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arXiv 2207.03427cs.ITcs.DSeess.SPmath.ITstat.ML

二进制迭代硬阈值法在1位压缩感知中以最优测量数收敛

Binary Iterative Hard Thresholding Converges with Optimal Number of Measurements for 1-Bit Compressed Sensing

Namiko Matsumoto, Arya Mazumdar

AI总结:

本文证明二进制迭代硬阈值算法在1位压缩感知中以最优测量数收敛,为非凸问题提供了有效解法。

摘要:

压缩感知是一种非常成功的高维信号获取和恢复技术,依赖于线性操作。然而,信号的实际测量必须在存储或处理前进行量化。1位压缩感知是压缩感知的强烈量化版本,其中每个信号的线性测量被简化为一个比特:测量的符号。一旦收集到足够的此类测量,1位压缩感知的恢复问题旨在尽可能准确地找到原始信号。该恢复问题与学习理论中的传统

英文摘要:

Compressed sensing has been a very successful high-dimensional signal acquisition and recovery technique that relies on linear operations. However, the actual measurements of signals have to be quantized before storing or processing. 1(One)-bit compressed sensing is a heavily quantized version of compressed sensing, where each linear measurement of a signal is reduced to just one bit: the sign of the measurement. Once enough of such measurements are collected, the recovery problem in 1-bit compressed sensing aims to find the original signal with as much accuracy as possible. The recovery problem is related to the traditional "halfspace-learning" problem in learning theory. For recovery of sparse vectors, a popular reconstruction method from 1-bit measurements is the binary iterative hard thresholding (BIHT) algorithm. The algorithm is a simple projected sub-gradient descent method, and is known to converge well empirically, despite the nonconvexity of the problem. The convergence property of BIHT was not theoretically justified, except with an exorbitantly large number of measurements (i.e., a number of measurement greater than $\max\{k^{10}, 24^{48}, k^{3.5}/ε\}$, where $k$ is the sparsity, $ε$ denotes the approximation error, and even this expression hides other factors). In this paper we show that the BIHT algorithm converges with only $\tilde{O}(\frac{k}ε)$ measurements. Note that, this dependence on $k$ and $ε$ is optimal for any recovery method in 1-bit compressed sensing. With this result, to the best of our knowledge, BIHT is the only practical and efficient (polynomial time) algorithm that requires the optimal number of measurements in all parameters (both $k$ and $ε$). This is also an example of a gradient descent algorithm converging to the correct solution for a nonconvex problem, under suitable structural conditions.

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