Incentivizing Generative Zero-Shot Learning via Outcome-Reward Reinforcement Learning with Visual Cues
Organizations: CCAI, Zhejiang University · Stanford University · State Key Laboratory of CAD&CG, Zhejiang University
Abstract
Recent advances in zero-shot learning (ZSL) have demonstrated the potential of generative models. Typically, generative ZSL synthesizes visual features conditioned on semantic prototypes to model the data distribution of unseen classes, followed by training a classifier on the synthesized data. However, the synthesized features often remain task-agnostic, leading to degraded performance. Moreover, inferring a faithful distribution from semantic prototypes alone is insufficient for classes that are semantically similar but visually distinct. To address these and advance ZSL, we propose RLVC, an outcome-reward reinforcement learning RL framework with visual cues for generative ZSL. At its core, RL empowers the generative model to self-evolve, implicitly enhancing its generation capability. In particular, RLVC updates the generative model using an outcome-based reward, encouraging the synthesis of task-relevant features. Furthermore, we introduce class-wise visual cues that (i) align synthesized features with visual prototypes and (ii) stabilize the RL training updates. For the training process, we present a novel cold-start strategy. Comprehensive experiments and analyses on three prevalent ZSL benchmarks demonstrate that RLVC achieves state-of-the-art results with a 4.7% gain.
Figures & tables
| Method | Backbone | CUB | SUN | AWA2 | ||||||||||
| Acc | U | S | H | Acc | U | S | H | Acc | U | S | H | |||
| Embedding | CLIP ⋆ [ICML’21] [ 61 ] | ViT | – | 55.2 | 54.8 | 55.0 | – | – | – | – | – | – | – | – |
| TransZero++ [TPAMI’22] [ 8 ] | ResNet | 78.3 | 67.5 | 73.6 | 70.4 | 67.6 | 48.6 | 37.8 | 42.5 | 72.6 | 64.6 | 82.7 | 72.5 | |
| DUET [AAAI’23] [ 19 ] | ViT | 72.3 | 62.9 | 72.8 | 67.5 | 64.4 | 45.7 | 45.8 | 45.8 | 69.9 | 63.7 | 84.7 | 72.7 | |
| ICIS [ICCV’23] [ 20 ] | ResNet | 60.6 | 45.8 | 73.7 | 56.5 | 51.8 | 45.2 | 25.6 | 32.7 | 64.6 | 35.6 | 93.3 | 51.6 | |
| HAS [ACM MM’23] [ 18 ] | ResNet | 76.5 | 69.6 | 74.1 | 71.8 | 63.2 | 42.8 | 38.9 | 40.8 | 71.4 | 63.1 | 87.3 | 73.3 | |
| Method | Semantic prototype | CUB | SUN | AWA2 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Acc | U | S | H | Acc | U | S | H | Acc | U | S | H | ||
| Vanilla model | word embedding | 61.8 | 52.4 | 66.3 | 58.5 | 72.0 | 55.4 | 46.4 | 50.5 | 73.1 | 62.8 | 82.3 | 71.2 |
| RLVC | word embedding | 62.8 (+1.0) | 51.5 | 70.9 | 59.7 (+1.2) | 72.1 (+0.1) | 55.0 | 50.3 | 52.5 (+2.0) | 74.5 (+1.4) | 61.3 | 91.7 | 73.5 (+2.3) |
| Vanilla model | attribute vector | 88.6 | 71.0 | 79.8 | 75.1 | 75.8 | 58.3 | 52.3 | 55.1 | 75.7 | 70.1 | 76.0 | 72.8 |
| RLVC | attribute vector | 90.1 (+1.5) | 80.9 | 81.4 | 81.2 (+6.1) | 77.7 (+1.9) | 59.6 | 55.6 | 57.6 (+2.6) | 84.0 (+8.3) | 78.4 | 82.4 | 80.4 (+7.6) |
| Configuration | CUB | SUN | AWA2 | |||
| Acc | H | Acc | H | Acc | H | |
| RLVC w/o RL & visual cues | 88.6 | 75.1 | 75.8 | 55.1 | 75.7 | 72.8 |
| RLVC w/o RL ( i.e . , Eq. ( 11 )) | 89.2 | 80.1 | 76.1 | 55.6 | 79.4 | 73.9 |
| RLVC w/o visual cues ( i.e . , Eq. ( 13 )) | 88.9 | 79.2 | 77.0 | 56.9 | 74.9 | 76.6 |
| RLVC w/o fine-tuning visual encoder | 89.2 | 77.5 | 76.0 | 56.4 | 81.1 | 76.3 |
| RLVC w/o advantage ( i.e . , Eq. ( 9 )) | 89.6 | 79.7 | 76.0 | 56.0 | 82.4 | 78.2 |
| Loss | CUB | SUN | AWA2 | |||
|---|---|---|---|---|---|---|
| Acc | H | Acc | H | Acc | H | |
| 88.9 | 80.1 | 77.2 | 58.2 | 76.4 | 76.4 | |
| 89.2 | 80.9 | 77.3 | 57.8 | 75.9 | 77.6 | |
| 90.1 | 81.2 | 77.7 | 57.6 | 84.0 | 80.4 | |
Zero-Shot Learning
Zero-shot learning lets models recognize classes or solve tasks absent from task-specific training examples by using semantic descriptions or pretrained knowledge.
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