  Masked Autoencoders (MAE) have been popular paradigms for large-scale vision
representation pre-training. However, MAE solely reconstructs the low-level RGB
signals after the decoder and lacks supervision upon high-level semantics for
the encoder, thus suffering from sub-optimal learned representations and long
pre-training epochs. To alleviate this, previous methods simply replace the
pixel reconstruction targets of 75% masked tokens by encoded features from
pre-trained image-image (DINO) or image-language (CLIP) contrastive learning.
Different from those efforts, we propose to Mimic before Reconstruct for Masked
Autoencoders, named as MR-MAE, which jointly learns high-level and low-level
representations without interference during pre-training. For high-level
semantics, MR-MAE employs a mimic loss over 25% visible tokens from the encoder
to capture the pre-trained patterns encoded in CLIP and DINO. For low-level
structures, we inherit the reconstruction loss in MAE to predict RGB pixel
values for 75% masked tokens after the decoder. As MR-MAE applies high-level
and low-level targets respectively at different partitions, the learning
conflicts between them can be naturally overcome and contribute to superior
visual representations for various downstream tasks. On ImageNet-1K, the MR-MAE
base pre-trained for only 400 epochs achieves 85.8% top-1 accuracy after
fine-tuning, surpassing the 1600-epoch MAE base by +2.2% and the previous
state-of-the-art BEiT V2 base by +0.3%. Code and pre-trained models will be
released at https://github.com/Alpha-VL/ConvMAE.
