Affine hull

Discrete mathematics

Pattern recognition (psychology)

Metric (unit)

Pure mathematics

Mathematics

Kernel (algebra)

Reproducing kernel Hilbert space

Politics

Gene

Support vector machine

Kernel method

Mathematical analysis

Political science

Artificial intelligence

Economics

Affine space

Set (abstract data type)

Chemistry

Programming language

Operations management

Representation (politics)

Computer science

Biochemistry

Hilbert space

Robustness (evolution)

Affine transformation

IEEE Transactions on Neural Networks and Learning Systems

With the rapid advances in digital imaging and communication technologies, recently image set classification has attracted significant attention and has been widely used in many real-world scenarios. As an effective technology, the class-specific representation theory-based methods have demonstrated their superior performances. However, this type of methods either only uses one gallery set to measure the gallery-to-probe set distance or ignores the inner connection between different metrics, leading to the learned distance metric lacking robustness, and is sensitive to the size of image sets. In this article, we propose a novel joint metric learning-based class-specific representation framework (JMLC), which can jointly learn the related and unrelated metrics. By iteratively modeling probe set and related or unrelated gallery sets as affine hull, we reconstruct this hull sparsely or collaboratively over another image set. With the obtained representation coefficients, the combined metric between the query set and the gallery set can then be calculated. In addition, we also derive the kernel extension of JMLC and propose two new unrelated set constituting strategies. Specifically, kernelized JMLC (KJMLC) embeds the gallery sets and probe sets into the high-dimensional Hilbert space, and in the kernel space, the data become approximately linear separable. Extensive experiments on seven benchmark databases show the superiority of the proposed methods to the state-of-the-art image set classifiers.

Joint Metric Learning-Based Class-Specific Representation for Image Set Classification