Sparse coding with an overcomplete basis set: A strategy employed by V1?
Sparse coding with an overcomplete basis set: A strategy employed by V1?
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DOI：
10.1016/s0042-6989(97)00169-7
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发表时间：
1997-12-01
期刊：
影响因子：
1.8
通讯作者：
Field, DJ
中科院分区：
文献类型：
--
作者：
Olshausen, BA;Field, DJ
哺乳动物纹状体皮层中简单细胞的空间感受野在生理上已经得到了合理的描述，并且可以被表征为局部化、定向和带通，与小波变换的基函数相当。以前，我们已经表明，这些感受野特性可以根据响应于自然图像产生稀疏分布的输出活动的策略来解释。除了以更广泛的方式描述这项工作之外，我们还研究了稀疏编码的神经生物学含义。特别感兴趣的是当编码过完整时的情况-即，当码元的数目大于输入空间的有效维数时，因为基函数是非正交的并且彼此不是线性独立的，所以稀疏化码将仅使用表示给定输入所必需的那些基函数，并且因此输入-输出函数将偏离纯线性，这些偏离线性提供了一个潜在的解释弱形式的非线性皮质简单细胞的响应特性中观察到的，他们进一步作出预测的预期相互作用的单位在响应自然刺激。(C)1997 Elsevier Science Ltd.
The spatial receptive fields of simple cells in mammalian striate cortex have been reasonably well described physiologically and can be characterized as being localized, oriented, and bandpass, comparable with the basis functions of wavelet transforms, Previously, we have shown that these receptive field properties may be accounted for in terms of a strategy for producing a sparse distribution of output activity in response to natural images, Here, in addition to describing this work in a more expansive fashion, we examine the neurobiological implications of sparse coding, Of particular interest is the case when the code is overcomplete-i.e., when the number of code elements is greater than the effective dimensionality of the input space, Because the basis functions are non-orthogonal and not linearly independent of each other, sparsifying the code will recruit only those basis functions necessary for representing a given input, and so the input-output function will deviate from being purely linear, These deviations from linearity provide a potential explanation for the weak forms of non-linearity observed in the response properties of cortical simple cells, and they further make predictions about the expected interactions among units in response to naturalistic stimuli. (C) 1997 Elsevier Science Ltd.