Contrastive Feature Masking Open-Vocabulary Vision Transformer
Dahun Kim Anelia Angelova Weicheng Kuo
We present Contrastive Feature Masking Vision Transformer (CFM-ViT) - an
image-text pretraining methodology that achieves simultaneous learning of
image- and region-level representation for open-vocabulary object detection
(OVD). Our approach combines the masked autoencoder (MAE) objective into the
contrastive learning objective to improve the representation for localization
tasks. Unlike standard MAE, we perform reconstruction in the joint image-text
embedding space, rather than the pixel space as is customary with the classical
MAE method, which causes the model to better learn region-level semantics.
Moreover, we introduce Positional Embedding Dropout (PED) to address scale
variation between image-text pretraining and detection finetuning by randomly
dropping out the positional embeddings during pretraining. PED improves
detection performance and enables the use of a frozen ViT backbone as a region
classifier, preventing the forgetting of open-vocabulary knowledge during
detection finetuning. On LVIS open-vocabulary detection benchmark, CFM-ViT
achieves a state-of-the-art 33.9 AP$r$, surpassing the best approach by 7.6
points and achieves better zero-shot detection transfer. Finally, CFM-ViT
acquires strong image-level representation, outperforming the state of the art
on 8 out of 12 metrics on zero-shot image-text retrieval benchmarks.