pwc-archive/papers-with-abstracts huggingface dataset:
A Lightweight Single-Camera Polarization Compass With Covariance Estimation
Authors: Wolfgang Sturzl
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10

A lightweight visual compass system is presented as well as a direct method for estimating sun direction and its covariance. The optical elements of the system are described enabling estimation of sky polarization in a FOV of approx. 56 degrees with a single standard camera sensor. Using the proposed direct method, the sun direction and its covariance matrix can be estimated based on the polarization measured in the image plane. Experiments prove the applicability of the polarization sensor and the proposed estimation method, even in difficult conditions. It is also shown that in case the sensor is not leveled, combination with an IMU allows to determine all degrees of orientation. Due to the low weight of the sensor and the low complexity of the estimation method the polarization system is well suited for MAVs which have limited payload and computational resources. Furthermore, since not just the sun direction but also its covariance is estimated an integration in a multi-sensor navigation framework is straight forward.
Reflectance Capture Using Univariate Sampling of BRDFs
Authors: Zhuo Hui, Kalyan Sunkavalli, Joon-Young Lee, Sunil Hadap, Jian Wang, Aswin C. Sankaranarayanan
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: BRDF estimation, General Classification

We propose the use of a light-weight setup consisting of a collocated camera and light source --- commonly found on mobile devices --- to reconstruct surface normals and spatially-varying BRDFs of near-planar material samples. A collocated setup provides only a 1-D "univariate" sampling of the 4-D BRDF. We show that a univariate sampling is sufficient to estimate parameters of commonly used analytical BRDF models. Subsequently, we use a dictionary-based reflectance prior to derive a robust technique for per-pixel normal and BRDF estimation. We demonstrate real-world shape and capture, and its application to material editing and classification, using real data acquired using a mobile phone.
Estimating Defocus Blur via Rank of Local Patches
Authors: Guodong Xu, Yuhui Quan, Hui Ji
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10

This paper addresses the problem of defocus map estimation from a single image. We present a fast yet effective approach to estimate the spatially varying amounts of defocus blur at edge locations, which is based on the maximum, ranks of the corresponding local patches with different orientations in gradient domain. Such an approach is motivated by the theoretical analysis which reveals the connection between the rank of a local patch blurred by a defocus blur kernel and the blur amount by the kernel. After the amounts of defocus blur at edge locations are obtained, a complete defocus map is generated by a standard propagation procedure. The proposed method is extensively evaluated on real image datasets, and the experimental results show its superior performance to existing approaches.proposed method is extensively evaluated on real data, and the experimental results show its superior performance to existing approaches.
RGB-Infrared Cross-Modality Person Re-Identification
Authors: Ancong Wu, Wei-Shi Zheng, Hong-Xing Yu, Shaogang Gong, Jian-Huang Lai
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Cross-Modality Person Re-identification, Cross-Modal  Person Re-Identification, Person Re-Identification

Person re-identification (Re-ID) is an important problem in video surveillance, aiming to match pedestrian images across camera views. Currently, most works focus on RGB-based Re-ID. However, in some applications, RGB images are not suitable, e.g. in a dark environment or at night. Infrared (IR) imaging becomes necessary in many visual systems. To that end, matching RGB images with infrared images is required, which are heterogeneous with very different visual characteristics. For person Re-ID, this is a very challenging cross-modality problem that has not been studied so far. In this work, we address the RGB-IR cross-modality Re-ID problem and contribute a new multiple modality Re-ID dataset named SYSU-MM01, including RGB and IR images of 491 identities from 6 cameras, giving in total 287,628 RGB images and 15,792 IR images. To explore the RGB-IR Re-ID problem, we evaluate existing popular cross-domain models, including three commonly used neural network structures (one-stream, two-stream and asymmetric FC layer) and analyse the relation between them. We further propose deep zero-padding for training one-stream network towards automatically evolving domain-specific nodes in the network for cross-modality matching. Our experiments show that RGB-IR cross-modality matching is very challenging but still feasible using the proposed model with deep zero-padding, giving the best performance. Our dataset is available at http://isee.sysu.edu.cn/project/RGBIRReID.htm.
Intrinsic 3D Dynamic Surface Tracking Based on Dynamic Ricci Flow and Teichmuller Map
Authors: Xiaokang Yu, Na lei, Yalin Wang, Xianfeng GU
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10

3D dynamic surface tracking is an important research problem and plays a vital role in many computer vision and medical imaging applications. However, it is still challenging to efficiently register surface sequences which has large deformations and strong noise. In this paper, we propose a novel automatic method for non-rigid 3D dynamic surface tracking with surface Ricci flow and Teichmuller map methods. According to quasi-conformal Teichmuller theory, the Techmuller map minimizes the maximal dilation so that our method is able to automatically register surfaces with large deformations. Besides, the adoption of Delaunay triangulation and quadrilateral meshes makes our method applicable to low quality meshes. In our work, the 3D dynamic surfaces are acquired by a high speed 3D scanner. We first identified sparse surface features using machine learning methods in the texture space. Then we assign landmark features with different curvature settings and the Riemannian metric of the surface is computed by the dynamic Ricci flow method, such that all the curvatures are concentrated on the feature points and the surface is flat everywhere else. The registration among frames is computed by the Teichmuller mappings, which aligns the feature points with least angle distortions. We apply our new method to multiple sequences of 3D facial surfaces with large expression deformations and compare them with two other state-of-the-art tracking methods. The effectiveness of our method is demonstrated by the clearly improved accuracy and efficiency.
Range Loss for Deep Face Recognition With Long-Tailed Training Data
Authors: Xiao Zhang, Zhiyuan Fang, Yandong Wen, Zhifeng Li, Yu Qiao
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Face Recognition

Deep convolutional neural networks have achieved significant improvements on face recognition task due to their ability to learn highly discriminative features from tremendous amounts of face images. Many large scale face datasets exhibit long-tail distribution where a small number of entities (persons) have large number of face images while a large number of persons only have very few face samples (long tail). Most of the existing works alleviate this problem by simply cutting the tailed data and only keep identities with enough number of examples. Unlike these work, this paper investigated how long-tailed data impact the training of face CNNs and develop a novel loss function, called range loss, to effectively utilize the tailed data in training process. More specifically, range loss is designed to reduce overall intrapersonal variations while enlarge inter-personal differences simultaneously. Extensive experiments on two face recognition benchmarks, Labeled Faces in the Wild (LFW) and YouTube Faces (YTF), demonstrate the effectiveness of the proposed range loss in overcoming the long tail effect, and show the good generalization ability of the proposed methods.
Realistic Dynamic Facial Textures From a Single Image Using GANs
Authors: Kyle Olszewski, Zimo Li, Chao Yang, Yi Zhou, Ronald Yu, Zeng Huang, Sitao Xiang, Shunsuke Saito, Pushmeet Kohli, Hao Li
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: 3D geometry

We present a novel method to realistically puppeteer and animate a face from a single RGB image using a source video sequence. We begin by fitting a multilinear PCA model to obtain the 3D geometry and a single texture of the target face. In order for the animation to be realistic, however, we need dynamic per-frame textures that capture subtle wrinkles and deformations corresponding to the animated facial expressions. This problem is highly underconstrained, as dynamic textures cannot be obtained directly from a single image. Furthermore, if the target face has a closed mouth, it is not possible to obtain actual images of the mouth interior. To address this issue, we train a Deep Generative Network that can infer realistic per-frame texture deformations, including the mouth interior, of the target identity using the per-frame source textures and the single target texture. By retargeting the PCA expression geometry from the source, as well as using the newly inferred texture, we can both animate the face and perform video face replacement on the source video using the target appearance.
PanNet: A Deep Network Architecture for Pan-Sharpening
Authors: Junfeng Yang, Xueyang Fu, Yuwen Hu, Yue Huang, Xinghao Ding, John Paisley
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10

We propose a deep network architecture for the pan-sharpening problem called PanNet. We incorporate domain-specific knowledge to design our PanNet architecture by focusing on the two aims of the pan-sharpening problem: spectral and spatial preservation. For spectral preservation, we add up-sampled multispectral images to the network output, which directly propagates the spectral information to the reconstructed image. To preserve spatial structure, we train our network parameters in the high-pass filtering domain rather than the image domain. We show that the trained network generalizes well to images from different satellites without needing retraining. Experiments show significant improvement over state-of-the-art methods visually and in terms of standard quality metrics.
Recurrent Color Constancy
Authors: Yanlin Qian, Ke Chen, Jarno Nikkanen, Joni-Kristian Kamarainen, Jiri Matas
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Color Constancy

We introduce a novel formulation of temporal color constancy which considers multiple frames preceding the frame for which illumination is estimated. We propose an end-to-end trainable recurrent color constancy network -- the RCC-Net -- which exploits convolutional LSTMs and a simulated sequence to learn compositional representations in space and time. We use a standard single frame color constancy benchmark, the SFU Gray Ball Dataset, which can be adapted to a temporal setting. Extensive experiments show that the proposed method consistently outperforms single-frame state-of-the-art methods and their temporal variants.
Saliency Pattern Detection by Ranking Structured Trees
Authors: Lei Zhu, Haibin Ling, Jin Wu, Huiping Deng, Jin Liu
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: object-detection, Object Detection, RGB Salient Object Detection, Saliency Prediction, Salient Object Detection

In this paper we propose a new salient object detection method via structured label prediction. By learning appearance features in rectangular regions, our structural region representation encodes the local saliency distribution with a matrix of binary labels. We show that the linear combination of structured labels can well model the saliency distribution in local regions. Representing region saliency with structured labels has two advantages: 1) it connects the label assignment of all enclosed pixels, which produces a smooth saliency prediction; and 2) regular-shaped nature of structured labels enables well definition of traditional cues such as regional properties and center surround contrast, and these cues help to build meaningful and informative saliency measures. To measure the consistency between a structured label and the corresponding saliency distribution, we further propose an adaptive label ranking algorithm using proposals that are generated by a CNN model. Finally, we introduce a K-NN enhanced graph representation for saliency propagation, which is more favorable for our task than the widely-used adjacent-graph-based ones. Experimental results demonstrate the effectiveness of our proposed method on six popular benchmarks compared with state-of-the-art approaches.
Monocular Video-Based Trailer Coupler Detection Using Multiplexer Convolutional Neural Network
Authors: Yousef Atoum, Joseph Roth, Michael Bliss, Wende Zhang, Xiaoming Liu
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10

This paper presents an automated monocular-camera-based computer vision system for autonomous self-backing-up a vehicle towards a trailer, by continuously estimating the 3D trailer coupler position and feeding it to the vehicle control system, until the alignment of the tow hitch with the trailers coupler. This system is made possible through our proposed distance-driven Multiplexer-CNN method, which selects the most suitable CNN using the estimated coupler-to-vehicle distance. The input of the multiplexer is a group made of a CNN detector, trackers, and 3D localizer. In the CNN detector, we propose a novel algorithm to provide a presence confidence score with each detection. The score reflects the existence of the target object in a region, as well as how accurate is the 2D target detection. We demonstrate the accuracy and efficiency of the system on a large trailer database. Our system achieves an estimation error of 1.4 cm when the ball reaches the coupler, while running at 18.9 FPS on a regular PC.
Non-Rigid Object Tracking via Deformable Patches Using Shape-Preserved KCF and Level Sets
Authors: Xin Sun, Ngai-Man Cheung, Hongxun Yao, Yiluan Guo
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Object Tracking

Part-based trackers are effective in exploiting local details of the target object for robust tracking. In contrast to most existing part-based methods that divide all kinds of target objects into a number of fixed rectangular patches, in this paper, we propose a novel framework in which a set of deformable patches dynamically collaborate on tracking of non-rigid objects. In particular, we proposed a shape-preserved kernelized correlation filter (SP-KCF) which can accommodate target shape information for robust tracking. The SP-KCF is introduced into the level set framework for dynamic tracking of individual patches. In this manner, our proposed deformable patches are target-dependent, have the capability to assume complex topology, and are deformable to adapt to target variations. As these deformable patches properly capture individual target subregions, we exploit their photometric discrimination and shape variation to reveal the trackability of individual target subregions, which enables the proposed tracker to dynamically take advantage of those subregions with good trackability for target likelihood estimation. Finally the shape information of these deformable patches enables accurate object contours to be computed as the tracking output. Experimental results on the latest public sets of challenging sequences demonstrate the effectiveness of the proposed method.
Offline Handwritten Signature Modeling and Verification Based on Archetypal Analysis
Authors: Elias N. Zois, Ilias Theodorakopoulos, George Economou
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10

The handwritten signature is perhaps the most accustomed way for the acknowledgement of the consent of an individual or the authentication of the identity of a person in numerous transactions. In addition, the authenticity of a questioned offline or static handwritten signature still poses a case of interest, especially in forensic related applications. A common approach in offline signature verification system is to apply several predetermined image analysis models. Consequently, any offline signature sample which originates from either authentic persons or forgers, utilizes a fixed feature extraction base. In this proposed study, the feature space and the corresponding projection values depend on the training samples only; thus the proposed method can be found useful in forensic cases. In order to do so, we reenter a groundbreaking unsupervised learning method named archetypal analysis, which is connected to effective data analysis approaches such as sparse coding. Due to the fact that until recently there was no efficient implementation publicly available, archetypal analysis had only few cases of use. However, a fast optimization scheme using an active set strategy is now available. The main goal of this work is to introduce archetypal analysis for offline signature verification. The output of the archetypal analysis of few reference samples is a set of archetypes which are used to form the base of the feature space. Then, given a set of archetypes and a signature sample under examination archetypal analysis and average pooling provides the corresponding features. The promising performance of the proposed approach is demonstrated with the use of an evaluation method which employs the popular CEDAR and MCYT75 signature datasets.
Long Short-Term Memory Kalman Filters: Recurrent Neural Estimators for Pose Regularization
Authors: Huseyin Coskun, Felix Achilles, Robert DiPietro, Nassir Navab, Federico Tombari
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Camera Pose Estimation, Object Tracking, Pose Estimation

One-shot pose estimation for tasks such as body joint localization, camera pose estimation, and object tracking are generally noisy, and temporal filters have been extensively used for regularization. One of the most widely-used methods is the Kalman filter, which is both extremely simple and general. However, Kalman filters require a motion model and measurement model to be specified a priori, which burdens the modeler and simultaneously demands that we use explicit models that are often only crude approximations of reality. For example, in the pose-estimation tasks mentioned above, it is common to use motion models that assume constant velocity or constant acceleration, and we believe that these simplified representations are severely inhibitive. In this work, we propose to instead learn rich, dynamic representations of the motion and noise models. In particular, we propose learning these models from data using long short-term memory, which allows representations that depend on all previous observations and all previous states. We evaluate our method using three of the most popular pose estimation tasks in computer vision, and in all cases we obtain state-of-the-art performance.
Deep Spatial-Semantic Attention for Fine-Grained Sketch-Based Image Retrieval
Authors: Jifei Song, Qian Yu, Yi-Zhe Song, Tao Xiang, Timothy M. Hospedales
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Feature Correlation, Image Retrieval, Representation Learning, Retrieval, Sketch-Based Image Retrieval

Human sketches are unique in being able to capture both the spatial topology of a visual object, as well as its subtle appearance details. Fine-grained sketch-based image retrieval (FG-SBIR) importantly leverages on such fine-grained characteristics of sketches to conduct instance-level retrieval of photos. Nevertheless, human sketches are often highly abstract and iconic, resulting in severe misalignments with candidate photos which in turn make subtle visual detail matching difficult. Existing FG-SBIR approaches focus only on coarse holistic matching via deep cross-domain representation learning, yet ignore explicitly accounting for fine-grained details and their spatial context. In this paper, a novel deep FG-SBIR model is proposed which differs significantly from the existing models in that: (1) It is spatially aware, achieved by introducing an attention module that is sensitive to the spatial position of visual details; (2) It combines coarse and fine semantic information via a shortcut connection fusion block; and (3) It models feature correlation and is robust to misalignments between the extracted features across the two domains by introducing a novel higher order learnable energy function (HOLEF) based loss. Extensive experiments show that the proposed deep spatial-semantic attention model significantly outperforms the state-of-the-art.
Flip-Invariant Motion Representation
Authors: Takumi Kobayashi
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Action Classification, Action Recognition, General Classification, Temporal Action Localization

In action recognition, local motion descriptors contribute to effectively representing video sequences where target actions appear in localized spatio-temporal regions. For robust recognition, those fundamental descriptors are required to be invariant against horizontal (mirror) flipping in video frames which frequently occurs due to changes of camera viewpoints and action directions, deteriorating classification performance. In this paper, we propose methods to render flip invariance to the local motion descriptors by two approaches. One method leverages local motion flows to ensure the invariance on input patches where the descriptors are computed. The other derives a invariant form theoretically from the flipping transformation applied to hand-crafted descriptors. The method is also extended so as to deal with ConvNet descriptors through learning the invariant form based on data. The experimental results on human action classification show that the proposed methods favorably improve performance both of the handcrafted and the ConvNet descriptors.
Scene Categorization With Spectral Features
Authors: Salman H. Khan, Munawar Hayat, Fatih Porikli
Date: 2017-10-01 00:00:00
Proceeding: ICCV 2017 10
Tasks: Attribute, Deep Learning, image-classification, Image Classification

Spectral signatures of natural scenes were earlier found to be distinctive for different scene types with varying spatial envelope properties such as openness, naturalness, ruggedness, and symmetry. Recently, such handcrafted features have been outclassed by deep learning based representations. This paper proposes a novel spectral description of convolution features, implemented efficiently as a unitary transformation within deep network architectures. To the best of our knowledge, this is the first attempt to use deep learning based spectral features explicitly for image classification task. We show that the spectral transformation decorrelates convolutional activations, which reduces co-adaptation between feature detections, thus acts as an effective regularizer. Our approach achieves significant improvements on three large-scale scene-centric datasets (MIT-67, SUN-397, and Places-205). Furthermore, we evaluated the proposed approach on the attribute detection task where its superior performance manifests its relevance to semantically meaningful characteristics of natural scenes.