“…Most of the existing DA methods are designed for the homogeneous scenario [2,3,10,21], where the cross-domain features are of the same type. More recently, Heterogeneous Domain Adaptation (HDA) is proposed, where the cross-domain features can be represented by different types of features from various modalities [19,20,38,40,43]. Existing HDA methods can be roughly categorized as supervised [9,14,17,31] or semi-supervised methods [4,18,19,40,42].…”