Chapelle O, Haffner P, Vapnik V N
Speech and Image Processing Services Research Laboratory, AT&T Labs-Research, Red Bank, NJ 07701, USA.
IEEE Trans Neural Netw. 1999;10(5):1055-64. doi: 10.1109/72.788646.
Traditional classification approaches generalize poorly on image classification tasks, because of the high dimensionality of the feature space. This paper shows that support vector machines (SVM's) can generalize well on difficult image classification problems where the only features are high dimensional histograms. Heavy-tailed RBF kernels of the form K(x, y) = e(-rho)Sigma(i)/xia-yia/b with a < or = 1 and b < or = 2 are evaluated on the classification of images extracted from the Corel stock photo collection and shown to far outperform traditional polynomial or Gaussian radial basis function (RBF) kernels. Moreover, we observed that a simple remapping of the input x(i)-->x(i)(a) improves the performance of linear SVM's to such an extend that it makes them, for this problem, a valid alternative to RBF kernels.
由于特征空间的高维度,传统分类方法在图像分类任务上的泛化能力较差。本文表明,支持向量机(SVM)在仅以高维直方图为特征的困难图像分类问题上能够很好地泛化。对形式为K(x, y) = e(-rho)Sigma(i)/xia-yia/b且a <= 1和b <= 2的重尾径向基函数(RBF)核在从Corel图库照片集中提取的图像分类上进行了评估,结果显示其性能远优于传统多项式或高斯径向基函数(RBF)核。此外,我们观察到对输入x(i)-->x(i)(a)进行简单的重新映射可将线性支持向量机的性能提升到这样一种程度,即对于此问题,它成为了RBF核的有效替代方案。