Hierarchical prompt composition for memory-efficient open-world continual learning in vision-language foundation models
摘要
Foundation models pre-trained on large-scale vision-language data, such as CLIP, exhibit strong zero-shot visual recognition but suffer from catastrophic forgetting when fine-tuned on sequential task streams. We introduce the Hierarchical Prompt Composition Network (HPC-NET), a parameter-efficient architecture for continual learning in open-world environments. HPC-NET decomposes learnable prompts into three tiers: foundational prompts that encode broad visual primitives, compositional prompts that aggregate mid-level patterns, and instance prompts that capture category-specific features. A Semantic Prototype Anchoring (SPA) mechanism constrains each tier to stable CLIP reference embeddings, mitigating semantic drift. A Contrastive Prompt Router (CPR) dynamically selects a sparse subset of prompts per input via attention-based routing. Across five benchmarks–Split-CIFAR100, Split-ImageNet-R, CORe50, MedStream-7k, and Split-CUB200–HPC-NET achieves