了5倍左右,有助于对视网膜细胞的高分辨率观察。 相似文献
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传统的图像复原一般认为点扩散函数(PSF)是空间不变的,实际光学系统由于受到像差等因素的影响,并非严格的线性空间不变系统,基于空间变化PSF的非盲去卷积图像复原法逐渐体现其优越性。空间变化PSF的非盲去卷积图像复原法先准确估计图像空间变化的PSF,再利用非盲去卷积算法对图像进行复原,有利于恢复出高质量图像。本文从算法的角度综述了近几年提出的基于空间变化PSF的非盲去卷积图像复原方法,并对比了基于强边缘预测估计PSF的非盲去卷积法、基于模糊噪声图像对PSF估计非盲去卷积法等算法的优缺点,各算法分别在PSF估计精确度、振铃效应抑制效果、适用范围等方面体现出各自的优劣。空间变化PSF的非盲去卷积图像复原法的研究,有利于推进图像复原技术向更高水平发展,使光学系统往轻小型化方向发展,从而在多个科学领域发挥其重要作用。 相似文献
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为解决大气湍流造成的图像退化问题,本文鉴于现有的盲解卷积算法收敛性不稳定,计算量大等特点,提出了一种基于加权预测的迭代盲解卷积算法。对目前性能优秀的用迭代实现盲解卷积的L-R算法进行优化,在每次迭代结束后通过加权方法求出预测值,根据预测值计算方向加速算子,从而大大提高算法的收敛速度。实验表明:该算法不仅可对模糊退化图像进行很好的复原,同时与L-R算法相比收敛速度提高约43.8倍,其迭代速度快的特点决定了算法具有较高的工程实用价值。 相似文献
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多帧盲解卷积图像复原技术能够进一步提高自适应光学图像的分辨力,但其算法比较复杂,处理耗时过长,对序列图像复原经常需要几分钟甚至几十分钟的计算时间,对实际应用造成了极大不便。为了提升算法的运行速度,改善其耗时过长的问题,通过研究和分析盲解卷积算法原理和算法结构,采用目前高速发展的中央处理器(CPU)和图形处理器(GPU)异构加速技术,主要对耗时最长的矩阵卷积运算进行优化,通过使用库函数与算法结构微调相结合的方法并行加速,实现多帧盲解卷积的图像复原算法的并行化。使用并行算法对图像进行复原处理,针对16帧以上分辨率为256256像素的空间目标图像,可以实现17的加速比,为图像复原的实时/准实时提供一种可行的方案。 相似文献
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为了提高外场实验中远距离测量激光光斑位置的精度,提出利用盲解卷积技术对光斑图像进行事后复原来削弱大气湍流对光斑成像的影响。首先,介绍了经典盲解卷积算法,分析了其不足之处,并提出了一种改进的盲解卷积算法。为了提高目标函数的收敛性和收敛速度,在TV(Total Variation)目标函数加入惩罚项,并对交替迭代法进行改进。然后,用数学方法证明了改进的盲解卷积算法的收敛性。最后,进行了仿真实验。与传统算法相比,用改进算法恢复的图像信噪比至少提升了15%。文中给出了外场试验图像的实际复原效果。 相似文献
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在Poisson和Markov随机场分布假设基础上,改进了存在噪声时多通道互限制原则,提出了一种基于最大后验概率判据的多通道图像盲复原算法,可在无需已知通道内离散点扩散函数性质、类型和具体分布等先验知识的情况下,在图像幅度限制约束空间和离散点扩散函数能量恒定约束空间内,通过对图像和离散点扩散函数的交替迭代,使两者收敛到全局最优解,最终复原出超分辨率图像.对计算机模拟和实际存在微平移、微离焦情况的图像处理表明:算法在不同信噪比水平和非命中PSF尺寸下具有良好的图像复原效果和稳定性.
关键词:
泊松-马尔科夫分布
最大后验概率
多通道
盲复原 相似文献
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谱域光学相干层析(spectral domain optical coherence tomography, 简记为SD-OCT)系统的轴向点扩散函数(point spread function, 简记为PSF)并不具备空不变特性,无法直接应用于解卷积运算.为实现SD-OCT系统成像质量基于解卷积算法的优化,本文采用数值校正后的轴向扫描信号和轴向有效PSF来实施基于Lucy-Richardson算法的解卷积运算,进而实现了SD-OCT系统中图像质量尤其是轴向分辨率的改善.本文理论分析了SD-OCT系统中导致轴向有效PSF随成像深度增大而下降和图像模糊的因素,阐述了利用解卷积算法实现图像质量优化的过程,基于建立的SD-OCT系统实施了不同成像深度位置处PSF的标定,并利用离散轴向位置处PSF的峰值拟合了轴向有效PSF的调制函数.利用调制函数对所有轴向扫描信号进行数值校正,然后根据轴向有效PSF进行解卷积算法.典型样品的解卷积图像重建结果表明,提出的解卷积方法能有效提高系统的轴向分辨率,同时有效抑制系统灵敏度随成像深度增大而下降的趋势.
关键词:
谱域光学相干层析
Lucy-Richardson解卷积
有效点扩散函数 相似文献
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提出了一种新的适用于移变降质图像复原的算法——能量约束自适应迭代复原.算法采用能量约束复原的空域迭代形式,使其能够用于处理光学像差引起的移变降质复原问题;以局部能量约束取代总体能量约束,使算法具有空间自适应特性;并采用双通道处理方法,消除能量约束带来的图像亮度衰减,同时抑制图像边界截断引起的振荡波纹.场曲复原仿真实验结... 相似文献
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Lu W 《Optics letters》2006,31(12):1839-1841
A novel algorithm for blind image deconvolution using the zero-lag slice (ZLS) of higher-order statistics only is presented. This method first estimates the point-spread function (PSF) using the ZLS of its third-order moment (TOM) and then uses it with one of the known classical image deconvolution methods. The proposed method has simple computations for PSF estimation because it solves a nonlinear problem by using an iterative method with fast convergence. In each iteration, one need only calculate the ZLS of the TOM and estimate the PSF using simple two-dimensional operations. Furthermore, the method presented achieves good results, since the ZLS estimate obtained from the degraded image exhibits high reliability. The good performance of the proposed algorithm is demonstrated by applying it to synthetic and real data sets. 相似文献
12.
Dongfeng ShiChengyu Fan Hong ShenPengfei Zhang Jinghui ZhangChunhong Qiao Yingjian Wang 《Optics Communications》2012,285(24):4937-4940
A new single-frame blind deconvolution algorithm for the linear shift-invariant imaging system is presented. The algorithm processes the partial images segmented from one single degraded image by multi-frame approach to recover the point spread function (PSF). Then a deconvolution method is employed to restore the whole image with the recovered PSF. In addition, in order to improve the fidelity and resolution of the recovered PSF, the coprimeness of the partial images is utilized. Results of simulated and real atmospheric turbulence degraded images using the algorithm are reported. 相似文献
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Blind deconvolution: multiplicative iterative algorithm 总被引:2,自引:0,他引:2
A new algorithm has been developed for performing blind deconvolution on degraded images. The algorithm naturally preserves the nonnegative constraint on the iterative solutions of blind deconvolution and can produce a restored image of high resolution. Furthermore, benefiting from the multiplicative form, the algorithm is free from the instability of numerical computation. Results of applying the algorithm to simulated and real degraded images are reported. 相似文献
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Restoration of atmospheric turbulence degraded images 总被引:2,自引:0,他引:2
Dongfeng Shi Hong Shen Pengfei Zhang Chunhong Qiao Xiaoxing Feng Yingjian Wang 《Optics Communications》2011,284(24):5556-5561
A blind image deconvolution algorithm in the frequency domain is proposed which uses the edge-preserving method and generic bandwidth of optical system. Generic bandwidth of optical system is analyzed. With the benefits of bandwidth and edge-preserving method as compelling constraints, the algorithm cannot only suppress noise effectively but also restrict the bandwidth of point-spread function (PSF), so high-quality result can be obtained. The new algorithm is superior in handling unregistered channels. The performance of this approach is investigated with simulated data. As shown in our investigation, the algorithm can significantly alleviate the artifacts produced by the deconvolution process. 相似文献
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This paper proposes a new blind deconvolution method with additional phase spectral constraints for a blurred image. A degradation
of an original image is mathematically modeled by a convolution of an original image and a point-spread function (PSF). The
proposed method consists of the following three steps: (i) projection onto a complex set satisfying the phase spectral constraint
in a frequency space; (ii) minimization of a cost function preserving the constrained phase spectra; and (iii) projection
onto an image space satisfying nonnegative and support constraints. This method restores both the original image and the PSF
with high accuracy. The effectiveness of the proposed method is verified by applying it to some blind deconvolution problems
for digital images, and the experimental results show that the performance is superior to the conventional blind deconvolution
methods. 相似文献
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Although the use of blind deconvolution of image restoration is a widely known concept, only few reports have discussed in
detail its application to solving problem of restoration of underwater range-gated laser images. A comparative study of underwater
image restoration using the Richardson-Lucy algorithm, the least-squares algorithm, and the multiplicative iterative algorithm
for blind deconvolution is presented. All the deconvolution approaches use denoised underwater images and Wells’ small angle
approximation theory of derived point spread function as the initial object and degradation guess, respectively. Owing the
underwater no-reference imaging environment, image quality judgment based on the blur metric method is incorporated in our
comparison to determine the appropriate deconvolution iteration number for each algorithm, which objectively evaluates the
image restoration results. The performance of the three algorithms applied to underwater image restoration is discussed and
reported. 相似文献
18.
谱域光学相干层析(spectral domain optical coherence tomography, 简记为SD-OCT)系统的轴向点扩散函数(point spread function, 简记为PSF)并不具备空不变特性,无法直接应用于解卷积运算.为实现SD-OCT系统成像质量基于解卷积算法的优化,本文采用数值校正后的轴向扫描信号和轴向有效PSF来实施基于Lucy-Richardson算法的解卷积运算,进而实现了SD-OCT系统中图像质量尤其是轴向分辨率的改善.本文理论分析了SD-OCT系统中导致轴向有效PSF随成像深度增大而下降和图像模糊的因素,阐述了利用解卷积算法实现图像质量优化的过程,基于建立的SD-OCT系统实施了不同成像深度位置处PSF的标定,并利用离散轴向位置处PSF的峰值拟合了轴向有效PSF的调制函数.利用调制函数对所有轴向扫描信号进行数值校正,然后根据轴向有效PSF进行解卷积算法.典型样品的解卷积图像重建结果表明,提出的解卷积方法能有效提高系统的轴向分辨率,同时有效抑制系统灵敏度随成像深度增大而下降的趋势. 相似文献