Biography

I am a fourth-year Ph.D. student in APRIL Lab at Zhejiang University. My main research interest centers on deep learning and computer vision tasks. Currently, I’m focusing on self-supervised learning in visual geometry estimation.

Research and Interests

• Computer Vision
• Deep Learning
• Vision Geometry

Publications

• Xiaoyang Lyu, Liang Liu, Mengmeng Wang, Xin Kong, Lina Liu, Yong Liu, Xinxin Chen, and Yi Yuan. HR-Depth: High Resolution Self-Supervised Monocular Depth Estimation. In Proceedings of the 35th AAAI Conference on Artificial Intelligence (AAAI), 2021.
  [BibTeX] [Abstract] [arXiv] [PDF]

  Self-supervised learning shows great potential in monoculardepth estimation, using image sequences as the only source ofsupervision. Although people try to use the high-resolutionimage for depth estimation, the accuracy of prediction hasnot been significantly improved. In this work, we find thecore reason comes from the inaccurate depth estimation inlarge gradient regions, making the bilinear interpolation er-ror gradually disappear as the resolution increases. To obtainmore accurate depth estimation in large gradient regions, itis necessary to obtain high-resolution features with spatialand semantic information. Therefore, we present an improvedDepthNet, HR-Depth, with two effective strategies: (1) re-design the skip-connection in DepthNet to get better high-resolution features and (2) propose feature fusion Squeeze-and-Excitation(fSE) module to fuse feature more efficiently.Using Resnet-18 as the encoder, HR-Depth surpasses all pre-vious state-of-the-art(SoTA) methods with the least param-eters at both high and low resolution. Moreover, previousstate-of-the-art methods are based on fairly complex and deepnetworks with a mass of parameters which limits their realapplications. Thus we also construct a lightweight networkwhich uses MobileNetV3 as encoder. Experiments show thatthe lightweight network can perform on par with many largemodels like Monodepth2 at high-resolution with only20%parameters. All codes and models will be available at this https URL.

  @inproceedings{lyu2020hrdepthhr,
  title = {HR-Depth: High Resolution Self-Supervised Monocular Depth Estimation},
  author = {Xiaoyang Lyu and Liang Liu and Mengmeng Wang and Xin Kong and Lina Liu and Yong Liu and Xinxin Chen and Yi Yuan},
  year = 2021,
  booktitle = {Proceedings of the 35th AAAI Conference on Artificial Intelligence (AAAI)},
  abstract = {Self-supervised learning shows great potential in monoculardepth estimation, using image sequences as the only source ofsupervision. Although people try to use the high-resolutionimage for depth estimation, the accuracy of prediction hasnot been significantly improved. In this work, we find thecore reason comes from the inaccurate depth estimation inlarge gradient regions, making the bilinear interpolation er-ror gradually disappear as the resolution increases. To obtainmore accurate depth estimation in large gradient regions, itis necessary to obtain high-resolution features with spatialand semantic information. Therefore, we present an improvedDepthNet, HR-Depth, with two effective strategies: (1) re-design the skip-connection in DepthNet to get better high-resolution features and (2) propose feature fusion Squeeze-and-Excitation(fSE) module to fuse feature more efficiently.Using Resnet-18 as the encoder, HR-Depth surpasses all pre-vious state-of-the-art(SoTA) methods with the least param-eters at both high and low resolution. Moreover, previousstate-of-the-art methods are based on fairly complex and deepnetworks with a mass of parameters which limits their realapplications. Thus we also construct a lightweight networkwhich uses MobileNetV3 as encoder. Experiments show thatthe lightweight network can perform on par with many largemodels like Monodepth2 at high-resolution with only20%parameters. All codes and models will be available at this https URL.},
  arxiv = {https://arxiv.org/pdf/2012.07356.pdf}
  }

• Liang Liu, Jiangning Zhang, Ruifei He, Yong Liu, Yabiao Wang, Ying Tai, Donghao Luo, Chengjie Wang, Jilin Li, and Feiyue Huang. Learning by Analogy: Reliable Supervision From Transformations for Unsupervised Optical Flow Estimation. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), page 6488–6497, 2020.
  [BibTeX] [Abstract] [DOI] [arXiv] [PDF]

  Unsupervised learning of optical flow, which leverages the supervision from view synthesis, has emerged as a promising alternative to supervised methods. However, the objective of unsupervised learning is likely to be unreliable in challenging scenes. In this work, we present a framework to use more reliable supervision from transformations. It simply twists the general unsupervised learning pipeline by running another forward pass with transformed data from augmentation, along with using transformed predictions of original data as the self-supervision signal. Besides, we further introduce a lightweight network with multiple frames by a highly-shared flow decoder. Our method consistently gets a leap of performance on several benchmarks with the best accuracy among deep unsupervised methods. Also, our method achieves competitive results to recent fully supervised methods while with much fewer parameters.

  @inproceedings{liu2020learningba,
  title = {Learning by Analogy: Reliable Supervision From Transformations for Unsupervised Optical Flow Estimation},
  author = {Liang Liu and Jiangning Zhang and Ruifei He and Yong Liu and Yabiao Wang and Ying Tai and Donghao Luo and Chengjie Wang and Jilin Li and Feiyue Huang},
  year = 2020,
  booktitle = {2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
  pages = {6488--6497},
  doi = {https://doi.org/10.1109/cvpr42600.2020.00652},
  abstract = {Unsupervised learning of optical flow, which leverages the supervision from view synthesis, has emerged as a promising alternative to supervised methods. However, the objective of unsupervised learning is likely to be unreliable in challenging scenes. In this work, we present a framework to use more reliable supervision from transformations. It simply twists the general unsupervised learning pipeline by running another forward pass with transformed data from augmentation, along with using transformed predictions of original data as the self-supervision signal. Besides, we further introduce a lightweight network with multiple frames by a highly-shared flow decoder. Our method consistently gets a leap of performance on several benchmarks with the best accuracy among deep unsupervised methods. Also, our method achieves competitive results to recent fully supervised methods while with much fewer parameters.},
  arxiv = {http://arxiv.org/pdf/2003.13045}
  }

• Jiangning Zhang, Liang Liu, Zhucun Xue, and Yong Liu. APB2FACE: Audio-Guided Face Reenactment with Auxiliary Pose and Blink Signals. In 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), page 4402–4406, 2020.
  [BibTeX] [Abstract] [DOI] [arXiv] [PDF]

  Audio-guided face reenactment aims at generating photorealistic faces using audio information while maintaining the same facial movement as when speaking to a real person. However, existing methods can not generate vivid face images or only reenact low-resolution faces, which limits the application value. To solve those problems, we propose a novel deep neural network named APB2Face, which consists of GeometryPredictor and FaceReenactor modules. GeometryPredictor uses extra head pose and blink state signals as well as audio to predict the latent landmark geometry information, while FaceReenactor inputs the face landmark image to reenact the photorealistic face. A new dataset AnnV I collected from YouTube is presented to support the approach, and experimental results indicate the superiority of our method than state-of-the-arts, whether in authenticity or controllability.

  @inproceedings{zhang2020apb2faceaf,
  title = {APB2FACE: Audio-Guided Face Reenactment with Auxiliary Pose and Blink Signals},
  author = {Jiangning Zhang and Liang Liu and Zhucun Xue and Yong Liu},
  year = 2020,
  booktitle = {2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)},
  pages = {4402--4406},
  doi = {https://doi.org/10.1109/ICASSP40776.2020.9052977},
  abstract = {Audio-guided face reenactment aims at generating photorealistic faces using audio information while maintaining the same facial movement as when speaking to a real person. However, existing methods can not generate vivid face images or only reenact low-resolution faces, which limits the application value. To solve those problems, we propose a novel deep neural network named APB2Face, which consists of GeometryPredictor and FaceReenactor modules. GeometryPredictor uses extra head pose and blink state signals as well as audio to predict the latent landmark geometry information, while FaceReenactor inputs the face landmark image to reenact the photorealistic face. A new dataset AnnV I collected from YouTube is presented to support the approach, and experimental results indicate the superiority of our method than state-of-the-arts, whether in authenticity or controllability.},
  arxiv = {http://arxiv.org/pdf/2004.14569}
  }

• Jiangning Zhang, Chao Xu, Liang Liu, Mengmeng Wang, Xia Wu, Yong Liu, and Yunliang Jiang. Dtvnet: Dynamic time-lapse video generation via single still image. In ECCV, page 300–315, 2020.
  [BibTeX] [Abstract] [DOI] [arXiv] [PDF]

  This paper presents a novel end-to-end dynamic time-lapse video generation framework, named DTVNet, to generate diversified time-lapse videos from a single landscape image, which are conditioned on normalized motion vectors. The proposed DTVNet consists of two submodules: Optical Flow Encoder (OFE) and Dynamic Video Generator (DVG). The OFE maps a sequence of optical flow maps to a normalized motion vector that encodes the motion information inside the generated video. The DVG contains motion and content streams that learn from the motion vector and the single image respectively, as well as an encoder and a decoder to learn shared content features and construct video frames with corresponding motion respectively. Specifically, the motion stream introduces multiple adaptive instance normalization (AdaIN) layers to integrate multi-level motion information that are processed by linear layers. In the testing stage, videos with the same content but various motion information can be generated by different normalized motion vectors based on only one input image. We further conduct experiments on Sky Time-lapse dataset, and the results demonstrate the superiority of our approach over the state-of-the-art methods for generating high-quality and dynamic videos, as well as the variety for generating videos with various motion information.

  @inproceedings{zhang2020dtvnet,
  title = {Dtvnet: Dynamic time-lapse video generation via single still image},
  author = {Zhang, Jiangning and Xu, Chao and Liu, Liang and Wang, Mengmeng and Wu, Xia and Liu, Yong and Jiang, Yunliang},
  year = 2020,
  booktitle = {{ECCV}},
  pages = {300--315},
  doi = {https://doi.org/10.1007/978-3-030-58558-7_18},
  abstract = {This paper presents a novel end-to-end dynamic time-lapse video generation framework, named DTVNet, to generate diversified time-lapse videos from a single landscape image, which are conditioned on normalized motion vectors. The proposed DTVNet consists of two submodules: Optical Flow Encoder (OFE) and Dynamic Video Generator (DVG). The OFE maps a sequence of optical flow maps to a normalized motion vector that encodes the motion information inside the generated video. The DVG contains motion and content streams that learn from the motion vector and the single image respectively, as well as an encoder and a decoder to learn shared content features and construct video frames with corresponding motion respectively. Specifically, the motion stream introduces multiple adaptive instance normalization (AdaIN) layers to integrate multi-level motion information that are processed by linear layers. In the testing stage, videos with the same content but various motion information can be generated by different normalized motion vectors based on only one input image. We further conduct experiments on Sky Time-lapse dataset, and the results demonstrate the superiority of our approach over the state-of-the-art methods for generating high-quality and dynamic videos, as well as the variety for generating videos with various motion information.},
  arxiv = {https://arxiv.org/abs/2008.04776}
  }

• Jiangning Zhang, Xianfang Zeng, Mengmeng Wang, Yusu Pan, Liang Liu, Yong Liu, Yu Ding, and Changjie Fan. FReeNet: Multi-Identity Face Reenactment. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), page 5325–5334, 2020.
  [BibTeX] [Abstract] [DOI] [arXiv] [PDF]

  This paper presents a novel multi-identity face reenactment framework, named FReeNet, to transfer facial expressions from an arbitrary source face to a target face with a shared model. The proposed FReeNet consists of two parts: Unified Landmark Converter (ULC) and Geometry-aware Generator (GAG). The ULC adopts an encode-decoder architecture to efficiently convert expression in a latent landmark space, which significantly narrows the gap of the face contour between source and target identities. The GAG leverages the converted landmark to reenact the photorealistic image with a reference image of the target person. Moreover, a new triplet perceptual loss is proposed to force the GAG module to learn appearance and geometry information simultaneously, which also enriches facial details of the reenacted images. Further experiments demonstrate the superiority of our approach for generating photorealistic and expression-alike faces, as well as the flexibility for transferring facial expressions between identities.

  @inproceedings{zhang2020freenetmf,
  title = {FReeNet: Multi-Identity Face Reenactment},
  author = {Jiangning Zhang and Xianfang Zeng and Mengmeng Wang and Yusu Pan and Liang Liu and Yong Liu and Yu Ding and Changjie Fan},
  year = 2020,
  booktitle = {2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
  pages = {5325--5334},
  doi = {https://doi.org/10.1109/cvpr42600.2020.00537},
  abstract = {This paper presents a novel multi-identity face reenactment framework, named FReeNet, to transfer facial expressions from an arbitrary source face to a target face with a shared model. The proposed FReeNet consists of two parts: Unified Landmark Converter (ULC) and Geometry-aware Generator (GAG). The ULC adopts an encode-decoder architecture to efficiently convert expression in a latent landmark space, which significantly narrows the gap of the face contour between source and target identities. The GAG leverages the converted landmark to reenact the photorealistic image with a reference image of the target person. Moreover, a new triplet perceptual loss is proposed to force the GAG module to learn appearance and geometry information simultaneously, which also enriches facial details of the reenacted images. Further experiments demonstrate the superiority of our approach for generating photorealistic and expression-alike faces, as well as the flexibility for transferring facial expressions between identities.},
  arxiv = {http://arxiv.org/pdf/1905.11805}
  }

• Liang Liu, Guangyao Zhai, Wenlong Ye, and Yong Liu. Unsupervised Learning of Scene Flow Estimation Fusing with Local Rigidity. In 28th International Joint Conference on Artificial Intelligence (IJCAI), 2019.
  [BibTeX] [Abstract] [DOI] [PDF]

  Scene flow estimation in the dynamic scene remains a challenging task. Computing scene flow by a combination of 2D optical flow and depth has shown to be considerably faster with acceptable performance. In this work, we present a unified framework for joint unsupervised learning of stereo depth and optical flow with explicit local rigidity to estimate scene flow. We estimate camera motion directly by a Perspective-n-Point method from the optical flow and depth predictions, with RANSAC outlier rejection scheme. In order to disambiguate the object motion and the camera motion in the scene, we distinguish the rigid region by the re-project error and the photometric similarity. By joint learning with the local rigidity, both depth and optical networks can be refined. This framework boosts all four tasks: depth, optical flow, camera motion estimation, and object motion segmentation. Through the evaluation on the KITTI benchmark, we show that the proposed framework achieves state-of-the-art results amongst unsupervised methods. Our models and code are available at https://github.com/lliuz/unrigidflow.

  @inproceedings{liu2019unsupervisedlo,
  title = {Unsupervised Learning of Scene Flow Estimation Fusing with Local Rigidity},
  author = {Liang Liu and Guangyao Zhai and Wenlong Ye and Yong Liu},
  year = 2019,
  booktitle = {28th International Joint Conference on Artificial Intelligence (IJCAI)},
  doi = {https://doi.org/10.24963/ijcai.2019%2F123},
  abstract = {Scene flow estimation in the dynamic scene remains a challenging task. Computing scene flow by a combination of 2D optical flow and depth has shown to be considerably faster with acceptable performance. In this work, we present a unified framework for joint unsupervised learning of stereo depth and optical flow with explicit local rigidity to estimate scene flow. We estimate camera motion directly by a Perspective-n-Point method from the optical flow and depth predictions, with RANSAC outlier rejection scheme. In order to disambiguate the object motion and the camera motion in the scene, we distinguish the rigid region by the re-project error and the photometric similarity. By joint learning with the local rigidity, both depth and optical networks can be refined. This framework boosts all four tasks: depth, optical flow, camera motion estimation, and object motion segmentation. Through the evaluation on the KITTI benchmark, we show that the proposed framework achieves state-of-the-art results amongst unsupervised methods. Our models and code are available at https://github.com/lliuz/unrigidflow.}
  }

Links

• Google Scholar
• Github