EXOTIC: External Vision-driven Incomplete Multi-view Classification

Due to sensor failures and occlusions during data acquisition, multi-view data often suffer from partial missing samples, thereby producing incomplete multi-view data. Recently, Incomplete Multi-View Classification (IMVC) has become one of the research hot topics, where numerous IMVC methods have been proposed. Although these methods have achieved promising performance by exploiting internal semantic information from partially observed data, they primarily rely on limited internal supervision for view completion. Clearly, this largely constrains their performance ceiling. To overcome this limitation, we propose an EXternal visiOn-driven incomplete mulTi-vIew Classification (EXOTIC) paradigm that incorporates external vision knowledge as semantic guidance, thereby assisting in imputing incomplete views. To the best of our knowledge, it is the first work that leverages external vision knowledge as supervision signals, thereby guiding missing-view completion. Specifically, we first introduce an external vision knowledge library based on a pre-trained vision-language model. Then, we design a Knowledge Filtering module to adaptively select task-relevant knowledge. Afterwards, we present a Knowledge Purification module to align external knowledge with internal representations. Finally, we propose External Completion that leverages the refined knowledge to impute missing views, thereby enhancing the classification decision ability. Extensive experiments on multiple incomplete multi-view datasets demonstrate that the proposed EXOTIC consistently outperforms existing methods, especially under high missing rates. The code is available at: https://github.com/sstaree/EXOTIC.