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arXiv 1704.04511cs.CV
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用结构化低秩矩阵完备法恢复阻尼指数

Recovery of damped exponentials using structured low rank matrix completion

University of Iowa(爱荷华大学)

Arvind Balachandrasekaran, Vincent Magnotta, Mathews Jacob

摘要:

我们引入了一个结构化的低秩矩阵完成算法来恢复一系列的图像,从他们的欠采样测量,在每个像素沿参数维的信号是由指数的线性组合来描述。我们利用信号在每个像素处的指数行为,以及指数参数的空间平滑性来导出傅立叶域中的湮灭关系。这种关系转化为从傅立叶样本构造的结构化矩阵上的低秩属性。在恢复图像之前,我们将结构矩阵的低秩属性作为正则化。由于直接使用当前的低秩矩阵恢复计划,这个问题与高的计算复杂性和内存需求,我们采用了迭代重加权最小二乘(IRLS)算法,这有利于开发的卷积结构的矩阵。引入二维的快速傅里叶变换(FFT)的新近似,大大降低了内存需求和计算复杂性,有利于将结构化低秩方法推广到大规模三维问题。我们证明了我们的算法在MR参数映射设置和显示改进的国家的最先进的方法。

英文摘要:

We introduce a structured low rank matrix completion algorithm to recover a series of images from their under-sampled measurements, where the signal along the parameter dimension at every pixel is described by a linear combination of exponentials. We exploit the exponential behavior of the signal at every pixel, along with the spatial smoothness of the exponential parameters to derive an annihilation relation in the Fourier domain. This relation translates to a low-rank property on a structured matrix constructed from the Fourier samples. We enforce the low rank property of the structured matrix as a regularization prior to recover the images. Since the direct use of current low rank matrix recovery schemes to this problem is associated with high computational complexity and memory demand, we adopt an iterative re-weighted least squares (IRLS) algorithm, which facilitates the exploitation of the convolutional structure of the matrix. Novel approximations involving two dimensional Fast Fourier Transforms (FFT) are introduced to drastically reduce the memory demand and computational complexity, which facilitates the extension of structured low rank methods to large scale three dimensional problems. We demonstrate our algorithm in the MR parameter mapping setting and show improvement over the state-of-the-art methods.

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