SpeechCLIP+: Self-supervised multi-task representation learning for speech via CLIP and speech-image data
Hsuan-Fu Wang, Yi-Jen Shih, Heng-Jui Chang, Layne Berry, Puyuan Peng, Hung-yi Lee, Hsin-Min Wang, David Harwath
TL;DR
This work addresses how to further improve self-supervised speech representations through visual grounding by introducing CIF-based dynamic keyword segmentation and a hybrid multi-task framework that merges cascaded and parallel SpeechCLIP architectures. CIF enables monotonic, flexible subword segmentation and a trainable $L_{QUA}$ objective, while the Cascaded+ and Hybrid SpeechCLIP+ designs merge subword-level and utterance-level cues for improved speech-to-image alignment. Empirical results on Flickr8k and SpokenCOCO show that CIF-based cascaded models reduce keyword duplicates and improve word/BPE extraction, and that joint multi-task training boosts image-speech retrieval performance in certain settings, with some dataset-dependent variations. Overall, the paper demonstrates that combining monotonic segmentation with multi-task learning can enhance subword-level representations and cross-modal alignment in visually grounded speech systems.
Abstract
The recently proposed visually grounded speech model SpeechCLIP is an innovative framework that bridges speech and text through images via CLIP without relying on text transcription. On this basis, this paper introduces two extensions to SpeechCLIP. First, we apply the Continuous Integrate-and-Fire (CIF) module to replace a fixed number of CLS tokens in the cascaded architecture. Second, we propose a new hybrid architecture that merges the cascaded and parallel architectures of SpeechCLIP into a multi-task learning framework. Our experimental evaluation is performed on the Flickr8k and SpokenCOCO datasets. The results show that in the speech keyword extraction task, the CIF-based cascaded SpeechCLIP model outperforms the previous cascaded SpeechCLIP model using a fixed number of CLS tokens. Furthermore, through our hybrid architecture, cascaded task learning boosts the performance of the parallel branch in image-speech retrieval tasks.
