论文标题
更快的二进制嵌入式用于保存欧几里得距离
Faster Binary Embeddings for Preserving Euclidean Distances
论文作者
论文摘要
我们提出了一种快速,远距离的二进制嵌入算法,以将高维数据集转换为$ \ Mathcal {t} \ subseteq \ mathbb {r}^n $中的二进制序列中的二进制序列。当$ \ Mathcal {t} $由良好的(即非sparse)向量组成时,我们的嵌入方法将稳定的噪声量化方案应用于$ a x $,其中$ a \ in \ mathbb {r}^r}^r}^{m \ times n} $是一个稀疏的高斯随机矩阵。这与大多数二进制嵌入方法形成对比,这些方法通常使用$ x \ mapsto \ mathrm {sign}(ax)$作为嵌入。此外,我们表明$ \ Mathcal {t} $元素之间的欧几里得距离是由$ \ ell_1 $ norm近似于$ \ {\ pm pm 1 \}^m $在快速线性转换下的图像上的。这再次与标准方法形成鲜明对比,而标准方法则使用了锤距。我们的方法既快速又有效,随着时间复杂性$ O(M)$和空间复杂性$ O(M)$。此外,我们证明该方法是准确的,其相关误差与连续有价值的Johnson-Lindenstrauss嵌入以及量化错误的误差相当,该误差接收多项式衰减,因为嵌入尺寸$ m $增加。因此,实现所需精度所需的二进制代码的长度很小,我们表明它甚至可以进一步压缩,而不会损害准确性。为了说明我们的结果,我们在自然图像上测试了提出的方法,并表明其实现了强劲的性能。
We propose a fast, distance-preserving, binary embedding algorithm to transform a high-dimensional dataset $\mathcal{T}\subseteq\mathbb{R}^n$ into binary sequences in the cube $\{\pm 1\}^m$. When $\mathcal{T}$ consists of well-spread (i.e., non-sparse) vectors, our embedding method applies a stable noise-shaping quantization scheme to $A x$ where $A\in\mathbb{R}^{m\times n}$ is a sparse Gaussian random matrix. This contrasts with most binary embedding methods, which usually use $x\mapsto \mathrm{sign}(Ax)$ for the embedding. Moreover, we show that Euclidean distances among the elements of $\mathcal{T}$ are approximated by the $\ell_1$ norm on the images of $\{\pm 1\}^m$ under a fast linear transformation. This again contrasts with standard methods, where the Hamming distance is used instead. Our method is both fast and memory efficient, with time complexity $O(m)$ and space complexity $O(m)$. Further, we prove that the method is accurate and its associated error is comparable to that of a continuous valued Johnson-Lindenstrauss embedding plus a quantization error that admits a polynomial decay as the embedding dimension $m$ increases. Thus the length of the binary codes required to achieve a desired accuracy is quite small, and we show it can even be compressed further without compromising the accuracy. To illustrate our results, we test the proposed method on natural images and show that it achieves strong performance.