Transfering Low-Frequency Features for Domain Adaptation

Zhaowen Li, Xu Zhao, Chaoyang Zhao, Ming Tang, Jinqiao Wang

Abstract: Previous unsupervised domain adaptation methods did not handle the cross-domain problem from the perspective of frequency for computer vision. The images or feature maps of different domains can be decomposed into the low-frequency component and high-frequency component. This paper pro-poses the assumption that low-frequency information is more domain-invariant while the high-frequency information con-tains domain-related information. Hence, we introduce an approach, named low-frequency module (LFM), to extract domain-invariant feature representations. The LFM is constructed with the digital Gaussian low-pass filter. Our method is easy to implement and introduces no extra hyperparame-ter. We design two effective ways to utilize the LFM for domain adaptation, and our method is complementary to other existing methods and formulated as a plug-and-play unit that can be combined with these methods. Experimental results demonstrate that our LFM outperforms state-of-the-art meth-ods for various computer vision tasks, including image clas-sification and object detection.