mtybilly/Instruct2DS huggingface dataset:
SPIN: Simultaneous Perception Interaction and Navigation
Authors: Ananye Agarwal, Haoyu Xiong, Kenneth Shaw, Deepak Pathak Shagun Uppal
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: While there has been remarkable progress recently in the fields of manipulation and locomotion mobile manipulation remains a long-standing challenge. Compared to locomotion or static manipulation a mobile system must make a diverse range of long-horizon tasks feasible in unstructured and dynamic environments. While the applications are broad and interesting there are a plethora of challenges in developing these systems such as coordination between the base and arm reliance on onboard perception for perceiving and interacting with the environment and most importantly simultaneously integrating all these parts together. Prior works approach the problem using disentangled modular skills for mobility and manipulation that are trivially tied together. This causes several limitations such as compounding errors delays in decision-making and no whole-body coordination. In this work we present a reactive mobile manipulation framework that uses an active visual system to consciously perceive and react to its environment. Similar to how humans leverage whole-body and hand-eye coordination we develop a mobile manipulator that exploits its ability to move and see more specifically -- to move in order to see and to see in order to move. This allows it to not only move around and interact with its environment but also choose "when" to perceive "what" using an active visual system. We observe that such an agent learns to navigate around complex cluttered scenarios while displaying agile whole-body coordination using only ego-vision without needing to create environment maps. Videos are available at https://spin-robot.github.io
DREAM: Diffusion Rectification and Estimation-Adaptive Models
Authors: Tianyu Ding, Tianyi Chen, Jiachen Jiang, Ilya Zharkov, Zhihui Zhu, Luming Liang Jinxin Zhou
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: We present DREAM a novel training framework representing Diffusion Rectification and Estimation-Adaptive Models requiring minimal code changes (just three lines) yet significantly enhancing the alignment of training with sampling in diffusion models. DREAM features two components: diffusion rectification which adjusts training to reflect the sampling process and estimation adaptation which balances perception against distortion. When applied to image super-resolution (SR) DREAM adeptly navigates the tradeoff between minimizing distortion and preserving high image quality. Experiments demonstrate DREAM's superiority over standard diffusion-based SR methods showing a to faster training convergence and a to reduction in necessary sampling steps to achieve comparable or superior results. We hope DREAM will inspire a rethinking of diffusion model training paradigms.
Exploring the Potential of Large Foundation Models for Open-Vocabulary HOI Detection
Authors: Shaofeng Yin, Yang Liu Ting Lei
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Open-vocabulary human-object interaction (HOI) detection which is concerned with the problem of detecting novel HOIs guided by natural language is crucial for understanding human-centric scenes. However prior zero-shot HOI detectors often employ the same levels of feature maps to model HOIs with varying distances leading to suboptimal performance in scenes containing human-object pairs with a wide range of distances. In addition these detectors primarily rely on category names and overlook the rich contextual information that language can provide which is essential for capturing open vocabulary concepts that are typically rare and not well-represented by category names alone. In this paper we introduce a novel end-to-end open vocabulary HOI detection framework with conditional multi-level decoding and fine-grained semantic enhancement (CMD-SE) harnessing the potential of Visual-Language Models (VLMs). Specifically we propose to model human-object pairs with different distances with different levels of feature maps by incorporating a soft constraint during the bipartite matching process. Furthermore by leveraging large language models (LLMs) such as GPT models we exploit their extensive world knowledge to generate descriptions of human body part states for various interactions. Then we integrate the generalizable and fine-grained semantics of human body parts to improve interaction recognition. Experimental results on two datasets SWIG-HOI and HICO-DET demonstrate that our proposed method achieves state-of-the-art results in open vocabulary HOI detection. The code and models are available at https://github.com/ltttpku/CMD-SE-release.
Going Deeper With Convolutions
Authors: Wei Liu, Yangqing Jia, Pierre Sermanet, Scott Reed, Dragomir Anguelov, Dumitru Erhan, Vincent Vanhoucke, Andrew Rabinovich Christian Szegedy
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: We propose a deep convolutional neural network architecture codenamed Inception that achieves the new state of the art for classification and detection in the ImageNet Large-Scale Visual Recognition Challenge 2014 (ILSVRC2014). The main hallmark of this architecture is the improved utilization of the computing resources inside the network. By a carefully crafted design, we increased the depth and width of the network while keeping the computational budget constant. To optimize quality, the architectural decisions were based on the Hebbian principle and the intuition of multi-scale processing. One particular incarnation of this architecture, GoogLeNet, a 22 layers deep network, was used to assess its  quality in the context of object detection and classification.
Propagated Image Filtering
Authors: Yu-Chiang Frank Wang Jen-Hao Rick Chang
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: In this paper, we propose the propagation filter as a novel image filtering operator, with the goal of smoothing over neighboring image pixels while preserving image context like edges or textural regions. In particular, our filter does not to utilize explicit spatial kernel functions as bilateral and guided filters do. We will show that our propagation filter can be viewed as a robust estimator, which minimizes the expected difference between the filtered and desirable image outputs. We will also relate propagation filtering to belief propagation, and suggest techniques if further speedup of the filtering process is necessary. In our experiments, we apply our propagation filter to a variety of applications such as image denoising, smoothing, fusion, and high-dynamic-range (HDR) compression. We will show that improved performance over existing image filters can be achieved.
Web Scale Photo Hash Clustering on A Single Machine
Authors: Marcin Pawlowski, Fei Yang, Louis Brandy, Lubomir Bourdev, Rob Fergus Yunchao Gong
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper addresses the problem of clustering a very large number of photos (i.e. hundreds of millions a day) in a stream into millions of clusters. This is particularly important as the popularity of photo sharing websites, such as Facebook, Google, and Instagram. Given large number of photos available online, how to efficiently organize them is an open problem.   To address this problem, we propose to cluster the binary hash codes of a large number of photos into binary cluster centers. We present a fast binary k-means algorithm that works directly on the similarity-preserving hashes of images and clusters them into binary centers on which we can build hash indexes to speedup computation. The proposed method is capable of clustering millions of photos on a single machine in a few minutes. We show that this approach is usually several magnitude faster than standard k-means and produces comparable clustering accuracy.  In addition, we propose an online clustering method based on binary k-means that is capable of clustering large photo stream on a single machine, and show applications to spam detection and trending photo discovery.
Expanding Object Detector's Horizon: Incremental Learning Framework for Object Detection in Videos
Authors: Sung Ju Hwang, Bodo Rosenhahn, Leonid Sigal Alina Kuznetsova
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Over the last several years it has been shown that image-based object detectors are sensitive to  the training data and often fail to generalize to examples that fall outside the original training  sample domain (e.g., videos).  A number of domain adaptation (DA) techniques have been proposed to address this problem.  DA approaches are designed to adapt a fixed complexity model to the new (e.g., video) domain. We posit that unlabeled data should not only allow adaptation, but also improve (or at least maintain) performance on  the original and  other domains by dynamically adjusting model complexity and parameters.  We call this notion domain expansion.  To this end, we develop a new scalable and accurate incremental object detection algorithm,  based on several extensions of large-margin embedding (LME). Our detection model consists of an embedding space and multiple class prototypes in that embedding space,  that represent object classes; distance to those prototypes allows us to reason about multi-class detection. By incrementally detecting object instances in video and adding confident detections into the model, we are able to dynamically adjust the complexity of the detector over time  by instantiating new prototypes to span all domains  the model has seen. We test performance of our approach by expanding an object detector trained on ImageNet to detect objects  in ego-centric videos of Activity Daily Living (ADL) dataset and challenging YouTube Objects (YTO) dataset.
Supervised Discrete Hashing
Authors: Chunhua Shen, Wei Liu, Heng Tao Shen Fumin Shen
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Recently, learning based hashing techniques have attracted broad research interests due to the resulting efficient storage and retrieval of images, videos, documents, etc. However, a major difficulty of learning to hash lies in handling the discrete constraints imposed on the needed hash codes, which typically makes hash optimizations very challenging (NP-hard in general). In this work, we propose a new supervised hashing framework, where the learning objective for hashing is to make the optimal binary hash codes for classification. By introducing an auxiliary variable, we reformulate the objective such that it can be solved substantially efficiently by using a regularization algorithm. One of the key steps in the algorithm is to solve the regularization sub-problem associated with the NP-hard binary optimization. We show that with cyclic coordinate descent, the sub-problem admits an analytical solution. As such, a high-quality discrete solution can eventually be obtained in an efficient computing manner, which enables to tackle massive datasets. We evaluate the proposed approach, dubbed Supervised Discrete Hashing (SDH), on four large image datasets, and demonstrate that SDH outperforms the state-of-the-art hashing methods in large-scale image retrieval.
What do 15,000 Object Categories Tell Us About Classifying and Localizing Actions?
Authors: Jan C. van Gemert, Cees G. M. Snoek Mihir Jain
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper contributes to automatic classification and localization of human actions in video. Whereas motion is the key ingredient in modern approaches, we assess the benefits of having objects in the video representation. Rather than considering a handful of carefully selected and localized objects, we conduct an empirical study on the benefit of encoding 15,000 object categories for action using 6 datasets totaling more than 200 hours of video and covering 180 action classes. Our key contributions are i) the first in-depth study of encoding objects for actions, ii) we show that objects matter for actions, and are often semantically relevant as well. iii) We establish that actions have object preferences. Rather than using all objects, selection is advantageous for action recognition. iv) We reveal that object-action relations are generic, which allows to transferring these relationships from the one domain to the other. And, v) objects, when combined with motion, improve the state-of-the-art for both action classification and localization.
Landmarks-Based Kernelized Subspace Alignment for Unsupervised Domain Adaptation
Authors: Remi Emonet, Damien Muselet, Marc Sebban Rahaf Aljundi
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Domain adaptation (DA) has gained a lot of success in the recent years in computer vision to deal with situations where the learning process has to transfer knowledge from a source to a target domain. In this paper, we introduce a novel unsupervised DA approach based on both subspace alignment and selection of landmarks similarly distributed between the two domains. Those landmarks are selected so as to reduce the discrepancy between the domains and then are used to non linearly project the data in the same space where an efficient subspace alignment (in closed-form) is performed. We carry out a large experimental comparison in visual domain adaptation showing that our new method outperforms the most recent unsupervised DA approaches.
Blur Kernel Estimation Using Normalized Color-Line Prior
Authors: Jian-Jiun Ding, Yen-Yu Lin, Yung-Yu Chuang Wei-Sheng Lai
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper proposes a single-image blur kernel estimation algorithm that utilizes the normalized color-line prior to restore sharp edges without altering edge structures or enhancing noise. The proposed prior is derived from the color-line model, which has been successfully applied to non-blind deconvolution and many computer vision problems. In this paper, we show that the original color-line prior is not effective for blur kernel estimation and propose a normalized color-line prior which can better enhance edge contrasts. By optimizing the proposed prior, our method gradually enhances the sharpness of the intermediate patches without using heuristic filters or external patch priors. The intermediate patches can then guide the estimation of the blur kernel. A comprehensive evaluation on a large image deblurring dataset shows that our algorithm achieves the state-of-the-art results.
A Light Transport Model for Mitigating Multipath Interference in Time-of-Flight Sensors
Authors: Achuta Kadambi, Christoph Rhemann, Shahram Izadi, Ramesh Raskar, Sing Bing Kang Nikhil Naik
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Continuous-wave Time-of-flight (TOF) range imaging has become a commercially viable technology with many applications in computer vision and graphics. However, the depth images obtained from TOF cameras contain scene dependent errors due to multipath interference (MPI). Specifically, MPI occurs when multiple optical reflections return to a single spatial location on the imaging sensor. Many prior approaches to rectifying MPI rely on sparsity in optical reflections, which is an extreme simplification. In this paper, we correct MPI by combining the standard measurements from a TOF camera with information from direct and global light transport. We report results on both simulated experiments and physical experiments (using the Kinect sensor). Our results, evaluated against ground truth, demonstrate a quantitative improvement in depth accuracy.
Traditional Saliency Reloaded: A Good Old Model in New Shape
Authors: Thomas Werner, German Martin Garcia Simone Frintrop
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: In this paper, we show that the seminal, biologically-inspired   saliency model by Itti et al. is still competitive with current state-of-the-art methods for salient object   segmentation if some important adaptions are made.  We show which   changes are necessary to achieve high performance, with special   emphasis on the scale-space: we introduce a twin pyramid for   computing Difference-of-Gaussians, which enables a flexible   center-surround ratio.  The resulting system, called VOCUS2,   is elegant and coherent in structure, fast, and computes saliency at   the pixel level.  It is not only suitable for images with few objects, but also for   complex scenes as captured by mobile devices.  Furthermore, we   integrate the saliency system into an object proposal generation   framework to obtain segment-based saliency maps and boost the   results for salient object segmentation. We show that our system   achieves state-of-the-art performance on a large collection of   benchmark data.
Automatic Construction Of Robust Spherical Harmonic Subspaces
Authors: Yannis Panagakis, Stefanos Zafeiriou Patrick Snape
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: In this paper we propose a method to automatically recover a class specific low dimensional spherical harmonic basis from a set of in-the-wild facial images. We combine existing techniques for uncalibrated photometric stereo and low rank matrix decompositions in order to robustly recover a combined model of shape and identity. We build this basis without aid from a 3D model and show how it can be combined with recent efficient sparse facial feature localisation techniques to recover dense 3D facial shape. Unlike previous works in the area, our method is very efficient and is an order of magnitude faster to train, taking only a few minutes to build a model with over 2000 images. Furthermore, it can be used for real-time recovery of facial shape.
Leveraging Stereo Matching With Learning-Based Confidence Measures
Authors: Kuk-Jin Yoon Min-Gyu Park
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: We propose a new approach to associate supervised learning-based confidence prediction with the stereo matching problem. First of all, we analyze the characteristics of various confidence measures in the regression forest framework to select effective confidence measures using training data. We then train regression forests again to predict the correctness (confidence) of a match by using selected confidence measures. In addition, we present a confidence-based matching cost modulation scheme based on the predicted correctness for improving the robustness and accuracy of various stereo matching algorithms. We apply the proposed scheme to the semi-global matching algorithm to make it robust under unexpected difficulties that can occur in outdoor environments. We verify the proposed confidence measure selection and cost modulation methods through extensive experimentation with various aspects using KITTI and challenging outdoor datasets.
Saliency Detection via Cellular Automata
Authors: Huchuan Lu, Yiqun Xu, He Wang Yao Qin
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: In this paper, we introduce Cellular Automata--a dynamic evolution model to intuitively detect the salient object. First, we construct a background-based map using color and space contrast with the clustered boundary seeds. Then, a novel propagation mechanism dependent on Cellular Automata is proposed to exploit the intrinsic relevance of similar regions through interactions with neighbors. Impact factor matrix and coherence matrix are constructed to balance the influential power towards each cell's next state. The saliency values of all cells will be renovated simultaneously according to the proposed updating rule. It's surprising to find out that parallel evolution can improve all the existing methods to a similar level regardless of their original results. Finally, we present an integration algorithm in the Bayesian framework to take advantage of multiple saliency maps. Extensive experiments on six public datasets demonstrate that the proposed algorithm outperforms state-of-the-art methods.
Efficient Sparse-to-Dense Optical Flow Estimation Using a Learned Basis and Layers
Authors: Michael J. Black Jonas Wulff
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: We address the elusive goal of estimating optical flow both accurately and efficiently by adopting a sparse-to-dense approach. Given a set of sparse matches, we regress to dense optical flow using a learned set of full-frame basis flow fields. We learn the principal components of natural flow fields using flow computed from four Hollywood movies. Optical flow fields are then compactly approximated as a weighted sum of the basis flow fields. Our new PCA-Flow algorithm robustly estimates these weights from sparse feature matches. The method runs in under 200ms/frame on the MPI-Sintel dataset using a single CPU and is more accurate and significantly faster than popular methods such as LDOF and Classic+NL. For some applications, however, the results are too smooth. Consequently, we develop a novel sparse layered flow method in which each layer is represented by PCA-Flow. Unlike existing layered methods, estimation is fast because it uses only sparse matches. We combine information from different layers into a dense flow field using an image-aware MRF. The resulting PCA-Layers method runs in 3.2s/frame, is significantly more accurate than PCA-Flow, and achieves state-of-the-art performance in occluded regions on MPI-Sintel.
Learning Multiple Visual Tasks While Discovering Their Structure
Authors: Lorenzo Rosasco, Silvia Villa Carlo Ciliberto
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Multi-task learning is a natural approach for computer vision applications that require the simultaneous solution of several distinct but related problems, e.g. object detection, classification, tracking of multiple agents, or denoising, to name a few. The key idea is that exploring task relatedness (structure) can lead to better performances.  In this paper, we propose and study a novel sparse, non-parametric approach  exploiting the theory of Reproducing Kernel Hilbert Spaces for vector-valued functions. We develop a suitable regularization framework which can be formulated as a convex optimization problem,   and  is provably solvable using an alternating minimization approach. Empirical tests   show that the proposed method compares favorably to state of the art techniques and further allows to recover interpretable structures, a  problem of interest in its own right.
Projection Metric Learning on Grassmann Manifold With Application to Video Based Face Recognition
Authors: Ruiping Wang, Shiguang Shan, Xilin Chen Zhiwu Huang
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: In video based face recognition, great success has been made by representing videos as linear subspaces, which typically lie in a special type of non-Euclidean space known as Grassmann manifold. To leverage the kernel-based methods developed for Euclidean space, several recent methods have been proposed to embed the Grassmann manifold into a high dimensional Hilbert space by exploiting the well established Project Metric, which can approximate the Riemannian geometry of Grassmann manifold. Nevertheless, they inevitably introduce the drawbacks from traditional kernel-based methods such as implicit map and high computational cost to the Grassmann manifold. To overcome such limitations, we propose a novel method to learn the Projection Metric directly on Grassmann manifold rather than in Hilbert space. From the perspective of manifold learning, our method can be regarded as performing a geometry-aware dimensionality reduction from the original Grassmann manifold to a lower-dimensional, more discriminative Grassmann manifold  where more favorable classification can be achieved. Experiments on several real-world video face datasets demonstrate that the proposed method yields competitive performance compared with the state-of-the-art algorithms.
Structural Sparse Tracking
Authors: Si Liu, Changsheng Xu, Shuicheng Yan, Bernard Ghanem, Narendra Ahuja, Ming-Hsuan Yang Tianzhu Zhang
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Sparse representation has been applied to visual tracking by finding the best target candidate with minimal reconstruction error by use of target templates. However, most sparse representation based trackers only consider holistic or local representations and do not make full use of the intrinsic structure among and inside target candidates, thereby making the representation less effective when similar objects appear or under occlusion. In this paper, we propose a novel Structural Sparse Tracking (SST) algorithm, which not only exploits the intrinsic relationship among target candidates and their local patches to learn their sparse representations jointly, but also preserves the spatial layout structure among the local patches inside each target candidate. We show that our SST algorithm accommodates most existing sparse trackers with the respective merits. Both qualitative and quantitative evaluations on challenging benchmark image sequences demonstrate that the proposed SST algorithm performs favorably against several state-of-the-art methods.
Data-Driven Depth Map Refinement via Multi-Scale Sparse Representation
Authors: Yu-Wing Tai, Stephen Lin HyeokHyen Kwon
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Depth maps captured by consumer-level depth cameras such as Kinect are usually degraded by noise, missing values, and quantization. In this paper, we present a data-driven approach for refining degraded RAW depth maps that are coupled with an RGB image. The key idea of our approach is to take advantage of a training set of high-quality depth data and transfer its information to the RAW depth map through multi-scale dictionary learning. Utilizing a sparse representation, our method learns a dictionary of geometric primitives which captures the correlation between high-quality mesh data, RAW depth maps and RGB images. The dictionary is learned and applied in a manner that accounts for various practical issues that arise in dictionary-based depth refinement. Compared to previous approaches that only utilize the correlation between RAW depth maps and RGB images, our method produces improved depth maps without over-smoothing. Since our approach is data driven, the refinement can be targeted to a specific class of objects by employing a corresponding training set. In our experiments, we show that this leads to additional improvements in recovering depth maps of human faces.
Uncalibrated Photometric Stereo Based on Elevation Angle Recovery From BRDF Symmetry of Isotropic Materials
Authors: Imari Sato, Yoichi Sato Feng Lu
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper addresses the problem of uncalibrated photometric stereo with isotropic reflectances. Existing methods face difficulty in solving for the elevation angles of surface normals when the light sources only cover the visible hemisphere. Here, we introduce the notion of "constrained half-vector symmetry" for general isotropic BRDFs and show its capability of elevation angle recovery. This sort of symmetry can be observed in a 1D BRDF slice from a subset of surface normals with the same azimuth angle, and we use it to devise an efficient modeling and solution method to constrain and recover the elevation angles of surface normals accurately. To enable our method to work in an uncalibrated manner, we further solve for light sources in the case of general isotropic BRDFs. By combining this method with the existing ones for azimuth angle estimation, we can get state-of-the-art results for uncalibrated photometric stereo with general isotropic reflectances.
Attributes and Categories for Generic Instance Search From One Example
Authors: Arnold W.M. Smeulders, Shih-Fu Chang Ran Tao
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper aims for generic instance search from one example where the instance can be an arbitrary 3D object like shoes, not just near-planar and one-sided instances like buildings and logos. Firstly, we evaluate state-of-the-art instance search methods on this problem. We observe that what works for buildings loses its generality on shoes. Secondly, we propose to use automatically learned category-specific attributes to address the large appearance variations present in generic instance search. On the problem of searching among instances from the same category as the query, the category-specific attributes outperform existing approaches by a large margin. On a shoe dataset containing 6624 shoe images recorded from all viewing angles, we improve the performance from 36.73 to 56.56 using category-specific attributes. Thirdly, we extend our methods to search objects without restricting to the specifically known category. We show the combination of category-level information and the category-specific attributes is superior to combining category-level information with low-level features such as Fisher vector.
Heat Diffusion Over Weighted Manifolds: A New Descriptor for Textured 3D Non-Rigid Shapes
Authors: Aly Farag, David Swanson, Moumen T. El-Melegy Mostafa Abdelrahman
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper propose an approach for modeling textured 3D non-rigid models based on Weighted Heat Kernel Signature(W-HKS). As a first contribution, we show how to include photometric information as a weight over the shape manifold, we also propose a novel formulation for heat diffusion over weighted manifolds. As a second contribution we present a new discretization method for the proposed equation using finite element approximation. Finally, the weighted heat kernel signature is used as a shape descriptor. The proposed descriptor encodes both the photometric, and geometric information based on the solution of one equation. We also propose a new method to introduce the scale invariance for the weighted heat kernel signature. The performance is tested on two benchmark datasets. The results have indeed confirmed the high performance of the proposed approach on the textured shape retrieval problem, and show that the proposed method is useful in coping with different challenges of shape analysis where pure geometric and pure photometric methods fail.
A Dynamic Programming Approach for Fast and Robust Object Pose Recognition From Range Images
Authors: Adrian Penate-Sanchez, Minh-Tri Pham Christopher Zach
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Joint object recognition and pose estimation solely from range images is an important task e.g. in robotics applications and in automated manufacturing environments. The lack of color information and limitations of current commodity depth sensors make this task a challenging computer vision problem, and a standard random sampling based approach is prohibitively time-consuming. We propose to address this difficult problem by generating promising inlier sets for pose estimation by early rejection of clear outliers with the help of local belief propagation (or dynamic programming). By exploiting data-parallelism our method is fast, and we also do not rely on a computationally expensive training phase. We demonstrate state-of-the art performance on a standard dataset and illustrate our approach on challenging real sequences.
Beyond Gaussian Pyramid: Multi-Skip Feature Stacking for Action Recognition
Authors: Ming Lin, Xuanchong Li, Alex G. Hauptmann, Bhiksha Raj Zhengzhong Lan
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Most state-of-the-art action feature extractors involve differential operators, which act as highpass filters and tend to attenuate low frequency action information. This attenuation introduces bias to the resulting features and generates ill-conditioned feature matrices. The Gaussian Pyramid has been used as a feature enhancing technique that encodes scale-invariant characteristics into the feature space in an attempt to deal with this attenuation. However, at the core of the Gaussian Pyramid is a convolutional smoothing operation, which makes it incapable of generating new features at coarse scales. In order to address this problem, we propose a novel feature enhancing technique called Multi-skIp Feature Stacking (MIFS), which stacks features extracted using a family of differential filters  parameterized with multiple time skips and encodes shift-invariance into the frequency space. MIFS compensates for information lost from using differential operators by recapturing information at coarse scales. This recaptured information allows us to match actions at different speeds and ranges of motion.  We prove that MIFS enhances the learnability of differential-based features exponentially. The resulting feature matrices from MIFS have much smaller conditional numbers and variances than those from conventional methods. Experimental results show significantly improved performance on challenging action recognition and event detection tasks. Specifically, our method exceeds the state-of-the-arts on Hollywood2, UCF101 and UCF50 datasets and is comparable to state-of-the-arts on HMDB51 and Olympics Sports datasets. MIFS can also be used as a speedup strategy for feature extraction with minimal or no accuracy cost.
A Geodesic-Preserving Method for Image Warping
Authors: Kaiming He, Jian Sun, Kun Zhou Dongping Li
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: The manipulation of panoramic/wide-angle images is usually achieved via image warping. Though various techniques have been developed for preserving shapes and straight lines for warping, these are not sufficient for panoramic/wide-angle images. The image projections will turn the straight lines into curved "geodesic lines", and it is fundamentally impossible to keep all these lines straight. In this work, we propose a geodesic-preserving method for content-aware image warping. An energy term is introduced to preserve the geodesic appearance of the geodesic lines, and can be used with shape-preserving terms. Our method is demonstrated in various applications, including rectangling panoramas, resizing panoramic/wide-angle images, and wide-angle image manipulation. An extension to ellipse preservation for general images is also presented.
Shape Driven Kernel Adaptation in Convolutional Neural Network for Robust Facial Traits Recognition
Authors: Junliang Xing, Zhiheng Niu, Shiguang Shan, Shuicheng Yan Shaoxin Li
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: One key challenge of facial traits recognition is the large non-rigid appearance variations due to irrelevant real world factors, such as viewpoint and expression changes. In this paper, we explore how the shape information, i.e. facial landmark positions, can be explicitly deployed into the popular Convolutional Neural Network (CNN) architecture to disentangling such irrelevant non-rigid appearance variations. First, instead of using fixed kernels, we propose a kernel adaptation method to dynamically determine the convolutional kernels according to the distribution of facial landmarks, which helps learning more robust features. Second, motivated by the intuition that different local facial regions may demand different adaptation functions, we further propose a tree-structured convolutional architecture to hierarchically fuse multiple local adaptive CNN subnetworks. Comprehensive experiments on WebFace, Morph II and MultiPIE databases well validate the effectiveness of the proposed kernel adaptation method and tree-structured convolutional architecture for facial traits recognition tasks, including identity, age and gender classification. For all the tasks, the proposed architecture consistently achieves the state-of-the-art performances.
From Categories to Subcategories: Large-Scale Image Classification With Partial Class Label Refinement
Authors: Juergen Gall, Matthieu Guillaumin, Luc Van Gool Marko Ristin
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: The number of digital images is growing extremely rapidly, and so is the need for their classification. But, as more images of pre-defined categories become available, they also become more diverse and cover   finer semantic differences. Ultimately, the categories themselves need to be divided into subcategories to account for that semantic refinement. Image classification in general has improved significantly over  the last few years, but it still requires a massive amount of manually annotated data. Subdividing categories into subcategories multiples the number of labels, aggravating the annotation problem. Hence, we    can expect the annotations to be refined only for a subset of the already labeled data, and exploit coarser labeled data to improve classification. In this work, we investigate how coarse category labels can   be used to improve the classification of subcategories. To this end, we adopt the framework of Random Forests and propose a regularized objective function that takes into account relations between categories   and subcategories. Compared to approaches that disregard the extra coarse labeled data, we achieve a relative improvement in subcategory classification accuracy of up to 22% in our large-scale image            classification experiments.
Combination Features and Models for Human Detection
Authors: Jinwen Ma Yunsheng Jiang
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: This paper presents effective combination models with certain combination features for human detection. In the past several years, many existing features/models have achieved impressive progress, but their performances are still limited by the biases rooted in their self-structures, that is, a particular kind of feature/model may work well for some types of human bodies, but not for all the types. To tackle this difficult problem, we combine certain complementary features/models together with effective organization/fusion methods. Specifically, the HOG features, color features and bar-shape features are combined together with a cell-based histogram structure to form the so-called HOG-III features. Moreover, the detections from different models are fused together with the new proposed weighted-NMS algorithm, which enhances the probable "true" activations as well as suppresses the overlapped detections. The experiments on PASCAL VOC datasets demonstrate that, both the HOG-III features and the weighted-NMS fusion algorithm are effective (obvious improvement for detection performance) and efficient (relatively less computation cost): When applied to human detection task with the Grammar model and Poselet model, they can boost the detection performance significantly; Also, when extended to detection of the whole VOC 20 object categories with the deformable part-based model and deepCNN-based model, they still show competitive improvements.
Improving Object Detection With Deep Convolutional Networks via Bayesian Optimization and Structured Prediction
Authors: Kihyuk Sohn, Ruben Villegas, Gang Pan, Honglak Lee Yuting Zhang
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Object detection systems based on the deep convolutional neural network (CNN) have recently made ground- breaking advances on several object detection benchmarks. While the features learned by these high-capacity neural networks are discriminative for categorization, inaccurate localization is still a major source of error for detection. Building upon high-capacity CNN architectures, we address the localization problem by 1) using a search algorithm based on Bayesian optimization that sequentially proposes candidate regions for an object bounding box, and 2) training the CNN with a structured loss that explicitly penalizes the localization inaccuracy. In experiments, we demonstrated that each of the proposed methods improves the detection performance over the baseline method on PASCAL VOC 2007 and 2012 datasets. Furthermore, two methods are complementary and significantly outperform the previous state-of-the-art when combined.
A Metric Parametrization for Trifocal Tensors With Non-Colinear Pinholes
Authors: Roberto Tron, Kostas Daniilidis Spyridon Leonardos
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: The trifocal tensor, which describes the relation between projections of points and lines in three views, is a fundamental entity of geometric computer vision. In this work, we investigate a new parametrization of the trifocal tensor for calibrated cameras with non-colinear pinholes obtained from a quotient Riemannian manifold.  We incorporate this formulation into state-of-the art methods for optimization on manifolds, and show, through experiments in pose averaging, that it produces a meaningful way to measure distances between trifocal tensors.
An Efficient Volumetric Framework for Shape Tracking
Authors: Jean-Sebastien Franco, Edmond Boyer Benjamin Allain
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Recovering 3D shape motion using visual information is an important problem with many applications in computer vision and computer graphics, among other domains.  Most existing approaches rely on surface-based strategies, where surface models are fit to visual surface observations. While numerically plausible, this paradigm ignores the fact that the observed surfaces often delimit volumetric shapes, for which deformations are constrained by the volume inside the shape. Consequently, surface-based strategies can fail when the observations define several feasible surfaces, whereas volumetric considerations are more restrictive with respect to the admissible solutions. In this work, we investigate a novel volumetric shape parametrization to track shapes over temporal sequences. In constrast to Eulerian grid discretizations of the observation space, such as voxels, we consider general shape tesselations yielding more convenient cell decompositions, in particular the Centroidal Voronoi Tesselation. With this shape representation, we devise a tracking method that exploits volumetric information, both for the data term evaluating observation conformity, and for expressing deformation constraints that enforce prior assumptions on motion. Experiments on several datasets demonstrate similar or improved precisions over state-of-the-art methods, as well as improved robustness, a critical issue when tracking sequentially over time frames.
Structured Sparse Subspace Clustering: A Unified Optimization Framework
Authors: Rene Vidal Chun-Guang Li
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: Subspace clustering refers to the problem of segmenting data drawn from a union of subspaces. State of the art approaches for solving this problem follow a two-stage approach. In the first step, an affinity matrix is learned from the data using sparse or low-rank minimization techniques. In the second step, the segmentation is found by applying spectral clustering to this affinity. While this approach has led to state of the art results in many applications, it is sub-optimal because it does not exploit the fact that the affinity and the segmentation depend on each other. In this paper, we propose a unified optimization framework for learning both the affinity and the segmentation. Our framework is based on expressing each data point as a structured sparse linear combination of all other data points, where the structure is induced by a norm that depends on the unknown segmentation. We show that both the segmentation and the structured sparse representation can be found via a combination of an alternating direction method of multipliers with spectral clustering. Experiments on a synthetic data, the Hopkins 155 motion segmentation database, and the Extended Yale B data set demonstrate the effectiveness of our approach.
Delving Into Egocentric Actions
Authors: Zhefan Ye, James M. Rehg Yin Li
Published in: IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015 (Main Conference Track), 2015

Abstract: We address the challenging problem of recognizing the camera wearer's actions from videos captured by an egocentric camera. Egocentric videos encode a rich set of signals regarding the camera wearer, including head movement, hand pose and gaze information. We propose to utilize these mid-level egocentric cues for egocentric action recognition. We present a novel set of egocentric features and show how they can be combined with motion and object features. The result is a compact representation with superior performance. In addition, we provide the first systematic evaluation of motion, object and egocentric cues in egocentric action recognition. Our benchmark leads to several surprising findings. These findings uncover the best practices for egocentric actions, with a significant performance boost over all previous state-of-the-art methods on three publicly available datasets.