1. INTRODUCTION
In the era of big data, the presence of multiple modalities in data is prevalent [1], [2], [3], [4]. However, it is common for data to be missing during the data collection process [5]. As depicted in Fig. 1(a) and Fig. 1(b), two common types of missing data patterns can be observed [6], [7], [8]. One type is charac-terized by many instances containing all views, while some instances have only one view. The other type involves randomly missing views. Therefore, a number of algorithms for incomplete multiview representation learning (IMRL) have been proposed to learn consistent representations in the presence of missing views [9], [10].