pwc-archive/papers-with-abstracts huggingface dataset:
Decoupled Representation Learning for Skeleton-Based Gesture Recognition
Authors: Jianbo Liu,  Yongcheng Liu,  Ying Wang,  Veronique Prinet,  Shiming Xiang,  Chunhong Pan
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Gesture Recognition, Representation Learning

Skeleton-based gesture recognition is very challenging, as the high-level information in gesture is expressed by a sequence of complexly composite motions. Previous works often learn all the motions with a single model. In this paper, we propose to decouple the gesture into hand posture variations and hand movements, which are then modeled separately. For the former, the skeleton sequence is embedded into a 3D hand posture evolution volume (HPEV) to represent fine-grained posture variations. For the latter, the shifts of hand center and fingertips are arranged as a 2D hand movement map (HMM) to capture holistic movements. To learn from the two inhomogeneous representations for gesture recognition, we propose an end-to-end two-stream network. The HPEV stream integrates both spatial layout and temporal evolution information of hand postures by a dedicated 3D CNN, while the HMM stream develops an efficient 2D CNN to extract hand movement features. Eventually, the predictions of the two streams are aggregated with high efficiency. Extensive experiments on SHREC'17 Track, DHG-14/28 and FPHA datasets demonstrate that our method is competitive with the state-of-the-art.
An Efficient PointLSTM for Point Clouds Based Gesture Recognition
Authors: Yuecong Min,  Yanxiao Zhang,  Xiujuan Chai,  Xilin Chen
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Gesture Recognition, Hand Gesture Recognition

Point clouds contain rich spatial information, which provides complementary cues for gesture recognition. In this paper, we formulate gesture recognition as an irregular sequence recognition problem and aim to capture long-term spatial correlations across point cloud sequences. A novel and effective PointLSTM is proposed to propagate information from past to future while preserving the spatial structure. The proposed PointLSTM combines state information from neighboring points in the past with current features to update the current states by a weight-shared LSTM layer. This method can be integrated into many other sequence learning approaches. In the task of gesture recognition, the proposed PointLSTM achieves state-of-the-art results on two challenging datasets (NVGesture and SHREC'17) and outperforms previous skeleton-based methods. To show its advantages in generalization, we evaluate our method on MSR Action3D dataset, and it produces competitive results with previous skeleton-based methods.
Deep Facial Non-Rigid Multi-View Stereo
Authors: Ziqian Bai,  Zhaopeng Cui,  Jamal Ahmed Rahim,  Xiaoming Liu,  Ping Tan
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 3D Face Reconstruction, Face Reconstruction

We present a method for 3D face reconstruction from multi-view images with different expressions. We formulate this problem from the perspective of non-rigid multi-view stereo (NRMVS). Unlike previous learning-based methods, which often regress the face shape directly, our method optimizes the 3D face shape by explicitly enforcing multi-view appearance consistency, which is known to be effective in recovering shape details according to conventional multi-view stereo methods. Furthermore, by estimating face shape through optimization based on multi-view consistency, our method can potentially have better generalization to unseen data. However, this optimization is challenging since each input image has a different expression. We facilitate it with a CNN network that learns to regularize the non-rigid 3D face according to the input image and preliminary optimization results. Extensive experiments show that our method achieves the state-of-the-art performance on various datasets and generalizes well to in-the-wild data.
Attention-Driven Cropping for Very High Resolution Facial Landmark Detection
Authors: Prashanth Chandran,  Derek Bradley,  Markus Gross,  Thabo Beeler
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 4k, Facial Landmark Detection, Vocal Bursts Intensity Prediction

Facial landmark detection is a fundamental task for many consumer and high-end applications and is almost entirely solved by machine learning methods today. Existing datasets used to train such algorithms are primarily made up of only low resolution images, and current algorithms are limited to inputs of comparable quality and resolution as the training dataset. On the other hand, high resolution imagery is becoming increasingly more common as consumer cameras improve in quality every year. Therefore, there is need for algorithms that can leverage the rich information available in high resolution imagery. Naively attempting to reuse existing network architectures on high resolution imagery is prohibitive due to memory bottlenecks on GPUs. The only current solution is to downsample the images, sacrificing resolution and quality. Building on top of recent progress in attention-based networks, we present a novel, fully convolutional regional architecture that is specially designed for predicting landmarks on very high resolution facial images without downsampling. We demonstrate the flexibility of our architecture by training the proposed model with images of resolutions ranging from 256 x 256 to 4K. In addition to being the first method for facial landmark detection on high resolution images, our approach achieves superior performance over traditional (holistic) state-of-the-art architectures across ALL resolutions, leading to a general-purpose, extremely flexible, high quality landmark detector.
BidNet: Binocular Image Dehazing Without Explicit Disparity Estimation
Authors: Yanwei Pang,  Jing Nie,  Jin Xie,  Jungong Han,  Xuelong Li
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 3D Object Detection, Disparity Estimation, Image Dehazing, object-detection, Object Detection

Heavy haze results in severe image degradation and thus hampers the performance of visual perception, object detection, etc. On the assumption that dehazed binocular images are superior to the hazy ones for stereo vision tasks such as 3D object detection and according to the fact that image haze is a function of depth, this paper proposes a Binocular image dehazing Network (BidNet) aiming at dehazing both the left and right images of binocular images within the deep learning framework. Existing binocular dehazing methods rely on simultaneously dehazing and estimating disparity, whereas BidNet does not need to explicitly perform time-consuming and well-known challenging disparity estimation. Note that a small error in disparity gives rise to a large variation in depth and in estimation of haze-free image. The relationship and correlation between binocular images are explored and encoded by the proposed Stereo Transformation Module (STM). Jointly dehazing binocular image pairs is mutually beneficial, which is better than only dehazing left images. We extend the Foggy Cityscapes dataset to a Stereo Foggy Cityscapes dataset with binocular foggy image pairs. Experimental results demonstrate that BidNet significantly outperforms state-of-the-art dehazing methods in both subjective and objective assessments.
Deep Shutter Unrolling Network
Authors: Peidong Liu,  Zhaopeng Cui,  Viktor Larsson,  Marc Pollefeys
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Decoder, Motion Estimation, Rolling Shutter Correction

We present a novel network for rolling shutter effect correction. Our network takes two consecutive rolling shutter images and estimates the corresponding global shutter image of the latest frame. The dense displacement field from a rolling shutter image to its corresponding global shutter image is estimated via a motion estimation network. The learned feature representation of a rolling shutter image is then warped, via the displacement field, to its global shutter representation by a differentiable forward warping block. An image decoder recovers the global shutter image based on the warped feature representation. Our network can be trained end-to-end and only requires the global shutter image for supervision. Since there is no public dataset available, we also propose two large datasets: the Carla-RS dataset and the Fastec-RS dataset. Experimental results demonstrate that our network outperforms the state-of-the-art methods. We make both our code and datasets available at https://github.com/ethliup/DeepUnrollNet.
Joint Texture and Geometry Optimization for RGB-D Reconstruction
Authors: Yanping Fu,  Qingan Yan,  Jie Liao,  Chunxia Xiao
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 3D Reconstruction, Quantization, RGB-D Reconstruction

Due to inevitable noises and quantization error, the reconstructed 3D models via RGB-D sensors always accompany geometric error and camera drifting, which consequently lead to blurring and unnatural texture mapping results. Most of the 3D reconstruction methods focus on either geometry refinement or texture improvement respectively, which subjectively decouples the inter-relationship between geometry and texture. In this paper, we propose a novel approach that can jointly optimize the camera poses, texture and geometry of the reconstructed model, and color consistency between the key-frames. Instead of computing Shape-From-Shading (SFS) expensively, our method directly optimizes the reconstructed mesh according to color and geometric consistency and high-boost normal cues, which can effectively overcome the texture-copy problem generated by SFS and achieve more detailed shape reconstruction. As the joint optimization involves multiple correlated terms, therefore, we further introduce an iterative framework to interleave the optimal state. The experiments demonstrate that our method can recover not only fine-scale geometry but also high-fidelity texture.
Auto-Tuning Structured Light by Optical Stochastic Gradient Descent
Authors: Wenzheng Chen,  Parsa Mirdehghan,  Sanja Fidler,  Kiriakos N. Kutulakos
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6

We consider the problem of optimizing the performance of an active imaging system by automatically discovering the illuminations it should use, and the way to decode them. Our approach tackles two seemingly incompatible goals: (1) "tuning" the illuminations and decoding algorithm precisely to the devices at hand---to their optical transfer functions, non-linearities, spectral responses, image processing pipelines---and (2) doing so without modeling or calibrating the system; without modeling the scenes of interest; and without prior training data. The key idea is to formulate a stochastic gradient descent (SGD) optimization procedure that puts the actual system in the loop: projecting patterns, capturing images, and calculating the gradient of expected reconstruction error. We apply this idea to structured-light triangulation to "auto-tune" several devices---from smartphones and laser projectors to advanced computational cameras. Our experiments show that despite being model-free and automatic, optical SGD can boost system 3D accuracy substantially over state-of-the-art coding schemes.
MARMVS: Matching Ambiguity Reduced Multiple View Stereo for Efficient Large Scale Scene Reconstruction
Authors: Zhenyu Xu,  Yiguang Liu,  Xuelei Shi,  Ying Wang,  Yunan Zheng
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6

The ambiguity in image matching is one of main factors decreasing the quality of the 3D model reconstructed by PatchMatch based multiple view stereo. In this paper, we present a novel method, matching ambiguity reduced multiple view stereo (MARMVS) to address this issue. The MARMVS handles the ambiguity in image matching process with three newly proposed strategies: 1) The matching ambiguity is measured by the differential geometry property of image surface with epipolar constraint, which is used as a critical criterion for optimal scale selection of every single pixel with corresponding neighbouring images. 2) The depth of every pixel is initialized to be more close to the true depth by utilizing the depths of its surrounding sparse feature points, which yields faster convergency speed in the following PatchMatch stereo and alleviates the ambiguity introduced by self similar structures of the image. 3) In the last propagation of the PatchMatch stereo, higher priorities are given to those planes with the related 2D image patch possesses less ambiguity, this strategy further propagates a correctly reconstructed surface to raw texture regions. In addition, the proposed method is very efficient even running on consumer grade CPUs, due to proper parameterization and discretization in the depth map computation step. The MARMVS is validated on public benchmarks, and experimental results demonstrate competing performance against the state of the art.
Uncertainty Based Camera Model Selection
Authors: Michal Polic,  Stanislav Steidl,  Cenek Albl,  Zuzana Kukelova,  Tomas Pajdla
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: model, Model Selection

The quality and speed of Structure from Motion (SfM) methods depend significantly on the camera model chosen for the reconstruction. In most of the SfM pipelines, the camera model is manually chosen by the user. In this paper, we present a new automatic method for camera model selection in large scale SfM that is based on efficient uncertainty evaluation. We first perform an extensive comparison of classical model selection based on known Information Criteria and show that they do not provide sufficiently accurate results when applied to camera model selection. Then we propose a new Accuracy-based Criterion, which evaluates an efficient approximation of the uncertainty of the estimated parameters in tested models. Using the new criterion, we design a camera model selection method and fine-tune it by machine learning. Our simulated and real experiments demonstrate a significant increase in reconstruction quality as well as a considerable speedup of the SfM process.
Local Implicit Grid Representations for 3D Scenes
Authors: Chiyu "Max" Jiang,  Avneesh Sud,  Ameesh Makadia,  Jingwei Huang,  Matthias Niessner,  Thomas Funkhouser
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 3D Shape Representation, Decoder, Diversity, Surface Reconstruction

Shape priors learned from data are commonly used to reconstruct 3D objects from partial or noisy data. Yet no such shape priors are available for indoor scenes, since typical 3D autoencoders cannot handle their scale, complexity, or diversity. In this paper, we introduce Local Implicit Grid Representations, a new 3D shape representation designed for scalability and generality. The motivating idea is that most 3D surfaces share geometric details at some scale -- i.e., at a scale smaller than an entire object and larger than a small patch. We train an autoencoder to learn an embedding of local crops of 3D shapes at that size. Then, we use the decoder as a component in a shape optimization that solves for a set of latent codes on a regular grid of overlapping crops such that an interpolation of the decoded local shapes matches a partial or noisy observation. We demonstrate the value of this proposed approach for 3D surface reconstruction from sparse point observations, showing significantly better results than alternative approaches.
Robust Homography Estimation via Dual Principal Component Pursuit
Authors: Tianjiao Ding,  Yunchen Yang,  Zhihui Zhu,  Daniel P. Robinson,  Rene Vidal,  Laurent Kneip,  Manolis C. Tsakiris
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Homography Estimation, valid

We revisit robust estimation of homographies over point correspondences between two or three views, a fundamental problem in geometric vision. The analysis serves as a platform to support a rigorous investigation of Dual Principal Component Pursuit (DPCP) as a valid and powerful alternative to RANSAC for robust model fitting in multiple-view geometry. Homography fitting is cast as a robust nullspace estimation problem over either homographic or epipolar/trifocal embeddings. We prove that the nullspace of epipolar or trifocal embeddings in the homographic scenario, of dimension 3 and 6 for two and three views respectively, is defined by unique, computable homographies. Experiments show that DPCP performs on par with USAC with local optimization, while requiring an order of magnitude less computing time, and it also outperforms a recent deep learning implementation for homography estimation.
Uncertainty-Aware Mesh Decoder for High Fidelity 3D Face Reconstruction
Authors: Gun-Hee Lee,  Seong-Whan Lee
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 3D Face Reconstruction, Decoder, Face Reconstruction, Generative Adversarial Network, Specificity, Vocal Bursts Intensity Prediction

3D Morphable Model (3DMM) is a statistical model of facial shape and texture using a set of linear basis functions. Most of the recent 3D face reconstruction methods aim to embed the 3D morphable basis functions into Deep Convolutional Neural Network (DCNN). However, balancing the requirements of strong regularization for global shape and weak regularization for high level details is still ill-posed. To address this problem, we properly control generality and specificity in terms of regularization by harnessing the power of uncertainty. Additionally, we focus on the concept of nonlinearity and find out that Graph Convolutional Neural Network (Graph CNN) and Generative Adversarial Network (GAN) are effective in reconstructing high quality 3D shapes and textures respectively. In this paper, we propose to employ (i) an uncertainty-aware encoder that presents face features as distributions and (ii) a fully nonlinear decoder model combining Graph CNN with GAN. We demonstrate how our method builds excellent high quality results and outperforms previous state-of-the-art methods on 3D face reconstruction tasks for both constrained and in-the-wild images.
3FabRec: Fast Few-Shot Face Alignment by Reconstruction
Authors: Bjorn Browatzki,  Christian Wallraven
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Decoder, Face Alignment, Facial Landmark Detection, GPU

Current supervised methods for facial landmark detection require a large amount of training data and may suffer from overfitting to specific datasets due to the massive number of parameters. We introduce a semi-supervised method in which the crucial idea is to first generate implicit face knowledge from the large amounts of unlabeled images of faces available today. In a first, completely unsupervised stage, we train an adversarial autoencoder to reconstruct faces via a low-dimensional face embedding. In a second, supervised stage, we interleave the decoder with transfer layers to retask the generation of color images to the prediction of landmark heatmaps. Our framework (3FabRec) achieves state-of-the-art performance on several common benchmarks and, most importantly, is able to maintain impressive accuracy on extremely small training sets down to as few as 10 images. As the interleaved layers only add a low amount of parameters to the decoder, inference runs at several hundred FPS on a GPU.
Weakly-Supervised Domain Adaptation via GAN and Mesh Model for Estimating 3D Hand Poses Interacting Objects
Authors: Seungryul Baek,  Kwang In Kim,  Tae-Kyun Kim
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: 3D Hand Pose Estimation, Domain Adaptation, Generative Adversarial Network, Hand Pose Estimation, Pose Estimation

Despite recent successes in hand pose estimation, there yet remain challenges on RGB-based 3D hand pose estimation (HPE) under hand-object interaction (HOI) scenarios where severe occlusions and cluttered backgrounds exhibit. Recent RGB HOI benchmarks have been collected either in real or synthetic domain, however, the size of datasets is far from enough to deal with diverse objects combined with hand poses, and 3D pose annotations of real samples are lacking, especially for occluded cases. In this work, we propose a novel end-to-end trainable pipeline that adapts the hand-object domain to the single hand-only domain, while learning for HPE. The domain adaption occurs in image space via 2D pixel-level guidance by Generative Adversarial Network (GAN) and 3D mesh guidance by mesh renderer (MR). Via the domain adaption in image space, not only 3D HPE accuracy is improved, but also HOI input images are translated to segmented and de-occluded hand-only images. The proposed method takes advantages of both the guidances: GAN accurately aligns hands, while MR effectively fills in occluded pixels. The experiments using Dexter-Object, Ego-Dexter and HO3D datasets show that our method significantly outperforms state-of-the-arts trained by hand-only data and is comparable to those supervised by HOI data. Note our method is trained primarily by hand-only images with pose labels, and HOI images without pose labels.
GHUM & GHUML: Generative 3D Human Shape and Articulated Pose Models
Authors: Hongyi Xu,  Eduard Gabriel Bazavan,  Andrei Zanfir,  William T. Freeman,  Rahul Sukthankar,  Cristian Sminchisescu
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Pose Estimation

We present a statistical, articulated 3D human shape modeling pipeline, within a fully trainable, modular, deep learning framework. Given high-resolution complete 3D body scans of humans, captured in various poses, together with additional closeups of their head and facial expressions, as well as hand articulation, and given initial, artist designed, gender neutral rigged quad-meshes, we train all model parameters including non-linear shape spaces based on variational auto-encoders, pose-space deformation correctives, skeleton joint center predictors, and blend skinning functions, in a single consistent learning loop. The models are simultaneously trained with all the 3d dynamic scan data (over 60,000 diverse human configurations in our new dataset) in order to capture correlations and ensure consistency of various components. Models support facial expression analysis, as well as body (with detailed hand) shape and pose estimation. We provide fully train-able generic human models of different resolutions- the moderate-resolution GHUM consisting of 10,168 vertices and the low-resolution GHUML(ite) of 3,194 vertices-, run comparisons between them, analyze the impact of different components and illustrate their reconstruction from image data. The models will be available for research.
Bayesian Adversarial Human Motion Synthesis
Authors: Rui Zhao,  Hui Su,  Qiang Ji
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Bayesian Inference, Data Augmentation, Diversity, Motion Synthesis

We propose a generative probabilistic model for human motion synthesis. Our model has a hierarchy of three layers. At the bottom layer, we utilize Hidden semi-Markov Model (HSMM), which explicitly models the spatial pose, temporal transition and speed variations in motion sequences. At the middle layer, HSMM parameters are treated as random variables which are allowed to vary across data instances in order to capture large intra- and inter-class variations. At the top layer, hyperparameters define the prior distributions of parameters, preventing the model from overfitting. By explicitly capturing the distribution of the data and parameters, our model has a more compact parameterization compared to GAN-based generative models. We formulate the data synthesis as an adversarial Bayesian inference problem, in which the distributions of generator and discriminator parameters are obtained for data synthesis. We evaluate our method through a variety of metrics, where we show advantage than other competing methods with better fidelity and diversity. We further evaluate the synthesis quality as a data augmentation method for recognition task. Finally, we demonstrate the benefit of our fully probabilistic approach in data restoration task.